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You are here: Home / Publications / Bibliographies and Resource Guides / West Nile Virus Bibliography, 2004 -2007 / Diagnosis/Testing/Detection  Printer Friendly Page
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West Nile Virus Bibliography, 2004-2007
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 Diagnosis/Testing/Detection

Anonymous (2006). First West Nile Virus screening test approved. FDA Consumer 40(1): 3.
Descriptors: West Nile fever diagnosis, West Nile virus isolation and purification, screening tests.

Anonymous (2005). Summaries for patients. The cost-effectiveness of screening the U.S. blood supply for West Nile virus. Annals of Internal Medicine 143(7): I44.
Descriptors: blood transfusion, blood borne pathogens, West Nile virus, computer simulation, cost benefit analysis, markov chains, humans, nucleic acid amplification techniques, United States.
Notes: Original Report In: Ann Intern Med. 2005 Oct 4;143(7):486-92.

Avalos Bock, S.A. (2005). West Nile virus and the U.S. blood supply: New tests substantially reduce the risk of transmission via donated blood products. American Journal of Nursing 105(12): 34, 36-37.
Descriptors: blood donors, nucleic acid amplification techniques, RNA, viral blood, West Nile fever, United States, West Nile virus.

Balasuriya, U.B., P.Y. Shi, S.J. Wong, V.L. Demarest, I.A. Gardner, P.J. Hullinger, G.L. Ferraro, J.D. Boone, C.L. De Cino, A.L. Glaser, R.W. Renshaw, M. Ledizet, R.A. Koski, and N.J. MacLachlan (2006). Detection of antibodies to West Nile virus in equine sera using microsphere immunoassay. Journal of Veterinary Diagnostic Investigation 18(4): 392-395.
Abstract: One hundred and ninety-one sera from horses that recently were exposed to West Nile virus (WNV) by either vaccination or natural infection or that were not vaccinated and remained free of infection were used to evaluate fluorescent microsphere immunoassays (MIAs) incorporating recombinant WNV envelope protein (rE) and recombinant nonstructural proteins (rNS1, rNS3, and rNS5) for detection of equine antibodies to WNV. The rE MIA had a diagnostic sensitivity and specificity, respectively, of 99.3% and 97.4% for detection of WNV antibodies in the serum of horses that were recently vaccinated or naturally infected with WNV, as compared to the plaque reduction neutralization test (PRNT). The positive rE MIA results were assumed to be WNV-specific because of the close agreement between this assay and the PRNT and the fact that unvaccinated control horses included in this study were confirmed to be free of exposure to the related St Louis encephalitis virus. The NS protein-based MIA were all less sensitive than either the rE MIA or PRNT (sensitivity 0-48.0), although the rNSI MIA distinguished horses vaccinated with the recombinant WNV vaccine from those that were immunized with the inactivated WNV vaccine (P < 0.0001) or naturally infected with WNV (P < 0.0001). The rE MIA would appear to provide a rapid, convenient, inexpensive, and accurate test for the screening of equine sera for the presence of antibodies to WNV.
Descriptors: antibodies, horse diseases, West Nile fever, West Nile virus.

Batuello, J.T., J. Youngwerth, and R. Gabel (2005). Increased serum lipase in West Nile virus infection. New England Journal of Medicine 352(4): 420-421.
Descriptors: lipase blood, West Nile fever enzymology, humans.

Beasley, D.W. (2005). Recent advances in the molecular biology of west nile virus. Current Molecular Medicine 5(8): 835-850.
Abstract: Since the mid-1990s, West Nile virus (WNV) has emerged as a significant agent of arboviral encephalitis in several regions of the world. In 1999, WNV was introduced into the northeastern United States and was associated with an outbreak of encephalitis affecting humans, birds and horses. Subsequently, the virus has spread across the country, and across southern Canada, and in 2002 and 2003 was associated with the largest outbreaks of arboviral encephalitis recorded in the Western hemisphere. Interestingly, the more recent spread of WNV into Mexico, Central America and the Caribbean has not been associated with the high levels of clinical disease observed in North America. This review addresses the most recent results from studies investigating the molecular biology and evolution of WNV, as well as progress in the development of diagnostic and therapeutic reagents.
Descriptors: West Nile fever, West Nile virus, United States.

Bell, J.A., C.M. Brewer, N.J. Mickelson, G.W. Garman, and J.A. Vaughan (2006). West Nile virus epizootiology, central Red River Valley, North Dakota and Minnesota, 2002-2005. Emerging Infectious Diseases 12(8): 1245-1247.
Abstract: West Nile virus (WNV) epizootiology was monitored from 2002 through 2005 in the area surrounding Grand Forks, North Dakota. Mosquitoes were tested for infection, and birds were surveyed for antibodies. In 2003, WNV was epidemic; in 2004, cool temperatures precluded WNV amplification; and in 2005, immunity in passerines decreased, but did not preclude, WNV amplification.
Descriptors: bird diseases, West Nile virus, insect vectors, Minnesota, North Dakota, zoonoses.

Brenner, W., G. Storch, R. Buller, R. Vij, S. Devine, and J. Dipersio (2005). West nile virus encephalopathy in an allogeneic stem cell transplant recipient: Use of quantitative PCR for diagnosis and assessment of viral clearance. Bone Marrow Transplantation 36(4): 369-370. ISSN: 0268-3369.
Descriptors: encephalopathy, quadriplegia, chronic myeloid leukemia, neoplastic disease, heart disease, magnetic resonance imaging, diagnostic techniques, stem cell transplantation, quantitative polymerase chain reaction, viral clearance.

Buckley, A., A. Dawson, and E.A. Gould (2006). Detection of seroconversion to West Nile virus, Usutu virus and Sindbis virus in UK sentinel chickens. Virology Journal 3: 71.
Abstract: We previously reported evidence of West Nile virus (WNV) circulation in UK birds, probably introduced by migratory birds from overseas. We now demonstrate WNV-specific seroconversion in sentinel chickens raised on an English farm. Maternal neutralizing antibodies to WNV in hatchlings declined within three weeks. During the following months, healthy chickens developed WNV neutralizing antibodies that were confirmed by immunoblotting and indirect immunofluorescence tests using WNV antigens. The proportion of seropositive chickens was higher for WNV than for Usutu virus or Sindbis virus. Attempts to isolate infectious virus or to detect viral RNA in the sera, failed.
Descriptors: alphavirus infections, viral blood, chickens, encephalitis, flavivirus, sindbis virus, bird diseases, western blotting, Great Britain, fluorescence microscopy, sentinel surveillance, seroepidemiologic studies, West Nile virus isolation and purification.

Bunde, J.M., E.J. Heske, N.E. Mateus Pinilla, J.E. Hofmann, and R.J. Novak (2006). A survey for West Nile virus in bats from Illinois. Journal of Wildlife Diseases 42(2): 455-458.
Abstract: A blocking enzyme-linked immunosorbent assay was used to test 97 serum samples from big brown bats (Eptesicus fuscus) captured in six counties in Illinois between May 2002 and February 2004 for West Nile virus (WNV) antibodies. One female big brown bat tested positive for WNV antibodies. Samples of kidney, liver, and heart tissue were collected from 312 bats of seven species that were submitted to the Illinois (USA) Department of Public Health or the Illinois Department of Agriculture diagnostic laboratories between January 2001 and December 2003. Tissue samples were tested for WNV using TaqMan reverse transcriptase polymerase chain reaction and all were negative. Prevalence of WNV antibodies in the bats (1%) was lower than previously reported for other flaviviruses, but similar to the prevalence (2%) of WNV antibodies reported in bats from New Jersey and New York, USA. Additional research is needed to determine potential impact of WNV infections on bats and to determine whether they play a role in the WNV transmission cycle.
Descriptors: viral blood antibodies, big brown bats, West Nile fever, West Nile virus, enzyme linked immunosorbent assay methods, myocardium, reverse transcriptase polymerase chain reaction methods.

Burkhalter, K.L., R. Lindsay, R. Anderson, A. Dibernardo, W. Fong, and R.S. Nasci (2006). Evaluation of commercial assays for detecting West Nile virus antigen. Journal of the American Mosquito Control Association 22(1): 64-69.
Abstract: Two commercially available West Nile virus (WNV) detection assays (RAMP WNV test, Response Biomedical Corp., Burnaby, British Columbia, Canada; and VecTest WNV antigen assay, Medical Analysis Systems, Inc., Camarillo, CA) were compared for sensitivity, specificity, and ability to detect WNV in field-collected mosquito pools. Serially diluted stock seed WNV and St. Louis encephalitis virus (SLEV) were used to determine sensitivity and specificity. The RAMP WNV test detected WNV at concentrations as low as 3.17 log10 plaque-forming units per milliliter (PFU/ml), whereas the VecTest assay detected WNV at concentrations as low as 5.17 log10 PFU/ml. Neither test cross-reacted with SLEV. A WNV-specific reverse transcriptase polymerase chain reaction was used to identify positives among field-collected mosquito pools. The RAMP WNV test detected 94% of positive pools and the VecTest assay detected 65% of the positive field-collected pools. Despite these differences, both assays have characteristics that make them useful in WNV surveillance programs.
Descriptors: viral antigens, mosquitoes, diagnostic reagent kits, West Nile virus, immunoenzyme techniques, insect vectors, reverse transcriptase polymerase chain reaction.

Busch, M.P., S. Caglioti, E.F. Robertson, J.D. McAuley, L.H. Tobler, H. Kamel, J.M. Linnen, V. Shyamala, P. Tomasulo, and S.H. Kleinman (2005). Screening the blood supply for West Nile virus RNA by nucleic acid amplification testing. New England Journal of Medicine 353(5): 460-467.
Abstract: BACKGROUND: The use of nucleic acid amplification tests of "minipools" of 16 samples to screen blood donors for West Nile virus RNA began in July 2003. We report the yield and characteristics of positive donations and the incremental yield and safety of nucleic acid amplification tests of individual donations. METHODS: Reactive minipools were analyzed to identify the individual reactive donations. For the regions with the highest yield on minipool testing, retrospective nucleic acid amplification testing was performed on individual donations that were negative on minipool testing. Reactive donations were confirmed by alternative nucleic acid amplification tests and IgM and IgG tests, and donors were followed to document seroconversion. RESULTS: From July 1 through October 31, 2003, 677,603 donations were prospectively screened for West Nile virus by minipool testing, yielding 183 confirmed viremic donations (0.027 percent, or 1 in 3703 donations). Retrospective individual testing of 23,088 donations from high-prevalence regions that were negative on minipool testing yielded 30 additional units with a low level of viremia, with 14 additional viremic units detected by prospective testing of individual donations late in the 2003 transmission season. Of all the viremic units detected, 5 percent were detected only by individual testing and were negative for IgM antibody, 29 percent were detected by individual testing after IgM seroconversion, and 66 percent were detected by minipool testing. West Nile virus infection was confirmed in both recipients of IgM-negative units that were reactive on individual testing, whereas neither recipient of antibody-positive blood components that were reactive on individual testing was infected. In 2004, prospective testing of individual donations in regions that yielded donations that were reactive on minipool testing resulted in a 32 percent incremental yield of units with a low level of viremia that would have been missed by minipool testing. CONCLUSIONS: Although nucleic acid amplification testing of minipools of blood donations prevented hundreds of cases of West Nile virus infection in 2003, it failed to detect units with a low level of viremia, some of which were antibody-negative and infectious. These data support the use of targeted nucleic acid amplification testing of individual donations in high-prevalence regions, a strategy that was implemented successfully in 2004. Copyright 2005 Massachusetts Medical Society.
Descriptors: blood donors, nucleic acid amplification techniques, viral blood RNA, West Nile fever, West Nile virus isolation and purification, retrospective studies, viremia.
Notes: Comment In: N Engl J Med. 2005 Aug 4;353(5):516-7.

Chen, Y.P., Y.J. Yang, X.D. Wu, and Z.L. Wang (2006). [Preparation of monoclonal antibodies against West Nile virus envelope protein domain.]. Zhonghua Shi Yan He Lin Chuang Bing Du Xue Za Zhi; Zhonghua Shiyan He Linchuang Bingduxue Zazhi; Chinese Journal of Experimental and Clinical Virology 20(3): 213-5.
Abstract: BACKGROUND: To prepare monoclonal antibodies against West Nile virus (WNV) envelope protein domain. METHODS: BALB/c mice were immunized with recombinant antigen of West Nile virus envelope protein domain, and the spleen cells of the mice were used to prepare the monoclonal antibodies (McAb) by hybridoma technique. RESULTS: Three hybridoma cell strains secreting McAbs against WNV envelope protein domain, designated as 4F7, 6H3 and 8E4, respectively, were obtained and were identified by indirect enzyme linked immunosorbent assay (ELISA), they belonged to IgG1, IgG1 and Ig2a, respectively. Two epitopes of envelope protein domain were determined, among them, 4F7 and 6H3 were against the same epitope and 8E4 to another one. CONCLUSIONS: The results of indirect ELISA, Western blot and indirect immunofluorescence experiment indicated that these three McAbs were specific for West Nile virus envelope protein domain and did not cross-react with Japanese encephalitis virus and other viruses, so they can be used for specific detection of West Nile virus.
Descriptors: West Nile virus, envelope protein, spleen cells, mice, monoclonal antibodies, western blot, enzyme linked immunosorbent assay, Japanese encephalitis.
Language of Text: Chinese.

Chevalier, V., R. Lancelot, A. Diaite, B. Mondet, B. Sall, and X. DE Lamballerie (2006). Serological assessment of west nile Fever virus activity in the pastoral system of ferlo, senegal. Annals of the New York Academy of Sciences 1081: 216-25.
Abstract: The Ferlo area (north-central Senegal) is characterized by a system of temporary ponds favorable to arboviruses among which West Nile fever (WNF) was already identified. During the rainy season in 2003, a serological study was undertaken on horses to assess the activity of the WNF virus (WNFV) in Barkedji (Ferlo). The observed serological prevalence rate was 78.3% for neutralizing antibodies, with a 95% confidence interval (CI) of [64.0, 92.7]. This prevalence rate significantly increased with age (P = 10(-5)). This study confirmed that WNF was endemic in the Ferlo. The transmission risks depended on the introduction of the WNFV in the ecosystem-probably with migrating birds, on its amplification in hosts and on the vector-population dynamic. Further studies are needed to investigate how the cycle is initiated in Barkedji at the beginning of the rainy season and the impact of climatic variations on the risk of transmission of WNF. A surveillance system should be implemented: (a) to assess the clinical impact of the WNF on human and equine populations, (b) to provide an early detection of virulent strains, and (c) to assess the risk of WNF transmission to disease-free ecosystems via migrating birds.
Descriptors: West Nile virus, serological assessment, virus activity, ponds, horses, antibodies, transmission, migrating birds.

Cunha, B.A. (2006). West Nile virus encephalitis: clinical diagnostic and prognostic indicators in compromised hosts. Clinical Infectious Diseases an Official Publication of the Infectious Diseases Society of America 43(1): 117.
Descriptors: immunocompromised host, West Nile fever diagnosis, lymphoma, b cell complications, b cell immunology, prognosis, serologic tests, West Nile fever immunology.
Notes: Comment On: Clin Infect Dis. 2006 Mar 1;42(5):680-3.

Deng-Yong-Qiang, Jiang-Tao, Yu-Man, Qin-Cheng-Feng, Chen-Shui-Ping, Zhu-Qing-Yu, and Qin-E-De (2005). Detection of West Nile virus using real-time PCR assay. Zhonghua Weishengwuxue He Mianyixue Zazhi 25(6): 519-522. ISSN: 0254-5101.
Descriptors: West Nile virus detection, real time PCR assay, reverse transcriptase polymerase chain reaction, genetic techniques.
Language of Text: Chinese.

Ellis, A.E., D.G. Mead, A.B. Allison, S.E.J. Gibbs, N.L. Gottdenker, D.E. Stallknecht, and E.W. Howerth (2005). Comparison of Immunohistochemistry and Virus Isolation for Diagnosis of West Nile Virus. Journal of Clinical Microbiology. 43(6): 2904-2908. ISSN: 0095-1137.
Abstract: Immunohistochemistry and virus isolation were performed on 1,057 birds. Immunohistochemistry, virus isolation, or both found 325 birds to be West Nile virus positive. Of these, 271 were positive by both methods. These results indicate that virus isolation and immunohistochemistry are approximately equal in their ability to detect West Nile virus.
Descriptors: West Nile virus, diagnosis, birds, virus isolation, immunohistochemistry, comparison.

Ezenwa, V.O., M.S. Godsey, R.J. King, and S.C. Guptill (2006). Avian diversity and West Nile virus: Testing associations between biodiversity and infectious disease risk. Proceedings. Biological Sciences The Royal Society 273(1582): 109-117.
Abstract: The emergence of several high profile infectious diseases in recent years has focused attention on our need to understand the ecological factors contributing to the spread of infectious diseases. West Nile virus (WNV) is a mosquito-borne zoonotic disease that was first detected in the United States in 1999. The factors accounting for variation in the prevalence of WNV are poorly understood, but recentideas suggesting links between high biodiversity and reduced vector-borne disease risk may help account for distribution patterns of this disease. Since wild birds are the primary reservoir hosts for WNV, we tested associations between passerine (Passeriform) bird diversity, non-passerine (all other orders) bird diversity and virus infection rates in mosquitoes and humans to examine the extent to which bird diversity is associated with WNV infection risk. We found that non-passerine species richness (number of non-passerine species) was significantly negatively correlated with both mosquito and human infection rates, whereas there was no significant association between passerine species richness and any measure of infection risk. Our findings suggest that non-passerine diversity may play a role in dampening WNV amplification rates in mosquitoes, minimizing human disease risk.
Descriptors: biodiversity, birds, West Nile fever transmission, West Nile virus, bird genetics, Culex sp., statistical data interpretation, geography, passeriformes, risk factors, West Nile fever epidemiology.

Farajollahi, A., W.J. Crans, D. Nickerson, P. Bryant, B. Wolf, A. Glaser, and T.G. Andreadis (2005). Detection of West Nile virus RNA from the louse fly Icosta americana (Diptera: Hippoboscidae). Journal of the American Mosquito Control Association 21(4): 474-476.
Abstract: West Nile virus (WNV) was detected by Taqman reverse transcription-polymerase chain reaction in 4 of 85 (4.7%) blood-engorged (n = 2) and unengorged (n = 2) Icosta americana (Leach) hippoboscid flies that were collected from wild raptors submitted to a wildlife rehabilitation center in Mercer County, NJ, in 2003. This report represents an additional detection of WNV in a nonculicine arthropod in North America and the first documented detection of the virus in unengorged hippoboscid flies, further suggesting a possible role that this species may play in the transmission of WNV in North America.
Descriptors: West Nile virus, New Jersey, viral RNA analysis, reverse transcriptase polymerase chain reaction, West Nile fever transmission.

Fox, J.L., S.L. Hazell, L.H. Tobler, and M.P. Busch (2006). Immunoglobulin G avidity in differentiation between early and late antibody responses to West Nile virus. Clinical and Vaccine Immunology 13(1): 33-36. ISSN: 1556-6811.
Abstract: In 1999 West Nile virus (WNV) surfaced in the United States in the city of New York and spread over successive summers to most of the continental United States, Canada, and Mexico. Because WNV immunoglobulin M (IgM) antibodies have been shown to persist for up to 1 year, residents in areas of endemicity can have persistent WNV IgM antibodies that are unrelated to a current illness with which they present. We present data on the use of IgG avidity testing for the resolution of conflicting data arising from the testing of serum or plasma for antibodies to WNV. Thirteen seroconversion panels, each consisting of a minimum of four samples, were used. All samples were tested for the presence of WNV IgM and IgG antibodies, and the avidity index for the WNV IgG-positive samples was calculated. Panels that exhibited a rise in the WNV IgM level followed by a sequential rise in the WNV IgG level were designated "primary." Panels that exhibited a marked rise in the WNV IgG level followed by a sequential weak WNV IgM response and that had serological evidence of a prior flavivirus infection were designated "secondary." All samples from the "primary" panels exhibited low avidity indices (less than 40%) for the first 20 to 30 days after the recovery of the index sample (the sample found to be virus positive). All of the "secondary" samples had elevated WNV IgG levels with avidity indices of > or =55%, regardless of the number of days since the recovery of the index sample. These data demonstrate that it is possible to differentiate between recent and past exposure to WNV or another flavivirus through the measurement of WNV IgG avidity indices.
Descriptors: viral blood antibodies, blood immunoglobulin G, West Nile fever, West Nile virus, biological assay, enzyme linked immunosorbent assay, serologic tests, time factors.

Gallian, P., P. De Micco, X. de Lamballerie, T. Levayer, F. Levacon, P. Guntz, B. Mercier, I. Dupond, C. Cornillot, and G. Andreu (2005). Prevention of West Nile virus transmission by blood transfusion: a comparison of nucleic acid test screening assays. Transfusion 45(9): 1540-1541.
Descriptors: blood transfusion, mass screening methods, viral RNA, West Nile fever prevention and control, West Nile virus isolation and purification, blood borne pathogens, viral analysis.

Ge, J., B. Chen, M.Y. Zhang, Q.L. Song, Y.X. Zhao, J. Pace, P. Lam, Y. Zhang, C. Obiezu-Forster, H. Goldman, J.H. Keffer, and N. Shaikh (2006). A novel immunochromatographic assay rapidly detecting West Nile virus-specific IgM in patient's serum and plasma. Clinical Chemistry 52(6, Suppl. S): A41. ISSN: 0009-9147.
Descriptors: West Nile virus detection in serum plasma, immunologic techniques, solid phase sandwich immunoassay, bioassay techniques.
Notes: Meeting Information: 58th Annual Meeting of the American Association of Clinical Chemistry, Chicago, Illinois, USA; July 23 -27, 2006.

Gibbs, S.E., A.E. Ellis, D.G. Mead, A.B. Allison, J.K. Moulton, E.W. Howerth, and D.E. Stallknecht (2005). West Nile virus detection in the organs of naturally infected blue jays (Cyanocitta cristata). Journal of Wildlife Diseases 41(2): 354-362.
Abstract: Blue jays (Cyanocitta cristata) are an effective indicator species for West Nile virus (WNV) and may be regionally important in surveillance efforts. The sites of WNV replication and sensitivity of virus detection techniques are undefined for blue jays. The objectives of this study were to describe the gross and microscopic pathology associated with natural WNV infection in blue jays, as well as determine the most appropriate tissues to be used for virus isolation, reverse transcription-nested polymerase chain reaction, and immunohistochemistry (IHC) techniques. Blue jays were collected in Georgia, USA, between May and September 2001. Initial screening by virus isolation indicated that 36 of 59 blue jays chosen for evaluation were WNV positive. From this group, 20 positive and five negative birds were chosen to compare virus detection techniques. Six positive and five negative birds were selected for histopathology examination. Splenomegaly and poor body condition were the most consistent gross findings among positive birds. The most consistent histopathologic findings in the tissues of WNV-positive blue jays were mononuclear leukocytosis and epicarditis/myocarditis. Brain, heart, and lung had the highest viral titers, and WNV antigen was most often detected by IHC in heart, kidney, liver, and lung. Reverse transcription-nested polymerase chain reaction proved to be the most sensitive diagnostic test applied in this study irrespective of the tissue type. Brain tissue could be used effectively for both virus isolation and RT-nPCR, and this tissue is simple to remove and process. The success of IHC is highly dependent on tissue selection, and the use of multiple tissues including heart, kidney, liver, or lung is recommended.
Descriptors: blue jays, Cyanocitta cristata, WNV indicator species, disease surveillance, virus detection techniques, immunohistochemistry techniques (IHC), tissue selection, heart, kidney, lung, liver.

Gibbs, S.E., D.M. Hoffman, L.M. Stark, N.L. Marlenee, B.J. Blitvich, B.J. Beaty, and D.E. Stallknecht (2005). Persistence of antibodies to West Nile virus in naturally infected rock pigeons (Columba livia). Clinical and Diagnostic Laboratory Immunology 12(5): 665-667.
Abstract: Wild caught rock pigeons (Columba livia) with antibodies to West Nile virus were monitored for 15 months to determine antibody persistence and compare results of three serologic techniques. Antibodies persisted for the entire study as detected by epitope-blocking enzyme-linked immunosorbent assay and plaque reduction neutralization test. Maternal antibodies in squabs derived from seropositive birds persisted for an average of 27 days.
Descriptors: viral blood antibodies, West Nile fever, West Nile virus transmission, wild animals, disease transmission, enzyme-linked immunosorbent assay, plaque assay.

Gibbs, S., A. Ellis, D. Mead, A. Allison, J. Moulton, E. Howerth, and D. Stallknecht (2005). West Nile virus detection in the organs of naturally infected blue jays (Cyanocitta cristata). Journal of Wildlife Diseases. 41(2): 354-362. ISSN: 0090-3558.
Descriptors: wild birds, sentinel animals, disease detection, immunohistochemistry, reverse transcriptase polymerase chain reaction, Georgia, blue jays, West Nile virus.

Godhardt, J.A., K. Beheler, M.J. O'Connor, T.J. Whyte, E.S. Reisdorf, S.J. Ubl, P.N. Bochsler, and K.L. Toohey Kurth (2006). Evaluation of antigen-capture ELISA and immunohistochemical methods for avian surveillance of West Nile virus. Journal of Veterinary Diagnostic Investigation 18(1): 85-89.
Abstract: Accurate detection of West Nile virus (WNV) in corvids is essential for monitoring the spread of virus during the mosquito season. Viremia in corvids is very high, with titers approaching 10(8) viral particles/ml. In the presence of such marked viremia, the sensitivity of real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis is unnecessary, and more cost-effective methods should be assessed. To this end, antigen-capture ELISA (ACE) and immunohistochemical (IHC) assays were evaluated. Skin, cloacal swab specimens, and feathers from corvids were tested by use of ACE, and results were compared with results obtained from use of real-time RT-PCR analysis. Of the 3 sample types, skin gave the best sensitivity (98%) and specificity (100%). Skin, brain, kidney, and spleen from corvids were analyzed by IHC, and results were compared with real-time RT-PCR results. Kidney and spleen were more often positive by use of IHC than were brain and skin tissue; however, IHC did not perform as well as ACE in the identification of virus-positive birds. Results of this study support the use of a skin sample in an ACE format as an effective surveillance method for corvids.
Descriptors: West Nile virus, ELISA, avian surveillance, antigen capture, evaluation, immunohistochemical methods, accurate detection.

Herrmann, S., B. Leshem, S. Landes, B. Rager-Zisman, and R.S. Marks (2005). Chemiluminescent optical fiber immunosensor for the detection of anti-West Nile virus IgG. Talanta 66(1): 6-14. ISSN: 0039-9140.
Descriptors: West Nile virus IgG, chemiluminescent optical fiber immunosensor, clinical techniques, diagnostic techniques, ELISA, disease detection.

Hukkanen, R.R., H.D. Liggitt, S.T. Kelley, R. Grant, D. Anderson, B.J. Beaty, N.L. Marlenee, R.A. Hall, and H. Bielefeldt Ohmann (2006). Comparison of commercially available and novel West Nile virus immunoassays for detection of seroconversion in pig-tailed macaques (Macaca nemestrina). Comparative Medicine 56(1): 46-54.
Abstract: We report the assessment and validation of an NS1 epitope-blocking enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to West Nile virus (WNV) in macaques. Sera from naturally infected Macaca nemestrina were tested by ELISA and plaque reduction neutralization test (PRNT). Results were correlated with hemagglutination inhibition (HAI) data. Our results demonstrate that the blocking ELISA rapidly and specifically detects WNV infection in M. nemestrina. In addition, the diagnostic value of 7 commercially available immunoassays (PanBio immunoglobulin [Ig] M ELISA, PanBio IgG ELISA, PanBio immunofluorescence assay (IFA), InBios IgG ELISA, InBios IgM ELISA, Focus Diagnostics IgG ELISA, and Focus Diagnostics IgM ELISA) in M. nemestrina was evaluated and compared with that of the epitope-blocking ELISA. The PanBio IgG ELISA was found to effectively diagnose WNV exposure in M. nemestrina. Further, PanBio IFA slides are fast and reliable screening tools for diagnosing flaviviral exposure in M. nemestrina.
Descriptors: West Nile virus, immunoassays, detection, pig-tailed macques, NS1 epitope-blocking enzyme-linked immunosorbent assay (ELISA), antibodies, plaque reduction neutralization test (PRNT).

Jacobson, E.R., A.J. Johnson, J.A. Hernandez, S.J. Tucker, A.P.2. Dupuis, R. Stevens, D. Carbonneau, and L. Stark (2005). Validation and use of an indirect enzyme-linked immunosorbent assay for detection of antibodies to West Nile virus in American Alligators (Alligator mississippiensis) in Florida. Journal of Wildlife Diseases 41(1): 107-114.
Abstract: In October 2002, West Nile virus (WNV) was identified in farmed American alligators (Alligator mississippiensis) in Florida showing clinical signs and having microscopic lesions indicative of central nervous system disease. To perform seroepidemiologic studies, an indirect enzyme-linked immunosorbent assay (ELISA) was developed to determine exposure of captive and wild alligators to WNV. To validate the test, a group of WNV-seropositive and -seronegative alligators were identified at the affected farm using hemagglutination inhibition (HAI) and the plaque reduction neutralization test (PRNT). The indirect ELISA utilized a rabbit anti-alligator immunoglobulins polyclonal antibody as the secondary antibody, and inactivated WNV-infected Vero cells were used as the coating antigen. For all samples (n=58), the results of the ELISA were consistent with the HAI and PRNT findings. Plasma was collected from 669 free-ranging alligators from 21 sites across Florida in April and October 2003. Four samples collected in April and six in October were positive for WNV antibodies using HAI, PRNT, and the indirect ELISA. This indicated that wild alligators in Florida have been exposed to WNV. These findings can be used as a baseline for future surveys.
Descriptors: alligators, crocodiles, West Nile fever, West Nile virus, disease reservoirs, enzyme linked immunosorbent assay methods, Florida, seroepidemiologic studies.

Jiang ShuFang, Zhang YingMei, Zhao TongYan, and Dong YanDe (2006). Establishment and application of plaque assay for the detection of West Nile virus. Chinese Journal of Vector Biology and Control 17(2): 81-82. ISSN: 1003-4692.
Descriptors: West Nile virus, quantitative detection, plaque assay, animal models, vero cells, poultry, agarose overlay, Culex pipiens.
Language of Text: Chinese; Summary in English.

Jiang Yan, Zhang ChangYin, and Chen GuoQiang (2005). Construction of RT-PCR for detection of West Nile virus. Chinese Journal of Animal Quarantine 22(5): 25-27. ISSN: 1005-944x.
Descriptors: West Nile virus, detection, RT-PCR, reverse transcription polymerase chain reaction, E gene.
Language of Text: Chinese; Summary in English.

Johnson, A.J., A.J. Noga, O. Kosoy, R.S. Lanciotti, A.A. Johnson, and B.J. Biggerstaff (2005). Duplex microsphere-based immunoassay for detection of anti-West Nile virus and anti-St. Louis encephalitis virus immunoglobulin M antibodies. Clinical and Diagnostic Laboratory Immunology 12(5): 566-574. ISSN: 1071-412X.
Descriptors: West Nile virus, St. Louis virus, viral detection, ELISA, immunoglobulin, IgM, duplex microsphere based immunoassay.

Korves, C.T., S.J. Goldie, and M.B. Murray (2006). Cost-effectiveness of alternative blood-screening strategies for West Nile Virus in the United States. PLoS Medicine 3(2): E21.
Abstract: BACKGROUND: West Nile virus (WNV) is endemic in the US, varying seasonally and by geographic region. WNV can be transmitted by blood transfusion, and mandatory screening of blood for WNV was recently introduced throughout the US. Guidelines for selecting cost-effective strategies for screening blood for WNV do not exist. METHODS AND FINDINGS: We conducted a cost-effectiveness analysis for screening blood for WNV using a computer-based mathematical model, and using data from prospective studies, retrospective studies, and published literature. For three geographic areas with varying WNV-transmission intensity and length of transmission season, the model was used to estimate lifetime costs, quality-adjusted life expectancy, and incremental cost-effectiveness ratios associated with alternative screening strategies in a target population of blood-transfusion recipients. We compared the status quo (baseline screening using a donor questionnaire) to several strategies which differed by nucleic acid testing of either pooled or individual samples, universal versus targeted screening of donations designated for immunocompromised patients, and seasonal versus year-long screening. In low-transmission areas with short WNV seasons, screening by questionnaire alone was the most cost-effective strategy. In areas with high levels of WNV transmission, seasonal screening of individual samples and restricting screening to blood donations designated for immunocompromised recipients was the most cost-effective strategy. Seasonal screening of the entire recipient pool added minimal clinical benefit, with incremental cost-effectiveness ratios exceeding USD 1.7 million per quality-adjusted life-year gained. Year-round screening offered no additional benefit compared to seasonal screening in any of the transmission settings. CONCLUSIONS: In areas with high levels of WNV transmission, seasonal screening of individual samples and restricting screening to blood donations designated for immunocompromised recipients is cost saving. In areas with low levels of infection, a status-quo strategy using a standard questionnaire is cost-effective.
Descriptors: mass screening economics, West Nile fever, blood donors, blood transfusion, cost benefit analysis, immunocompromised host, econometric models, prospective studies, quality adjusted life years, retrospective studies, seasons, United States.
Notes: Comment In: PLoS Med. 2006 Feb;3(2):e99.

Kuehn, B.M. (2006). Studies propose targeted screening of blood for West Nile virus. JAMA the Journal of the American Medical Association 295(11): 1235-1236.
Descriptors: blood bank standards, blood donors, West Nile fever diagnosis and transmission, West Nile virus isolation and purification, blood transfusion, mass screening, United States.

Lampman, R.L., N.M. Krasavin, M. Szyska, and R.J. Novak (2006). A comparison of two West Nile virus detection assays (TaqMan reverse transcriptase polymerase chain reaction and VecTest antigen assay) during three consecutive outbreaks in northern Illinois. Journal of the American Mosquito Control Association 22(1): 76-86.
Abstract: Mosquitoes identified as female Culex (Culex) species, primarily mixtures or uniform batches of Culex pipiens and Culex restuans, were collected daily from gravid traps by 2 mosquito abatement districts (MADs) in Cook County, Illinois. From 2002 through 2004, batches (pools) of mosquitoes were tested by the MADs for West Nile virus (WNV) by using VecTest WNV antigen assays and the same samples were retested, usually within 1-2 wk, for WNV RNA by the TaqMan reverse transcriptase polymerase chain reaction (RT-PCR). There were 952 TaqMan-positive pools out of 3,953 pools over the 3 years, and about one half of that number were VecTest-positive. The difference between the 2 detection assays varied between and within years. The VecTest assays detected about 57% and 69% of the TaqMan RT-PCR-positive pools from Des Plaines Valley MAD and Northwest MAD in 2002, but only about 40% and 46% in 2003, and 36% and 55% in 2004, respectively. Based on a subset of the 2004 data, a linear relationship was found between VecTest detection of WNV and TaqMan cycle threshold between 18 and 28 cycles. A temporal decrease in the difference between the 2 assays was observed in 2003 and 2004, which we conjecture is due, at least partially, to a seasonal decline in the proportion of recently infected mosquitoes. This trend was not observed in 2002 because infection rates indicated a high likelihood of more than 1 infected mosquito per pool at the peak of transmission. Unlike a previous study, the 95% confidence intervals of infection rates based on the 2 detection methods did not always overlap. The highest infection rates occurred in 2002 when mean monthly temperatures were above average.
Descriptors: Culex sp., reverse transcriptase polymerase chain reaction, West Nile virus, disease outbreaks, Illinois, insect vectors, seasons, temperature, West Nile fever epidemiology.

Lee, B.Y. and B.J. Biggerstaff (2006). Screening the United States blood supply for West Nile Virus: A question of blood, dollars, and sense. PLoS Medicine 3(2): E99.
Descriptors: mass screening, West Nile fever, blood bank standards, blood donors, blood transfusion, cost of illness, cost-benefit analysis, health policy, seasons, specimen handling.
Notes: Comment On: PLoS Med. 2006 Feb;3(2):E21.

Lee, D.H., J. Mathew, W. Pfahler, D. Ma, J. Valinsky, A.M. Prince, and L. Andrus (2005). Individual Donor Nucleic Acid Amplification Testing for Detection of West Nile Virus. Journal of Clinical Microbiology. 43(10): 5111-5116. ISSN: 0095-1137.
Abstract: We have developed an economical, high-throughput nucleic acid amplification test (NAT) for blood-borne viruses, suitable for use in the screening of plasma samples from individual blood donors. This assay system includes a semiautomated procedure, using 96-well glass fiber plates for the extraction of viral nucleic acids from plasma and "universal beacon" technology which permits the detection of all genotypes of highly variable viruses (e.g., human immunodeficiency virus and hepatitis C virus). In this detection system, two fluorescent- detection technologies were employed successfully in a single tube: molecular beacon for West Nile virus (WNV) detection using a 6-carboxyfluorescein fluorophore and TaqMan for internal control detection using a VIC fluorophore. To establish proof of concept, we focused on the development of a robust individual donor NAT for WNV. The assay showed no reactivity to 15 other viruses tested or to 420 blood donor samples from the WNV pre-epidemic season. No cross-contamination was observed on an alternating positive-/negative-well test. The sensitivity (limit of detection, 95%) of the assay for WNV is between 3.79 and 16.3 RNA copies/ml, depending on which material was used as a standard. The assay detected all positive blood donation samples identified by the Roche WNV NAT. The assay can be performed qualitatively for screening and quantitatively for confirmation.
Descriptors: West Nile virus, detection, testing, nucleic acid amplification, blood born viruses, assay, screening, plasma samples.

Levett, P.N., K. Sonnenberg, F. Sidaway, S. Shead, M. Niedrig, K. Steinhagen, G.B. Horsman, and M.A. Drebot (2005). Use of Immunoglobulin G Avidity Assays for Differentiation of Primary from Previous Infections with West Nile Virus. Journal of Clinical Microbiology. 43(12): 5873-5875. ISSN: 0095-1137.
Abstract: Since its introduction in 1999, West Nile virus (WNV) infections have spread rapidly across the North American continent. Diagnosis of acute WNV infection by detection of WNV-specific immunoglobulin M (IgM) is complicated by the persistence of detectable IgM for more than 1 year in some patients. IgG antibody avidity testing was assessed as a supplemental assay in the diagnosis of current infections. Three groups of serum samples were assayed in parallel by two different IgG avidity test systems (indirect immunofluorescence test [IIFT] and prototype enzyme-linked immunosorbent assay [ELISA]; EUROIMMUN, Luebeck, Germany). Group I (40 sera taken between 2 and 9 days after the onset of influenza-like symptoms) and group II (40 sera taken between 10 and 43 days after onset) were acute and convalescent specimens from patients with a positive anti-WNV IgM test (ELISA; Focus Diagnostics, Cypress, CA). Group III consisted of 43 patient sera collected between 6 and 12 months after infection. IgG antibodies specific for WNV were detected in 38% (ELISA) and 50% (IIFT) of group I sera, in 90% (ELISA and IIFT) of group II sera, and in 100% (ELISA and IIFT) of group III sera. Low-avidity IgG antibodies were demonstrated in 86% (ELISA) and 95% (IIFT) of IgG-positive patient samples taken between 2 and 43 days after the onset of symptoms (groups I and II). High-avidity IgG antibodies were detected in 100% of group III sera obtained 6 months or more after the onset of symptoms (ELISA and IIFT). IgG avidity tests for WNV infections are rapid and simple to perform. The determination of IgG avidity provides additional diagnostic certainty in differentiating between recently acquired and previous infections with WNV.
Descriptors: West Nile virus, diagnosis, detection, specific immunoglobulin, IgM, differentiate, previous infection, recent infection.

Li, L., A. Barrett, and D. Beasley (2005). Differential expression of domain III neutralizing epitopes on the envelope proteins of West Nile virus strains. Virology 335(1): 99-105. ISSN: 0042-6822.
Descriptors: West Nile virus, viral proteins, viral antigens, epitopes, neutralization, amino acid sequences, antigenic variation, nucleotide sequences, structure activity relationships, viral-envelope-protein, viral-antibodies, molecular-sequence-data, Internet-resource.

Lim, C.K. and I. Kurane (2005). [Diagnostic tests: West Nile virus]. Japanese Journal of Clinical Medicine 63(Suppl 7): 321-323.
Descriptors: viral blood antibodies, immunoglobulin M blood, RNA, viral isolation and purification, reverse transcriptase polymerase chain reaction, serologic tests, West Nile fever diagnosis, West Nile virus isolation, enzyme linked immunosorbent assay (ELISA) methods, neutralization tests, zoonoses.
Language of Text: Japanese.

Long, M.T., W. Jeter, J. Hernandez, D.C. Sellon, D. Gosche, K. Gillis, E. Bille, and E.P. Gibbs (2006). Diagnostic performance of the equine IgM capture ELISA for serodiagnosis of West Nile virus infection. Journal of Veterinary Internal Medicine 20(3): 608-613.
Abstract: The objectives of these studies were to assess the diagnostic performance (sensitivity and specificity) of the IgM capture enzyme-linked immunosorbent assay (ELISA; MAC) for diagnosis of West Nile (WN) virus in horses and to examine the performance of this test by using different criteria for seropositivity. A total of 36 horses classified as WN virus infected (group 1) and 383 horses from 4 subpopulations of hoses classified as noninfected (groups 2, 3, 4, and 5) were used in the study. The sensitivity (proportion of infected horses that tested positive for WN virus IgM antibodies) and specificity (proportion of noninfected horses that tested negative) were calculated at different cutoff points by using receiver operating curve (ROC) analysis. Using a selected cutoff point = 2.0, the sensitivity and specificity of the MAC were 91.7 and 99.2%, respectively. The area under the ROC curve = 0.95 (95% confidence interval [CI], 0.89 to 1.0), suggesting that the MAC is a useful tool for diagnosis of recent WN virus exposure in horses. In fulfillment of the 2nd objective, 2 other indices were developed and these indices approached 1.0 for the AUC with smaller 95% CIs. These indices were then used to test 602 additional diagnostic samples submitted from suspect horses between 2002 and 2004. Using the standard cutoff, 194 (32%) of the horses were interpreted as positive. Utilizing newly predicted cutoff criteria from each index, additional horses were identified as positive. In conclusion, the MAC as used for identification of WN virus-diseased horses undergoing recent exposure performs reliably at the standard cutoff for seropositivity. A negative test might not completely rule out WN virus disease, but horses that test negative were most likely not exposed to WNV. Performance of the test can be further improved by investigation of other indexes of seropositivity.
Descriptors: sensitivity and specificity of the IgM capture enzyme-linked immunosorbent assay (ELISA), diagnosis of West Nile virus, horses, seropositivity, predictive value of tests, serologic tests, West Nile fever.

Mandalakas, A.M., C. Kippes, J. Sedransk, J.R. Kile, A. Garg, J. McLeod, R.L. Berry, and A.A. Marfin (2005). West Nile virus epidemic, northeast Ohio, 2002. Emerging Infectious Diseases 11(11): 1774-1777. ISSN: 1080-6040.
Abstract: Serum samples and sociodemographic data were obtained from 1,209 Ohio residents. West Nile virus immunoglobulin M (IgM) and IgG antibodies were detected by enzyme-linked immunosorbent assay and confirmed. Children were 4.5 times more likely to become infected yet 110 times less likely to have neuroinvasive disease develop.
Descriptors: viral blood antibodies, disease outbreaks, West Nile fever epidemiology, West Nile virus, humans, enzyme linked immunosorbent assay, blood immunoglobulin G, blood immunoglobulin M, Ohio.

Marciniak, C. and E.L. Rosenfeld (2005). Serial electrodiagnostic studies in West Nile virus-associated acute flaccid paralysis. American Journal of Physical Medicine and Rehabilitation 84(11): 904-910.
Abstract: A man in his 70s presented for acute rehabilitation with severe acute flaccid asymmetric weakness in both lower limbs. Cerebrospinal fluid and serum immunoglobulin M titers were positive for West Nile virus. Electrodiagnostic studies demonstrated severe diffuse motor axonopathy consistent with an anterior myelitis. Electrodiagnostic and clinical improvements were monitored. Electrodiagnostic testing at 6 and 18 mos demonstrated continuing reinnervation; nascent voluntary motor unit action potentials were first noted proximally and, at 18 mos, distally in the left lower limb, including muscles in which motor unit potentials were not initially noted. Corresponding clinical improvements, though slow, were demonstrated even at 1(1/2) yrs after onset. Thus, motoric changes after West Nile virus-associated anterior myelitis need to be monitored over a prolonged time period to allow accurate assessment of prognosis for recovery in rehabilitation programs.
Descriptors: myelitis, West Nile fever complications, West Nile virus isolation and purification, acute disease, viral cerebrospinal fluid, muscle weakness, skeletal muscle, paraplegia rehabilitation, time factors.

Mawhorter, S.D., A. Sierk, S.M. Staugaitis, R.K. Avery, R. Sobecks, R.A. Prayson, G.W. Procop, and B. Yen Lieberman (2005). Fatal West Nile Virus infection after rituximab/fludarabine--induced remission for non-Hodgkin's lymphoma. Clinical Lymphoma and Myeloma 6(3): 248-250.
Abstract: West Nile virus (WNV) infections are potentially life threatening in immunocompromised hosts. Currently, the best diagnostic test is serology. Reverse-transcriptase polymerase chain reaction (RT-PCR) testing has a role, but, because WNV is a cell-associated neurotropic virus, RT-PCR results are frequently negative even in cases of active infection. We present a case in which serology results were persistently negative because the patient was immunocompromised following lymphoma treatment. The role of humoral immunity in resolution of WNV is also discussed.
Descriptors: monoclonal antibodies, administration and dosage, antineoplastic agents, follicular lymphoma, West Nile fever, West Nile virus fatal outcome, lymphoma, follicular drug therapy, remission, vidarabine administration and dosage.

Mazurek, J.M., K. Winpisinger, B.J. Mattson, R. Duffy, and R.L. Moolenaar (2005). The epidemiology and early clinical features of West Nile virus infection. American Journal of Emergency Medicine 23(4): 536-543.
Abstract: We studied early clinical features of the West Nile virus (WNV) infection. Case patients were Ohio residents who reported to the Ohio Department of Health from August 14 to December 31, 2002, with a positive serum or cerebrospinal fluid for anti-WNV IgM. Of 441 WNV cases, medical records of 224 (85.5%) hospitalized patients were available for review. Most frequent symptoms were fever at a temperature of 38.0 degrees C or higher (n = 155; 69.2%), headache (n = 114; 50.9%), and mental status changes (n = 113; 50.4%). At least one neurological symptom, one gastrointestinal symptom, and one respiratory symptom was present in 186 (83.0%), 119 (53.1%), and 46 (20.5%) patients, respectively. Using multivariate logistic regression and controlling for age, we found that the initial diagnosis of encephalitis (P = .001) or reporting abdominal pain (P < .001) was associated with death. Because initial symptoms of WNV infection are not specific, physicians should maintain a high index of suspicion during the epidemic season, particularly in elderly patients with compatible symptoms.
Descriptors: West Nile fever, hospital statistics, numerical data, encephalitis, guillain barre syndrome, meningitis, Ohio, health care, humans.

Meece, J.K., T.A. Kronenwetter Koepel, M.F. Vandermause, and K.D. Reed (2006). West Nile virus infection in commercial waterfowl operation, Wisconsin. Emerging Infectious Diseases 12(9): 1451-1453. ISSN: 1080-6040 .
Abstract: A West Nile virus (WNV) outbreak occurred at a commercial waterfowl operation in Wisconsin in 2005. Retrospective analysis of dead and live birds was conducted. WNV was detected by PCR in 84.1% of 88 dead birds; neutralizing antibodies were found in 14 of 30 randomly sampled asymptomatic or recovered birds.
Descriptors: animal husbandry, disease outbreaks, ducks, geese, poultry diseases epidemiology, West Nile fever, Wisconsin.

Murgai, M., M. Mayda, M. Rios, R. Hammamieh, and M. Jett (2006). Gene expression analysis of the West Nile virus and the Dengue serotypes. FASEB Journal 20(4, Part 1): A62. ISSN: 0892-6638.
Descriptors: West Nile virus, Dengue fever, vector borne diseases, meningitis, encephalitis, microarray gene expression analysis, genetic technique, cDNA microarrays.
Notes: Meeting Information: Experimental Biology 2006 Meeting, San Francisco, California, USA; April 01 -05, 2006.

Niedrig, M., S. Linke, H. Zeller, and C. Drosten (2006). First international proficiency study on West Nile virus molecular detection. Clinical Chemistry 52(10): 1851-185.
Abstract: BACKGROUND: West Nile virus (WNV) molecular detection is being conducted by a growing number of laboratories, but the degree of proficiency may vary between them. External quality control is needed. METHODS: We have conducted an international quality assurance study on WNV molecular detection. Participating laboratories tested noninfectious samples inactivated by heat and gamma irradiation. Participants received 7 coded lyophilized samples containing WNV of genetic lineages 1a, 1b, and 2 at 2600 to 18 000 000 RNA copies/mL, 3 samples containing heterologous flaviviruses, and 2 negative samples. RESULTS: Thirty laboratories participated. The average laboratory achieved 50% detection probability from 7762 copies/mL onward (probit analysis; 95% CI = 1174-24547 copies/mL). Lineages 1a and 1b were detected with equal efficiencies, but the lineage 2 strain (Ug37) was detected at significantly lower rates. Only 27% of participants were able to detect the 6 samples containing > or =1.8 x 10(4) copies/mL. Three laboratories generated false-positive results in negative samples. Six of 30 laboratories reported correct strain identification in 3 samples containing non-WNV flaviviruses. We observed a significant positive correlation between the capability of detecting non-WNV flaviviruses and detecting WNV lineage 2. CONCLUSIONS: Most participants showed good performance in detecting lineage 1 WNV, the predominant virus in the Northern Hemisphere. The inability of some laboratories to detect even highly concentrated lineage 2 WNV downgraded the overall outcome. The lineage 2 material received through this study will provide laboratories with the necessary template for improving their assays. Such material is otherwise hard to obtain.
Descriptors: West Nile virus, Cercopithecus aethiops, false positive reactions, international cooperation, molecular diagnostic techniques, quality control, vero cells, virology methods.

Niedrig, M., K. Sonnenberg, K. Steinhagen, and J.T. Paweska (2007). Comparison of ELISA and immunoassays for measurement of IgG and IgM antibody to West Nile virus in human sera against virus neutralisation. Journal of Virological Methods 139(1): 103-105.
Abstract: Two commercial assays for the detection of IgG antibody to West Nile virus (WNV), an indirect enzyme-linked immunosorbent assay (I-ELISA) and indirect fluorescent antibody test (IFAT), were evaluated against the virus neutralisation test. Excellent agreement with the virus neutralisation was obtained with both tests, i.e., 99.5% by I-ELISA and 100% by IFAT. The well-known serological cross-reactivity within the family of the Flaviviridae was analysed using sera with known antibodies against dengue virus, tick borne encephalitis virus and yellow fever virus. IgM and/or IgG positive sera were examined for reactivity by WNV-ELISA and WNV-IFAT. While cross-reactivity between 0 and 18.2% was recorded with IgM positive sera, there was extensive cross-reactivity of 15.7-100% with IgG positive sera.
Descriptors: West Nile virus, antibody, IgG, IgM, immunoassays, ELISA, camparison, indirect fluorescent antibody test.

Nixon, M.L. and H.E. Prince (2006). West Nile virus immunoglobulin A (WNV IgA) detection in cerebrospinal fluid in relation to WNV IgG and IgM reactivity. Journal of Clinical Virology 37(3): 174-178.
Abstract: BACKGROUND: Diagnostic criteria for neurologic involvement in WNV infection include WNV IgM detection in CSF; however, WNV IgM can persist in CSF >6 months. CSF IgA characterizes other flavivirus infections, but WNV IgA in CSF has not been evaluated. WNV IgM in CSF correlates with IgM in serum but the presence of WNV IgA in CSF compared to serum is unknown. OBJECTIVES: Evaluate WNV IgA detection in CSF as a marker of WNV neuroinvasive infection, initially with samples pre-selected based on WNV IgG and IgM reactivity and subsequently with all available CSF samples submitted for WNV antibody testing over an entire WNV season. STUDY DESIGN: Selected CSF samples and CSF/serum pairs previously tested for WNV IgG and IgM were assayed for WNV IgA. Subsequently, all available CSF samples tested for WNV antibodies during the 2005 season were tested for WNV IgA, including those where paired sera were available and tested for IgA, IgG and IgM. RESULTS: For most samples, including paired CSF and serum, the IgA result qualitatively agreed with the IgM result, regardless of the IgG result. CONCLUSION: IgA detection is equivalent to IgM detection as a marker of WNV infection in CSF.
Descriptors: West Nile virus, detection, cerebrolspinal fluid, IgM, IgA, diagnostic criteria.

Ohajuruka, O.A., R.L. Berry, S. Grimes, and S. Farkas (2005). West Nile Virus detection in kidney, cloacal, and nasopharyngeal specimens. Emerging Infectious Diseases 11(9): 1437-1439. ISSN: 1080-6040 .
Abstract: We compared kidney tissue samples and cloacal and nasopharyngeal swab samples from field-collected dead crows and blue jays for West Nile virus surveillance. Compared to tissue samples, 35% more swab samples were false negative. Swab samples were usually positive only when the corresponding tissue sample was strongly positive.
Descriptors: cloaca, crow, kidney, nasopharynx, West Nile virus isolation and purification, false negative reactions, linear models, Ohio, population surveillance methods, reverse transcriptase polymerase chain reaction.

Ollis, G., L. Morin, and A. Visser (2005). Laboratory confirmed positive cases of equine West Nile virus in Alberta in 2003. Canadian Veterinary Journal 46(2): 131-133. ISSN: 0008-5286.
Descriptors: horse diseases, West Nile virus, disease incidence, geographical distribution, symptoms, horses, risk factors, disease surveillance, disease detection, diagnostic techniques, blood serum, immunoglobulin M, enzyme linked immunosorbent assay, disease diagnosis, Alberta.

Padgett, K.A., B. Cahoon Young, R. Carney, L. Woods, D. Read, S. Husted, and V. Kramer (2006). Field and laboratory evaluation of diagnostic assays for detecting West Nile virus in oropharyngeal swabs from California wild birds. Vector Borne and Zoonotic Diseases 6(2): 183-191. ISSN: 1530-3667.
Abstract: Three diagnostic assays for detecting West Nile virus (WNV) in avian oral swabs were evaluated in California in 2004 and 2005: two commercial antigen-capture assays, VecTest and Rapid Analyte Measurement Platform (RAMP), and reverse transcriptase-polymerase chain reaction (RT-PCR) of oral swabs in a specialized viral transport medium (VTM). Results from this study demonstrated that VTM was excellent for transportation and maintenance of WNV in avian oral swab samples and allowed for detection by RT-PCR and subsequent confirmation by virus isolation. Oral swabs and kidney tissue in VTM tested by RT-PCR were found to have similar accuracy in detecting WNV in corvids. The two antigen-capture assays, VecTest and RAMP, provided few false positives for corvids, with over 95% specificity. When performed by multiple local agencies throughout the state, VecTest and RAMP were similarly sensitive for oral swabs of American Crows (Corvus brachyrhynchos) (70% and 64%, respectively). Data from known WNV positive corvid oral swabs in VTM tested by antigen-capture assays at a diagnostic laboratory suggested that RAMP was more sensitive than VecTest. Due to high probability of false negatives, neither test is recommended for use on non-corvids. While WNV antigen-capture assays were effective screening tools for corvids, they were markedly less sensitive for Western Scrub Jays (Aphelocoma californica).
Descriptors: bird diseases, oropharynx, West Nile fever, West Nile virus, false negative reactions, false positive reactions, reproducibility of results, reverse transcriptase polymerase chain reaction methods, species specificity.

Panella, N.A., K.L. Burkhalter, S.A. Langevin, A.C. Brault, L.M. Schooley, B.J. Biggerstaff, R.S. Nasci, and N. Komar (2005). Rapid West Nile virus antigen detection. Emerging Infectious Diseases 11(10): 1633-1635. ISSN: 1080-6040.
Abstract: We compared the VecTest WNV antigen assay with standard methods of West Nile virus (WNV) detection in swabs from American Crows (Corvus brachyrhynchos) and House Sparrows (Passer domesticus). The VecTest detected WNV more frequently than the plaque assay and was comparable to a TaqMan reverse transcription-polymerase chain reaction.
Descriptors: viral analysis, bird diseases, diagnostic reagent kits, West Nile fever, West Nile virus isolation and purification, crows, plaque assay, reverse transcriptase polymerase chain reaction, sparrows, specimen handling methods, time factors.

Pierson, T.C., M.D. Sanchez, B.A. Puffer, A.A. Ahmed, B.J. Geiss, L.E. Valentine, L.A. Altamura, M.S. Diamond, and R.W. Doms (2006). A rapid and quantitative assay for measuring antibody-mediated neutralization of West Nile virus infection. Virology 346(1): 53-65. ISSN: 0042-6822.
Abstract: West Nile virus (WNV) is a neurotropic flavivirus within the Japanese encephalitis antigenic complex that is responsible for causing West Nile encephalitis in humans. The surface of WNV virions is covered by a highly ordered icosahedral array of envelope proteins that is responsible for mediating attachment and fusion with target cells. These envelope proteins are also primary targets for the generation of neutralizing antibodies in vivo. In this study, we describe a novel approach for measuring antibody-mediated neutralization of WNV infection using virus-like particles that measure infection as a function of reporter gene expression. These reporter virus particles (RVPs) are produced by complementation of a sub-genomic replicon with WNV structural proteins provided in trans using conventional DNA expression vectors. The precision and accuracy of this approach stem from an ability to measure the outcome of the interaction between antibody and viral antigens under conditions that satisfy the assumptions of the law of mass action as applied to virus neutralization. In addition to its quantitative strengths, this approach allows the production of WNV RVPs bearing the prM-E proteins of different WNV strains and mutants, offering considerable flexibility for the study of the humoral immune response to WNV in vitro. WNV RVPs are capable of only a single round of infection, can be used under BSL-2 conditions, and offer a rapid and quantitative approach for detecting virus entry and its inhibition by neutralizing antibody.
Descriptors: viral antibodies immunology, West Nile virus, cell line, Cercopithecus aethiops, cricetinae, reporter genes, neutralization tests, time factors, viral envelope proteins, West Nile fever immunology.

Prince, H.E. and M. Lape Nixon (2005). Evaluation of a West Nile virus immunoglobulin A capture enzyme-linked immunosorbent assay. Clinical and Diagnostic Laboratory Immunology 12(1): 231-233.
Abstract: An in-house-developed enzyme-linked immunosorbent assay detected West Nile virus (WNV) immunoglobulin A (IgA) in 65 of 68 sera from WNV-infected patients; 40 of 63 WNV IgM-positive, IgG-negative serum or plasma specimens; 65 of 67 WNV IgM-positive, IgG-positive specimens; 0 of 70 WNV IgM-negative, IgG-negative specimens; and 0 of 64 archived blood donation sera. WNV IgA is thus highly prevalent among WNV-infected patients and typically appears after WNV IgM but before WNV IgG.
Descriptors: enzyme-linked immunosorbent assay, immunoglobulin A immunology, West Nile fever, West Nile virus, immunoglobulin G, immunoglobulin M, reproducibility of results.

Prince, H.E., M. Lape Nixon, M.P. Busch, L.H. Tobler, G.A. Foster, and S.L. Stramer (2005). Utilization of follow-up specimens from viremic blood donors to assess the value of west nile virus immunoglobulin G avidity as an indicator of recent infection. Clinical and Diagnostic Laboratory Immunology 12(9): 1123-1126.
Abstract: The value of West Nile virus immunoglobulin G avidity for distinguishing recent from past infection was investigated using 348 follow-up specimens from 170 viremic blood donors. Low avidity accurately indicated infection within the previous 4 months. However, due to rapid avidity maturation in some individuals, high avidity did not accurately indicate past infection.
Descriptors: blood donors, West Nile fever, West Nile virus antibodies, antibody affinity, follow-up studies, blood immunoglobulin G.

Reds-Study-Grp (2005). Detection of West Nile virus RNA and antibody in frozen plasma components from a voluntary market withdrawal during the 2002 peak epidemic. Transfusion (Malden) 45(4): 480-486. ISSN: 0041-1132.
Descriptors: West Nile virus, frozen blood components, viremia, serologic markers, RNA, IgM, risk factors.

Reisen, W.K., S.S. Wheeler, S. Yamamoto, Y. Fang, and S. Garcia (2005). Nesting Ardeid colonies are not a focus of elevated West Nile virus activity in southern California. Vector Borne and Zoonotic Diseases 5(3): 258-266. ISSN: 1530-3667.
Abstract: A large nesting colony of Ardeid birds at the Finney-Ramer Wildlife Refuge in Imperial County, California, did not appear to be a focus of West Nile virus (WNV) amplification during the summer of 2004. Blood samples taken during June and July from 155 nestlings of four species of Ardeid birds (cattle egrets, black-crowned night herons, great egrets, and snowy egrets) and five nestling double-crested cormorants yielded a single WNV isolation from a 3-week-old cattle egret. Antibody was detected by enzyme immunoassay from 20 nestlings (13%), 14 (70%) of which were confirmed as positive by plaque reduction neutralization test (PRNT). However, titration end points against WNV and St. Louis encephalitis virus (SLEV) were similar precluding viral identification. The grouping of positives within few nests, highest PRNT titers in youngest birds (<1 weeks of age), the decline of titer with nestling age, and the lack of antibody specificity indicated that antibody may have been acquired maternally and did not represent new infections. Infection rates in Culex tarsalis mosquitoes collected near the Ardeid colony at Ramer Lake (3.1 per 1,000) were statistically similar to rates estimated at the nearby Wister Unit wetlands (5.3 per 1,000) that lacked an Ardeid nesting colony. Black-crowned night heron nestlings experimentally infected with the NY99 strain of WNV produced viremias >5 log10 plaque forming units (PFU)/mL and were considered moderately competent hosts, whereas cattle egret nestlings had viremias that remained <5 log10 PFU/mL and were incompetent hosts.
Descriptors: viral blood antibodies, bird diseases, culex mosquitoes, insect vectors, West Nile fever, West Nile virus, wild animals, birds, California, disease reservoirs, St. Louis encephalitis virus, neutralization tests, species specificity, zoonoses.

Reisen, W., S. Wheeler, S. Yamamoto, Y. Fang, and S. Garcia (2005). Nesting ardeid colonies are not a focus of elevated West Nile virus activity in southern California. Vector Borne and Zoonotic Diseases 5(3): 258-266. ISSN: 1530-3667.
Abstract: A large nesting colony of Ardeid birds at the Finney-Ramer Wildlife Refuge in Imperial County, California, did not appear to be a focus of West Nile virus (WNV) amplification during the summer of 2004. Blood samples taken during June and July from 155 nestlings of four species of Ardeid birds (cattle egrets, black-crowned night herons, great egrets, and snowy egrets) and five nestling double-crested cormorants yielded a single WNV isolation from a 3-week-old cattle egret. Antibody was detected by enzyme immunoassay from 20 nestlings (13%), 14 (70%) of which were confirmed as positive by plaque reduction neutralization test (PRNT). However, titration end points against WNV and St. Louis encephalitis virus (SLEV) were similar precluding viral identification. The grouping of positives within few nests, highest PRNT titers in youngest birds (<1 weeks of age), the decline of titer with nestling age, and the lack of antibody specificity indicated that antibody may have been acquired maternally and did not represent new infections. Infection rates in Culex tarsalis mosquitoes collected near the Ardeid colony at Ramer Lake (3.1 per 1,000) were statistically similar to rates estimated at the nearby Wister Unit wetlands (5.3 per 1,000) that lacked an Ardeid nesting colony. Black-crowned night heron nestlings experimentally infected with the NY99 strain of WNV produced viremias >5 log10 plaque forming units (PFU)/mL and were considered moderately competent hosts, whereas cattle egret nestlings had viremias that remained <5 log10 PFU/mL and were incompetent hosts.
Descriptors: Ardea alba, Bubulcus ibis, Egretta thula, Nycticorax nycticorax, Phalacrocorax auritus, viral diseases, West Nile virus, nestling infection rate and host competence survey, California, Imperial County, Finney Ramer Wildlife Refuge.

Saldanha, J., S. Shead, A. Heath, and M. Drebot (2005). Collaborative study to evaluate a working reagent for West Nile virus RNA detection by nucleic acid testing. Transfusion 45(1): 97-102. ISSN: 0041-1132.
Descriptors: West Nile virus, RNA detection, nucleic acid testing, assays.

Sanchez Guerrero, S.A., S. Romero Estrella, A. Rodriguez Ruiz, L. Infante Ramirez, A. Gomez, E. Villanueva Vidales, M. Garcia Torres, A.M. Dominguez, J.A. Vazquez, E.D. Calderon, L. Valiente Banuet, J.M. Linnen, A. Broulik, W. Harel, and R.A. Marin Y Lopez (2006). Detection of West Nile virus in the Mexican blood supply. Transfusion 46(1): 111-117.
Abstract: BACKGROUND: West Nile virus (WNV) is the etiologic agent of an emerging disease in the Western Hemisphere that can be transmitted to humans by blood transfusion. WNV first appeared in the United States in 1999, in Canada in 2001, and in Mexico in 2002. The aim of this nationwide study was to determine the prevalence of WNV in blood donors in Mexico as a first step in preventing its transfusion-associated transmission. STUDY DESIGN AND METHODS: In July and August 2004, a total of 3856 fresh plasma specimens collected from each state's center for blood transfusion in 29 of 31 Mexican states were screened with an investigational WNV assay (Procleix,(R) Gen-Probe Inc. and Chiron Corp.), a nucleic acid test based on transcription-mediated amplification (TMA). Reactive specimens were confirmed with a second TMA-based test, the alternative WNV assay (Gen-Probe), and with WNV capture enzyme-linked immunosorbent assays (ELISAs) for detection of immunoglobulin M (IgM) and IgG antibodies. In addition, 3714 frozen plasma samples collected in 2002 and 2003 were similarly tested. RESULTS: One of 3856 fresh samples from an asymptomatic donor from Chihuahua was reactive by both TMA-based tests and IgM ELISA, suggesting a recently acquired infection. The observed percentage of viremic donors blood donors was 0.03 percent. Results from frozen samples were not included in the prevalence calculation and none were TMA-reactive for WNV. CONCLUSIONS: WNV is present in the Mexican blood supply and measures should be taken to reduce the risk of transfusion transmission.
Descriptors: viral antibodies in blood, blood banks, blood donors, communicable diseases, West Nile fever, West Nile virus, blood transfusion, emerging diseases prevention and control, enzyme linked immunosorbent assay, Mexico, reverse transcriptase polymerase chain reaction.

Shaikh, N., H. Goldman, J. Ge, M. Zhang, B. Chen, J. Paice, P. Lam, and J. Keffer (2006). Efficacy of spectral's WNV IgM status test to rapidly detect the presence of WNV IgM antibodies in patients suspected of West Nile virus infection. Clinical Chemistry 52(6, Suppl. S): A48. ISSN: 0009-9147.
Descriptors: West Nile virus, IgM antibodies, serology, nervous system disease, ELISA, immunologic techniques.
Notes: Meeting Information: 58th Annual Meeting of the American Association of Clinical Chemistry, Chicago, Illinois, USA; July 23 -27, 2006.

Shirato, K., H. Miyoshi, H. Kariwa, and I. Takashima (2005). Detection of West Nile virus and Japanese encephalitis virus using real-time PCR with a probe common to both viruses. Journal of Virological Methods 126(1-2): 119-125.
Abstract: A diagnostic method to distinguish between West Nile virus (WNV) and Japanese encephalitis virus (JEV) based on fluorogenic real-time polymerase chain reaction (TaqMan) assays was developed. To detect WNV and JEV with a single probe, a probe was designed to correspond to sequences in the core protein region that are shared by both viruses. The specificity of this assay depended on the primer sets used, which were specific to the target virus sequences: the primer set for WNV could detect only WNV strains and the primer set for JEV could detect only JEV strains. The assays were tested by detection of viruses from experimentally infected animal tissues. The method described in this study will be useful for the simultaneous discrimination of WNV and JEV in areas where JEV is endemic, such as East Asia.
Descriptors: Japanese encephalitis virus (JEV), diagnosis, polymerase chain reaction methods, West Nile virus, DNA primers, specificity of assays, core protein regions.

Sirigireddy, K.R., G.A. Kennedy, A. Broce, L. Zurek, and R.R. Ganta (2006). High prevalence of west nile virus: a continuing risk in acquiring infection from a mosquito bite. Vector Borne and Zoonotic Diseases 6(4): 351-360. ISSN: 1530-3667.
Abstract: The prevalence of West Nile Virus (WNV) was evaluated by diplex real-time RT-PCR assay for the years 2001-2005 in Culex species of mosquitoes, several species of dead birds, and clinically suspected mammals collected in Kansas. The analysis was performed using a TaqMan-based diplex real-time RT-PCR assay targeted against two regions of the WNV genome, envelope glycoprotein gene and 3' untranslated region. The assay aided in the accurate detection of WNV in mosquitoes at high prevalence for the years 2002-2005. Similarly, high incidence of birds that tested positive for WNV was detected in 2002-2004. WNV positives in mammals by the diplex real rime RT-PCR assay included horses, squirrels, mules, sheep and a mountain goat. Majority of the equine WNV positives were detected only in the year 2002. Sequence analysis of a segment of the envelope glycoprotein gene from 31 randomly selected WNV positive samples revealed variations in six samples at one or two nucleotide positions. The identity of high levels of WNV positives in Kansas parallels the recent reports on the widespread distribution of the virus in the United States. The continued detection of WNV in the mosquitoes is of significant public health concern and calls for continued surveillance and public health activities.
Descriptors: West Nile virus, prevalnce, risk, evaluated, dead birds, mosquitoes, surveillance, public health, distribution.

Stone, W.B., J.E. Therrien, R. Benson, L. Kramer, E.B. Kauffman, M. Eidson, and S. Campbell (2005). Assays to detect west Nile virus in dead birds. Emerging Infectious Diseases 11(11): 1770-1773. ISSN: 1080-6040.
Abstract: Using oral swab samples to detect West Nile virus in dead birds, we compared the Rapid Analyte Measurement Platform (RAMP) assay with VecTest and real-time reverse-transcriptase-polymerase chain reaction. The sensitivities of RAMP and VecTest for testing corvid species were 91.0% and 82.1%, respectively.
Descriptors: aves, diagnostic techniques, oral swab sampling and molecular assays to detect viral pathogen in dead specimens, comparative study, viral diseases, West Nile virus, comparative evaluation.

Stramer, S.L., B. Custer, M.P. Busch, and R.Y. Dodd (2006). Strategies for testing blood donors for West Nile virus. Transfusion 46(12): 2036-2037.
Descriptors: blood donors, West Nile virus, surveillance, strategies, detection, testing.

Tang, Y., C. Anne Hapip, B. Liu, and C.T. Fang (2006). Highly sensitive TaqMan RT-PCR assay for detection and quantification of both lineages of West Nile virus RNA. Journal of Clinical Virology 36(3): 177-182.
Abstract: BACKGROUND: Starting in 1999, the West Nile virus (WNV) epidemic represents the largest outbreak of arboviral encephalitis ever recorded in the U.S. The effective means to determine an infection are detection of viral nucleic acid and/or viral specific immunoglobulin, IgM and/or IgG. OBJECTIVE: To develop a highly sensitive and specific TaqMan RT-PCR assay for the detection and quantification of WNV RNA of lineage 1 and lineage 2. STUDY DESIGN: A TaqMan RT-PCR primer-probe was designed to perfectly match target sequences of all sequenced WNV strains and isolates, which added a layer of protection against false-negative results due to strain variability. In addition, the inclusion of a low level RNA internal control (IC) in the assay increased the precision and accuracy of the assay. RESULTS: By optimizing the RNA preparation procedure for increased WNV RNA recovery, together with optimizing the primer-probe and TaqMan conditions for improved amplification efficiency, we developed a highly sensitive assay with the detection limit of 10 copies/mL. To evaluate the assay, we tested plasma samples from 12 transfusion-transmitted implicated cases in 2002 and from 68 positive blood donors in 2003. All tested specimens were WNV positive. The viral load of 68 positive blood donor samples collected in 2003 ranged from 10 copies/mL to 67,000 copies/mL with a mean of 8100 copies/mL. Furthermore, high sensitivity of the assay was achieved without compromising specificity. All 100 routine donor samples tested negative. CONCLUSIONS: The assay results demonstrate that our in-house TaqMan RT-PCR procedure can detect and quantify WNV RNA of lineage1 and lineage 2 in human plasma with high sensitivity and specificity.
Descriptors: viral blood RNA, reverse transcriptase polymerase chain reaction, West Nile fever, West Nile virus isolation and purification, blood donors, blood transfusion, DNA primers.

Tanner, J., J. Traub Dargatz, A. Hill, H. Van Campen, A. Knight, W. Cunningham, and M. Salman (2006). Evaluation of factors associated with positive IgM capture ELISA results in equids with clinical signs compatible with West Nile virus infection: 1,017 cases (2003). Journal of the American Veterinary Medical Association. 228(3): 414-421. ISSN: 0003-1488.
Descriptors: horses, horse diseases, West Nile virus, viral diseases of animals and humans, immunoglobulin M, enzyme linked immunosorbent assay, disease diagnosis, disease prevalence, vaccination, symptoms, gender differences, disease severity, risk factors, Colorado.

Tilley, P.A., J.D. Fox, G.C. Jayaraman, and J.K. Preiksaitis (2006). Nucleic acid testing for west nile virus RNA in plasma enhances rapid diagnosis of acute infection in symptomatic patients. Journal of Infectious Diseases 193(10): 1361-1364.
Abstract: Although nucleic acid amplification testing (NAAT) for West Nile virus (WNV) is useful in screening blood donors, such methods have not been studied in symptomatic patients. For diagnosis of WNV infection, 1.0 mL of plasma was tested by NAAT, and WNV-specific immunoglobulin M was assayed. Of 276 WNV cases, 191 were tested by both serology and NAAT. Of these, 86 (45.0%), 111 (58.1%), and 180 (94.2%) were detected by NAAT, serology, and combined NAAT and serology, respectively. NAAT-based screening was most useful within 8 days of the onset of symptoms. Viremia is common in early symptomatic WNV infection, and NAAT enhances diagnostic yield.
Descriptors: nucleic acid amplification techniques, viral RNA analysis, West Nile fever, West Nile virus isolation and purification, Alberta, routine diagnostic tests, immunoglobulin M, predictive value of tests, viral blood RNA, reverse transcriptase polymerase chain reaction, specimen handling, viremia diagnosis.

Tilley, P.A., G.A. Zachary, R. Walle, and P.F. Schnee (2005). West Nile virus detection and commercial assays. Emerging Infectious Diseases 11(7): 1154-1155. ISSN: 1080-6040.
Descriptors: viral blood antibodies, blood immunoglobulin M, diagnostic reagent kits, West Nile fever diagnosis, West Nile virus isolation and purification, blood immunoglobulin G, time factors.

Tilley, P.A.G., R. Walle, A. Chow, G.C. Jayaraman, K. Fonseca, M.A. Drebot, J. Preiksaitis, and J. Fox (2005). Clinical Utility of Commercial Enzyme Immunoassays during the Inaugural Season of West Nile Virus Activity, Alberta, Canada. Journal of Clinical Microbiology. 43(9): 4691-4695. ISSN: 0095-1137.
Abstract: West Nile virus (WNV) has spread rapidly across North America, creating a need for rapid and accurate laboratory diagnosis on a large scale. Immunoglobulin M (IgM) capture enzyme immunoassays (EIA) became commercially available in the summer of 2003, but limited data are available on their clinical performance. Consolidated human WNV diagnostic testing for the province of Alberta, Canada, at the public health laboratory permitted a large-scale evaluation of the assays, covering a wide clinical spectrum. Two thousand nine hundred sixty-nine sera were tested, from 2,553 Alberta residents, and 266 cases were identified. Sensitivities of the Focus assay and first-generation Panbio IgM capture EIA were 79 and 80%, respectively. During the first week of illness only 53 to 58% of cases were positive, but sensitivity was 96 to 97% after day 8. Sensitivity for neurological cases was 92% overall. Specificity was high for the Focus kit at 98.9%, but only 82.9% for the first Panbio kit. A positive Focus WNV IgG result with a twofold rise in IgG index was a reliable indicator of acute flavivirus infection (67/67 WNV). Agreement between the IgG test and hemagglutinin inhibition titers in paired sera was at least 82%. Commercial IgM and IgG EIA proved useful for WNV diagnosis, provided follow-up sera were collected after 8 days of illness.
Descriptors: West Nile virus, detection, surveillance, diagnosis, immunoglobulin M, enzyme assays, EIA, Canada.

Tobler, L.H., C. Bianco, S.A. Glynn, G.B. Schreiber, B.J. Dille, H.E. Prince, R.S. Lanciotti, J.M. Linnen, J. Gallarda, V. Shyamala, D. Smith, S.H. Kleinman, and M.P. Busch (2005). Detection of West Nile virus RNA and antibody in frozen plasma components from a voluntary market withdrawal during the 2002 peak epidemic. Transfusion 45(4): 480-486.
Abstract: BACKGROUND: The US West Nile virus (WNV) epidemic in the summer and fall of 2002 included the first documented cases of transfusion-transmitted WNV infection. In December 2002, the FDA supported a voluntary market withdrawal by the blood banking community of frozen blood components collected in WNV high-activity areas. At the time, the prevalence of viremia and serologic markers for WNV in the blood supply was undefined. STUDY DESIGN AND METHODS: In collaboration with America's Blood Centers, 1468 frozen plasma components (of approx. 60,000 frozen units voluntarily withdrawn from the market) were selectively retrieved from the peak epidemic regions and season (June 23, 2002-September 28, 2002). These units were unlinked, subaliquoted, and tested by WNV enzyme immunoassays (EIAs; Focus Technologies and Abbott Laboratories) and nucleic acid amplification tests (NATs; Gen-Probe Inc. and Roche Molecular Systems). RESULTS: Of the 1468 EIA results from Abbott and Focus, 7 were anti-immunoglobulin M (IgM)- and anti-immunoglobulin G (IgG)-reactive by both assays, 8 and 1 were IgM-only-reactive, and 8 and 23 were IgG-only-reactive, respectively. NAT by Gen-Probe and Roche Molecular Systems yielded one RNA-positive, antibody-negative unit containing approximately 440 RNA copies per mL. An additional 10-fold replicate NAT testing by Gen-Probe on 14 of 15 IgM-reactive specimens yielded 2 additional IgM- and IgG-reactive units with low-level viremia (i.e., 7/10 and 2/10 replicates tested reactive). CONCLUSION: The prevalence of acute (RNA-positive) and recent (IgM-seroreactive) WNV infections indicates that transfusion risk in high-risk areas could have been considerable and that voluntary market withdrawal of frozen components likely averted some WNV transfusion transmissions. The existence of very-low-level viremic units raises concerns, because WNV minipool NAT screening will miss such units and individual NAT may not completely correct this situation.
Descriptors: blood banks, plasma virology, West Nile fever epidemiology, West Nile virus isolation and purification, viral blood antibodies, consumer product safety, disease outbreaks, viral analysis, risk factors, seroepidemiologic studies.
Notes: Comment In: Transfusion. 2005 Apr;45(4):460-2.

Tong, Y., X.p. Zeng, T. Liu, X. Xiao, J.w. Zhu, and B. Tucker (2006). Studies on West Nile virus detection using two rapid methods. Zhongguo Meijieshengwuxue Ji Kongzhi Zazhi 17(4): 307-310. ISSN: 1003-8280.
Descriptors: mosquitoes, diagnostic techniques, quick detection methods, evaluation for viral disease, viral diseases, West Nile virus(WNV), Ramp system, VecTest, China.
Language of Text: Chinese; Summary in Chinese, English.

Tonry, J.H., C.B. Brown, C.B. Cropp, J.K. Co, S.N. Bennett, V.R. Nerurkar, T. Kuberski, and D.J. Gubler (2005). West Nile virus detection in urine. Emerging Infectious Diseases 11(8): 1294-1296. ISSN: 1080-6040.
Abstract: We report West Nile virus (WNV) RNA in urine collected from a patient with encephalitis 8 days after symptom onset. Viral RNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). Sequence and phylogenetic analysis confirmed the PCR product to have > or = 99% similarity to the WNV strain NY 2000-crow3356.
Descriptors: West Nile fever, West Nile virus isolation and purification, viral blood antibodies, viral genetics, reverse transcriptase polymerase chain reaction, sequence alignment, DNA sequence analysis.

Tyler, K.L., J. Pape, R.J. Goody, M. Corkill, and B.K. Kleinschmidt DeMasters (2006). CSF findings in 250 patients with serologically confirmed West Nile virus meningitis and encephalitis. Neurology 66(3): 361-365.
Abstract: OBJECTIVE: To provide a large, comprehensive evaluation of the CSF findings in patients with serologically confirmed West Nile virus (WNV), CNS disease, and their correlation with outcome. METHODS: CSF samples from 334 WNV-infected hospitalized patients were analyzed. Information was available and extracted from the medical records of 250 of these patients, and CSF parameters correlated with clinical and epidemiologic features of disease (e.g., patient age, sex, outcome). RESULTS: Patients with meningitis had a mean of 226 cells/mm3, and those with encephalitis had a mean of 227 cells/mm3. Three percent of meningitis patients and 5% of encephalitis patients had fewer than 5 cells/mm3, and approximately 8% of both groups had more than 500 cells/mm3. Patients with meningitis had a mean of 41% neutrophils, and those with encephalitis had 45%. Forty-five percent of meningitis patients and 37% of encephalitis patients had at least 50% neutrophils in their initial CSF specimen. Neither the mean percent neutrophils nor their distribution differed significantly between groups. Forty-seven percent of encephalitis patients and 16% of meningitis patients had CSF protein of 100 mg/dL or greater (p < 0.01). Although specific CSF parameters, including nucleated cell count and protein concentration, correlated significantly with outcome, multivariate analysis suggested that their total predictive value was modest. Age was an additional predictor of outcome independent of CSF variables in all patients. CONCLUSIONS: Serologically confirmed West Nile virus meningitis and encephalitis produce similar degrees of CSF pleocytosis and are frequently associated with substantial CSF neutrophilia. Patients with encephalitis have higher CSF protein concentrations and are more likely to have adverse outcomes, including admission to long-term care facilities or even death after their acute illness. CSF findings were only a modest predictor of disease outcome, with patient age adding important independent prognostic information.
Descriptors: encephalitis, cerebrospinal fluid, viral meningitis, West Nile fever, age factors, cell count, leukocytosis, multivariate analysis, osmolar concentration, predictive value of tests, serologic tests, treatment outcome.

Vinayagamoorthy, T., K. Mulatz, M. Drebot, and R. Hodkinson (2005). Molecular typing of West Nile Virus, Dengue, and St. Louis encephalitis using multiplex sequencing. Journal of Molecular Diagnostics 7(2): 152-159.
Abstract: We report the development of an assay to simultaneously identify three of the clinically important flaviviruses (West Nile Virus, Dengue, and St. Louis encephalitis). This assay is based on the nucleotide sequence variations within a 266-bp region of the non-structural protein 5. Further, based on the nucleotide variations in the same region of the non-structural protein 5, four of the present Dengue serotypes were identified. To identify some of the subtypes of WNV we have developed a second assay using multiplex sequencing technology. The format of the result of this assay is an electropherogram of two genomic segments of the WNV genome: a 48-nucleotide sequence from the anchored core protein C and a 45-nucleotide sequence coding for the non-structural proteins (proteinase and putative helicase genes).
Descriptors: dengue virus, St. Louis encephalitis virus, viral genome, DNA sequence analysis, West Nile virus, DNA base sequence, viral genetics, molecular sequence data, variation genetics, West Nile virus classification.

Wunschmann, A., J. Shivers, J. Bender, L. Carroll, S. Fuller, M. Saggese, A. Van Wettere, and P. Redig (2005). Pathologic and immunohistochemical findings in goshawks (Accipiter gentilis) and great horned owls (Bubo virginianus) naturally infected with West Nile virus. Avian Diseases. 49(2): 252-259. ISSN: 0005-2086.
Abstract: The carcasses of 25 great horned owls and 12 goshawks were investigated for West Nile virus (WNV) infection by immunohistochemistry (IHC) performed on various organs, including brain, spinal cord, heart, kidney, eye, bone marrow, spleen, liver, lungs, pancreas, intestine, and proventriculus, using a WNV-antigen-specific monoclonal antibody and by WNV-specific reverse transcriptase-polymerase chain reaction (RT-PCR), performed on fresh brain tissue only. WNV infection was diagnosed by IHC in all owls and all goshawks. WNV-specific RT-PCR amplified WNV-RNA in the brain of all goshawks but only 12 owls (48%). Cachexia was a common macroscopic finding associated with WNV infection in owls (76%). Myocarditis was occasionally macroscopically evident in goshawks (33%). Microscopically, inflammatory lesions, including lymphoplasmacytic and histiocytic encephalitis, myocarditis, endophthalmitis, and pancreatitis were present in both species but were more common and more severe in goshawks than in owls. The most characteristic brain lesion in owls was the formation of glial nodules, in particular in the molecular layer of the cerebellum, while encephalitis affecting the periventricular parenchyma of the cerebral cortex was common in the goshawks. In owls, WNV-antigen-positive cells were present usually only in very small numbers per organ. Kidney (80%), heart (39%), and cerebellum (37%) were the organs that most commonly contained WNV antigen in owls. WNV antigen was frequently widely distributed in the organs of infected goshawks, with increased amounts of WNV antigen in the heart and the cerebrum. Spleen (75%), cerebellum (66%), heart (58%), cerebrum (58%), and eye (50%) were often WNV-antigen positive in goshawks. In contrast with the goshawks, WNV antigen was not present in cerebral and retinal neurons of owls. WNV infection appears to be capable of causing fatal disease in great horned owls and goshawks. However, the distribution and severity of histologic lesions, the antigen distribution in the various organs, and the amount of antigen varied among both species. Therefore, the diagnostician may choose organs for histology and immunohistochemistry as well as RT-PCR depending on the investigated species in order to avoid false-negative results.
Descriptors: Accipiter gentilis, Bubo virginianus, wild birds, birds of prey, West Nile virus, bird diseases, pathogenesis, immunohistochemistry, immunopathology, disease incidence, animal organs, monoclonal antibodies, antigens, reverse transcriptase polymerase chain reaction, cachexia, viral diseases of animals and humans.
Language of Text: Summary in Spanish.

Zhang, J.S., P.H. Zhang, B.Y. Si, H. Yang, and W.C. Cao (2005). [Comparison and discrimination of the biological characteristics between West Nile virus and Japanese encephalitis virus]. Chinese Journal of Experimental and Clinical Virology 19(4): 340-343.
Abstract: BACKGROUND: To compare the biological characteristics of West Nile virus (WNV) and Japanese encephalitis virus (JEV), including cells sensitivity, pathogenicity, viral morphology, as well as the results of immunological and molecular biological detection. METHODS: Cytopathic effect (CPE) and pathogenicity were observed in C6/36 cells and in suckling mice inoculated intracerebrally with the WNV or JEV, respectively. The sliced tissue samples for electron microscopic examination were prepared for the morphologic observation of the viruses. Serum antibody to WNV or JEV was detected using indirect immunofluorescence assay (IFA), and the viral RNA was analyzed by RT-PCR method. RESULTS: WNV or JEV-caused CPE was characterized by cell fusion and cell shedding, respectively. There was no significant difference in the pathogenicity to suckling mice between WNV and JEV. The morphologic observation showed that the shape and size of the two virions were similar. WNV and JEV were found to have antigenic cross-reactivity. The viral RNA could be detected from both WNV and JEV samples with universal primer set, but only nucleoside fragments of corresponding virus could be amplified when specific primers were used. CONCLUSION: CPE in C6/36 cell and detection of the viral RNA should be useful in discrimination of WNV and JEV, and simultaneously examining the titers of serum antibodies against WNV and JEV may be helpful to diagnosis of infection with these agents.
Descriptors: West Nile virus, Japanese encephalitis virus, biological characteristics, pathogenicity, morphology, viral RNA, diagnosis.
Language of Text: Chinese.

Zhang, Z., F. Wilson, R. Read, L. Pace, and S. Zhang (2006). Detection and characterization of naturally acquired West Nile virus infection in a female wild turkey. Journal of Veterinary Diagnostic Investigation 18(2): 204-208.
Abstract: An adult female wild turkey exhibiting disorientation and failure to flee when approached was submitted to the Mississippi Veterinary Research and Diagnostic Laboratory. Gross pathologic examination revealed evidence of dehydration and the presence of modest numbers of adult nematodes in the small intestine. Histologic examination revealed extensive multifocal perivascular lymphocytic infiltration in brain, marked heterophilic hyperplasia in bone marrow, and multifocal interstitial lymphocytic infiltration in heart, pancreas, ventriculus, and skeletal muscles. West Nile virus (WNV) was isolated from the brain, lung, and kidney tissues using cultured Vero cells. Higher copies of viral RNA were detected from brain, lung, and kidney than from heart, liver, or spleen by quantitative real-time reverse transcription-polymerase chain reaction (RRT-PCR) analysis. Immunohistochemical (IHC) analysis detected WNV antigen in various tissues including neurons, kidney, respiratory tract epithelium, heart, and bone marrow. On the basis of the data from this investigation, it is concluded that WNV caused encephalitis along with many other pathologic changes in the affected wild turkey.
Descriptors: poultry diseases, turkeys, West Nile fever, West Nile virus isolation and purification, wild animals, Cercopithecus aethiops, histocytochemistry, kidney, lung pathology, pathology of adult female wild turkey.

 

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