Deegan, C.S., J.E. Burns, M. Huguenin, E.Y. Steinhaus, N.A. Panella, S. Beckett, and N. Komar (2005). Sentinel pigeon surveillance for West Nile virus by using lard-can traps at differing elevations and canopy cover classes. Journal of Medical Entomology 42(6): 1039-1044.
Abstract: Sentinel pigeons, Columba livia, were installed in lard-can traps at heights of 1.5 m and 7.6-9.1 m within differing canopy cover classes in New York City. Adult mosquitoes were collected weekly from July to October 2002, as were serum samples from each pigeon. Culex pipiens L. and Culex restuans Theobald comprised 97% of mosquitoes collected and were most numerous in canopy-level, forested traps. The West Nile virus (family Flaviviridae, genus Flavivirus, WNV) seroconversion rate was significantly greater for pigeons in canopy-level traps, although seroconversions occurred concurrently with human cases in the city and were of little prognostic value to public health agencies. Our results indicate that sentinel pigeons were most effective for monitoring enzootic transmission of WNV when placed in single-sentinel caging 7.6-9.1 m above ground level.
Descriptors: bird diseases, insect vectors, sentinel surveillance, West Nile fever, New York City, polymerase chain reaction methods, species specificity, trees.
Gibbs, S.E., N.L. Marlenee, J. Romines, D. Kavanaugh, J.L. Corn, and D.E. Stallknecht (2006). Antibodies to West Nile virus in feral swine from Florida, Georgia, and Texas, USA. Vector Borne and Zoonotic Diseases 6(3): 261-265. ISSN: 1530-3667.
Abstract: West Nile virus (WNV) exposure has not yet been reported in feral swine (Sus scrofa) despite the broad geographic range and population density of this species. The objectives of this study were to determine the prevalence of antibodies to WNV in feral pigs, and to evaluate serologic diagnostics as applied to this species. Feral pig serum from three states was evaluated for antibodies to WNV. The overall WNV seroprevalence rate for 222 samples collected in 2001-2004 was 22.5%. Seroprevalence rates in Florida, Georgia, and Texas were 17.2%, 26.3%, and 20.5%, respectively. The results of this study demonstrate that feral pigs could represent useful mammalian sentinels of WNV.
Descriptors: West Nile virus, animal sentinals, feral swine, pig serum antibodies, seroprevalence rate, serologic diagnostics.
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.
Godsey, M.J., M. Blackmore, N. Panella, K. Burkhalter, K. Gottfried, L. Halsey, R. Rutledge, S. Langevin, R. Gates, and K. Lamonte (2005). West Nile virus epizootiology in the southeastern United States, 2001. Vector Borne and Zoonotic Diseases. 5(1): 82-89. ISSN: 1530-3667.
Descriptors: West Nile virus, virus transmission, insect vectors, Culex, Culiseta melanura, mosquitoes, disease reservoirs, birds, disease detection, antibody detection, seroprevalence, chickens, sentinel animals, Southeastern United States, Florida, Georgia.
Lefrancois, T., B.J. Blitvich, J. Pradel, S. Molia, N. Vachiery, and D. Martinez (2006). West nile virus in guadeloupe: introduction, spread, and decrease in circulation level: 2002-2005. Annals of the New York Academy of Sciences 1081: 206-215. ISSN: 0077-8923.
Abstract: In July 2002, a surveillance system was implemented on Guadeloupe to detect for the potential introduction and monitor the spread of West Nile virus (WNV). From 2002 to 2004, equines and chickens were serologically assayed for antibodies to WNV by IgG and IgM enzyme-linked immunosorbent assay (ELISA), epitope-blocking ELISA, and plaque reduction neutralization tests. After introduction, probably through migratory birds at the end of 2001, many seroconversions occurred between July and October 2002 resulting in a high seroprevalence (19.3%) in equines in 2003. WNV circulation levels decreased dramatically in 2003 and 2004 as assessed by the absence of seroconversion in equine and the very low prevalence in chickens. This decrease coincided with a 7-month drought that presumably caused a decrease in vector populations. In 2005, a sentinel survey was implemented in equines and chickens placed in areas at high risk and the very low rate of seroconversion (1 equine out of 106, no chicken) demonstrated that WNV circulation is now occurring at a very low level.
Descriptors: West Nile virus, equines, chickens, antibodies, serological assay, ELISA, birds, vector populations.
Shaman, J., J. Day, and M. Stieglitz (2005). Drought-induced amplification and epidemic transmission of West Nile virus in southern Florida. Journal of Medical Entomology. 42(2): 134-141. ISSN: 0022-2585.
Abstract: We show that the spatial-temporal variability of human West Nile (WN) cases and the transmission of West Nile virus (WNV) to sentinel chickens are associated with the spatial-temporal variability of drought and wetting in southern Florida. Land surface wetness conditions at 52 sites in 31 counties in southern Florida for 2001-2003 were simulated and compared with the occurrence of human WN cases and the transmission of WNV to sentinel chickens within these counties. Both WNV transmission to sentinel chickens and the occurrence of human WN cases were associated with drought 2-6 mo prior and land surface wetting 0.5-1.5 mo prior. These dynamics are similar to the amplification and transmission patterns found in southern Florida for the closely related St. Louis encephalitis virus. Drought brings avian hosts and vector mosquitoes into close contact and facilitates the epizootic cycling and amplification of the arboviruses within these populations. Southern Florida has not recorded a severe, widespread drought since the introduction of WNV into the state in 2001. Our results indicate that widespread drought in the spring followed by wetting during summer greatly increase the probability of a WNV epidemic in southern Florida.
Descriptors: West Nile virus, virus transmission, drought, disease outbreaks, sentinel animals, chickens, humans, spatial variation, temporal variation, insect vectors, Culex nigripalpus, Culicidae, simulation models, Florida, virus-amplification, land-surface-wetting, hydrology-models.