Evaluate H5N1 highly pathogenic avian influenza viruses from Vietnam and other Southeast Asia countries for antigenic diversity with the purpose of selecting representative challenge strains for vaccine efficacy studies. The objective is to determine if current vaccination strategies in Vietnam are effective against currently circulating strains of virus.
APPROACH: The viruses will have all eight gene segments sequenced, and will be inoculated into birds to evaluate differences in clinical disease. Select viruses will be cloned for antibody production using a DNA vaccine approach and antigenic analysis using HI cross neutralization will be performed. Based on the sequencing, animal inoculations, and antigenic analysis, two viruses that are representative of the viruses received will be used for vaccine challenge studies. Birds will be vaccinated with different vaccines, preferably those that are present in Vietnam, and after vaccination the birds will be challenged and evaluated for clinical protection and virus shedding. Recommendations on vaccine effectiveness will then be provided to the FAS and the Vietnamese government.
PROGRESS: 2005/10 TO 2006/09
Progress Report 4d Progress report. This report serves to document research conducted with an agreement between ARS and the USDA Foreign Agricultural Service (FAS). Additional details of research can be found in the report for the parent project #6612-32000-039-00D, Application of molecular biological techniques to the diagnosis & control of avian influenza. One of the key objective in the parent CRIS is to evaluate vaccine efficacy for the control of avian influenza. In several countries, including Vietnam, vaccination is being used as a control tool for avian influenza. This project is designed to evaluate the viruses found in Vietnam and determine if current vaccines are still protective. Analysis of 20 viruses has shown that two different lineages of virus are circulating in Vietnam at the time of sampling. These H5N1 viruses are pathogenic for both chickens and ducks. Future studies include plans for vaccination studies to evaluate how well currently used vaccines protect against both circulating strains of avian influenza.