Research at the University of Georgia, published in the November 2006 issue of Emerging Infectious Diseases (Vol. 12, No. 11), has identified two North American wild bird species that are susceptible to infection from two highly pathogenic avian influenza (HPAI) virus strains, reports the Wildlife Management Institute.

Laughing gulls and five duck species were inoculated with two different strains of HPAI H5N1 virus. The species were selected to represent a diversity of habitats and behaviors of "critical" North American waterfowl, including traditional avian influenza virus (AIV) reservoir species, such as the mallard. Only laughing gulls and wood ducks contracted the highly pathogenic strains. After inoculation, both exhibited illness before death.

Following the outbreaks and subsequent spread of HPAI H5N1 in wild avian birds in Europe and Africa in 2005, however, migratory birds have been under scrutiny as possible vectors for distribution of HPAI viruses. (Natural occurrences of low pathogenic avian influenza [LPAI] are common in native waterfowl populations and often have little to no noticeable effect on infected individuals.) Prior to the University of Georgia study, the susceptibility of North American waterfowl to HPAI viruses was unknown.

Although the most recent AIV sampling protocols in the United States were established in March 2006, with finalization of a National Strategic Plan for detection, the current surveillance system is rigorous enough to detect HPAI viruses potentially present in wild bird communities as well as those that may arrive in the future, according to Dr. Thomas DeLiberto, National Wildlife Disease Coordinator for the U.S. Department of Agriculture's Animal and Plant Health Inspection Service. "The Georgia study," commented Dr. DeLiberto, "provided very valuable information and really reinforces that the surveillance methods we have in place are robust and effective in detecting avian influenza viruses."

Since this past March, avian influenza surveillance has expanded to encompass all four of the major flyways in the United States. The primary goal of the plan, coordinated by the U.S. Department of Agriculture and the Interior, is to collect 75,000-100,000 wild bird samples and 50,000 environmental samples nationwide this year. Samples are taken from birds found dead, captured live birds and wild bird habitat.

To learn more about avian influenza news and research, visit http://www.usda.gov/birdflu or http://www.doi.gov/issues/avianflu.html. To examine the research report in Emerging Infectious Diseases, go to http://www.cdc.gov/ncidod/EID/vol12no11/06-0652.htm.