Role of Wild Birds in the Spread and Maintenance of Zoonotic Pathogens

Wild birds are implicated in the spread and maintenance of pathogens that pose significant health risks to wild and domestic animals, as well as humans. These pathogens include, but are not limited to, West Nile virus, avian influenza, eastern equine encephalitis, and the bacteria causing Lyme disease (Borrelia spp.). The objectives of the research program for the next five years are as follows: <OL> <LI> Evaluate the potential role of migrating waterfowl and shorebirds in the dispersal of highly pathogenic and low pathogenic avian influenza. We propose to examine the migratory behavior and correlates of migratory performance (e.g., timing of molt, fat deposition, foraging behavior) of several species of migratory birds from two avian orders, Charadriiformes (shorebirds, gulls, terns) and Anseriformes (ducks, swans, geese), when infected with avian influenza, both low pathogenic (LPAI) and HPAI strains. The work will be conducted both with captive birds infected with LPAI or HPAI and free-living birds infected with LPAI on two different continents, North America and Asia (specifically, Mongolia). The data collected on migratory behavior of infected birds will be incorporated into spatially-explicit individual-based models with different sub-models (demographic, infection, movement) that will be capable of predicting the temporal and spatial spread of AIV by migrating birds. <LI> Evaluate physiological condition (stress, reproductive hormones, energetic stores) and how it impacts a bird's reservoir competency, susceptibility to infection, and reactivation of latent infections. Specifically, we will evaluate how fluctuations in the nutritional condition of migratory waterfowl influence a bird's ability to serve as a reservoir of low pathogenic avian influenza. In another study, we will determine whether the innate immune response (acute phase response) is important in protecting a wild bird, in this case the Northern Cardinal, during a viral infection. In addition, determine whether physiological stress depresses an organism's immune response to a virus, such as West Nile virus. <LI> Determine the prevalence of disease in double-crested cormorant colonies in the Great Lake region. Describe the daily movements of adult cormorants as it relates to spread of disease. We will evaluate the potential role of cormorants in the Great Lakes in regional spread of disease by conducting surveillance on their previous exposure to or current infection status of three pathogens, avian influenza, avian cholera, and Newcastle disease. These pathogens pose a potential risk to the poultry industry. <LI> Evaluate species differences in resistance and tolerance for a variety of zoonotic pathogens, including, West Nile virus and Borrelia spp. The relative importance of different species in the enzootic transmission cycle is not currently known for many pathogens. The long term objective of the proposed research is to determine why some species of birds are more likely to support infectious agents (i.e., are more competent) than others.