The Ecology of West Nile Virus in Atlanta, Georgia

Abstract

West Nile virus (WNV) is a vector-borne virus that has caused hundreds of human deaths and has cost the United States millions of dollars each year since its first emergence in 1999. To understand the ecology of West Nile virus prevalence and the influence of the dilution effect, I will build on preliminary results to test several hypotheses related to the population and habitat of mosquito and birds in Atlanta, Georgia. The dilution effect, which states that disease prevalence can be reduced by biodiversity, has yet to be tested in the southeast United States in relation to both tree and avian diversity. To address these questions, I established a series of sites in Atlanta that span from different forest patch sizes, pine and hardwood composition, and socio economic scenarios. The data indicate that the number of adult and gravid mosquitoes are positively related to older homes, surrounded by primarily hardwood trees. The vector index (VI) was also positively related to older homes and hardwood habitat. However, the VI was not correlated to either avian or tree diversity. This study demonstrated that avian diversity and evenness were associated with smaller trees with less species diversity. Additionally, avian species diversity was higher in newer neighborhoods that were built after the 1960s. Avian diversity was also highly correlated to the number of corvids, which rejected the hypothesis that predicted corvids having a negative impact on avian diversity indices. Sites with a large number of avian individuals were associated with higher amounts of both blue jays and American robins. Corvids were not abundant in sites that were more urban and consisted mostly of pine trees. Finally, this study detected no correlation between the vector for WNV and any of the parameters involving avian diversity or specific species abundance.