This research will investigate the ecology of human granulocytic anaplasmosis (HGA), an emerging disease on three continents and examine the effects of species diversity on disease transmission. HGA is caused by a rickettsial bacterium, Anaplasma phagocytophilum, that is transmitted from host to host through the bite of an infected ixodid tick. The research will include a characterization of reservoir competence of wildlife hosts and determine whether host reservoir competence is a function of coinfection with the bacterium that causes Lyme disease. The researchers will build and test models to predict how risk of human exposure to HGA will vary with changes in the diversity and species composition of host communities. They also will experimentally evaluate specific mechanisms underlying effects of variable diversity on risk by manipulating key hosts in natural communities. Finally, they will educate local health-care providers about this emerging disease and expand the HGA surveillance capabilities of the local (Dutchess County, NY) health department. The enhanced surveillance data will be used to test for spatial correlations between ecological risk and human incidence. The project will train more than 40 undergraduates and provide for them an opportunity to conduct independent research. Understanding disease transmission dynamics is crucial for the appropriate management of communities and landscapes to reduce the total burden of zoonotic disease.
