Ecology, evolution and disease risks of bats in a changing world [electronic resource]
Keywords: Biology.

Humans have profoundly altered natural environments across the globe. These changes create challenges for ecosystems, wildlife and humans alike. One challenge of the Anthropocene is altered disease regimes -- whether from introduction of novel pathogens or hosts to ecosystems, perturbations of natural disease dynamics or spillover of infection from one host to another. Factors such as deforestation can catalyze adverse disease events through numerous mechanisms such as stressing organisms, making them more susceptible to infection and prone to shedding infectious particles and forcing novel species interactions with potential for spillover. One group of organisms of particular concern for both conservationists and public health officials are bats. Bats are the second largest order of mammals in the world and one of the most ecologically diverse, ranging from the large, tree roosting, fruit-eating flying foxes of Australasia to the small, cave roosting, insectivorous vespertilionids to the true vampire bats. Bats are also recognized as the reservoirs for a number of highly lethal emerging infectious diseases that infect humans including SARS, Marburg fever, Hendra virus and rabies. However, the majority of bat-associated zoonoses are restricted to the Old World; the Neotropics, despite being the center of bat species diversity, were comparatively understudied. Using a combination of field work, ecological statistics, phylogenetics and molecular genetic and genomic techniques, I sought to understand the ecology and evolution of the interaction of reservoirs with their infections and how these dynamics can change with human intervention. The first portion of my dissertation focuses on bats in an agricultural mosaic landscape in southern Costa Rica, in which I examined: the impact of deforestation on Costa Rican bat communities and the factors that impact bat species persistence in anthropogenic habitats (Ch. 2); the impact of deforestation and community change on ectoparasitism of Costa Rican bats (Ch. 3); and the prevalence, distribution and ecology of bat-associated viral and Bartonella infections in Costa Rican bats (Ch. 4). I then broadly considered bats globally and the impact of bat ecology, behavior and biogeography on the macroevolution of their genes for proteins that interact with pathogens (Ch. 5). Finally, I expanded my view to consider the impact of humans on disease globally by examining the evolution and distribution of Bartonella bacteria and the legacy of human impact on the ecology and evolution of this bacterial genus (Ch. 6). Taken together, these results show that bats and their pathogens have a coevolutionary legacy that restricts disease evolutionarily, geographically and ecologically. However, human interventions can disrupt these relationships by altering vector communities and prevalence as well as the prevalence of natural pathogens and introduced pathogens. Some viral groups are currently uncommon in the Neotropics but could survive in the New World if introduced by humans. Bats are a major source of emerging infectious disease but humans are an ultimate driver of the adverse disease patterns affecting both wildlife and humans.