DeBrock, Spencer Christian (2020-10). Tracking Avian Malaria Parasite Infection in Spring Migratory and Resident Passerine Birds in Coastal Texas, 2014-2019. Master's Thesis.
Thesis
Avian migration can have significant effects on disease dynamics in populations and provides a mechanism for large-scale geographic parasite dispersal. For example, birds can be infected by diverse Haemosporidian blood parasites that can cause avian malaria with impacts on host fitness. To characterize the Haemosporidian parasites transported by migratory birds, and identify the physical, ecological, and life history characteristics of the avian hosts associated with infections, we studied spring migrating passerines arriving to the US coast of the Gulf of Mexico and sympatric resident birds that over winter on the US Gulf Coast. We used mist nets to trap birds and collect blood samples in Matagorda County, Texas, in the springs of 2014-2019. We used PCR and DNA sequencing of the Haemosporidian cytB gene from avian blood samples to determine infection status and characterize the lineages of blood parasites. We found an overall Haemosporidian prevalence of 48.4% in trans-Gulf migrant and resident birds in which some avian families had greater odds of infection than others. Furthermore, birds that over wintered in Central America had significantly greater odds of infection with Plasmodium spp. compared to those that over wintered in the US or South America. Additionally, birds foraging on the ground and in the understory had the greatest odds of Plasmodium spp. infection compared to canopy foraging birds. Using the MalAvi database of Haemosporidian parasites, we identified 46 different Haemosporidian lineages present in the samples, including 71% in the genus Plasmodium and 29% in the genus Haemoproteus; this includes 17 novel lineages-never before reported- and six lineages that have not been previously reported in North America. Furthermore, our data reveal 6 novel geographic associations and 47 novel associations between an established lineage and a bird family. Given recent reports of dramatic declines in North American bird populations over the past five decades, further quantifications of host-parasite relationships in migratory birds and impacts on health are critically important.
