Current Research

Ecology and Evolution of Chagas Disease in Anthropogenically Disturbed Landscapes

Chagas disease, caused by Trypanosoma cruzi, a multi-host vector borne protozoan pathogen, is a neglected tropical disease and a significant cause of morbidity and mortality in many human populations in Latin America. In collaboration with Drs. Jose Calzada and Azael Saldana of the Parasitology Department of the Gorgas Memorial Institute in Panama and Dr. Luis Fernando Chaves of Nagasaki University, we study how and why the parasite that causes Chagas disease, Trypanosoma cruzi, persists in nature, and how its transmission responds to anthropogenic change, such as deforestation. Our research has shown that vector (R. pallescens) infection prevalence and vector abundance increases in fragmented forests. We have also found that changes in host community structure in these disturbed areas favoring r-selected species (animals that 'reproduce fast and die young'), appear to drive increased vector infection with T. cruzi. We use a combination of theoretical (e.g. life history and community ecology theory, mathematical modeling) and applied approaches (e.g. molecular identification of blood meals, measurement of vector flight performance, xenodiagnostic studies) to evaluate the effects of anthropogenic environmental change (deforestation, climate change) on the transmission of Chagas disease in vectors, reservoir hosts, and human infection risk. Current doctoral research by Christina Varian evaluates how vector microhabitat food webs and vector abundance change in response to anthropogenic disturbance. A better understanding of impacts of anthropogenic environmental change on T. cruzi transmission allows for continued development of disease prevention and control strategies. We are also expanding our study to include the ecology of cutaneous leishmaniasis in response to environmental change.

Impact of urbanization on the ecology and evolution of raccoon pathogens

Urbanization can influence within and cross-species disease transmission by increasing raccoon abundance and interspecific contact (e.g. contact with feral cats). We are taking a molecular phylogenetic approach to evaluate impacts of urbanization on pathogen evolution and cross-species transmission. Pathogens of interest include Bartonella spp., Mycoplasma spp., and canine distemper virus. We also study how pathogen community structure in raccoons changes in response to urbanization. Dr. Jusun Hwang, doctoral student, is a key collaborator in this research project.

Integrating pathology and ecology to understand impacts of infectious diseases in wildlife

Integrating pathology and ecology to understand impacts of infectious diseases in wildlife- a hierarchical perspective from a cellular, individual to a population approach. We currently have two projects that are attempting to understand why some individuals, when infected with a particular parasite or suite of parasites, become sick and/or die of disease, and how environmental transmission may allow for disease persistence or influence an individual's risk of infection and/or disease. Dr. Annie Page, a doctoral student, studies factors that determine latency, environmental shedding, and expression of the tumor-inducing fibropapilloma virus in green sea turtles in order to better understand, prevent, and control the disease in rehabilitation centers and in the wild. Another study, led by Chilean Fulbright Fellow Dr. Mauricio Seguel, investigates why some individual fur seals die of hookworm infection, while others survive. He is evaluating how interactions between pup and dam nutritional condition, fishing pressure, coinfecting pathogens, and other enviromental factors interact with endocrine function and immunity to predict pup survival, morbidity, and mortality in response to hookworm infection. Because there is a large phylogeographic variability in the susceptibility of fur seal pups to hookworm infection, Dr. Seguel will also investigate how the genetic composition and population structure of hookworm subspecies may influence regional differences in overall hookworm pathogenicity. Dr. Seguel is also evaluating risks of introduced pathogens to fur seal .

Other ongoing projects

Other ongoing projects include the histology and pathology of Bowhead Whales in collaboration with the Department of Wildlife Management of the North Slope Borough, Barrow Alaska and the diagnostic pathology of marine mammals off the Georgia Coast with Clay Georgia of the Georgia Department of Natural Resources in Brunswick, GA.

Lab Members

Graduate Students

• Jusun Hwang, DVM, PhD student, Influence of Urbanization on feral cat disease transmission
• Annie Page, DVM, PhD student, Pathology of Fibropapillomavirus in sea turtles
• Mauricio Seguel, Combined PhD student and Pathology resident, Fur seal pathology
• Christina Varian, PhD student, Effects of anthropogenic change on food web composition in relation to Chagas disease vector abundance

Veterinary Students

• Nicole Woller, 2013, Georgia Veterinary Scholars Program

Undergraduate Students

• Ronke Olojowesiku, Genetics and Spanish double major, Comparing sampling strategy to detect T. cruzi infection in common opossums and next-generation approaches to evaluating blood meal species composition in Rhodnius pallescens, Chagas disease vector
• Chandler Sharp, lab volunteer, Blood meal analysis
• Kebora Keebler, lab volunteer

Former Lab Members

• Celia Romero, Class of 2013, UGA, lab manager
• Heather Danaceau, GVSP/Merial Scholar 2012, UGA CVM Class of 2014
• Hou-Ming Fung, MS 2012, Veterinary Biomedical Sciences, studied Chagas disease in dogs in Panama, Currently at CDC
• Karen Christ, lab assistant
• Rachel Lampley, GVSP/Merial Scholar, veterinary student at University of Tennessee
• Carolyn Hodo, UGA CVM class of 2011, NAPIRE field experience, Costa Rica (2010), combined pathology resident/PhD student at Texas A&M
• Maggie Trefney, DVM, GVSP/Merial Scholar 2010, currently in private practice in Alaska
• Jessica Beck, DVM, lab volunteer 2010, currently in an NIH combined pathology residency-PhD program at Purdue University
• Mark Montes, molecular identification of Rhodnius pathogens, currently an environmental consultant in Atlanta
• Si-ing Chen, Undergraduate laboratory technician, UGA (Fall 2009-Spring 2010) - molecular techniques, pharmacy student