Oral Presentation 64th International Conference of the Wildlife Disease Association 2015

Methods to mitigate Trypanosoma cruzi transmission while encouraging wildlife presence (#68)

Lisa A Shender 1 , Jonna Mazet 1
  1. Wildlife Health Center/One Health Institute, University of California, Davis, Davis, California, United States
Trypanosoma cruzi is a protozoan parasite that infects more than 100 mammalian species, causes fatal cardiomyopathy in humans and dogs (Chagas disease), and is maintained by numerous wildlife reservoir species. Although humans are most frequently infected in Latin American countries, Chagas disease has become a global concern, with an estimated 300,000 chronically infected persons living in the US, 80,000 in Europe, and 1,500 in Australia. In general, heightened zoonotic disease awareness is often accompanied by fear and may lead to needless killing or removal of wildlife species, threatening biodiversity and disrupting food chains and ecosystem processes. It is therefore important to understand local Chagas disease transmission cycles, including T. cruzi presence in wildlife reservoirs and vectors. Our study took place in northern California (CA), where we evaluated reservoir, vector, and environmental components of the local T. cruzi cycle. First, we performed mark-recapture of woodrats (Neotoma species) on several private rural residential properties. Blood samples screened via polymerase chain reaction (PCR) assays yielded an overall T. cruzi prevalence of 14%, suggesting that woodrats likely serve as T. cruzi reservoirs in a previously unstudied northern CA region. Second, we collected Triatoma protracta (a T. cruzi vector found in the western US and northern Mexico) to assess T. cruzi prevalence and identify subtypes known as discrete typing units (DTUs). Only DTU TcI was represented, with approximately 55% of the vector specimens testing PCR-positive, highlighting the potential risk for T. cruzi transmission to people and domestic animals. Finally, via hierarchical logistic regression we evaluated woodrat microhabitat use with respect to vegetation parameters. Our habitat analyses, in combination with woodrat movement data, provide guidance for habitat modifications to decrease the risk of human exposure to T. cruzi, while still allowing for the presence of woodrats and the ecosystem benefits that they offer.