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.