The prevalence of Trypanosoma cruzi, the causal agent of human Chagas disease, detected in rodent host populations in Texas
Trypanosoma cruzi is the parasite that causes Chagas disease, which affects over eight million people in at least 21 countries in Central and South America. While Chagas disease has been recognized as a significant health threat to the 28 million people living in Central America, it has not been historically considered a significant threat to the people in the United States. However, efforts to screen potential wildlife host populations for the parasite are only recently being undertaken in the southern USA. Since rodents are one of the reservoir hosts for T. cruzi and can be abundant close to human housing, detections of T. cruzi in rodents provide a good approximation of the prevalence of Chagas disease and the associated potential for the disease threat to human health. The purpose of this study was to determine the incidence of rodents infected with T. cruzi in five geographical regions across Texas, along with Triatoma vectors collected from three collection sites in Texas. DNA of the parasite T. cruzi was detected by real-time quantitative PCR (qPCR) in DNA extracted from heart tissue of rodents and the hindgut from Triatoma vectors, and prevalence assessed as a function of location, time of the season, and of rodent species. For the Triatoma vectors prevalence was assessed as a function of location, life stage and of Triatoma species. Of approximately 544 rodent samples analyzed, eight samples representing five rodent species were infected with T. cruzi. All of the positive detections of rodents occurred in the most southern geographical region of Texas, with significantly more detections in Winter compared to Spring and Fall. Of thirty Triatoma vectors analyzed, 15 samples representing two Triatoma species were infected with T. cruzi. The data indicate that rodent and Triatoma populations in selected regions of Texas are infected with T. cruzi. Further studies need to be conducted to assess if other animal populations, or other rodent populations in Texas are infected with T. cruzi with the ultimate goal of understanding what the presence of this wildlife zoonotic means to human health in affected regions of our state.
Biology, Zoonotic disease
Aleman, A. (2015). <i>The prevalence of Trypanosoma cruzi, the causal agent of human Chagas disease, detected in rodent host populations in Texas</i> (Unpublished thesis). Texas State University, San Marcos, Texas.