Abstract
BackgroundTrypanosoma cruzi, causative agent of Chagas disease in humans and dogs, is a vector-borne zoonotic protozoan parasite that can cause fatal cardiac disease. While recognized as the most economically important parasitic infection in Latin America, the incidence of Chagas disease in the United States of America (US) may be underreported and even increasing. The extensive genetic diversity of T. cruzi in Latin America is well-documented and likely influences disease progression, severity and treatment efficacy; however, little is known regarding T. cruzi strains endemic to the US. It is therefore important to expand our knowledge on US T. cruzi strains, to improve upon the recognition of and response to locally acquired infections.Methodology/Principle FindingsWe conducted a study of T. cruzi molecular diversity in California, augmenting sparse genetic data from southern California and for the first time investigating genetic sequences from northern California. The vector Triatoma protracta was collected from southern (Escondido and Los Angeles) and northern (Vallecito) California regions. Samples were initially screened via sensitive nuclear repetitive DNA and kinetoplast minicircle DNA PCR assays, yielding an overall prevalence of approximately 28% and 55% for southern and northern California regions, respectively. Positive samples were further processed to identify discrete typing units (DTUs), revealing both TcI and TcIV lineages in southern California, but only TcI in northern California. Phylogenetic analyses (targeting COII-ND1, TR and RB19 genes) were performed on a subset of positive samples to compare Californian T. cruzi samples to strains from other US regions and Latin America. Results indicated that within the TcI DTU, California sequences were similar to those from the southeastern US, as well as to several isolates from Latin America responsible for causing Chagas disease in humans.Conclusions/SignificanceTriatoma protracta populations in California are frequently infected with T. cruzi. Our data extend the northern limits of the range of TcI and identify a novel genetic exchange event between TcI and TcIV. High similarity between sequences from California and specific Latin American strains indicates US strains may be equally capable of causing human disease. Additional genetic characterization of Californian and other US T. cruzi strains is recommended.
Highlights
Trypanosoma cruzi is a protozoan parasite that, in both humans and dogs, may cause an insidious onset of fatal cardiac disease[1]
Our data show that Tr. protracta populations in both northern and southern California have high frequencies of T. cruzi infection, indicating that the risk for transmission to people and domestic animals is widespread in these regions
While this study’s prevalence of T. cruzi in Tr. protracta populations in southern California (~30%) was similar to earlier findings, an even higher prevalence was detected in our northern California study region
Summary
Trypanosoma cruzi is a protozoan parasite that, in both humans and dogs, may cause an insidious onset of fatal cardiac disease[1]. Known as Chagas disease, T. cruzi is the most economically important parasitic infection in Latin America, where an estimated 8–9 million people are living with the chronic disease [2]. Seven authochthonous clinical cases of Chagas disease in humans have been officially documented in the United States despite the fact that nine endemic Triatoma species are known to harbor T. cruzi [1]. The prevalence of T. cruzi in various wildlife species has ranged upwards from 50% in Texas and some southeastern states [8, 9]. While recognized as the most economically important parasitic infection in Latin America, the incidence of Chagas disease in the United States of America (US) may be underreported and even increasing. It is important to expand our knowledge on US T. cruzi strains, to improve upon the recognition of and response to locally acquired infections
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
