Survey of Feral Swine (Sus scrofa) Infection with the Agent of Chagas Disease (Trypanosoma cruzi) in Texas, 2013–14

Abstract

Feral swine (Sus scrofa) are an invasive species and reservoir of numerous zoonotic pathogens in the US, and Texas leads the nation in the estimated population size of feral hogs. Texas also harbors enzootic transmission cycles of the protozoan parasite Trypanosoma cruzi, agent of Chagas disease. Given previous evidence that swine can serve as reservoirs of T. cruzi in Latin America and new evidence of triatomines (kissing bugs) feeding on swine in Texas, we measured the prevalence of T. cruzi infection in feral swine in Texas. From 2013 to 2014, we sampled blood and/ or cardiac tissue from 78 feral swine across 14 Texas counties (seven with and seven without prior documentation of kissing bug occurrence) and used PCR and histopathology to detect T. cruzi infection. We determined an overall infection prevalence of 6% (3 of 54) based on PCR evaluation of cardiac tissue, and no blood samples were positive (n¼72). All three positive pigs were from counties where kissing bugs are documented. No T. cruzi amastigotes were noted on histopathology (n¼54). Sarcocysts were observed in 10 (18%) of the samples, five of which also had mild focal areas of degeneration and inflammatory cell infiltration. Eco-epidemiologic investigations can provide an assessment of contributions of feral hogs to maintenance of T. cruzi across a landscape to help protect human and animal health.

Prevalence and Seroprevalence of Trypanosoma cruzi Infection in a Military Population in Texas

“…The apparent mismatch between these reassuring findings and the troubling biosurveillance signals—to include cases of canine Chagasic cardiomyopathy and a high volume of T. cruzi –infected triatomines—could have several explanations. Exposure of our study subjects to triatomines may have been limited by several anteceding countermeasures: vegetation reduction 23 and application of pyrethroid-based insecticides 2 around tents and field training sites; aggressive reduction of zoonotic reservoirs, particularly woodrats 24 and feral swine 25 ; requirements pertaining to field uniform wear (i.e., long pants bloused under boots and long sleeves secured at the wrist with buttons); distribution of DEET-based insect repellents free of charge; and, specifically for students during their field training exercise, sleeping in permethrin-treated bed nets. 26…”

Biosafety Concerns Related toBrucellaand Its Potential Use as a Bioweapon

“…In the United States, B. suis is endemic in feral swine, an invasive species present in at least 41 states with a population estimated to be greater than 6 million animals. 13 Prevalence of brucellosis in feral swine may differ by region but in a study in 2 abattoirs in Texas, Brucella was isolated from 13% of feral swine randomly sampled (Olsen, S.C. unpublished data). Brucella abortus is endemic in bison and elk in Yellowstone National Park and in surrounding areas.…”

Chagas Disease Infection Prevalence and Vector Exposure in a High-Risk Population of Texas Hunters

“…We believe this lack of barrier protection use is concerning, as 23 mammalian species serve as reservoirs for Chagas disease in Texas, including white-tailed deer, feral hogs, opossums, and armadillos. 9,15,16 Without proper protection during the field-dressing process, there is a potential for blood-borne FIGURE 1. Participant recruitment.…”