Reproductive Outcomes in Rhesus Macaques (Macaca mulatta) with Naturally-acquired Trypanosoma cruzi Infection

Abstract

Chagas disease is a zoonotic vector-borne disease caused by infection with the protozoan parasite Trypanosoma cruzi. T. cruzi is found in Latin America and the Southern United States, where it infects many species, including humans and nonhuman primates (NHPs). NHPs are susceptible to natural infection and can develop clinical symptoms consistent with human disease, including Chagasic cardiomyopathy, gastrointestinal disease and transplacental transmission, leading to congenital infection. Due to evidence of Chagas transmission in Texas, this study hypothesized T. cruzi infection was present in a closed, outdoor-housed breeding colony of rhesus macaques (Macaca mulatta) located at a biomedical research facility in Central Texas. In addition, we questioned whether seropositive female rhesus macaques might experience reproductive complications consistent with maternal-fetal Chagas disease. The seroprevalence of T. cruzi infection in the colony was assessed using an Enzyme Linked Immunosorbant Assay (ELISA) to detect antibodies against Tc24 antigen as a screening assay, and a commercially available immunochromatographic test (Chagas Stat Pak) as a confirmatory assay. Retrospective serologic analysis was performed to confirm the status of all T. cruzi-infected animals between the years 2012 to 2016. The medical history of all seropositive and seronegative breeding females within the colony from 2012 to 2016 was reviewed to determine each animals' level of reproductive fitness. The percentage of T. cruzi-seropositive animals ranged from 6.7% to 9.7% in adult animals and 0% to 0.44% in juveniles or weanling animals, depending on the year. An overall 3.9% seroprevalence of T. cruzi infection was found in the total population. No significant differences in any measure of reproductive outcomes were identified between seropositive and seronegative females from 2012 to 2016. The lack of significant adverse reproductive outcomes reported here may help inform future management decisions regarding seropositive female rhesus macaques within breeding colonies.