Characterizing the transmission dynamics of Trypanosoma cruzi in Triatoma sanguisuga collected from dog kennels in southern Texas.

BACKGROUND

Chagas disease, caused by the protozoan Trypanosoma cruzi, remains a significant public health issue in South America, with increasing concern over its potential transmission in the USA. Triatoma sanguisuga, a triatomine vector, is found in Southern states of the USA, including Texas, raising questions about the local transmission dynamics of T. cruzi. This study aims to characterize Trypanosoma cruzi infection in Triatoma sanguisuga collected from dog kennels in Bulverde and Spring Branch, Texas, with a focus on parasite prevalence and load, genotypic diversity, and blood-feeding sources.

METHODS

A total of 48 T. sanguisuga insects were collected from kennels in Bulverde (N = 37) and Spring Branch (N = 11). DNA extraction was followed by quantitative polymerase chain reaction (qPCR) to detect and quantify T. cruzi, genotyping via Oxford Nanopore Sequencing of the Miniexon gene, and blood-feeding source identification using the 12S rRNA gene was also conducted. Statistical analysis was performed to assess differences in parasitic load among the locations.

RESULTS

Of the 48 insects, 81.1% from Bulverde and 100% from Spring Branch tested positive for T. cruzi. The median parasitic load was log 8.09 equivalent parasites/mL, with significant differences in parasitic load between locations. Genotyping revealed that all samples were infected with TcI, with some co-infection of TcI and TcIV. Blood meal analysis identified multiple feeding sources, including dogs (Canis lupus), humans (Homo sapiens), and wildlife species.

CONCLUSIONS

This study provides insights into T. cruzi transmission dynamics in southern Texas, demonstrating the active role of domestic dogs and wildlife in the local cycle of infection suggesting endemism of T. cruzi in this region. These findings emphasize the need for continued surveillance and vector control measures to mitigate the risk of Chagas disease transmission in the USA.