Sylvatic host associations of Triatominae and implications for Chagas disease reservoirs: a comprehensive review and new host records based on archival specimens

Abstract

Background: The 148 species of kissing bug include important vectors of the debilitating, chronic, and often fatal Chagas disease, which affects several million people in Central and South America. An understanding of the natural hosts of this speciose group of blood-feeding insects has and will continue to aid ongoing efforts to impede the spread of Chagas disease. However, information on kissing bug biology is piecemeal and scattered, developed using methods with varying levels of accuracy over more than 100 years. Existing host records are heavily biased towards well-studied primary vector species and are derived from primarily three different types of observations, associational, immunological or DNAbased, with varying reliability. Methods:We here gather a comprehensive and unparalleled number of sources reporting host associations via rigorous targeted searches of publication databases to review all known natural, or sylvatic, host records including information on how that record was collected. We integrate this information with novel host records obtained via attempted amplification and sequencing of a ~160 base pair (bp) region of the vertebrate 12S mitochondrial gene from the gastrointestinal tract of 64 archival specimens of Triatominae representing 19 species collected primarily in sylvatic habitats throughout the southern U.S. and Central and South America during the past 10 years. We show the utility of this method for uncovering novel and under-studied groups of Triatominae hosts, as well as detecting the presence of the Chagas disease pathogen via Polymerase Chain Reaction (PCR) of a ~400 bp sequence of the trypanosome 18S gene.Results: New host associations for several groups of arboreal mammals were determined including sloths, New World monkeys, coatis, arboreal porcupines and, for the first time as a host of any Triatominae, tayras. A thorough review of previously documented sylvatic hosts, organized by triatomine species and the type of observation (associational, antibody-based, or DNA-based), is presented in a phylogenetic context and highlights large gaps in our knowledge of Triatominae biology. Conclusion:The application of DNA-based methods of host identification towards additional species of Triatominae, including rarely collected species that may require use of archival specimens, is the most efficient and promising way to resolve recognized shortfalls.

Molecular bloodmeal analyses reveal that Trypanosoma cruzi‐infected, native triatomine bugs often feed on humans in houses in central Brazil

“…It is caused by infection with Trypanosoma cruzi , a protozoan parasite transmitted by blood‐feeding bugs in the family Reduviidae, subfamily Triatominae (Lent & Wygodzinsky, ). Over 150 triatomine species have been described to date; most of these remain associated with wild habitats and hosts, but some are often found infesting houses and can feed on domestic animals and humans (Georgieva et al ., ). About 200 mammal species in at least nine orders have been found infected with T. cruzi across several ecosystems (Jansen et al ., ).…”

“…About 200 mammal species in at least nine orders have been found infected with T. cruzi across several ecosystems (Jansen et al ., ). The determination of T. cruzi infection frequency and bloodmeal sources in triatomines can further current understanding of vector–host relationships and help to identify species with higher potential to become important disease vectors (Georgieva et al ., ).…”

“…Several approaches have been used to determine bloodmeal sources in triatomines, including immunological tests (Silva et al ., ), polymerase chain reaction (PCR)‐based methods (Peña et al ., ; Georgieva et al ., ) and mass spectrometry (Keller et al ., ). High‐resolution melting (HRM) is a post‐PCR analysis that detects small variations in nucleic acid sequences based on the temperature‐dependent dissociation (melting) behaviour of double‐stranded DNA treated with a fluorescent dye.…”