Disentangling Trypanosoma cruzi transmission cycle dynamics through the identification of blood meal sources of natural populations of Triatoma dimidiata in Yucatán, Mexico

Abstract

BackgroundIn the Yucatán Peninsula, Mexico, Triatoma dimidiata is the main vector of Trypanosoma cruzi, the causative agent of Chagas disease. Little effort has been made to identify blood meal sources of T. dimidiata in natural conditions in this region, although this provides key information to disentangle T. cruzi transmission cycles and dynamics and guide the development of more effective control strategies. We identified the blood meals of a large sample of T. dimidiata bugs collected in different ecotopes simultaneously with the assessment of bug infection with T. cruzi, to disentangle the dynamics of T. cruzi transmission in the region.MethodsA sample of 248 T. dimidiata bugs collected in three rural villages and in the sylvatic habitat surrounding these villages was used. DNA from each bug midgut was extracted and bug infection with T. cruzi was assessed by PCR. For blood meal identification, we used a molecular assay based on cloning and sequencing following PCR amplification with vertebrate universal primers, and allowing the detection of multiple blood meals in a single bug.ResultsOverall, 28.7% of the bugs were infected with T. cruzi, with no statistical difference between bugs from the villages or from sylvatic ecotopes. Sixteen vertebrate species including domestic, synanthropic and sylvatic animals, were identified as blood meal sources for T. dimidiata. Human, dog and cow were the three main species identified, in bugs collected in the villages as well as in sylvatic ecotopes. Importantly, dog was highlighted as the main blood meal source after human. Dog was also the most frequently identified animal together with human within single bugs, and tended to be associated with the infection of the bugs.ConclusionsDog, human and cow were identified as the main mammals involved in the connection of sylvatic and domestic transmission cycles in the Yucatán Peninsula, Mexico. Dog appeared as the most important animal in the transmission pathway of T. cruzi to humans, but other domestic and synanthropic animals, which most were previously reported as important hosts of T. cruzi in the region, were evidenced and should be taken into account as part of integrated control strategies aimed at disrupting parasite transmission.

Identification of blood-feeding sources in Panstrongylus, Psammolestes, Rhodnius and Triatoma using amplicon-based next-generation sequencing

“…These findings suggest a high dispersal ratio of the studied species, which challenges the current vector control programmes in Colombia. This agrees with previous findings in our country and other countries [ 8 , 9 , 50 , 51 ] but contradicts other reports in El Salvador where domestic T. dimidiata fed mainly on H. sapiens , C. lupus familiaris and domestic birds [ 43 ].…”

Dynamics of food sources, ecotypic distribution and Trypanosoma cruzi infection in Triatoma brasiliensis from the northeast of Brazil

“…Indeed, as expected, they found a distinct set of mammals probably involved in T. cruzi exchanges between sylvatic and domestic environments, such as dogs, humans and cows. Overall, 28.7% of T. dimidiata were infected by T. cruzi [29]. A matter of concern is that we found a much higher prevalence of T. cruzi (59%) in T. brasiliensis, because a large proportion of T. cruzi infected bugs were physically closer (40%, 73/181) to humans-in peridomestic ecotopes.…”

“…dimidiata in the Andean valleys/Yucatan-Mexico by the domestication of guinea pigs (Cavia spp.) [29,30,31,32,33]. It is also well known that cavimorphs maintain high T. cruzi parasitemia [31,33,34,35].…”

“…The diversity of blood meals found in this study was similar to the ones found for T . dimidiata in Yucatán, Mexico [ 29 ]. Indeed, as expected, they found a distinct set of mammals probably involved in T .…”

“…dimidiata were infected by T . cruzi [ 29 ]. A matter of concern is that we found a much higher prevalence of T .…”