Comparison of the Bacterial Gut Microbiome of North American Triatoma spp. With and Without Trypanosoma cruzi.

Chagas disease, caused by the hemoflagellate protist Trypanosoma cruzi, affects nearly 6 million people worldwide, mainly in Latin America. Hematophagous triatomine insects ("kissing bugs") are the primary vectors of T. cruzi throughout the Americas and feed on a variety of animals, including humans. Control of triatomines is central to the control of T. cruzi infection. Recent advances in mitigation of other insect-borne diseases via the manipulation of insect-associated bacteria as a way to halt or slow disease transmission has opened questions to the applicability of these methods to Chagas disease vectors. Few studies have examined the hindgut microbiome of triatomines found in North America. In the current study, two species of triatomines were collected across Texas, United States, screened for the presence of T. cruzi, and analyzed for the bacterial composition of their hindguts using a 16S rRNA gene-fragment metabarcoding approach. We compared diversity of microbial community profiles across 74 triatomine insects to address the hypothesis that the richness and abundance of bacterial groups differ by T. cruzi infection and strain type, blood meal engorgement status, insect species, sex, and collection location. The gut microbial community of individual triatomines was characterized by low intraindividual taxonomic diversity and high interindividual variation that was weakly predicted by triatomine species, and was not predicted by triatomine sex, collection location, T. cruzi infection status, or blood meal score. However, we did find bacterial groups enriched in T. cruzi-positive individuals, including Enterobacterales, and Petrimonas. Additionally, we detected Salmonella enterica subspecies diarizonae in three triatomine individuals; this species is commonly associated with reptiles and domesticated animals and is a pathogen of humans. These data suggest that Triatoma spp. in Texas have variable patterns of colonized and transient bacteria, and may aid in development of novel means to interfere with transmission of the Chagas disease parasite T. cruzi. Deeper understanding of the effects of parasite infection on diverse insect vector microbiomes may highlight disease transmission risk and facilitate discovery of possible intervention strategies for biological control of this emerging vector-borne disease of global health significance.

CARRAPATICIDAS E INSETICIDAS NO CONTROLE QUÍMICO DE TRIATOMÍNEOS / Tickicides and insecticides in the chemical control of Triatomines

Diversos trabalhos foram realizados ao longo da história do Brasil com o intuito de se controlar e erradicar os bichos barbeiros do ambiente habitado por seres humanos, incluindo a realização de controle químico com hexaclorociclohexanos. O objetivo desta pesquisa foi avaliar a eficácia da acaricidas e inseticidas no controle de triatomíneos em municípios da região noroeste do Estado de São Paulo, Brasil. Foram capturados 94 triatomíneos com 81,91% (77/94) da espécie T. sordidae 18,08% (17/94) P. megistus.Os produtos a base de piretróides e imiprotrina associada a permetrina promoveram a morte 100% dos insetos em até 60 segundos. Observou-se que os produtos com maior taxa de letalidade também foram os que tiveram maior ação repelente. Os produtos a base depiretróide e citronela, imiprotrina associada a permetrina e a cipermetrina associada ao clorpirifós e citronelal repeliram os insetos por até 16 dias nos locais de aplicação. O amitraz demonstrou eficácia reduzida no controle destas duas espécies de parasitos. Pode-se concluir com estes resultados que diferentes produtos químicos foram eficazes no controle de triatomíneos em áreas rurais da região noroeste do estado de São Paulo, sendo estes produtos, em sua maioria, apresentados comercialmente como carrapaticidas e inseticidas.