After five years of chemical control: Colonies of the triatomine Eratyrus mucronatus are still present in Bolivia

[Display omitted] ► Colonies of Eratyrus mucronatus in peridomicile; intrusion of adults and nymphs in intradomicile. ► No evidence of local vectorial transmission of Trypanosoma cruzi. ► Similar infestation of dwellings after five years of chemical control. ► Colonies live in curahuas (boundary wall in rammed mud) which could protect them from insecticide. ► Curahuas could be one of the sources of E. mucronatus intrusion in dwellings. Chagas disease, which is caused by the parasite Trypanosoma cruzi, is transmitted to humans by blood-sucking bugs (Triatominae). Eratyrus mucronatus is a well-dispersed triatomine species, found sometimes in dwellings. In the Apolo region of Bolivia, people continue to complain of bites by this bug despite five years of chemical control. For the first time, the domiciliation process of E. mucronatus was evaluated in a zone treated by insecticide, and it was compared with a previous situation 14 years ago. Both an entomological and a serological study were carried out: 152 dwellings were visited and 491 blood samples were analyzed with Stat-Pack and ELISA tests. In 34 dwellings (23% of the total visited dwellings), 160 triatomines of all stages were collected belonging to two species, E. mucronatus (98% of the capture) and Panstrongylus geniculatus. A domiciliation of E. mucronatus is demonstrated, particularly in the peridomicile. Bugs were captured more frequently in bedrooms in the intradomicile, and in curahuas (boundary walls in rammed mud) in the peridomicile. A P. geniculatus adult was found infected with T. cruzi. No evidence of a local vectorial transmission was found. In particular, the limited effect of the insecticide on the presence of E. mucronatus and the role of the curahuas as a source of intrusion/domiciliation process are discussed.