Entomological surveillance of Trypanosoma cruzi vectors in Rio Grande do Norte, Brazil.

Abstract

In Rio Grande do Norte, Brazil, updated studies on synanthropic triatomines are needed to elucidate population dynamics and identify high-risk areas for parasite transmission. This study evaluated active searching, vector control, and entomological indicator activities, as well as the distribution of triatomine species captured in domestic environments across different mesoregions of the state from 2005 to 2022. Secondary data on triatomine captures in domiciliary units (DUs) from municipalities in the Agreste, Central, and West mesoregions were analysed. These data were provided by the Rio Grande do Norte State Secretariat for Public Health. Entomological surveillance activities were implemented discontinuously throughout the period, ranging from 2 to 12 years. No entomological surveillance activities were performed in the East mesoregion, nor in 46.5% (20/43) of municipalities in the Agreste, 18.9% (7/37) in the Central, and 11.3% (7/62) in the West mesoregions. Triatomine presence was recorded in most municipalities where entomological surveillance activities were conducted, and the number of surveyed and positive DUs was higher in the Central and West mesoregions. The overall infestation index was highest in the West and Central mesoregions municipalities. Additionally, the natural infection index by Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae) was elevated in all three mesoregions. Triatoma brasiliensis and Triatoma pseudomaculata were the most frequently captured species. The West mesoregion exhibited the highest number of specimens captured and the greatest diversity of triatomines. Discontinuities in entomological surveillance and vector control, combined with insufficient systematic monitoring and limited integration between the community and health services, likely contributed to persistent infestation and colonization of anthropic environments by triatomines. Furthermore, the constant presence of native triatomine species infected with T. cruzi in dwellings underscores the ongoing risk of parasite transmission to humans and domestic animals.