[Peridomiciliary changes and implications for Triatoma brasiliensis control].

Area of Science:

• Vector control
• Medical entomology
• Chagas disease research

Context:

• Chagas disease is a significant public health concern in Brazil, transmitted by triatomine bugs.
• Triatoma brasiliensis and Triatoma pseudomaculata are key vectors in the semi-arid region of Northeast Brazil.
• Rural dwellings and their annexes serve as primary habitats for these vectors.

Purpose:

• To evaluate the effectiveness of pyrethroid insecticide spraying in controlling Triatoma brasiliensis and Triatoma pseudomaculata infestations.
• To assess the long-term impact of insecticide interventions on vector populations in rural annexes.
• To identify factors influencing reinfestation and recommend targeted control strategies.

Summary:

• A study in Boa Viagem County, Ceará, Brazil, investigated 9,906 annexes across 1,541 rural dwellings infested by Triatoma brasiliensis and Triatoma pseudomaculata.
• Initial annex infestation was 4.0%, predominantly in animal shelters (7.0%), with low mean insect density.
• Insecticide spraying led to a decrease in infestations, but new annexes became significant reinfestation foci, with 25% infested by the study's end.
• Reinfestation was slow and more common in animal shelters; no significant difference was found between pyrethroid and slow-release organophosphate formulations.

Impact:

• Insecticide spraying effectively reduced initial annex infestations, but reinfestation highlights the need for ongoing surveillance.
• New construction poses a challenge, as new annexes rapidly become infestation sites.
• Selective spraying of newly constructed annexes is recommended to prevent the establishment of new foci and improve long-term vector control.