Rocky Mountain spotted fever (RMSF) is a significant health problem in Sonora, Mexico. The tick vector, Rhipicephalus sanguineus, feeds almost exclusively on domestic dogs that, in this region, also serve as the reservoir for the tick-borne pathogen, Rickettsia rickettsii. A process-based mathematical model of the life cycle of R. sanguineus was developed to predict combinations of insecticidal dog collars and long-lasting insecticidal wall treatments resulting in suppression of indoor tick populations. Because of a high burden of RMSF in a rural community near the Sonora state capital of Hermosillo, a test area was treated with a combination of insecticidal dog collars and long-lasting insecticidal wall treatments from March 2018 to April 2019, with subsequent reduction in RMSF cases and deaths. An estimated 80% of the dogs in the area had collars applied and 15% of the houses were treated. Data on tick abundance on walls and dogs, collected during this intervention, were used to parameterize the model. Model results show a variety of treatment combinations likely to be as successful as the one carried out in the test community.

Integrated management of Aedes aegypti, the primary urban vector of dengue, Zika, and chikungunya, requires effective, environmentally safe larvicides with sufficient residual activity for operational use. We developed and evaluated MAALEM-Btmosquito, a novel floating granular formulation based on Bacillus thuringiensis subsp. israelensis (Bti), designed to maintain larvicidal activity under routine water use and partial water replacement in domestic water containers. Outdoor semi-field bioassays were conducted in 20 L buckets and 200 L drums under three water-replacement regimes (0%, 10%, and 50%). Groups of 25 late third- and early fourth-instar Ae. aegypti larvae were exposed at successive post-treatment intervals, and mortality was assessed at 24 and 48 h over 30 days. MAALEM-Btmosquito caused 100% mortality at 24 h on the first day and maintained >94.5% larval mortality throughout the study. Overall mean 24 h mortality across treatments was 98.8%, with treatment means ranging from 94.7% (95% CI, 91.9–96.5) to 99.7% (95% CI, 98.5–99.9). The greatest reduction in activity was observed in 20 L containers subjected to 50% water replacement. Operational performance was evaluated during three application cycles involving more than 700 households in Puente de Ixtla, Morelos, Mexico. The Breteau Index decreased by 72.6%, 64.6%, and 81.1%, while the mean egg count per ovitrap decreased from 93.2 ± 76.10 before the first MAALEM-Btmosquito application to 25.4 ± 20.44 eggs after completion of the field interventions. Because the community evaluation was conducted without a concurrent untreated control area, these field observations are associative and cannot be attributed solely to MAALEM-Btmosquito. Potential confounding factors include seasonality, rainfall, other vector-control activities, and household water-use behavior. Together with the controlled semi-field results, these findings support the potential of MAALEM-Btmosquito as a larvicide for integrated mosquito vector management.

Dosis letal y diagnóstica de carbamatos para Centruroides limpidus Karsch 1879 (Scorpiones: Buthidae), de Morelos, México