Comparison of oviposition and adult trapping to monitor Mel introgression for based vector control.

introgression into mosquito populations has been shown to be effective in preventing dengue and is being evaluated for WHO prequalification. Monitoring the long-term introgression of (Mel)-positive mosquitoes, however, requires labor-intensive and costly BG-Sentinel traps (BG-traps). More affordable alternatives, such as using oviposition traps (ovitraps), have not been fully evaluated. eggs and adults were collected from 124 ovitraps and 237 BG-traps, respectively, across 12 clusters in Belo Horizonte, Brazil from March to May 2023 as part of the EVITA Dengue trial. We used a qPCR assay to detect Mel in a sample of L3-L4 stage larvae (up to 29) that were reared from eggs in ovitraps and adults from BG-traps (up to 10 per BG-trap). We used mixed effects models to compare estimates of cluster-level Mel introgression from ovitrap and BG-trap data over time. Among 3,675 larvae reared from ovitraps, Mel prevalence was 0.50 (95% CI: 0.48-0.51). Among 1,244 adult tested from BG-traps, Mel prevalence was 0.45 (95% CI: 0.42-0.48). Cluster-level Mel introgression in larvae and adults was highly correlated (Spearman's r = 0.70, p = 6.71e-06). Multivariate analysis found that ovitrap estimates of introgression were associated with BG-trap estimates in the same month when models incorporated the previous month's ovitrap Mel-positive count, the proportion of Mel in ovitraps in the current and previous month, and abundance. Leveraging this model, predicted Mel introgression from ovitrap data were highly correlated with observed introgression from BG-trap data (r=0.98, p=1.53e-14; r=0.82, p=0.11e-05) and provided greater precision than crude ovitrap-based estimates. These findings indicate that ovitrap-based monitoring represents a low cost, more efficient approach to evaluating introgression as the -based interventions are scaled up and implemented broadly in high burden regions for dengue and other arboviral diseases.