THE PROBOSCIS SENSORY INDEX PREDICTS VECTOR ANTHROPOPHILY AND HOST SELECTION IN NORTHERN NIGERIA
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Background
Unexplained spatial heterogeneity in field-observed Human Blood Index (HBI) hinders vector-borne disease control. We synthesized micro-morphological sensory structure densities across primary disease vectors to formulate a novel Proboscis Sensory Index (PSI) from micro-morphological sensory structure densities to evaluate its capacity to predict vector anthropophily, zooprophylactic modulation, and spatial transmission risk across Northern Nigeria.
Methods
A systematic review of 42 studies (N = 18,647 blood-fed mosquitoes across 126 georeferenced sites, 2005–2025) synthesized baseline species-specific PSI metrics from electron microscopy sensilla counts. A multi-variable binomial Generalized Linear Mixed Model (GLMM) evaluated interactions between PSI, livestock, human density, and environmental covariates. Predictive accuracy was validated against field-derived Entomological Inoculation Rates (EIR) and historical outbreak records.
Results
The overall pooled HBI was 0.642 (95% CI: 0.588 – 0.694), exhibiting significant variation across the Sudan (0.728), Guinea (0.615), and Sahel (0.584) savannas. Species-specific PSI values graded from Anopheles gambiae s.s. (8.91 ± 0.34), Anopheles funestus (8.12 ± 0.38), and Anopheles arabiensis (7.68 ± 0.41) to Culex quinquefasciatus (4.87 ± 0.52). In GLMM analysis, PSI was the strongest predictor of anthropophily (β = 0.89, aOR = 2.44, 95% CI: 2.32 – 2.56, p < 0.001), with fixed effects explaining 78% of total field variance (Marginal R 2 = 0.78). High-PSI species maintained elevated anthropophily regardless of livestock availability, whereas low-PSI species displayed steep zooprophylactic diversion (ΔHBI = −0.71, p < 0.001) under high cattle density. Incorporating PSI reduced localized EIR prediction error by 64.2% (RMSE = 15.0 vs. 41.8 infective bites/person/month), and high-resolution (1 km2) predictive mapping correctly identified 87.1% (27/31) of historically documented outbreak Local Government Areas.
Conclusion
Micro-sensory organ density dictates vector host preference and livestock-mediated zooprophylactic potential. Integrating PSI into spatial models resolves localized transmission heterogeneity, guiding targeted vector control prioritizing indoor residual spraying and dual-ingredient nets in high-PSI foci, while leveraging endectocides and larval management in low-PSI pastoral corridors.
