A systematic review and meta-analysis of mosquito arboviral infections detected through xenosurveillance in Africa : a focus on West Nile, Rift Valley fever, and chikungunya virus infections

Abstract

This systematic review and meta-analysis comprehensively evaluated the mosquito arboviral infections with West Nile virus (WNV), Rift Valley fever virus (RVFV), and chikungunya virus (CHIV), detected through xenosurveillance, reported in mosquito vectors across Africa in the last 25 years (2000–2024). The study analysed xenosurveillance data from 45 studies conducted with over 115,000 mosquito specimens, and incorporated moderator analyses to assess the influence of trap type, seasonality, regional location, settlement type, and screening methods on virus detection rates. The estimated pooled prevalence of WNV was 1.18% (95% CI: 0.60–3.43%), with higher rates observed in Culex quinquefasciatus and Culex pipiens, particularly in Northern Africa. RVFV prevalence was 2.00% (95% CI: 0.96–4.52%), with notable detections in Cx. tritaeniorhynchus and Aedes mcintoshi in Eastern Africa. Pooled prevalence was highest for CHIV (8.00%, 95% CI: 2.92–22.25%), primarily in Ae. aegypti and Ae. albopictus in Central and Eastern Africa. In meta-regression analysis, qRT-PCR and indirect immunofluorescence were identified as screening methods associated with higher WNV detection, while wet season sampling and CDC light traps were linked to elevated RVFV prevalence. There was substantial heterogeneity (I2 > 97%) in regional and methodological approaches. The disparities underscore the need for standardised xenosurveillance protocols, region-specific strategies, and enhanced diagnostics to mitigate arboviral risks in Africa. Limitations included sparse CHIV data and underrepresentation of studies from Southern and Central Africa, emphasising the need for expanded longitudinal and geographically inclusive research.

HIGHLIGHTS • Pooled WNV prevalence was 1.18%, with higher values for Cx. quinquefasciatus and Cx. pipiens in Northern Africa. • Pooled RVFV prevalence was 2.00%, primarily in Cx. tritaeniorhynchus and Ae. mcintoshi in Eastern Africa. • CHIV showed the highest pooled prevalence, mainly in Ae. aegypti and Ae. albopictus in Central and Eastern Africa. • qRT-PCR and indirect immunofluorescence were screening methods associated with higher WNV detection in mosquitoes. • Wet season sampling using CDC light traps was associated with elevated RVFV prevalence.