Human Blood Index of Anopheles arabiensis in Ethiopia: A Systematic Review and Meta-Analysis

Abstract

Background: Anopheles arabiensis, the primary malaria vector in Ethiopia, exhibits diverse feeding behaviors influenced by geography, climate, and control strategies. Understanding its blood-feeding preference is crucial for devising effective interventions. This study aimed to conduct a systematic review and meta-analysis of existing evidence on An. arabiensis human blood index (HBI) in Ethiopia. Methods: A comprehensive search of multiple electronic databases was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Study quality was assessed using criteria adopted from the Joanna Briggs Institute (JBI) appraisal checklist. Data were analyzed using Stata Version 17, employing a random-effects model to estimate the pooled HBI at 95% confidence interval (CI). Subgroup analysis and meta-regression were performed based on regions and mosquito collection methods. Heterogeneity was assessed using the I2 test. Results: A total of 19 studies published from 1997 to 2023 were included, encompassing 12,794 blood-fed An. arabiensis. The meta-analysis revealed a pooled HBI of 37.18% (95% CI: 21.26–44.28). Subgroup analysis showed regional variation, with the highest HBI reported in Mixed Region 3 (covering Afar, Oromia, and the Amhara Regional States) at 64.02% (95% CI: 61.78–66.25), and the lowest in the Amhara Regional State at 7.53% (95% CI: −1.58–16.65). Temporal analysis indicated fluctuations over time, with the highest HBI reported in 2014 (70.62%, 95% CI: 68.72–72.46) and the lowest in 2021 (0%, 95% CI: 0.00–1.30). Conclusion: The present study found that An. arabiensis in Ethiopia exhibits a moderate preference for human blood, with a pooled HBI of 37.18%. However, significant variation exists across regions and over time. Continuous surveillance and further research are needed to explore the underlying factors influencing HBI and to guide evidence-based malaria prevention and control strategies.