Human blood index of Anopheles arabiensis in Ethiopia: a systematic review and meta-analysis

Abstract

Background Malaria is a significant public health challenge in Ethiopia, with approximately 60% of the population being at risk to the disease. Anopheles arabiensis, the primary malaria vector, exhibits varied feeding behaviors influenced by factors such as geography, climate and control intervention. Understanding the mosquito's preference for blood meal is crucial for devising effective control strategies. This study thus aimed to conduct a systematic review and meta-analysis of existing evidence on An. arabiensis' human blood index (HBI) in Ethiopia, with the goal of providing insights into its feeding patterns and informing targeted malaria control efforts. Methods A comprehensive search was conducted across multiple electronic databases to select relevant studies following the PRISMA guidelines. A format on an Excel Spreadsheet was prepared for data extraction; focused on study characteristics, including publication year, study location, mosquito collection methods, and proportion of HBI. Quality assessment of the included studies was performed using criteria adapted from the Joanna Briggs Institute (JBI) appraisal checklist. STATA version-15 software was employed for data analysis, with random-effects models used to estimate the pooled HBI at 95% confidence intervals (CI). Subgroup analysis and meta-regression were conducted across regions and mosquito collection methods. Heterogeneity across studies was assessed using I² test. Results Twenty studies published from 1997 to 2023 were included and a total of 15,028 blood-fed An. arabiensis were identified. The meta-analysis revealed a pooled HBI of An. arabiensis in Ethiopia was 31.4% (95% CI: 21.25–41.54). Subgroup analysis demonstrated varying HBIs across different regions, with the highest proportion observed in mixed region 3 (64.02%, 95% CI: 61.78–66.25) and the lowest in the Amhara Regional State (7.53%, 95% CI: -1.58-16.65). Temporal fluctuations of HBI were also evident over time, with the highest HBI recorded 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 showed that the pooled proportion of HBI in Ethiopia was 31.4%, which denotes the mosquito’s human blood meal preference in the country remain high. Yet, the proportion varies across regions and settings. Insights into its feeding patterns in the country highlight the importance of tailored malaria control strategies. Continuous surveillance and further research is warranted to understand the factors driving variations in HBI and to develop evidence-based prevention and control measures.