Systematic review and meta-analysis of global prevalence of neurotoxic and hemotoxic snakebite envenomation

Background: The World Health Organization estimates that there are approximately 5.4 million snakebites and 1.8–2.7 million cases of envenomation, with 81 410–137 880 deaths each year worldwide. Aims: To estimate the prevalence of neurotoxic and haemotoxic snakebite envenomation through a comprehensive systematic review and meta-analysis. Methods: We searched Medline/PubMed, Scopus and Cochrane Library up to January 2021 using keywords such as snakebite and snake envenomation. Bibliographic and random searches were also performed. Prospective or retrospective observational studies and randomized controlled trials were included for the review. Results: We included 271 of 9711 studies published between 1963 and 2020. The pooled prevalence of snakebite from 188 studies with a total of 207 235 participants showed the highest prevalence in North America (69.20%; 95% confidence interval, CI: 57.06–81.34%) and lowest in Africa (28.10%; 95% CI: 22.22–33.98%). There was a pooled prevalence of 24.94% (95% CI: 22.84–27.03%) for haemotoxicity, with a highest prevalence of coagulopathy (43.76%; 95% CI: 33.15–54.37%). The overall prevalence of neurotoxicity was 38.20% (95% CI: 31.88–44.53%), with a highest prevalence of ptosis (53.57%; 95% CI: 38.51–68.62%). Conclusion: There was a higher prevalence of snakebites in North America. The most prevalent haemotoxicity and neurotoxicity were coagulopathy and ptosis, respectively. The overall quality of evidence was good with a non-significant publication bias.