Infection rates, species diversity, and distribution of zoonotic Babesia parasites in ticks: a global systematic review and meta-analysis.

ABSTRACT

Zoonotic Babesia species are emerging public health threats globally, and are the cause of a mild to severe malaria-like disease which may be life threatening in immunocompromised individuals. In this study, we determine the global infection rate, distribution, and the diversity of zoonotic Babesia species in tick vectors using a systematic review and meta-analysis. We used the random-effects model to pool data and determined quality of individual studies using the Joanna Briggs Institute critical appraisal instrument for prevalence studies, heterogeneity using Cochran's Q test, and across study bias using Egger's regression test. Herein, we reported a 2.16% (3915/175345, 95% CI 1.76-2.66) global infection rate of zoonotic Babesia species (B. divergens, B. microti, and B. venatorum) in tick vectors across 36 countries and 4 continents. Sub-group infection rates ranged between 0.65% (95% CI 0.09-4.49) and 3.70% (95% CI 2.61-5.21). B. microti was the most prevalent (1.79%, 95% CI 1.38-2.31) species reported in ticks, while Ixodes scapularis recorded the highest infection rate (3.92%, 95% CI 2.55-5.99). Larvae 4.18% (95% CI 2.15-7.97) and females 4.08% (95% CI 2.56-6.43) were the tick stage and sex with the highest infection rates. The presence of B. divergens, B. microti, and B. venatorum in tick vectors as revealed by the present study suggests possible risk of transmission of these pathogens to humans, especially occupationally exposed population. The control of tick vectors through chemical and biological methods as well as the use of repellants and appropriate clothing by occupationally exposed population are suggested to curtail the epidemiologic, economic, and public health threats associated with this emerging public health crisis.