The global seroprevalence of Toxoplasma gondii among wild boars: A systematic review and meta-analysis

This systematic review and meta-analysis study was performed to evaluate the worldwide seroprevalence of Toxoplasma gondii among wild boar. We searched PubMed, Science Direct, Web of Science, Cochrane, Scopus, EBSCOhost and Google Scholar databases for studies reporting T. gondii seroprevalence in wild boars between January 1995 and March 2017. Inclusion and exclusion criteria were applied. We estimated the pooled seroprevalence of T. gondii in wild boars using a random-effects model, and evaluated overall seroprevalence in different geographical areas. A total of 43 articles that included 16788 wild boar from 23 countries fulfilled our eligibility criteria. Of these, 4759 wild boar had been defined T. gondii seropositive and we estimated the pooled worldwide seroprevalence of toxoplasmosis in wild boars to be 23% (95% CI: 19-27%). The pooled seroprevalence in North America (32%, 20-45%; odds ratio [OR] 2.09) and Europe (26%, 21-30%; OR 1.72), was higher than Asia (13%, 5-23%). The lowest seroprevalence was estimated in South America (5%, 3-8%). An increased seropositivity was observed with elevation in geographical latitude. In subgroup analyses, the pooled seroprevalence of T. gondii was higher in wild boar older than 12 months of age (28%, 22-35%; OR 1.57) compared to those up to 12 months of age (20%, 16-25%). Our findings suggest that wild boar have an important role in human infection and the epidemiological cycle of T. gondii infection.