Toxoplasmosis in Blood Donors: A Systematic Review and Meta-Analysis.

Transfusion-transmissible infections include pathogens that may cause severe and debilitating diseases. Toxoplasmosis is a cosmopolitan neglected parasitic infection that can lead to severe complications including death in immune-compromised patients or following infection in utero. Multiple studies have demonstrated the transmission of Toxoplasma gondii by blood transfusion. The objective of this review was to comprehensively assess the seroprevalence rate of Toxoplasma in blood donors from a worldwide perspective. Seven electronic databases (PubMed, Science Direct, Web of Science, Scopus, Cochrane, Ovid, and Google Scholar) were searched using medical subject headings terms. A total of 43 records met the inclusion criteria in which 20,964 donors were tested during the period from January 1980 to June 2015. The overall weighted prevalence of exposure to toxoplasmosis in blood donors was 33% (95% confidence interval [CI], 28%-39%). The seroprevalences of immunoglobulin (Ig)M and both IgG and IgM antibodies were 1.8% (95% CI, 1.1%-2.4%) and 1.1% (95% CI, 0.3%-1.8%), respectively. The highest and the lowest seroprevalences of toxoplasmosis were observed in Africa (46%; 95% CI, 14%-78%) and in Asia (29%; 95% CI, 23%-35%), respectively. Brazil (75%) and Ethiopia (73%) were identified as countries with high seroprevalence. Because positive serology does not imply infectiousness and because seroprevalence is high in some nations, a positive serology test result alone cannot be used as an effective method for donor screening. Future research for methods to prevent transfusion-transmitted toxoplasmosis may derive benefit from studies conducted in areas of high endemicity.