Prevalence and risk factors associated with Toxoplasma gondii infection among blood donors in eastern China.

Background: Toxoplasmagondii is a zoonotic parasite infecting approximately one-third of blood donors worldwide; hence, a better understanding of the prevalence of and associated risk factors for T. gondii infection among blood donors is necessary. This study, therefore, aimed to elucidate the infection risk in Zhejiang Province, China via cross-sectional investigation combined with a case-control design.

Methods: Blood samples were collected from 1807 blood donors for the cross-sectional survey between January 2023 and December 2024 in Zhejiang, eastern China. Enzyme-linked immunosorbent assay and quantitative polymerase chain reaction were used to investigate the prevalence of T. gondii. Questionnaires were used to collect demographic information. In total, 40 seropositive and 40 seronegative participants were selected for risk factor investigation. Univariate and multivariate logistic regression analyses were conducted.

Results: The overall prevalence of anti-T. gondii antibodies was 5.9% (95% confidence interval [CI]: 4.9-7.1%), with 100, one, and six participants found to be IgG-positive only (5.5%, 95% CI: 4.5-6.7%), IgM-positive only (0.1%, 95% CI: 0-0.4%), and IgG- and IgM-positive, respectively (0.3%, 95% CI: 0.1-0.8%). All samples were negative for T. gondii as per polymerase chain reaction test results. T. gondii seroprevalence exhibited an age-dependent increase from 2.4% (18-29 years) to 8.2% (50-59 years). Age and occupational distribution patterns varied between eastern and southern regions. Univariate analysis revealed that occupation was a risk factor for T. gondii infection. Repeated blood donation (P = 0.044, OR = 0.243, 95%CI: 0.061-0.964) was negatively associated with T. gondii infection. Multivariate logistic regression demonstrated that age (P = 0.031) and first-time donors (P = 0.011) were significantly associated with higher prevalence rates.

Conclusion: Strategies for prevention of transfusion-transmitted toxoplasmosis should be targeted to older and first-time donors. This study provides evidence-based insights to guide prevention strategies and ensure blood safety.