Different patterns of <i>Toxoplasma gondii</i> infection epidemiology in the general population, animal contact workers, and blood donors in southeastern China between 2019 and 2023: a cross-sectional study

There are estimated to be over one billion human infections of Toxoplasma gondii worldwide. However, significant spatial heterogeneity exists across countries and regions. For this study, a total of 2,943 participants were enrolled between 2019 and 2023 in Zhejiang Province, southeastern China including 519 animal contact workers, 1,722 people from the general population, and 702 blood donors. Anti-T. gondii IgG and IgM in sera were assessed using an enzyme-linked immunosorbent assay. The overall seroprevalence of IgG and IgM was 4.08% and 0.41%, respectively. IgG positivity was highest in the (50, 60] years age group (5.47%, 29/530), while IgM was found in the (60, 70] years age group (1.21%, 3/247). The general population showed the lowest IgG seroprevalence (1.68%) compared to animal contact workers (10.40%) and blood donors (5.27%) (p < 0.001). Patterns of T. gondii IgG prevalence varied by participant type. Increasing seroprevalence with age was observed among animal contact workers, indicating a cumulative effect, while frequency was highest in the (50, 60] and (30, 40] age groups in the general population and blood donors, respectively. Animal contact workers with two types of animal exposure had higher IgG positivity rates (13.16%) than those with one type (8.50%). Occupational exposure to cattle was associated with the highest frequency of IgG (12.69%), followed by pigs (9.69%), and sheep (8.85%). This study provides critical insights into the epidemiological characteristics of T. gondii infections across distinct population groups in Eastern China.