Dynamics of anti-Toxoplasma gondii antibodies and seroconversion during pregnancy and lactation in naturally infected goats.

The objective of this work was to evaluate the dynamics of anti-T. gondii antibodies and seroconversion in naturally infected goats from the last third of pregnancy to 100 days of lactation and relate it to hematological and dehydration parameters. Blood samples were obtained from 56 goats in the different physiological states (pregnancy, kidding and lactation) as in different years (2019, 2021 and 2022). A total of 266 serum samples were obtained and evaluated by indirect fluorescent antibody test (IFAT) to end titer. The overall T. gondii seropositivity was 80.4% (45/56), with titers ranging from 100 to 25.600. The goats older than 3 years (4967 ± 1329) had significantly higher IFAT titers than the younger goats (2705 ± 681). The highest rate of positive seroconversion 31.1% (14/45) was found between kidding and 70 days of lactation; and of negative seroconversion 28.9% (13/45) between late pregnancy and kidding. The highest proportion of slightly dehydrated animals was found in the last third of pregnancy (14/25) and kidding (9/28). The correlation between seroconversion and T. gondii antibody titers was negative to the established dehydration index. These data suggest that in all physiological states and at different ages of goats, there is seroconversion which is not related to hydration status. Pregnancy, kidding and peak of lactation are stressful physiological periods, facilitating the reactivation of chronic T. gondii infections which are expressed by higher antibodies titers.