Eleven years of Toxoplasma gondii serological follow-up in a goat herd and association of toxoplasmosis with reproductive losses.

Toxoplasmosis is considered one of the most important causes of abortion in small ruminants. The aim of this study was to evaluate the relationship between Toxoplasma gondii antibody titres and reproductive losses over an 11 year period in a goat farm located in Buenos Aires province, Argentina. Blood samples were obtained from 85 goats, representing three breeds, during the last third of gestation (n = 165 gestations), in consecutive pregnancies (2008-2019), and from 51 goats during kidding to analyze seroconversion. Serum was evaluated by IFAT with T. gondii antigen, using 1:100 dilution as the cut-off titre and processed to end titre. An overall reproductive loss of 31% (51/165) was detected, including 16.4% (27/165) abortions and 14.6% (24/165) perinatal deaths. The seropositivity to T. gondii was 100% (85/85) with all animals positive in successive samplings and, therefore, considered chronically infected. Antibody titres showed average values greater than 1100 in each year and breed group. Differences in antibody levels were associated with breed and were lower in those that were predominately Creole and higher in those that were predominately Saanen. Seroconversion was detected in 16.2% (6/37) and 57.1% (8/14) of goats from the Creole and Sannen breed groups, respectively. There were no significant differences in the antibody titre average between goats with reproductive losses and those with healthy kids, although the goats with perinatal deaths had a significantly higher titre average. These results suggest reinfection or reactivation, although no association with reproductive losses was observed. Higher antibody titres were associated with perinatal deaths. The high T. gondii antibody titres in a farm with 100% seroprevalence did not allow for association with reproductive losses, particularly abortion, to be assessed.