Theileria equi infection causing abortion in a mare in Brazil.

This research article investigates a case in Brazil where a mare’s abortion was attributed to an infection by the parasite Theileria equi, transmitted through the placenta. The findings suggest the need for further investigation into equine theileriosis as a possible cause of abortion in mares.

Introduction and Methodology

• The aim of the study was to ascertain the cause of abortion in a mare in Brazil’s Federal District.
• The team focused on Theileria equi, a parasite observed in the aborted fetus’s erythrocytes.
• A universal and multiplex PCR assay was used to test twelve breeding mares for the presence of T. equi, including the mare that had experienced the abortion.

Findings

• The aborted fetus had a high parasitemia of 80%, demonstrated by the presence of oval and Maltese-cross forms of T. equi in its erythrocytes.
• The fetus showed signs of organ congestion, jaundice, anemia, and marked spleno- and hepatomegaly (enlarged spleen and liver).
• All twelve tested mares were found to be positive for T. equi, indicating the possible prevalence of T. equi infection among mares in the region.

Significance of the Findings

• There were no histopathological changes such as inflammation or necrosis in the placenta and fetal tissues. This, combined with negative microbiological results and negative serology for Leptospira spp. in the mare that aborted, helped to rule out other infectious agents usually associated with equine abortion.
• The study highlights the possibility of T. equi being transmitted through the placenta, significantly contributing to miscarriages in mares.

Conclusion

• The study suggests that equine theileriosis, caused by the T. equi parasite, may be a significant cause of abortion in mares.
• The researchers advocate for greater investigative focus on theileriosis in regions where the condition is endemic, such as Brazil’s Federal District.