Abortion in association with transplacental Theileria equi infection in a mare from the State of Espírito Santo, southeast Brazil: case report

Abstract

Equine piroplasmosis is a tick-borne disease caused by the protozoan parasites Babesia caballi and Theileria equi. We report a case of abortion in association with transplacental Theileria equi infection in a mare from the State of Espírito Santo, southeast Brazil. An apparently healthy mare aborted at the tenth month of gestation. At necropsy, the subcutaneous tissue, skeletal muscles, and visible mucosae of the aborted fetus were pale, and there was moderate hydrothorax and marked splenomegaly. Microscopic findings included splenic lymphoid hyperplasia and nephrosis. Merozoite-infected erythrocytes were found within blood vessels of all organs examined and were most numerous in the brain. DNA extracted from the spleen, liver, kidney, and thymus was used as a template for PCR. Generic primers were employed for the detection of piroplasm 18S ribosomal gene. All samples were positive for piroplasm DNA by PCR. Amplicons were purified and then sequenced. Sequencing analysis of these amplicons revealed 98% identity to T. equi sequences. Based on our findings, we suggest that abortion in this case resulted from transplacental Theileria infection.

Twenty Years of Equine Piroplasmosis Research: Global Distribution, Molecular Diagnosis, and Phylogeny

“…Transplacental transmission in the equine host has been reported for T. equi and may lead to abortion, the birth of a sick foal with peracute neonatal EP, or the birth of unapparent carrier foal [9][10][11][12][13][14][15][16][17][18][19]. In some endemic areas, T. equi is considered to be a major cause of abortion [20,21]; however, the role of this parasite as a cause of abortion is not well established [22].…”

Transplacental Transmission of Theileria equi Is Not a Common Cause of Abortions and Infection of Foals in Israel

“…The sporozoites present in the tick salivary glands are transmitted via saliva during the blood meal. Transplacental transmission of parasites has also been documented and may result in late-term abortion or neonatal piroplasmosis, which often lead to the death of the infected foal [3][4][5][6][7][8]. In some endemic areas, T. equi is a significant cause of abortion and has considerable economic consequences due to fetal loss and foal deaths [9].…”