Transplacental Transmission of Trypanosoma evansi From Experimentally Infected Donkey Mare to Neonatal Foal

Abstract

The present study is an observation of transplacental transmission of Trypanosoma evansi in a donkey neonatal foal. One experimentally infected pregnant donkey mare gave a normal birth to a foal after 3 months of experimental infection. No trypanosome was seen in wet blood film (WBF) on microscopic examination in the experimentally infected donkey mare at the time of foal birth; however, in serum, a significant level of antitrypanosmal immunoglobulin G (IgG) antibodies on enzyme-linked immunosorbent assay (ELISA) and many immunodominant polypeptide bands on immunoblotting were observed. In the neonatal foal, live moving trypanosomes were observed in WBF just after birth before colostrum feeding. The foal serum sample (collected before colostrum feeding) was found negative on ELISA and immunoblotting indicating that IgG antibodies has not crossed placental barrier in the mother donkey. After 24 hours of birth, the clinical symptoms appeared in the foal showing recumbency, unable to stand and suckle, and poor reflexes. The foal was administered fluid therapy, but could survive only up to 36 hours after birth. The study indicated transplacental transmission of T. evansi in the donkey, but the mechanism responsible for crossing the placental barrier needs to be further elucidated.