Vertical transmission of Trypanosoma evansi in a dromedary camel calf that spontaneously recovered after colostrum consumption

Abstract

A weak dromedary calf with signs of prematurity was born in April of 2023 to a healthy multiparous camel with a good body condition. The calf was diagnosed strongly positive to Trypanosoma evansi by haematocrit centrifugation technique (immediately after birth). The mother at that time was asymptomatic and negative by haematocrit centrifugation technique and PCR of blood. Indirect ELISA of the calf's serum before colostrum ingestion showed negligible levels of antibodies. However, 12 hours after colostrum ingestion and without any treatment, the levels of antibodies increased significantly, which coincided with negative haematocrit centrifugation technique. This indicates a possible role of colostral antibodies in neutralising the trypanosomes in the calf's blood. Examination of the placenta showed placentitis, and PCR confirmed a positive result for Trypanosoma nucleic acid. The importance of vertical transmission in maintaining the infection in a herd is discussed, as well as the role of colostrum in decreasing calf mortalities due to trypanosomosis.