Leukocyte changes in pregnant Yankasa ewes experimentally infected with Trypanosoma evansi

Abstract

Pregnancy and trypanosomosis are associated with leukocyte changes. The leukocyte response of pregnant Yankasa ewes during experimental Trypanosoma evansi infection was determined using twenty pregnant ewes. They ewes were divided into 3 groups with 6 ewes in group A, while groups B and C were made up of 7 ewes each. The ewes in group A served as control, whereas those in group B and C were infected with approximately 1.0 x10⁶ parasite/mL of T. evansi (Sokoto isolate) per ewe through the jugular vein on days 59 and 110 of pregnancy, respectively. Blood from each ewe was collected weekly and used to monitor leukocyte changes from the time of parasitaemia till the end of the study. There was significant (p<0.05) leukopenia in group B at week 1 pi, followed by significant (p<0.05) leukocytosis at week 4 pi and leukopenia at week 7 pi compared with the control. The leukopenic animals were characterized by neutropenia and monocytosis, while the leukocytosis was due to eosinophilia, neutrophilia and monocytosis that were observed with peak parasitaemia. Ewes in group C had significant (p<0.05) leukopenia at week 3 compared to the control and this preceded peak parasitaemia but characterized by lymphocytopenia and eosinopenia. In conclusion, the study shows that T. evansi (Sokoto isolate) causes leukocyte changes in pregnant ewes infected at second trimester different from ewes infected at third trimester, suggesting that trimester of pregnancy affects leukocyte response in T. evansi infection.

Keywords: Ewe, Leucocytosis, Leucopenia, Monocytosis, Pregnancy, Trypanosoma evansi