Epidemiology of Babesia Infection in Sheep in Kajiado Central Sub-county, Kenya

Abstract

Ovine Babesia infection is a tick borne disease caused by hematotropic parasites of the genus Babesia. Babesia infections in sheep and goats are caused by three Babesia species, namely Babesia motasi, Babesia. crassa and Babesia ovis. Significant economic losses due to the disease have been reported in tropical and subtropical part of the world yet the status of Babesia infection in Kenya remains largely unclear. The objectives of the study were to 1) To determine the Babesia haemoparasites infecting sheep in Kajiado central 2) To identify the possible risk factors associated with the Babesia infection of sheep in Kajiado central sub County 3) To compare the performance of microscopy and PCR in detecting Babesia infection of sheep in the study areas. This study was a cross-sectional study and was conducted in purposively selected locations of Oldonyork, Matasi, Bissil, Namanga Portland, Ngaatatock, Sajiloni, and Oloosuyian in Kajiado central sub-county. Farmers owning sheep were initially identified and random sample of 31 flocks selected to participate in the study. To determine risks factors associated with Babesia infection of sheep, data on flock characteristics and management practices including common diseases and treatment status of the flocks were collected using questionnaires administered to sheep owners. A total of 395 blood samples were also collected from sheep and blood smears prepared for subsequent examination by microscopy for presence of Babesia parasites. Thereafter, DNA was extracted from the blood samples and the presence of Babesia DNA was determined by polymerase chain reaction. The collected data were entered in MS Excel® and analyzed by using Stata® statistical program. Kappa statistic was used to assess agreement between PCR and microscopy tests. A univariate analysis was done to screen for possible risk factors associated with infection of sheep with Babesia (p<10%). Microscopic examinations revealed presence of Babesia parasites in sheep erythrocytes. PCR analysis confirmed the presence of 239 bp specific band corresponding to the DNA of Babesia species. Of the 395 sheep sampled, 22 (5.6%) were positive for Babesia spp. upon microscopic examination whereas 13 (3.3%) were positive for the presence of Babesia spp by PCR. The level of agreement between microscopic test and PCR was 73%.Farmers managed diseases either by spraying with acaricides (96.8%), deworming or by injections (3.2%). The sex of sheep and presence of ticks on dogs were significantly associated with ovine Babesia infection. The findings indicate that sheep in Kajiado County are infected with Babesia parasites and it would be interesting to establish their pathogenicity. This study provides useful baseline data, which when shared with relevant government authorities, could be useful in designing surveillance strategies for effective control and better management of sheep. Subsequently, it is recommended that further research on molecular epidemiology of Babesia spp in sheep in pastoralist areas, especially in Kajiado to build on the results obtained in this study.