Phylogenetic analysis revealed the presence of Babesia ovata in cattle of Chattogram Division, Bangladesh

Abstract

Bovine babesiosis is the most economically important haemoprotozoan disease caused by Babesia spp. The present study was conducted in selected hilly, coastal and plain areas of Bangladesh to determine the prevalence and identification of risk factors along with the molecular characterization of Babesia spp. Using traditional blood smear examination and Giemsa staining, 1.43% (n=1680) of cattle were found positive for Babesia infection during this study. The prevalence of babesiosis was 1.17% (7 out of 600 cases) in the hilly areas; 1.67% (10 out of 600 cases) in the coastal areas and 1.46% (7 out of 480 cases) in the plain areas. The prevalence of Babesia spp. was found higher (P>0.05) in crossbred cattle compared to local or indigenous cattle. Seasonal variation of disease prevalence indicated that babesiosis was significantly higher (P<0.05) in the summer, followed by the rainy and winter months. Animals aged 6-18 months were found more susceptible to the infection based on collected samples from three different geographic areas of Bangladesh. Animals kept on the natural soil-type floor (mati floor) were found to be more affected by babesiosis than those kept on the cemented floor (Paka floor). No statistical difference was seen between male and female affected animals. Further molecular studies through PCR and DNA sequencing of all microscopically positive samples (by amplifying the 18S rRNA gene) confirmed the genus and their phylogenetic relationship. Interestingly, two distinct clusters were found through phylogenetic analyses of which one was closely related to Babesia ovata, and another cluster was closely related to Babesia bigemina. The knowledge will ultimately help develop effective control strategies, which mainly depend on vector control and farm management.