Quantitative Real Time PCR (qPCR) Screening Confirms Babesia Bovis Infections in Cattle in Kenya

Abstract

BackgroundAmong protozoan parasites in the genus Babesia, Babesia bigemina is endemic and widespread in the East African region while the status of the more pathogenic Babesia bovis remains unclear despite the presence of the tick vector, Rhipicephalus microplus which transmits both species. Recent studies have confirmed the occurrence of R. microplus in coastal Kenya and although B. bovis DNA has previously been detected in cattle blood in Kenya, no surveillance has been done to establish its prevalence. This study therefore investigated the occurrence of B. bovis in cattle in Kwale County, Kenya, where R. microplus is present in large numbers. MethodA quantitative species-specific multiplex Taqman PCR assay targeting two Babesia bovis genes, 18S ribosomal RNA and mitochondrially-encoded cytochrome b and Babesia bigemina cytochrome b gene was used to screen 506 cattle blood DNA samples collected from Kwale County for presence of Babesia parasite DNA. ResultsA total of 131 animals (25.8%) were found to have bovine babesiosis. Of these, 87 (17.2%) were positive for B. bovis while 70 (13.8%) had B. bigemina while 26 (5.1%) were observed to be co-infected with both Babesia species. A total of 61 animals (12.1%) were found to be infected with B. bovis parasites only, while 44 animals (8.7%) had B. bigemina only. B. bovis infections were detected in 11 sites while B. bigemina was detected in 9 out of the 12 sites sampled in three Kwale sub-Counties.ConclusionThese findings reveal high prevalence of pathogenic B. bovis in a Kenyan area cutting across a busy transboundary livestock trade route with neighboring Tanzania. The Babesia multiplex assay used in this study is specific and can detect and differentiate the two Babesia species and should be used for routine B. bovis surveillance to monitor the spread and establishment of the pathogen in other African countries where B. bigemina is endemic. Moreover, these findings reveal a potential threat of fatal babesiosis in the absence of endemic stability in the local cattle populations.