Phylogeny and Evolution of Theileria and Babesia Parasites in Selected Wild Herbivores of Kenya

Abstract

Factors that influence transmission dynamics, pathogenicity, and virulence are complex and diverse yet important in understanding the epidemiology of many diseases. Theileria and Babesia are genera of tick-borne protozoan that are globally spread and infect nearly all warm-blooded animals in which they cause either latent infection or symptomatic and lethal disease. Wild animals are the considered hosts of many species of Theileria and Babesia and yet their diversity and prevalence is not explicit in the rich wild mammalian host diversity in Kenya. Morever, the close interactions between wildlife and livestock, wide range of grazing, migrations as well as geographical isolation of populations are some of the factors that may cause a parasite to adapt and subsequently evolve. This study identified Theileria and Babesia species, their prevalence in elephants, wildebeest, impalas and reedbucks and established their phylogenetic relationship. Genomic DNA was extracted from 128 blood samples obtained from elephants, reedbucks, impalas and wildebeest from Tsavo, Narok and Laikipia ecosystem. The genomic DNA was then amplified by an optimized nested amplification method of Theileria and Babesia 18S rRNA gene. Electrophoresis was then carried out on the secondary PCR products on a 2% agarose gel and the bands viewed under a UV light. The band size for 18S rRNA was found to range from 400bp to 500bp. Amplicons were then sequenced. Theileria and Babesia were identified in elephants, wildebeest, impalas and reedbucks in Kenya. The prevalence of Babesia was high in elephants, while that of Theileria was high in reedbucks, impalas and wildebeest. Two haplotypes of Babesia were identified in African elephant while nine Theileria haplotypes were identified from elephants, wildebeest, impalas and reedbucks of Kenya. The molecular phylogeny revealed presence of potentially novel species of Theileria and Babesia in elephants, wildebeest, impalas and reedbucks in Kenya. It also revealed the diversity of Theileria and Babesia species in the wild herbivores of Kenya. This is the first molecular study in Kenya undertaken to identify Theileria and Babesia in elephants, wildebeest, impalas and reedbuck.