Phenotypic and Genotypic Identification of Ticks Sampled from Wildlife Species in Selected Conservation Sites of Kenya

Abstract

Hard ticks are blood feeding ectoparasites that infest humans and animals and are vectors of pathogenic micro- organism that cause severe infectious diseases. Morphological identification has been the main approach of identifying ticks but the technique is considered inaccurate and difficult. Molecular techniques have recently been considered to be appropriate approaches for accurate and rapid identification and Internal Transcribed Spacer 2 (ITS 2) has been shown to differentiate genus of hard ticks. Currently, genetic identification of ticks using ITS 2 has not been carried out in Kenya. In this study, 80 tick samples were collected from Lake Nakuru and Tsavo National Parks and were identified morphologically using appropriate identification keys. DNA was extracted from the appendages using DNA extraction kit followed by partial amplification of ITS 2 gene. The PCR products were then analyzed by gel electrophoresis and positive PCR products were sequenced. Of the tick samples four genera were identified morphologically; Amblyomma , Hyalomma , Rhipicephalus and Dermacentor . Of the tick samples identified and compared with the sequences in the GenBank, six and seven samples showed 98-100% homology with A. variegatum and R. pulchellus respectively and they clustered in their respective monophyletic group in the phylogeny tree with a bootstrap of 99%. Two samples showed 92% homology with H. dromedarii and the study sequences clustered with the reference sequence with a bootstrap of 99% while six samples showed 95% homology with H. marginatum rufipes, however, only four of these samples clustered together with the reference sequence in the phylogeny with a bootstrap of 95%. One sample showed 91% homology with A. humerali and did not cluster together in the phylogeny tree. Congruency between both techniques was high with a correlation coefficient of 0.941. This is the first report of phenotypic and genotypic traits of tick species in Kenya and the findings will add