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

Carolyn Wanjira Muruthi

doi:10.4172/2157-7579.1000293

Abstract

Hard ticks are blood feeding ectoparasites that infest humans and animals and are vectors of pathogenic microorganism 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 value to the existing knowledge in identification of ticks.

Highlights

Ticks are ubiquitous blood feeding ectoparasites of humans and animals and are vectors of a plethora of pathogens that cause severe infectious diseases in humans and livestock [1]
The purpose of this study is to genetically identify tick samples and confirm whether the distinctive phenotypic traits for tick species differentiation are congruent with genetic traits
Ethics statement The ethics committee of the Kenya Wildlife Service (KWS) approved the study as it was based on opportunistic tick collection from immobilized elephants, buffaloes and rhinoceros during translocation, collaring and veterinary exercises in Lake Nakuru and Tsavo National Parks

Summary

Introduction

Ticks are ubiquitous blood feeding ectoparasites of humans and animals and are vectors of a plethora of pathogens that cause severe infectious diseases in humans and livestock [1]. The diversity and number of wildlife species is enormous all over the world and this diversity sustain a large and diverse tick- borne vectors of pathogens [3,4]. Most wild herbivores, including buffaloes and elephants are believed to be significant reservoirs of tick-borne pathogens that affect humans and animals [5] as they support a large population of tick species [6]. Morphological characterization based on phenotypic traits has been the traditional method of identifying ticks. Morphological identification method is further weakened by the fact that traits used to differentiate species tend to overlap between species or vary within species or according to age and size [7]. The advent of molecular techniques and development of markers that can identify ticks have revolutionized our understanding of other insect vectors and may be useful in studies of tick taxonomy and diversity

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