The Rhipicephalus appendiculatus tick vector of Theileria parva is absent from cape buffalo (Syncerus caffer) populations and associated ecosystems in northern Uganda

I Obara,R P Bishop,D Odongo,P H Clausen,J Ahmed,J Krücken,G Owido,P Atimnedi,D Lubembe,A Nijhof,S Mwaura,N Githaka,D Mijele,A Njeri,A Nanteza

doi:10.1007/s00436-020-06728-x

Abstract

Rhipicephalus appendiculatus is the major tick vector of Theileria parva, an apicomplexan protozoan parasite that causes the most economically important and lethal disease of cattle in East and central Africa. The African cape buffalo (Syncerus caffer) is the major wildlife host of T. parva from southern Uganda and Kenya to southern Africa. We show herein that R. appendiculatus appears to be absent from the two largest national parks in northern Uganda. Syncerus caffer is common in both of these national parks, specifically Murchison falls (MFNP) and Kidepo Valley (KVNP). We re-confirmed the previously reported absence of T. parva in buffalo sampled in the two northern parks based on RLB data using a nested PCR based on the T. parva p104 gene. By contrast, T. parva-infected R. appendiculatus ticks and parasite-infected buffalo were present in Lake Mburo (LMNP) in South central Uganda. This suggests that the distribution of R. appendiculatus, which is predicted to include the higher rainfall regions of northern Uganda, may be limited by additional, as yet unknown factors.

Highlights

The distribution of ixodid tick species, including Rhipicephalus appendiculatus, is believed to be determined primarily by climatic factors, combined with the availabilitySection Editor: Bruno GottsteinMakerere University, Kampala, Uganda 4 School of Biological Sciences, University of Nairobi, Nairobi, Kenya 5 Uganda Wildlife Authority, Kampala, Uganda 6 Kenya Wildlife Service, Nairobi, Kenya 7 Department of Veterinary Microbiology & Pathology, WashingtonState University, Pullman, WA, USA of permissive mammalian hosts on which nymphal and adult ticks can feed to repletion
We demonstrate that in ecosystems typified by the two National parks in northern Uganda, both the R. appendiculatus tick vector and the T. parva parasite are not associated with Cape buffalo populations
The distribution of ixodid ticks and T. parva infection in buffalo was analysed in Murchison Falls National Park (MFNP) and Kidepo Valley National Park (KVNP) in northern Uganda, together with Lake Mburo national park (LMNP) in South central Uganda

Summary

Introduction

The distribution of ixodid tick species, including Rhipicephalus appendiculatus, is believed to be determined primarily by climatic factors, combined with the availability. For example at the wildlife-livestock disease interface, transmission of Theileria parva to cattle involves the African cape buffalo (Syncerus caffer), the major mammalian wildlife host, that is asymptomatic when infected with T. parva by the ixodid tick R. appendiculatus (Norval et al 1992; Young et al 1973). We demonstrate that in ecosystems typified by the two National parks in northern Uganda, both the R. appendiculatus tick vector and the T. parva parasite are not associated with Cape buffalo populations. The data indicates the absence of a buffalo wildlife reservoir of T. parva that could infect cattle in the northern Uganda region of East Africa. The surprising absence of R. appendiculatus in this region suggests a requirement for in-depth investigation of parameters determining the distribution of the tick, with implications for the wider dissemination of T. parva and East coast fever in hitherto unaffected regions of sub-Saharan Africa

Materials and methods

Results and discussion

Compliance with ethical standards