Diversity of trypanosomes in wildlife of the Kafue ecosystem, Zambia.

David Squarre,Herman Chambaro,Junya Yamagishi,Boniface Namangala,Ladslav Moonga,Naoko Kawai,Alex Gaithuma,Chihiro Sugimoto,Kyoko Hayashida

doi:10.1016/j.ijppaw.2020.04.005

Abstract

The Kafue ecosystem is a vast conservation protected area comprising the Kafue National Park (KNP) and the Game Management Areas (GMA) that act as a buffer around the national park. The KNP has been neglected as a potential foci for rhodesiense sleeping sickness despite the widespread presence of the tsetse vector and abundant wildlife reservoirs. The aim of this study was to generate information on circulating trypanosomes and their eminent threat/risk to public health and livestock production of a steadily growing human and livestock population surrounding the park. We detected various trypanosomes circulating in different mammalian wildlife species in KNP in Zambia by applying a high throughput ITS1-polymerase chain reaction (PCR)/nanopore sequencing method in combination with serum resistant associated-PCR/Sanger sequencing method. The prevalence rates of trypanosomes in hartebeest, sable antelope, buffalo, warthog, impala and lechwe were 6.4%, 37.2%, 13.2%, 11.8%, 2.8% and 11.1%, respectively. A total of six trypanosomes species or subspecies were detected in the wildlife examined, including Trypanosoma brucei brucei, T. godfreyi, T. congolense, T. simiae and T. theileri. Importantly we detected human infective T. b. rhodesiense in buffalo and sable antelope with a prevalence of 9.4% and 12.5%, respectively. In addition, T. b. rhodesiense was found in the only vervet monkey analyzed. The study thus reaffirmed that the Kafue ecosystem is a genuine neglected and re-emerging foci for human African trypanosomiasis. This is the first assessment of the trypanosome diversity circulating in free-ranging wildlife of the KNP.

Highlights

African trypanosomiasis affects both human and livestock populations in sub-Saharan Africa, resulting in measurable socio-economic and public health impacts, especially in poor rural communities (Mwiinde et al, 2017; Simwango et al, 2017; World Health Organization [WHO], 2015a)
The subspecies of Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense are responsible for human African trypanosomiasis (HAT), which is known as sleeping sickness (Deborggraeve et al, 2008)
internal transcribed spacer 1 (ITS1)-polymerase chain reaction (PCR) revealed that 17 wildlife animals were found to be infected by Trypanosoma spp

Summary

Introduction

African trypanosomiasis affects both human and livestock populations in sub-Saharan Africa, resulting in measurable socio-economic and public health impacts, especially in poor rural communities (Mwiinde et al, 2017; Simwango et al, 2017; World Health Organization [WHO], 2015a). The inherent foci and circulation of rHAT and nagana in Zambia follow an endemic vector distribution mostly in conservation areas and surrounding areas (Van den Bossche et al, 2010). Wildlife in these conservation areas serve as animal reservoirs for rHAT. Encroachment of human developments and migration of people and their livestock into conservation areas can create, extend or intensify the scale of the existing interface within conservation areas (Bengis et al, 2002; Mweempwa et al, 2015; Stoddard et al, 2009) This has led to increasingly frequent encounters between the vector and human communities, facilitating the spillover of infection from wildlife reservoirs into the human populations and livestock. More than any other disease, trypanosomiasis is closely associated with the conservation of biodiversity (Anderson et al, 2015)

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