Diversity of trypanosomes in wildlife of the Kafue ecosystem, Zambia

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.

Keywords: Kafue national park; Reservoir; Trypanosoma brucei rhodesiense.

Graphical abstract

Fig. 1

The Kafue ecosystem comprising of the KNP and surrounding GMAs. The black spots indicate sampling points and the red spots indicate areas where rHAT was detected. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

ITS1-PCR Gel analysis Gel image of the ITS-PCR-positive samples. The species were estimated by the band size. The expected sizes for each species are T. godfreyi: 220 bp, T. simiae: 331–343 bp, T. theileri: 269–350 bp, T. brucei: 415–431 bp, T. congolense: 560–705 bp (Gaithuma et al., 2019).

Fig. 3

The sequences of SRA-PCR–positive samples from buffalo, sable antelope, and vervet monkey are determined and the deduced amino acid were aligned with deposited representative sequences from Zambia, Kenya, and Uganda.