Rabies outbreak in black-backed jackals (Canis mesomelas), South Africa, 2016

C. T. Sabeta,T. Suzuki,D. Mohale,K. Mogano,K. Makita,E. Ngoepe,J. G. Chirima

doi:10.1017/s0950268821002685

Abstract

Rabies, a fatal and vaccine-preventable disease, is endemic throughout Africa. In 2016, a rabies outbreak occurred in black-backed jackals (Canis mesomelas) along the western boundary of Gauteng Province, South Africa. We investigated the possible drivers of the 2016 outbreak and established its origin. Using spatio-temporal locations of cases, we applied logistic regression and Geographic Information System techniques to investigate environmental covariates driving occurrences of emerging rabies cases in Gauteng Province. About 53.8% of laboratory-confirmed lyssaviruses in Gauteng Province in 2016 originated from jackals. Phylogenetic trees reconstructed from a partial region of the glycoprotein gene of these and historical rabies viruses (RABVs) demonstrated the lyssaviruses to be of canid origin with 97.7% nucleotide sequence similarity. The major cluster comprised jackal RABVs from the 2012 KwaZulu/Natal outbreak and the 2016 outbreak in Gauteng Province. The second cluster was composed of both jackal and dog RABVs. Both clusters correlated with independent RABV introductions into Gauteng by dogs and jackals, respectively. This study demonstrated an expansion of a jackal rabies cycle from north-west Province into Gauteng Province during the 2016 dry period, as jackals ranged widely in search for food resources leading to increased jackal-dog interactions, reminiscent of the intricate links of domestic and wildlife rabies cycles in South Africa.

Highlights

Rabies virus (RABV), is a prototype species of the Lyssavirus genus (Rhabdoviridae family, order Mononegavirales), and currently consists of 17 viral species [1]
With the exception of two bovine samples (592/16 & 988/16), both with a +3 grading, apple-green fluorescing viral particles typical of lyssavirus infection against a reddish background were observed in 100% of the microscopic fields of all the smears examined under UV-fluorescence
Many rabies viruses (RABVs) positive cases were laboratoryconfirmed in black-backed jackals in 2016, coinciding with the 2016 rabies outbreak in this wildlife species on the periphery of the province

Summary

Introduction

Rabies virus (RABV), is a prototype species of the Lyssavirus genus (Rhabdoviridae family, order Mononegavirales), and currently consists of 17 viral species [1]. The domestic dog (Canis familiaris) is the primary vector species for rabies and is responsible for at least 59 000 human deaths annually [3], with the majority (≥95%) of these deaths occurring in the low endemic countries of Africa and Asia [4, 5]. In the rabies endemic regions of Africa and Asia, the disease is highly under-reported primarily due to inadequate diagnostic facilities and the long distances specimens have to be transported to reach the diagnostic facilities [5, 6]. The disease is still endemic in some wildlife species (such as red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in some European countries [8, 9]

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