Oral bait preferences for rabies vaccination in free-ranging black-backed jackal (Canis mesomelas) and non-target species in a multi-site field study in a peri-urban protected area in South Africa

Retrospective analysis of sero-prevalence and bait uptake estimations in foxes after oral rabies vaccination programmes at European level: Lessons learned and paths forward

Rabies caused by the Classical Rabies Virus (Lyssavirus rabies abbreviated RABV) in the European Union has been close to elimination mainly thanks to Oral Rabies Vaccination (ORV) campaigns targeting wildlife (primarily red foxes). ORV programmes co-financed by the European Commission include a monitoring-component to assess the effectiveness of the ORV campaigns at national level. This assessment is performed by a random collection of red foxes in the vaccinated areas with control of antibodies presence by serological analysis and control of bait uptake by detection of biomarkers (tetracycline incorporated into the baits) in the bones and teeth. ORV programmes aim to a vaccine coverage high enough to immunize (ideally) 70 % of the reservoir population to control the spread of the disease. European Union (EU) programmes that led to almost elimination of rabies on the territory have been traditionally found to have a bait uptake average of 70 % (EU countries; 2010-2020 period) while the seroconversion data showed an average level of 40 % (EU countries; 2010-2020 period). To better understand variations of these indicators, a study was been set up to evaluate the impact of several variables (linked to the vaccination programme itself and linked to environmental conditions) on the bait uptake and the seroconversion rate. Thus, pooling data from several countries provides more powerful statistics and the highest probability of detecting trends. Results of this study advocate the use of a single serological test across the EU since data variation due to the type of test used was higher than variations due to field factors, making the interpretation of monitoring results at EU level challenging. In addition, the results indicates a negative correlation between bait uptake and maximum temperatures reached during ORV campaigns questioning the potential impact of climatic change and associated increase of temperatures on the ORV programmes efficiency. Several hypotheses requesting additional investigation are drawn and discussed in this paper.

A Case Report on a Human Bite Contact with a Rabid Honey Badger Mellivora capensis (Kromdraai Area, Cradle of Humankind, South Africa)

In South Africa, rabies cycles are sustained by both domestic and wildlife host species. Despite the fact that the majority of human rabies cases are associated with dog bite exposures, wildlife species can potentially transmit rabies virus (RABV) infection to humans. In July 2021, a honey badger (Mellivora capensis) from the Kromdraai area (Gauteng Province) bit a dog on a small farm. The following day the same honey badger attacked three adults in the area, with one of the victims requiring hospitalization for management of her injuries. The honey badger was subsequently shot and the carcass submitted to the Agricultural Research Council-Onderstepoort Veterinary Research (ARC-OVR) for RABV diagnosis. A positive rabies diagnosis was confirmed and phylogenetic analysis of the amplified glycoprotein gene of the rabies virus demonstrated the virus to be of dog origin.

Antibody response to Raboral VR-G® oral rabies vaccine in captive and free-ranging black-backed jackals (Canis mesomelas)

Rabies is a zoonotic disease that remains endemic in large parts of southern Africa because of its persistence in wildlife and domestic dog vectors. The black-backed jackals (Canis mesomelas) is primarily the wildlife vector responsible for rabies outbreaks in northern parts of South Africa. Two trials were carried out to investigate antibody responses to the oral rabies vaccine Raboral V-RG® in black-backed jackals under captive and free-ranging conditions. In captive jackals 10/12 (83%; 95% confidence interval [CI]: 52% - 98%), seroconverted after single oral vaccination. Nine captive jackals had protective antibody titres ( 0.5 IU/mL) at 4 weeks (median: 2.1 IU/mL; inter quartile range [IQR]: 0.6-5.7) and 10 jackals had at 12 weeks (median: 3.5 IU/mL; IQR: 1.5-8.3) and three maintained antibody titres for up to 48 weeks (median: 3.4 IU/mL; IQR: 2.0-6.3). Four sites were baited with Raboral V-RG® vaccine for wild jackals, using fishmeal polymer and chicken heads. Baits were distributed by hand or from vehicle at three sites in north-eastern South Africa, with an average baiting density of 4.4 baits/km2 and at one site in central South Africa, at 0.12 baits/km2. This resulted in protective antibody titres in 3/11 jackals (27%; 95% Cl: 6-61) trapped between 3 and 12 months after baiting in north-eastern South Africa, compared with 4/7 jackals (57%; 95% Cl: 18-90) trapped after 3-18 months in central South Africa. This study shows the potential utility of oral rabies vaccination for the control of wildlife-associated rabies in north-eastern and central South Africa, but extensive studies with wider distribution of bait are needed to assess its potential impact on rabies control in wild jackals.

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

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.

The golden jackal (Canis aureus) and the African swine fever pandemic: Its role is controversial but not negligible (a diet analysis study)

Background

In Europe, the African swine fever (ASF) pandemic mostly affects the environmental domain of health, which is a strongly human‐impacted ecosystem. However, the current control strategies focus solely on the wild boar and tend to disregard other epidemiologically relevant elements of the ecosystem.

Objectives

This study investigated the potential impact of the golden jackal on the surveillance effort and disease transmission.

Methods

For this reason, the authors analysed the content of 277 stomachs of this canid species within its westernmost inhabitant population, in order to determine the amount of suid remains, disposed.

Results

The findings confirmed that in a densely populated wild boar habitat, the main diet component of jackals was wild boar all the year round. The jackals disposed of 0.3–0.6 kg/km²/day offals that potentially contained suid remains. On the other hand, the scavenging activity removed the most important target objects on which the passive surveillance of ASF should be based.

Conclusions

This study cannot determine whether canid scavengers positively or negatively influence the control efforts; however, the impact of the jackal should not be disregarded. The results warn the necessity of a multidisciplinary approach to complex epidemiological situations within different ecosystems.

Carnivore Detection at the Domestic/Wildlife Interface within Mpumalanga Province, South Africa

Simple Summary

The management of carnivore populations in protected areas includes disease management and census taking. The presence of prey species and environmental variables influence the detection of wild carnivore species. The aim of this study was to identify the important predictors of wild carnivore detection within two South African wildlife reserves using motion-detection camera traps. The study further investigated the difference between traditional census call-up surveys and camera traps within nearby locations. Buffalo, impala, and warthog were associated with lion and spotted hyena detections. Detections of lions and spotted hyenas and also leopards and spotted hyena were correlated, suggesting competition between these wild carnivore species. Competition among wild carnivore species has importance for implementing appropriate management procedures, including infectious disease prevention.

Abstract

South African protected areas account for 8% of the total landmass according to World Bank indicators. Effective conservation of biodiversity in protected areas requires the development of specific reserve management objectives addressing species and disease management. The primary objective of the current study was to identify predictors of carnivore detection in an effort to inform carnivore species management plans on Andover and Manyeleti nature reserves in South Africa. A limited number of camera traps were placed randomly using a grid system. Species detection data were analysed using mixed-effects logistic regression and Spearman’s correlation coefficients. Deterministic inverse distance weighted distribution maps were used to describe the spatial distribution of carnivore species. Camera traps identified similar species as traditional call-up surveys during the study and would be useful as an adjunct census method. Carnivore detection was associated with several variables, including the presence of specific prey species. The measured intra-and interspecies interactions suggested the risk of disease transmission among species, and vaccination for prevalent diseases should be considered to manage this risk.

Risk factors for rabid animal bites: a study in domestic ruminants in Mymensingh district, Bangladesh

Rabies is endemic in Bangladesh. To identify risk factors, a case-control study was conducted based on hospital-reported rabid animal bite (RAB) cases in domestic ruminants, 2009 − 2018. RAB cases (n = 449) and three controls per case were selected. Dogs (87.8%) and jackals (12.2%) were most often identified as biting animals. In the final multivariable model, the risk of being a RAB case was significantly higher in cattle aged >0.5–2 years (odds ratio (OR) 2.89; 95% confidence interval (CI): 1.56–5.37), >2–5 years (OR 3.63; 95% CI: 1.97–6.67) and >5 years (OR 6.42; 95% CI: 3.39–12.17) compared to those aged <0.5 years. Crossbred cattle were at higher risk of being a RAB case (OR 5.48; 95% CI: 3.56–8.42) than indigenous. Similarly, female cattle were more likely to be a RAB case (OR 1.26; 95% CI: 1.15–2.29) than males. Cattle in rural areas (OR 39.48; 95% CI: 6.14–254.00) were at a much higher risk of being RAB cases than those in urban areas. Female, crossbred and older cattle, especially in rural areas should either be managed indoors during the dog breeding season (September and October) or vaccinated. A national rabies elimination program should prioritise rural dogs for mass vaccination. Jackals should also be immunised using oral bait vaccines. Prevention of rabies in rural dogs and jackals would also reduce rabies incidence in humans.

Update on lyssaviruses and rabies: will past progress play as prologue in the near term towards future elimination?

Rabies is an ancient, much-feared, and neglected infectious disease. Caused by pathogens in the family Rhabdoviridae, genus Lyssavirus, and distributed globally, this viral zoonosis results in tens of thousands of human fatalities and millions of exposures annually. All mammals are believed susceptible, but only certain taxa act as reservoirs. Dependence upon direct routing to, replication within, and passage from the central nervous system serves as a basic viral strategy for perpetuation. By a combination of stealth and subversion, lyssaviruses are quintessential neurotropic agents and cause an acute, progressive encephalitis. No treatment exists, so prevention is the key. Although not a disease considered for eradication, something of a modern rebirth has been occurring within the field as of late with regard to detection, prevention, and management as well as applied research. For example, within the past decade, new lyssaviruses have been characterized; sensitive and specific diagnostics have been optimized; pure, potent, safe, and efficacious human biologics have improved human prophylaxis; regional efforts have controlled canine rabies by mass immunization; wildlife rabies has been controlled by oral rabies vaccination over large geographic areas in Europe and North America; and debate has resumed over the controversial topic of therapy. Based upon such progress to date, there are certain expectations for the next 10 years. These include pathogen discovery, to uncover additional lyssaviruses in the Old World; laboratory-based surveillance enhancement by simplified, rapid testing; anti-viral drug appearance, based upon an improved appreciation of viral pathobiology and host response; and improvements to canine rabies elimination regionally throughout Africa, Asia, and the Americas by application of the best technical, organizational, economic, and socio-political practices. Significantly, anticipated Gavi support will enable improved access of human rabies vaccines in lesser developed countries at a national level, with integrated bite management, dose-sparing regimens, and a 1 week vaccination schedule.