Census and vaccination coverage of owned dog populations in four resource-limited rural communities, Mpumalanga province, South Africa

The seroprevalence of African horse sickness virus, and risk factors to exposure, in domestic dogs in Tshwane, South Africa

Dogs are the only non-equid species to develop the fatal form of African horse sickness (AHS). Research conducted in 2013 questioned the long-held belief that naturally occurring cases of AHS in dogs were contracted exclusively through the ingestion of contaminated horse meat. Culicoides midges, the vector of AHS virus (AHSV) for horses, have an aversion to dog blood meals and dogs were believed to be dead-end or incidental hosts. More recently, dog mortalities have occurred in the absence of horse meat consumption and vector transmission has been suspected. The current study is a retrospective serological survey of AHSV exposure in dogs from an endemic area. Dog sera collected from dogs (n = 366) living in the city of Tshwane, Gauteng Province, South Africa, were randomly selected from a biobank at a veterinary teaching hospital, corresponding to the years 2014-2019. The study used a laboratory in-house indirect recombinant VP7 antigen-based enzyme-linked immunosorbent assay (iELISA) with a test cut-off calculated from AHSV exposure-free dog sera (n = 32). Study AHSV seroprevalence was 6 % (22/366) with an estimated true prevalence of 4.1 % (95 % confidence interval (CI) = 1.3-8.1 %). Incidence was estimated for dogs with multiple serological results with seroconversion occurring at a rate of 2.3 seroconversions per 10 dog years at risk (95 % CI = 0.6-6.2). A subsection of the study sera was tested with AHSV viral neutralisation test (VN) (n = 42) for serotype determination. Antibodies to AHSV serotype 6 were most prevalent (90 %) in VN seropositive dogs (n = 20) with most dogs seemingly subclinically infected (>95 %). Seroprevalence descriptively varied by year and identified risk factors were annual rainfall > 754 mm (odds ratio (OR) = 5.76; 95 % CI = 2.22 - 14.95; p < 0.001), medium human population densities, 783-1663 people/km² (OR = 7.14; 95 % CI = 1.39 - 36.73; p = 0.019) and 1664-2029 people/km² (OR = 6.74; 95 % CI = 1.40 - 32.56; p = 0.018), and the month of March (OR = 5.12; 95 % CI = 1.41 - 18.61; p = 0.013). All identified risk factors were consistent with midge-borne transmission to dogs. The relatively high seroprevalence and seroconversion rates suggest frequent exposure of dogs to AHSV and indicates the need to investigate the role dogs might play in the overall epidemiology and transmission of AHSV.

Owned and free-roaming dogs in the North West of Tunisia: estimation, characteristics and application for the control of dog rabies

Understanding the structure of dog population and the evaluation of the accessibility of dogs to vaccination is essential to succeed in the fight against dog rabies and to adapt the strategy of its control. We studied the characteristics of the unowned and owned dogs using the beck method during a rabies vaccination campaign in randomly selected sectors (urban and rural sites) in the North West of Tunisia. During a door-to-door investigation of households, data on owned dogs were collected to describe the owned population dog. A photographic-recapture method was used to characterize and estimate the size of the unowned dogs. A total of 1432 households accounting for 5403 inhabitants were interviewed during the survey (1298 (90.6%) in the urban site and 134 (9.3%) in the rural site). The dog-owning households were significantly higher in the rural site (76.1% (102/134)) compared to the urban site (17.8% (231/1298)) (P < 0.000000). Of the 17.8% dog-owning households in urban site, 58.4% owned one dog and 9% between 4 and 8 dogs. While, of the 76.1% dog-owning households in rural site, 24.5% owned one dog and 32.3% owned between 4 and 10 dogs. The dog: human ratio was 1:11 in the urban site and 1:1.6 in the rural site. The dog population density was estimated at 16 dogs/km2 and 4 dogs/km2 in the urban and rural sites, respectively. The confinement practices varied significantly among the urban and rural sites (P < 0.000000). The percentage of free-roaming owned dogs was 51.1% in the rural site and 31.4% in the urban site. More than 60.0% of the owned dogs in the urban site were confined. The majority of dogs in the rural site were born in the house, although, a high percentage (56.7%) of owned dogs in the urban site was adopted from neighbours, others sectors, or countries. The vaccination coverage findings indicated that 77.8% and 84.2% of the owned dog were vaccinated in the urban and rural sites, respectively. The estimated size of the free-roaming dogs was 72 dogs in the urban site (Kalaat Senan) and 16 dogs in the rural site (Sod el Khir).

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.

Patterns of rabies cases in South Africa between 1993 and 2019, including the role of wildlife

Rabies is a global viral zoonosis endemic to South Africa, resulting in fatal encephalitis in warm-blooded animals, including humans. The loss of human lives and economic losses in rural areas through loss of livestock are substantial. A review was conducted of all confirmed animal rabies cases in South Africa from 1993 to 2019, with a total of 11 701 cases identified to species level to assess the role that wildlife plays in the epidemiology of rabies. A spatio-temporal cluster analysis using a discrete Poisson space-time probability model, accounting for underlying estimated dog and livestock densities, identified 13 significant clusters (p < .05). These included four long-term clusters lasting more than 8 years in duration and seven short-term clusters lasting less than 2 years, with the remaining two clusters being of intermediate length. Outside of these endemic clusters, wildlife outbreaks in the remainder of South Africa were often less than one and a half years in duration most likely due to the rapid decline of wildlife vectors, especially jackals associated with rabies infection. Domestic dogs accounted for 59.8% of cases, with domestic cats (3.2%), livestock (21.1%) and wildlife (15.8%) making up the remainder of the cases. Yellow mongoose (Cynictis penicillata) was the most frequently affected wildlife species, followed by bat-eared fox (Otocyon megalotis), black-backed jackal (Canis mesomelas), meerkat (Suricata suricatta) and aardwolf (Proteles cristatus). Rabies in wildlife species followed different spatial distributions: black-backed jackal cases were more common in the north-western parts of South Africa, yellow mongoose cases more frequent in central South Africa, and bat-eared fox and aardwolf cases were more frequent in southern and western South Africa. Clusters often spanned several provinces, showing the importance of coordinated rabies control campaigns across administrative boundaries, and high-risk areas were highlighted for rabies in South Africa.