This is a lay summary of the article published under the DOI: 10.1111/tbed.14080
Researchers have called for animal vaccinations against rabies in South Africa, especially for the many dogs that might spread the disease in the Kwa-Zulu Natal province. They found that 44% of all animal rabies cases occur in this province after looking at patterns of how, when, and where this deadly disease spreads in the country.
Rabies is a disease that is nearly always fatal to warm-blooded animals, including humans, once symptoms begin. Researchers track how rabies spreads between animals because it can also spread from animals to humans in a phenomenon known as zoonosis.
Rabies is common in South Africa and harms rural areas in particular, partly due to livestock losses.
Researchers believe domestic dogs are the biggest spreader of rabies in South Africa, followed by livestock. The biggest wildlife rabies spreader is thought to be the black-jackal, but they are not usually aggressive so expert opinions differ.
In this study, researchers wanted to map exactly how domestic and wild animals are spreading rabies in the country.
They reviewed 11 701 rabies cases stored in a national database between 1993 and 2019. Then they analysed the data to find any patterns in how rabies spread over time and geographical space, and between animals.
They found that 60% of the cases reported were in domestic dogs, 21% in livestock, and 16% in wildlife.
Interestingly, the wild animal that most commonly had rabies was the yellow mongoose.
They also found that wild animals were the main way that rabies spread between groups of wild and domestic animals.
The KwaZulu-Natal province had 44% of all rabies cases because of the many dogs in the area. On the other hand, the Freestate province had the highest wildlife cases. Even so, rabies commonly spread across provincial borders.
Previous studies focused on learning how rabies infects individuals rather than looking at how it moves and spreads through and between groups over time and space.
These researchers say that one of the best ways to fight rabies in South Africa is through repeated vaccination campaigns, especially among dogs in KZN.
The South African researchers focused on their home country, but their findings may be useful for other parts of Africa where similar animals are found.
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 rabies cases in South Africa from 1993 to 2019, with a total of 11 701 cases identified to species level to assess the wildlife plays in the epidemiology of rabies. A spatiotemporal cluster analysis using a discrete Poisson space-time probability model, accounting for underlying estimated dog and livestock densities, identified 13 significant clusters (p<0.05). 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 penicillate) 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.
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