The rise in cases of lumpy skin disease in South Africa could have a severe economic impact, as the disease weakens livestock, permanently damages hides, and can lead to 10% more deaths and abortions, experts have warned.

“This year’s above-average rainfall has led to an increased risk of insect-transmitted diseases. We’re seeing increasing numbers of lumpy skin disease outbreaks in cattle in South Africa,” Professor Jannie Crafford of the University of Pretoria Faculty of Veterinary Science’s Department of Veterinary Tropical Diseases (DVTD) said.

Above: Latest disease reports (January 2022 map) by the Ruminant Veterinary Association of South Africa indicate lumpy skin disease outbreaks in eight provinces (Source: National Animal Health Forum)

The latest disease report by the Ruminant Veterinary Association of South Africa indicated lumpy skin disease outbreaks in eight provinces. James Faber, chairperson of the Red Meat Producers’ Organisation, said lumpy skin disease could have a devastating impact on cattle production. “When the lumps burst open they can scar the animal’s skin, and this damage will have to be cut out, often rendering the hide worthless. The disease can also damage an animal’s fertility, and this can extend a farmer’s entire production season. When weighing the impact of this disease against the cost of vaccines, there is no argument. Farmers cannot afford not to vaccinate their herds,” Faber said.

Prof Crafford added that lumpy skin disease outbreaks usually occur during wet summer and autumn months when the virus was spread by biting flies, mosquitoes, and hard ticks such as the African brown ear tick (Rhipicephalus appendiculatus), bont tick (Amblyomma hebraeum) and African blue tick (Rhipicephalus decoloratus).

“Direct contact between animals plays only a minor role in the transmission of the virus. However, calves that suckle from infected cows can become infected. Farmers should also be careful not to spread the disease by using the same needle during vaccination of the herd.”

Clinical signs of the disease include characteristic skin nodules, fever, salivation, nasal discharge, and pink eye (conjunctivitis), with corneal opacity and blindness in some cases. Prof Crafford warned that infection of the udder could cause mastitis and a significant drop in milk production, while lesions in the reproductive organs of bulls and cows could lead to infertility. “Damage to the udder and reproductive organs could be permanent in severe cases,” he said.

Above: Clinical signs of the disease include characteristic skin nodules. Photo: Faculty of Veterinary Science (UP)

There are several vaccines available for the prevention of lumpy skin disease, and farmers need to closely follow the instructions on the vaccine pamphlet when inoculating their cattle. The diagnosis could be confirmed by a laboratory through isolating the virus in a blood or lesion sample. “Lumpy skin disease is a notifiable disease, and all suspected cases need to be reported to the local state veterinarian,” Prof Crafford said.

** Based on a story published in the March 2022 edition of Farmer’s Weekly.