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- Every year producers suffer substantial losses because of their cattle contracting lumpy skin disease – yet this disease is entirely preventable.
- Lumpy skin disease remains a major concern in the livestock industry.
- The disease is entirely preventable if the vaccine is properly administered.
- Only young animals older than six months of age should be vaccinated against lumpy skin disease.
- Lumpy skin disease and its effects are 100% preventable if producers work closely with their veterinarians.
Every year producers suffer substantial losses because of their cattle contracting lumpy skin disease – yet this disease is entirely preventable. This insect-borne viral disease appears annually in late summer and autumn when biting insect numbers tend to peak.
Lumpy skin disease remains a major concern in the livestock industry. Outbreaks can occur in some years with a higher rainfall. The current veterinarian disease reporting system – now available as an electronic map on the Red Meat Industry Services (RMIS) website (Figure 1) – unequivocally shows that the incidence of this disease increased over the past two years.
One of the reasons for the disease reporting system is to confirm whether diseases such as lumpy skin disease are indeed under control since we do have a highly effective vaccine available to prevent it.
Figure 1: Distribution of lumpy skin disease in South Africa.
Read more about seasonal diseases in spring and summer.
Cause and spread of the disease
Cattle are the only livestock susceptible to lumpy skin disease. It is caused by a smallpox virus which specifically targets and damages the cells of the skin (external), and the mucous membranes lining the internal organs (internal). It causes visible skin lesions and discernible lumps in and beneath the skin.
Affected animals present with a high fever, walk slowly and with difficulty, and refrain from feeding during the acute phase of the disease. The disease affects all susceptible beef and dairy cattle, as well as suckling calves in cases where the dams do not possess acquired immunity (through vaccination or previous natural exposure).
If the disease is moderate, the skin lumps will shrink once the animal starts developing immunity to the virus; in severe cases, however, the lumps may burst open. Secondary bacterial infection can contribute to the development of severe skin lesions (these can be treated with antibiotics).
Invisible losses
The aforesaid merely entails the visible part of the disease. During slaughter or a post-mortem on such an animal, closer investigation will reveal extensive damage to the subcutaneous tissue – this is the invisible part. In addition, the mucous membranes lining the organs (for example airway, lungs, gastrointestinal tract, uterus [cows] and testicles [bulls]) are also affected. This can lead to tissue damage and secondary bacterial infection.
Cows can abort and bulls can become infertile due to the fever reaction and damage to internal organs; infertility in bulls may become permanent if the viral infection damages the tissue of the testicles. If the outbreak is severe, up to 5% of cattle may succumb as a result of a secondary bacterial infection such as pneumonia, or as a result of severe damage to organs such as the heart.
Since lumpy skin disease is a viral disease, there is no primary treatment, and all treatment options are supportive until the animals themselves develop sufficient immunity to combat the virus.
Lumpy skin disease entered South Africa from the north 80 years ago, and veterinary researchers at the Onderstepoort Veterinary Institute conducted world-class research over many decades in a bid to develop a vaccine to fight it. They ultimately developed an extremely effective vaccine from a live attenuated strain of the virus. The disease is entirely preventable if the vaccine is properly administered.
Read more about Guard against eye diseases in livestock.
There is only one solution
The challenge in this case is obvious, namely that many cattle producers do not work together with their veterinarians to implement a vaccination programme that can prevent losses caused by the disease.
Only young animals older than six months of age should be vaccinated against lumpy skin disease. These highly susceptible replacement animals are the first ones that need protecting. Vaccinate the mature herd annually; vaccinations can be scaled back once the mature herd has been vaccinated for two years and longer.
The attenuated vaccine provides effective immunity after the second annual vaccination, which will protect the cattle in the long term. Lumpy skin disease and its effects are 100% preventable if producers work closely with their veterinarians who, based on the reliable data supplied via the disease monitoring and reporting system, know exactly how big the problem in their region is.
For more information, send an email to Dr Danie Odendaal at vnet1@absamail.co.za. – Dr Danie Odendaal, director, Veterinarian Network
