Lumpy skin disease (LSD), the infectious, eruptive, occasionally fatal disease continues to cause serious economic losses to many pastoral communities and livestock farmers in Africa.
In fact, veterinarians who know exactly how big the problem is report that mortality rates, as a result of LSD infection, are as high as 40 per cent or more.
According to Dr. Glyn Davies, the head of the ODA Virology Project, Veterinary Research Laboratories, Kenya, mortality rates of 10 to 40 per cent and even higher have been reported on occasion but the much lower range of 1 to 5 per cent is more usual.
This has caused economic losses depending on the morbidity rates brought about by mortality, the loss of production, the depression of growth rates and hide damage.
Vaccination with attenuated virus
Although the veterinarian says there is no specific antiviral treatment available for LSD infected cattle, vaccination with attenuated virus (weakened form of LSD) offers the most promising method of control and was effective in halting the spread of the disease.
“There is no specific antiviral treatment available for LSD-infected cattle. Two vaccines, however, Neethling and Kenya sheep and goat pox virus, have been used widely in Africa with success,” stated Davies in a study on Lumpy skin disease of cattle: A growing problem in Africa and the Near East published by the Food and Agriculture Organization (FAO) of the United Nations.
Dr Danie Odendaal, director, Veterinarian Network opines that veterinary researchers at the Onderstepoort Veterinary Institute developed an extremely effective vaccine from a live attenuated strain of LSD to curb the virus after it entered South Africa from the north 80 years ago.
“The disease is entirely preventable if the vaccine is properly administered,” said the veterinarian in an article for the Plaas Media.
According to him, one of the greatest challenges in this is that many cattle producers do not work together with their veterinarians to implement a vaccination programme that can prevent losses caused by the disease.
“Lumpy skin disease and its effects are 100% preventable when producers work closely with their veterinarians,” wrote Odendaal.
Young animals over six months old should be the first to receive the lumpy skin disease vaccine, as they are highly susceptible. The mature herd should be vaccinated annually, with the frequency reduced after two years of consistent vaccination.
The attenuated vaccine provides effective immunity after the second annual vaccination, protecting the cattle in the long term.
According to Dr. Davies, ring vaccination with a sheep pox strain can also help.
Other control measures
Additionally, it is recommended that sick animals may be removed from the herd and given supportive treatment consisting of local wound dressing to discourage fly worry and prevent secondary infections.
During the time, noted Dr. Davies, systemic antibiotics may be given for skin infections, cellulitis or pneumonia, and food and water should be made readily available.
He recommends that should LSD appear in cattle in another country beyond its previous range, all infected and contact cattle be slaughtered immediately and the carcasses destroyed in an attempt to eliminate the focus of infection. A vaccination cover with a 25 to 50 km radius may then be established around the focus and all cattle movements stopped within that zone.
History of lumpy skin disease
According to Dr. Davies, LSD was first reported in Zambia in 1929 and initially mistaken for poisoning or insect bite hypersensitivity. By the 1940s, it had spread to southern African countries, and its infectious nature was recognized during a major outbreak in South Africa, affecting millions of cattle. The disease later spread to East and West Africa, reaching Kenya in 1957 and Sudan in 1972.
In 1988, LSD was identified in Egypt, likely introduced through imported cattle, and quickly spread across the country. It later appeared in Israel in 1989 but was eradicated through culling and vaccination.
Today, LSD remains enzootic in sub-Saharan Africa and continues to threaten new regions, with concerns about its potential spread to North Africa and the Middle East.
Infection, symptoms and effects
Lumpy Skin Disease (LSD) is an acute infectious disease primarily affecting cattle of all ages, with rare cases reported in Asian water buffalo. The disease has an incubation period of 4–14 days and manifests with fever (40–41.5°C), lacrimation, nasal discharge, and hypersalivation.
Affected animals may show anorexia, depression, reluctance to move, and characteristic skin eruptions that develop into firm, raised nodules (5–50 mm in diameter) over various body parts, including the head, neck, perineum, udder, genitalia, and limbs. These lesions penetrate the full skin thickness and may be surrounded by a hemorrhagic ring.
As the disease progresses, nasal and oropharyngeal secretions increase, often accompanied by ulcerative lesions in the mouth, respiratory tract, and alimentary tract. Secondary bacterial infections can exacerbate symptoms, leading to mucopurulent discharges, persistent salivation, coughing, conjunctivitis, and keratitis. Swellings in the brisket, limbs, and genitalia may occur, further impacting mobility.
Severely affected animals suffer from necrotic skin sloughing, emaciation, and prolonged debility lasting one to six months. Milk production ceases, and feeding difficulties arise due to painful mouth lesions. Bulls may experience temporary infertility due to genital sores. Pneumonia is a common secondary complication, and abortion rates increase following outbreaks.
While mortality is usually low, LSD significantly impacts cattle through reduced milk yield, loss of condition, and decreased hide value. In extreme cases, dehydration and starvation in pastoral systems contribute to further losses.
