Lumpy skin diseaseDr Johan Cloete

What is lumpy skin disease?Lumpy skin disease is one of the main production and profit eroding diseases of cattle in Africa. It is caused by a pox virus, and is characterised by permanent skin damage and a sharp decline in the fertility and productivity of the herd.

How can your cattle contract lumpy skin disease?The disease is mainly transferred by biting insects such as stable flies. Because of the mobility of the vector, the disease can spread over a large area from a single infected animal. Most cases occur in late summer and early autumn, usually after years of above-average rainfall2. Within herds, the disease also spreads where the animals share drinking and feeding troughs, because the saliva of infected animals often ends up in these troughs. Cows excrete the virus in their milk and in this way also infect their calves. People can also spread the disease by using

contaminated farming equipment (such as used needles amongst cattle during outbreaks), or when cattle are artificially inseminated with infected semen3.

Which animals are susceptible to the disease?All unvaccinated animals are susceptible and between 3 % and 85 % of a herd can be affected4. Calves from unvaccinated cows are also susceptible, but calves from vaccinated cows are protected until about 6 months of age. As far as could be assessed, wild animals do not play a significant role in the spread of this disease1, 4.

Which symptoms are present in cattle with lumpy skin disease?At first, cattle develop fever accompanied by increased saliva production and eye and nasal secretions. Sometimes conjunctivitis and enlarged lymph nodes will be seen, followed by raised skin nodules of 1 cm to 5 cm

in diameter4. These nodules are especially prominent is short hair cattle, and are present all over the body. Lesions sometimes go deeper than the skin and extend into the tendon/sinew sheaths of the legs, where it may also cause lameness and subcutaneous water retention (oedema). Ulceration of the mouth, trachea and stomach can also occur. Secondary pneumonia can follow in cases where airway ulceration occurs. Lesions that occur on the scrotum and penis can lead to inflammation of the testis, which in turn often causes temporary or even permanent infertility. Lesions on the udder often lead to mastitis and consequent loss of udder function4. Sharp declines (50 %) in milk production can be expected in cows with lumpy skin disease2, 4.

What treatments are applicable?Treatment is symptomatic only. For this reason, it is recommended to rather try and prevent the disease through annual vaccination, combined with the effective control of ectoparasite vectors. Symptomatic treatment depends on the degree to which the animal is affected, and may include rehydration and administration of anti-inflammatory drugs and antibiotics. Milk ointment or acriflavin glycerine can also be applied on ulcerated nodules.

Are there other diseases that resemble lumpy skin disease?Yes; the main culprit is pseudo-lumpy skin disease. A veterinarian, in conjunction with a laboratory, can assist to identify and diagnose it.

How can the disease be prevented?Vaccination is the most effective means of prevention. Control of biting insects such as flies helps to limit the spread of the disease. Susceptible

animals should be vaccinated annually, preferably in spring before the insect populations increase drastically. Because

it is an attenuated live vaccine, there may be a temporary reduction in milk production in dairy cattle. Calves

younger than 6 months old born from vaccinated cows, should not be vaccinated. Calves born from

unvaccinated cows, should be vaccinated as soon as possible. It is safe to vaccinate pregnant cows with LUMPYVAX®.

The disease outbreaks seem to occur in cycles every few years, and some producers consequently tend to stop vaccination during the ‘good years’. This results in large parts of

the national herd being left unprotected. This can lead to massive outbreaks, often with a shortage

of vaccine during such times, resulting from lower vaccine production in the previous years. Plan ahead

and do not allow yourself to be caught by surprise!

Can animals still contract lumpy skin disease after vaccination?

It is possible that cases of lumpy skin disease may occur in a vaccinated herd. However, this is more often than not the result of one or more of the following secondary reasons4:

• The animal is already incubating the disease at the time of vaccination (as is often the case during an outbreak).

• Improper vaccine handling (e.g. breaking the cold chain, administration of expired vaccine, exposure to sunlight, freezing the vaccine and not using the reconstituted vaccine immediately).

• Incorrect administration of the vaccine (e.g. needle stuck accidentally through the skin or vaccine administered at the incorrect dose).

• Vaccinating calves before 6 months of age that was born from cows that were vaccinated before calving.

• In any population of animals there are always a very small percentage of animals that do not develop a good immunity despite vaccination. In addition, large viral loads (high infection levels) may overwhelm the immune system of some animals.

• Annual vaccination is recommended; if not, it is possible that some animals may lose their immunity.

What is the bottom line?Lumpy skin disease can be an economically devastating disease, but it can be prevented if vaccination is performed annually and correctly as per label instructions.References:

1. Coetzer, J. A. W. Lumpy skin disease. In: Infectious Diseases of Livestock: With Special Reference to Southern Africa. Eds: JAW Coetzer, GR Thomson & RC Tustin. 1994. Oxford University Press, Cornell University; Vol. 2, pp. 1268–1276.

2. Hunter, P. & Wallace, D. Lumpy skin disease in southern Africa : a review of the disease and aspects of control. Journal of the South African Veterinary Association 2001, 72 (2), 68–71.

3. Annandale, C.H, Holm, D.E, Ebersohn, K. & Venter, E. H. Seminal transmission of lumpy skin disease virus in heifers. Transboundary and Emerging Diseases, 2013, 61 (5), 443-448.

4. Tuppurainen, E.S.M, Oura, C.A.L Review: Lumpy skin disease: An emerging threat to Europe, the Middle East and Asia. Transboundary and Emerging Diseases, 2012, 59 (1), 40–48.

LUMPYVAX® G3673 (Act 36/1947), Namibia Reg. No. V06/24.4/184, Contains 104 TCID50 of freeze-dried, live, attenuated lumpy skin disease virus (SIS Neethling type) per 1 mℓ.