A070 - LUMPY SKIN DISEASE

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A070 - LUMPY SKIN DISEASE

Nature of the disease
Lumpy skin disease (LSD) is an acute virus disease of cattle characterised by eruption of variably sized skin nodules, oedema of the limbs and swelling of the superficial lymph nodes.
Classification
OIE List A disease
Susceptible species
LSD only affects cattle, although five cases have been seen in Asian water buffalo. European (Bos taurus) cattle are more susceptible than zebu (Bos indicus) cattle. Dairy breeds such as Jersey, Guernsey and Ayrshires are recognised as particularly susceptible.
Distribution
LSD occurs in Africa, south of the Sahara, and in Madagascar. It became established in Egypt in 1988 and spread to Israel where it has since been eradicated — the only country to achieve this. It may be present in other Middle Eastern countries.LSD has never been recorded in the Pacific region.
Clinical signs

LSD begins with fever, watery eyes, increased nasal secretions, loss of appetite, reduced milk production, depression and reluctance to move.
This is followed by the eruption of skin nodules that may cover the whole body. They can be found on any part of the body but are most numerous on the head and neck, perineum, genitalia and udder, and the limbs.
The nodules are 0.5–7 cm in diameter, slightly raised and extend the full thickness of the skin. Regional lymph nodes are enlarged and oedematous.Very few adult cattle die from LSD. However, there is a long period of debility leading to loss of production. Up to 10% of affected calves may die. Pregnant cows may abort.

Post-mortem findings
Nodules are found in the subcutaneous tissues, muscle fascia and muscles. They are grey-pink with necrotic cores. Nodules may also be found through the nasopharynx, trachea, bronchi, lungs, rumen, abomasum, renal cortex, testicles and uterus.
Differential diagnosis
· bovine herpesvirus 2 skin infection
· photosensitisation
· insect and tick bites
· skin allergies
· streptothricosis
· cutaneous tuberculosis
Specimens required for diagnosis
A presumptive diagnosis can be made on the clinical signs. To confirm the diagnosis, specimens should be collected.
Live animals
· sera
· nodular fluid
· scabs
· skin scrapings or skin biopsies
At post-mortem
Both fresh and fixed samples in formalin, should be taken from skin lesions and lesions in the respiratory and gastro-intestinal tract
Transmission
Capripox viruses are very resistant to inactivation and remain viable for long periods on or off the animal host.
Transmission by direct contact with infected animals can occur at a low level but this is not considered a major method of spread. Most infection is thought to be the result of insect transmission. Many different types of biting insects are thought to be involved. Transmission is thought to be mechanical rather than biological.
There is little information on spread through artificial breeding. Virus has been detected in semen up to 22 days after infection. Virus could be transmitted in milk.
Risk of introduction
Movement of infected animals is the main means by which LSD is spread to new areas. Because importation of live cattle or reproductive material from endemic countries does not occur, the risk of introducing LSD into Pacific Island countries would appear low.
Control / vaccines
An attenuated vaccine made from a capripox virus that affected both sheep and goats in Kenya has been produced. Immunity lasts at least two years, and probably for life. A South African LSD virus vaccine is also available. Local reactions at the site of injection occur in a high proportion of animals. It appears to provide good protection after a single inoculation.
References
  • GEERING WA, FORMAN AJ, NUNN MJ, Exotic Diseases of Animals, Aust Gov Publishing Service, Canberra, 1995, p155-162
  • Lumpy skin disease, In Merck Veterinary Manual, National Publishing Inc. Eight ed, 1998, Philadelphia, p 621-622
  • Lumpy skin disease, In Veterinary Medicine, Saunders, Eight ed, 1997, London p. 1131-1133
  • Office International des Epizooties, 2002