Lumpy skin disease

Naorem Bonson *

Introduction

Lumpy skin disease is an infectious viral disease of cattle. Originally found in Africa, it has also spread to countries in the Middle East, Asia & Eastern Europe.

All ages & breeds of cattle are affected but especially the young and cattle in the peak of lactation. The causative agent Capri-poxvirus, can also induce sheep pox and goat pox. Its incidence is highest in wet summer weather, but it may occur in winter. The disease is characterized by high fever and enlarged superficial lymph nodes on the skin & peculiar multiple nodules or lumps on the skin.

It can also lead to death, especially in animals that have not previously been exposed to the virus or how low immunity. The reason why the World Organization for Animal Health (OIE) has placed this transboundary disease on notifiable disease list is due to its significant economic losses & the potential for rapid disease.

Transmission

o The virus transmission occurs through the movement of animals or unrestricted movement of stray animals. Infected animals excrete viruses in saliva as well as in nasal and ocular discharges. It can remain in saliva for 11 days.

o The virus primarily transmitted by arthropod vectors like common biting flies, mosquitoes & some ticks are mainly responsible for its spread.

o The virus also persists in the semen of infected bulls, so natural mating & artificial insemination can also spread the disease.

o Disease can also spread from females to calves with skin nodules: suckling calves may get infection from milk. Virus remains viable in infected tissue of animals for around 120 days.

Sign & Symptoms

o Infected cattle develop fever, lacrimation nasal discharge and hypersalivation, followed by the characteristic eruptions on the skin and other parts of the body.
o Furthermore, the disease is characterized by firm, slightly raised, circumscribed skin nodules typically appear on the neck, legs, tail and back, shortly after the beginning of the fever.
o In most of the cases, diseased animals are experienced severe pain, limb swelling, loss of appetite & fever along with bleeding from the nodules.
o Pregnant cows may abort & remain in anestrous for several months.
o The morbidity rate various between 5 & 45%, the mortality rate is usually under 10%.

Economic Impact

o LSD has led to serious economic losses in affected countries. The disease causes a considerable reduction in milk yield, (from 10% to 85%) due to high fever & 2% mastitis.

Other consequence of the disease include damages hides, decline of the growth rate in beef cattle, temporary or permanent infertility, abortion, treatment & vaccination costs & death of infected animals.

Measures for prevention of disease

o In order to control lumpy skin disease, the movement of animals to & from the infected area should be completely restricted.

o Any livestock suspected of nodular skin disease along with fever should be isolated from the rest of the herd. If pox like lesions is observed in many animals simultaneously at the farm, take advice from a local vetenarion as soon as possible.

o Based on the symptoms, treatment of infected animal should be started immediately with all precautionary measures. Avoid visiting at other farms & do not allow anyone to your farm to stop spread of disease.

Disinfection of premises should be done at regular intervals.

o Disinfect the farm with 5% formalin (500ml in 10 liter of water) to minimize the risk of disease transmission.
o LSD vector can also control through application of insecticides.
o Large scale immunization of cattle along with restriction on the movement of animals is very effective measure to control the disease epidemic.
o Animal which are at least 5 to 6km from an infected area must be administered with doses.
o Proper disposal of the carcasses also play an important role in controlling the spread.

Ensure proper burial of dead animals, carcasses of affected animals should be disposed of through incineration or buried in pit with lime.

Conclusion

o LSD is one of the most economically significant transboundary, viral disease of domestic cattle. It is economically significant in animals because of chronic debility, decreased milk production and weight loss, damaged skins, abortion and mortality.

o The scientific literature suggests the arthropod transmission of LSD is the most likely strategy for which the virus spreads.

o Only mass vaccination were able to stop the spread of LSD.

o These reviews also provide much needed data to help farmers implement well targeted biosecurity measures to protect their cattle in case of an outbreak.