Just as the country was recovering from corona virus that devastated millions of human lives all across the globe, another virus has emerged. This time the virus is not threatening human beings but the livestock. The deadly virus has been the cause of Lumpy Skin Disease that has created havoc in India and its neighbouring countries. The virus mostly affects cows and buffaloes. The disease has spread to many parts of the country and has reportedly already killed tens of thousands of cattle. While morbidity is 5%-50%, the mortality rate of the cattle infested by the virus is 1 to 5 percent.
Origin and Extent of Spread: Traditionally, Lumpy Skin Disease was found in southern and eastern Africa, but in the 1970s it extended northwest through the continent into Sub-Saharan West Africa. Since 2000, it has spread to several countries of the Middle East and in 2013 extended west into Turkey and several countries in the Balkans. More recently, outbreaks were reported for the first time in Georgia, Russia, Bangladesh, and the People’s Republic of China. The recent geographic spread of Lumpy Skin Disease has caused international concern. The disease has not been recorded in the Western hemisphere or in Australia or New Zealand. In July 2019, the disease was reported from Bangladesh from where it is believed to have spread to many Asian countries. In India, the disease was first reported in from West Bengal in the year 2019. Since then, LSD has so far spread to about 15 states and Union Territories. These include the states of Punjab, Rajasthan, Uttar Pradesh, Madhya Pradesh, Haryana, Gujarat, Uttarakhand, Himachal Pradesh, Odisha, Bihar and Union Territories of Jammu and Kashmir and Andaman and Nicobar.
Causal Organism: The LSD virus, caused by the Capri-pox virus, is genetically related to the goat-pox and sheep-pox virus family. Sheep pox and Goat pox are serious fatal diseases characterised by widespread skin eruption. Lumpy Skin Disease appears epidemically or sporadically. Frequently, new foci of infection appear in areas far removed from the initial outbreak. Its incidence is highest in wet summer weather, but it may occur in winter. It is most prevalent along water courses and on low ground.
Mode of Spread: LSD is a contagious viral disease that spreads among cattle through blood feeding insects like mosquitoes, flies, lice, ticks and wasps by direct contact as also through contaminated food and water. Experimentally, three species of hard ticks found in Africa have also been shown to biologically transmit the virus. Because the disease can be experimentally transmitted by infected saliva, contact infection is another potential route of infection. Biting insects have also been suspected as mechanical vectors; however, outbreaks have occurred under conditions in which insects practically could be excluded. African buffalo are suspected as maintenance hosts in Africa, but other wildlife species may also be involved. However, there are no reports of its transmission from cattle to humans yet.
Symptoms: Clinical signs include fever, lacrimation, hypersalivation, and characteristic nodules on skin and other parts of the body which can lead to the death of the cattle. The incubation period is 4–14 days. The nodules are well circumscribed, round, slightly raised, firm, and painful and involve the entire cutis and the mucosa of the Gastro-Intestine, respiratory and genital tracts. Nodules may develop on the muzzle and within the nasal and buccal mucous membranes. The skin nodules contain a firm, creamy-gray or yellow mass of tissue. Regional lymph nodes are swollen, and edema develops in the udder, brisket and legs. Secondary infection sometimes occurs and causes extensive suppuration and sloughing; as a result, the animal may become extremely emaciated, and euthanasia may be warranted. In time, the nodules either regress or necrosis of the skin results in hard, raised areas clearly separated from the surrounding skin.
Economic Loss: When cattle are infected, the animals become weak due to nodule formation, fever and other symptoms. This severely affects milk production and survival depends upon the severity of the disease and immunity level of the animal. The greatest economic loss is due to reduced milk yield (up to 40%-50%), loss of condition, and rejection or reduced value of the hide.
Safety of Milk: Lumpy Skin Disease is a Non-Zoonotic infection and not transmissible from animals to humans. Hence, there is no danger to humans in eating meat or using the milk of animals that do not have the symptoms of the disease. According to Dr A.K. Mohanty, Joint Director of Indian Veterinary Research Institute IVRI, it is safe to consume milk from the infected cattle. There is no problem in the quality of milk even if you have it without boiling. However, experts advise boiling of milk at about 100 degrees Celsius to kill all the harmful bacteria and virus, if any present in the milk.
Prevention and Control: The spread of Lumpy Skin Disease in recent years beyond its ancestral home of Africa is alarming. Quarantine restrictions have proved to be of limited use. Vaccination with attenuated virus offers the most promising method of control and was also effective in halting the spread of the disease in the Balkans. Control and prevention of Lumpy Skin Disease rely on four tactics: movement control (quarantine), vaccination, slaughter campaigns, and management strategies. The management strategies include identification of the infected villages so that precautionary plans are carried out in a specific area and ring vaccination carried out in villages up to 5 km around the affected village. As the disease spreads through infection from diseased animal, the diseased animal should be isolated from the healthy ones. Animals should not be taken to Pashu mela or Pashu mandis as they run the risk of getting infected or spreading the infection. Elaborate arrangements for the control of mosquitoes, flies and ticks should be made in the animal sheds through smoking or by insecticides. Special attention should be paid to keep the animal shed clean and hygienic.
Animal handlers working with the animals should take care of their hygiene also. Animals dying from LSD should be properly disposed of. Dead animals can be buried in a pit 1.5 meter in depth after sprinkling salt on their dead bodies to ensure early and proper decomposition. Migration of animals from one place to another should also be avoided. Newly purchased animals should be kept under quarantine for two weeks. Homemade remedies like a mixture of fenugreek leaves, Garlic cloves, neem leaves, coconut or sesame seeds, turmeric powder which increase the immunity of animals should also be tried.
Unfortunately, there are no specific antiviral drugs available for the treatment of lumpy skin disease. The only treatment available is supportive care of cattle. This can include treatment of skin lesions using wound care sprays and the use of antibiotics to prevent secondary skin infections and pneumonia. As far as vaccination is concerned, cattle and buffaloes should be vaccinated with the available Goat pox vaccine (cattle and buffalo at the age of 4 months and above through the Sub Cutaneous route). However, affected animals should not be vaccinated. Preventive vaccination should also be undertaken in high-risk areas. Recently, Union Minister for Agriculture and Farmers Welfare Narendra Singh Tomar on August 10 launched the indigenous vaccine Lumpi-ProVac to protect livestock from Lumpy Skin Disease. The vaccine has been developed by the National Equine Research Center, Hisar (Haryana), in collaboration with the Indian Veterinary Research Institute, Izzatnagar (Bareilly). It will take time for the vaccination to be rolled out on an all-India basis. Farming community is advised not to panic and simply follow the management strategies and advisories as issued to them from time to time by the departments concerned.
The writer is Director Extension, SKUAST-K, Shalimar