[ Kuru Angha Yamii ]
During this Covid-19 pandemic, there has been more loss to the Indian economy because of another disease spreading in the country. Recently, a disease named the Lumpy Skin Disease (LSD) has been spreading among cattle in the northeastern parts of the country.
This disease causes the formation of nodules all over the body of cattle. The disease is characterized by fever, lymph node swelling, circumscribed nodules on the skin, causing severe emaciation, reduction in milk production and infertility.
The world organization for animal health (OIE) categorizes LSD as a notifiable disease due to its economic impact. LSD has been considered an agro-terrorism agent due to its ability to spread from Africa to other parts of the world. The economic implications of the disease are high due to morbidity rather than mortality, as the mortality rate is usually low.
Significant losses are due to severe emaciation, hide damage, infertility in males and females, mastitis, drop in milk production, and abortions.
Due to the reduction in the quality of the animals, the effect can be seen in the overall trade of live animals and animal products. This may cause huge financial losses to the meat industry, milk industry, leather industry, and other industries associated with livestock and its by-products. Not only industries, poor farmers holding the livestock have to suffer the crisis due to the disease.
The disease is endemic in African and Middle East countries but has started spreading to Asian and other countries. It has been recently reported from China and Bangladesh, sharing borders with India. Since August, there has been a high alert in Assam on LSD due to economic loss. Currently, the epidemiological status of the disease is unknown.
What is LSD?
Lumpy skin disease or LSD is a viral disease caused by the lumpy skin disease virus, a member of the Capripoxvirus genus of the Poxviridae family. It is a trans-boundary disease affecting cattle and water buffaloes. The disease is transported by arthropod vectors and causes high morbidity and low mortality. LSD is non- zoonotic, i.e it cannot be transmitted from animals to humans and vice versa.
The virus is secreted in milk, nasal secretions, saliva, blood, and lachrymal secretions, forming an indirect source of infection for animals sharing feeding and watering troughs. The infection has been assumed to be transmitted from infected mothers to calf via milk secretions and skin abrasions. The virus persists in the semen for up to 42 days. Humans are also resistant to the virus.
Cattle (Bos indicus and Bos taurus) and Buffalo (Bubalus bubalis) are susceptible hosts. Animals of all ages are susceptible but calves are more susceptible and develop lesions within 24 to 48 hours.
Clinical signs and lesions:
The incubation period of the disease in natural conditions is between two to five weeks.
The illness begins with biphasic fever, one or two lumps of nodules within two to three days of onset of fever, emaciation, ocular discharge and agalactia.
Later, nodular lesions, which are painful and hyperaemic, may be observed on the animal’s body, especially in the skin of the muzzle, nares, back, legs, scrotum, perineum, eyelids, lower ear, nasal and oral mucosa, and tail.
In severe conditions, more than a hundred nodules develop on the skin and all over the body. This stage persists for 7 to 12 days. The nodules are firm and slightly raised from the surrounding skin, separated by a narrow hemorrhagic ring. Nodule involves the entire epidermis, dermis. Healing of the lesions is very slow.
Prevention and control:
To date, no effective treatment against LSD has been developed. To control the disease, effective control and preventive measures need to be implemented, which include:
- a) Restrict movement: Movement of infected animals with LSD should be strictly prohibited to prevent the spread of trans-boundary disease within countries. They should be quarantined for inspection to prevent the rapid spread of the disease.
- b) Restrict vector movement: Vector movement due to prevailing winds may cause disease transmission. Vector control like the use of vector traps and use of insecticides can also be used to prevent the disease.
- C) Vaccination: A live attenuated vaccine is available for LSD. Neethling, bumpyvax, bovivax, sheep, and goatpox vaccine can be effective against the disease. Usually, animals are cured within five days.
The disease was confirmed in the month of June end of 2020. It is the second ‘exotic’ animal disease reported in Assam during the Covid-19 crisis after the African Swine Fever. To prevent one’s cattle from contracting LSD, one can also take prevention control methods mentioned above and consult one’s nearest veterinarian and get vaccinated.
Though this disease does not affect us directly, it inflicts a heavy loss to the economy as a whole and one should be responsible and spread awareness on LSD. (The contributor is a 3rd-year student from the College of Veterinary Science and Animal Husbandry, Aizawl, Mizoram.)