Lumpy Skin Disease (LSD): Taken roots in India & ruined farmer’s economy

Pashu Sandesh, 14 Aug 2021

Prashant Prajapati, Vishal Prajapati, Daljeet Chhabra, Rakesh Sharda, Ravi Sikrodia, Rakhi Gangil and Joycee Jogi

Department of Veterinary Microbiology

College of Veterinary Science and AH MHOW

LSD is a highly infectious skin disease of cattle and buffaloes which is characterized by a mild fever, appearance of nodules on all parts of the animal skin and generalized lymphadenitis. This disease is caused by a capripox (Neethling) virus of the Poxviridae family. This disease was first recognized in Zambia in 1929.

According to the United States National Library of Medicine (NLM) study reports, the first occurrence of this disease was reported in August 2019 in Orissa, India. In September 2020, over 93,000 cattle were infected with LSD in Maharashtra. Recently, the Bihar government declared an alert and issued an advisory on May 6, 2021, about the likely spread of LSD.

The mortality rate is 1 to 5%, the virus appears to be highly host-specific. The lumpy skin disease virus is not zoonotic. The proven cases show that this disease occurred in cattle but occasionally sheep can also be affected. The indigenous cattle show a low rate of infection but exotic breeds (such as Jersey and Guernsey) react more severely. In general, young calves and lactating animals are more susceptible. 

    Mode of transmission:

• The transmission may be due to direct contact with infected animals as the virus is present in discharge secreted from vesicles.
• Mechanical transmission is by the biting of arthropods mainly flies but some articles suggest that the virus has been isolated from the Stomoxys flies.
• It is suggested that the virus excreted in the milk of affected cows, infects the suckling calves.

Pathogenesis:

• The natural incubation period is of 3-7 days.
• Reactions may be peracute, acute, subacute or inapparent.
• Peracute reactions are characterized by a generalization of nodules on respiratory tract epithelia causing respiratory distress and death within ten days.
• Acute reactions are characterized by the sudden onset of fever, rhinitis, conjunctivitis and hyper-salivation.
• Subacute reactions develop in indigenous cattle with the onset of few nodules without any systematic complications. 
• The fever is usually diphasic which means the fever may persist for few days then body temperature becomes normal and after some days again increase in body temperature.
• The typical pox lesions appear on the skin.
• The lesions comprise of erythema, followed by papules, vesicles, blisters and pustules.
• Pustules finally converted into scabs.

Clinical findings:

• Generalized cutaneous eruptions are round, firm nodules varies from 0.5-5.0cm in diameter, it can be widespread but more commonly seen beneath the tail. 
• Nodules may also be seen on the oral, nasal, and genital mucous membranes.
• The nodules are characterized by the inflammatory reaction in the dermis.
• Nodules are oedematous and show cellular proliferation and infiltration.
• There is a thickening of the epidermis followed by necrosis and vesicle formation.
• Epithelial cells will contain eosinophilic cytoplasmic inclusion bodies.
• Enlargement of the superficial lymph nodes may also be seen.

      Diagnosis:

• By specific clinical signs and symptoms.
• The virus can be isolated in various cell cultures and the presence of the virus shows the cytopathology and cytoplasmic inclusion bodies.
• Presence of eosinophilic cytoplasmic inclusion bodies in the section of skin.
• Sometimes the early skin lesions can be confused with a pseudo lumpy skin disease which is caused by the bovine herpes virus.
• Fluorescent antibody and serum neutralization tests can be used.
• Negative contrast electron microscopy can be used to demonstrate the characteristic pox virions in the lesions.        

 Immunity:

• The duration of development of immunity is unknown but it is probably lifelong.
• A hypersensitivity test is used to detect the immune animals.

  Treatment:

• Treatment is symptomatic in nature.
• Emollient ointments containing antiseptic or antibiotics can be used.
• Whitfield ointment containing salicylic and benzoic acid.
• The povidone-iodine ointment may be applied to the lesions.

 Control and prevention:

• Strict hygiene measures should be adopted.
• Isolation and segregation of the infected animals from the herd.
• Proper bathing of animals as well as washing of floor and manger by the use of disinfectant.
• Control of the flies by the use of insecticides.
• No commercial vaccine is available in India but Orissa and Kerala used goat pox vaccine.
• Two vaccines are available: in South Africa, an attenuated virus vaccine and in Kenya, a strain of sheep/goat pox virus vaccine is used.