LUMPY SKIN DISEASE (LSD) :OBSERVATIONS BY THE FIELD VETERINARIANS

LUMPY SKIN DISEASE (LSD) :OBSERVATIONS BY THE FIELD VETERINARIANS

ANNARAO¹, TRUPTI SURYAKANT KATTIMANI², INDRALE UTPALA³, SHANTKUMAR SIDDESHWAR⁴

• SENIOR VETERINARY OFFICER VETERINARY HOSPITAL KALAGI TQ KALAGI DIST KALABURAGI
• VETERINARY OFFICER VETERINARY DISPENSARY SALAGAR BASANTPUR TQ CHINCHOLI DIST KALABURAGI
• SENIOR VETERINARY OFFICER VETERINARY DISPENSARY MANGALAGI TQ KALAGI DIST KALABURAGI
• SENIOR VETERINARY OFFICER VETERINARY DISPENSARY KALLUR TQ HUMANABAD DIST KALABURAGI

DEPT OF ANIMAL HUSBANDRY & VETERINARY SERVICES GOVT OF KARNATAKA REPUBLIC INDIA

Introduction: Lumpy skin disease is caused by the Lumpy skin disease virus, genus Capri pox virus, a brick-shaped double-stranded DNA virus belonging to the family Pox Viridae. The virus is highly host-specific and causes disease only in Cattle and buffalo, it’s an emerging viral disease of Cattle and Buffalo in India. Lumpy skin disease was first reported in 1929 in Zambia. Since 2012 it’s spread rapidly from African countries to Middle East Asia and South Eastern Europe. Lumpy skin disease is having high morbidity and low mortality. It is a deadly and devastating disease causing severe economic losses in terms of sudden fall in milk yield in female animals, loss of draft power in male animals, treatment costs, and permanent damage to hide. Lumpy skin disease doesn’t have zoonotic importance. The infection spreads faster in warm and wet weather. In India, Lumpy skin disease was first reported in Orissa state in august 2019. Later the disease spread to all over the country. Presently the disease became highly endemic in the Indian subcontinent causing huge economical losses in terms of sever morbidity and higher mortality.

Transmission: Virus isolated from blood, saliva, ocular discharge, nasal discharge, and semen of infected animals. Affected animals act as the source of infection. Vectors (ticks, flies, mosquitoes) are the main source of transmission from affected animals to healthy animals by bite, direct contact from affected animals, contaminated feed and water, and iatrogenic transmission from contaminated needles and other equipment.

Incubation period: varies from 2 to 5 weeks.

Pathogenesis: The virus is pantropic in nature, that is, it has an affinity for all three types of cells. Virus multiplication occurs in the ectoderm, endoderm, and mesoderm cells. After entry of the virus from the bite of the insects or other route of entry, there will be viremia followed by the virus localization in the mucus membrane, internal organs, and skin, which leads to the formation of lumps of size 0.5cm to 5cm in diameter all over the body and internal organs. Internal lumps cause ulcers leading to internal bleeding and death in severe cases. Later lumps undergo necrosis and become atrophied leading to the formation of scab which detaches from the body leading to ulcers or wound formation. These wounds on secondary bacterial invasion led to pyogenic wounds or on fly strike leads to myiasis causing permanent damage to hide. The detached scab is rich in viruses and acts as a potential source of infection. Nodules were observed in the gastrointestinal tract, the respiratory tract, the reproductive tract, and the lymphatic system were also affected, and even anemia was reported in cattle due to lumpy skin disease.

Clinical Signs: Varies from animal to animal. All age groups of animals are equally susceptible. The disease is more severe in local non-descript cattle compared to cross-bred cattle. Young calves and lactating cows are more severely affected. Clinical signs include pyrexia (up to 106⁰F), dullness, depression, anorexia, formation of raised unequal-sized lumps on the skin, and mucus membrane size varying from 1cm to 5cm diameter found all over the body of the animal including head, neck, tail, udder, scrotum, perineum, genitalia and limbs. These lumps are raised from the skin, firm, and painful on palpation. Enlarged superficial lymph nodes, edema of brisket and limbs, sudden fall in milk yield, loss of draft power in male animals, excessive salivation, dyspnoea, rhinitis, conjunctivitis, and lameness observed under field conditions. Pregnant cows may abort and the aborted fetus had small reddish coin-like lesions all over the body. In the course of the disease, these lumps will become necrotic and ulcerate and may predispose to myiasis by the fly strike. Affected animals with or without brisket edema and nodules, animals with or without nodules and having brisket edema, are observed in the field conditions. Limb edema, brisket edema, dyspnoea, grunting, melena, serous to blood mixed nasal discharges in the affected animals observed by the field veterinarian. Ulcers in the eye, on the muzzle, rectum and melena observed in the animals recorded by field veterinarians. Calves with lumps all over body, pyrexia, nasal discharges, severe respiratory distress observed in the field. As per the observation made by field veterinarian, the disease is more severe in native cattle compared to cress bred cattle, in buffalo the disease is less severe, respiratory and lymphatics form of disease is more fatal.

The outcome of disease: Recovered animals will be emaciated and needs more care and time for complete recovery. Due to the affection of tendons and joints animals may show permanent lameness. Recovered animals shown mortality after 2-3 months up to 30 per cent observation made by field veterinarian. Infected bulls will secret the virus in semen and will be a source of infection to female animals. Permanent damage to hide. Sudden fall in milk yield. The abortion of pregnant animals and long-standing anestrus is seen in recovered animals led to a huge loss in the dairy industry. Recovered animals will have solid immunity. Bulls may become temporary or permanently infertile. Disease predisposes the conditions like secondary pneumonia, emaciation, mastitis, and death.

Post-mortem lesions: Skin nodular lesions extending up to subcutaneous tissue and hemorrhages in the internal organs due to various-sized nodules all over the organs. Lesions start from the oral cavity, lymphatics tract, liver, spleen, digestive tract, edema, and hemorrhages in the muscle. Lumpy lesions in the trachea and the respiratory tract including the lungs show bronco-pneumonic changes.

Diagnosis

• Based on clinical signs including pyrexia (up to 106⁰ F), presence of lumps on skin and mucus membrane all over the body of the animal having a size of 1cm to 5cm diameter, enlarged superficial lymph nodes, anorexia, and sudden fall in milk yield.
• Necrotic nodular lesions, crusted nodules with or without ulcers on the body of an animal, depression, and emaciation in the chronic phase of the disease.
• Laboratory diagnosis by PCR, ELISA, Western blot technique, and Virus neutralization test.
• Isolation and identification of virus from blood and skin biopsy.
• Based on post-mortem examination lesions: Skin nodular lesions extending up to subcutaneous tissue and muscle with edema, congestion, and hemorrhages.
• Histo-pathology of skin biopsy: Epithelial cell degeneration, necrosis, intercellular and intracellular edema, and intracytoplasmic inclusion bodies.

Samples of choice for diagnosis:

1. Blood sample: a) EDTA Blood sample b) Serum sample
2. Skin Biopsy: a) Skin Biopsy in saline b) Skin Biopsy in Formalin

Treatment: There is no specific anti-viral therapy for lumpy skin disease. Anti-histamines and long-acting non-steroidal anti-inflammatory agents @ calculated doses for 5 to 7 days. Systemic antibiotic therapy to avoid secondary bacterial infection. Diuretic therapy is followed in lymphatic system-affected cases. Fly repellents and antiseptic ointments should be used in skin-affected cases. Isolation of affected animals and supportive treatment should be given in the early stage of the disease to avoid complications. During the recovery of the disease, care should be taken for the myiasis due to fly strikes from skin lesions. Energy boosters, vitamins, and minerals supplementation will help the early recovery from the disease.

Vaccination: LSD Vaccine Neethling strain is used in endemic areas at 2 ml s/c annually. In India goat pox vaccine Uttarkashi strain is recommended by scientists for vaccination and control of Lumpy skin disease in India, a dose of 1ml s/c route at neck area to healthy animals. Even Sheep pox vaccine also using in field conditions for the ring vaccination in outbreak areas and it has shown a protective effect against the disease.

Control:

Isolation and prompt treatment of affected animals are the primary things one should follow whenever symptoms were observed. Farm hygiene and sanitization are the keys to controlling the disease Insect bites act as a source of the virus from infected to healthy animals in a short period span, so control the vector population in and around the farm by using fly repellants and other vector control measures in both affected and unaffected areas. Culling of severely affected animals to avoid the source of infection. Proper cleaning, sanitization, and hygiene practices in the cattle shed should be followed including all bio-security measures to avoid the infection spreading from fomites. Vaccination should be done in healthy animals and annual vaccination should be followed in an endemic area. Strict quarantine measures are to be followed for animals as well as animal by-products like hiding from one country to another country. Proper disposal of the carcass of the animals should be done in the suspected or confirmed disease. Avoid animal movement in the endemic area; don’t mix the animals from different herds. Closure of local cattle markets, cattle show, and gathering cattle festivals to avoid the spreading of disease in endemic areas. Separate needles should be used for each animal for treatment and vaccination because iatrogenic transmission is possible.

References:

1. Fast facts: Lumpy skin disease- Centre for food security and public health-Iowa University, 2011.
2. OIE Technical disease cards: Lumpy skin disease.
3. MSD Veterinary manual.

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