Background

Sheep pox (SPP) and goat pox (GTP) are highly infectious viral diseases of sheep and goats caused by sheep pox virus (SPPV) and goat pox virus (GTPV), respectively. Both the virus are grouped with the genus Capripoxvirus belonging to the family Poxviridae. The sheep pox and goat pox viruses are highly contagious. The virus is transmitted through aerosol with contact with infected animals. The disease also spread through vectors like Stomoxys calcitrans and tsetse fly. In the oral and nasal secretions, the virus can survive for several weeks and several months in the scabs of animals. The spread of the virus can also occur through contact with contaminated materials. Both sheep and goat pox shows similar clinical symptoms. The incubation period for both the disease is 4-15 days. The symptoms in sheep pox are either malignant or benign. The malignant form of symptoms are usually found in lamb. Even, lamb may die without showing any sheep pox symptoms. Other symptoms include fever at 40-42°C, occulonasal discharge, dyspnea, and lesions on the skin. In benign sheep pox, only lesions on the skin occur under the tail and mostly affects adults. In this pox, the animal recovers in 3-4 weeks. The mortality in young maybe 100%, but overall, flock mortality is 50%. Sheep pox & goat pox are widespread in Africa, central Asia, and the Middle Eastern countries. Capripoxvirus is widely distributed in the Middle East, India, Pakistan, Iran, and Turkey. In India, the goat pox outbreak was first reported in 1936. Later, it was reported from different states of Uttar Pradesh, Haryana, Madhya Pradesh, Orissa, and West Bengal. However, sheep pox was reported from Tamil Nadu, Mumbai, and Mysore. The disease persists in India, despite the presence of efficient vaccines. Diseased animals are treated with antibiotics to avoid secondary bacterial infection. The other method to control the disease is vaccination with commercially available vaccines. The live attenuated vaccines are used as a significant agent to control sheep and goat pox in the endemic regions. When annual vaccination coverage is 75%, it provides excellent protection and can control outbreaks. According to FAO Regional Animal Disease Surveillance and Control Network for SPP eradication program, the SPP reduction and outbreak are controlled when the vaccine coverage is between 75 to 90%. This vaccine immunity is not long-lasting and killed vaccines are not efficient in field condition.

Cause

A virus disease caused by Capripoxvirus

Host Species

Goat and Sheep

• Contact: Close contact between infected and healthy animals
• Aerosol: The animal acquires aerosol infection via the respiratory tract in the flock
• The spread of the disease is also possible from contact with contaminated materials and through skin abrasions produced iatrogenically or by insects.
• The disease has been shown to transmit by the bites of Stomoxys calcitrans & the tsetse fly.

• The incubation period is of 12-14 days.
• The sheeppox is manifested in two forms depending on age of the animals. In lambs, the malignant form is the most common.
• High rise of temperature, severe depression, weakness, exhaustion, ocular and nasal discharge is common.
• Typical pox lesions develop papules, then nodules, vesicular, pustular and finally as scab.
• Sometimes the size of pox lesion progresses from nodules to tumor-like masses.
• The lesions are mostly seen on unwooled skin and on the buccal, respiratory, digestive, and urogenital tract mucosae.
• Affected lambs may die during this stage before development of typical pox lesions.
• The mortality rate in this form of the disease may reach up to 50%.
• The benign form is more common in adults.
• In this form, only skin lesions are prominant, particularly under the tail. No systemic reaction is seen and animals recover in 3-4 weeks.
• The pregnant animals may abort with complications of secondary pneumonia.
• Goatpox in sheep is more severe than sheeppox, and lesions occur on the lips and oral mucosa, the teats and udder.

No specific treatment is there for sheeppox. Only following supportive treatment will help.

• Good nursing is essential.
• Sick animals should be isolated and kept in clean, well ventilated pens and palatable food on high plain of nutrition.
• Fluid and electrolyte therapy may be required if animal is unable to take food.
• Antibiotic is prescribed to prevent secondary bacterial infections.
• Eyes and nostrils should be washed with 2% boric acid and 1:10,000 potassium permanganate solution, respectively.
• Antiseptic, spray, ointment or powder is to be applied topically on scab or ulcerated lesions.
• Contact veterinary doctors for further treatment.

Preventive measures

• If culling is not possible, the infected herds/sick animals are isolated for recovery.
• Proper disposal of cadavers and products-burning or burial is often used.
• Stringent cleaning and disinfection of farms and equipmente's undertaken.
• Quarantine of new animals before introduction into herds
• Control of animal and vehicle movement within infected areas
• Vaccination may be considered when the disease has spread more widely

Control

Regular vaccination is the only effective way to control the disease.

Type of vaccines

Live attenuated cell culture sheeppox virus vaccine

Vaccination schedule

The vaccination against sheeppox is recommended to sheep at the age around 4 months of age and yearly vaccination.

Dose

1mL S/C route or following manufacturer's instructions

Note: Deworming is must at least 15 days before vaccination.

Source/manufacturer of vaccine in India

Indian Immunologicals, Hyderabad (Telangana) Brilliant Bio Pharma. Ltd., Hyderabad (Talangana)

Institure of Veterinary Biologicals, Lucknow (UP), Ranipet (Tamilnadu)