Cow-pox (vaccinia)

Epidemiology: This infection, although mostly occurring in cows, sometimes also occurs in buffaloes. Under natural conditions, the infection takes place through inoculation by the cutaneous route and readily spreads from one animal to another through the agency of milkers.

The occurrence of cow-pox is frequently associated with the incidence of small- pox in human beings. Instances are on record in which cow-pox in all stages has been transmitted through the milkers. The reservoir host of cow pox virus is rodents. The cowpox infection in domestic cats often causes more severe disease than cattle or humans. In cheetahs pneumonia is common and is accompanied with a high mortality rate.

Symptoms: After an incubation period of 2 to 5 days, there is some rise in body temperature. The animal develops pin-point red spots and papules of the size of mustard or sago which can be felt by hand. Later, these papules coalesce into vesicles. Papules occurring on the udder are generally circular, but those on the teats are elongated. The lesions heal in the course of 15 to 20 days and the udder and the teats regain their normal appearance. In males, the disease is very often unnoticed, because the lesions, beings on the scrotum and inside of the thighs, are often covered with dirt and consequently hidden from view.

Diagnosis: Diagnosis is based on the lesions, virus isolation in cell- cultures and chick embryos and electron microscopy of skin scrapings.

Treatment, prevention and control: The lesions heal by themselves in the normal course and the adoption of special measures is not called for; only the usual rules of hygiene need to be observed. The lesions should be cleaned with a 1:1,000 solution of potassium permanganate followed by the application of an antiseptic ointment such as 1:10 boric acid. The affected animals should be isolated and milked by separate attendants. Milk from affected animals should be boiled before use. If the disease assumes serious proportions, vaccination may be undertaken by scarification in the perineum with calf lymph or with material collected from lesions from the affected animal.