Systematic Veterinary Virology

COW POX

• Cowpox virus, from the genus Orthpoxvirus, is another poxvirus that causes human disease through zoonosis. Cowpox virus has been found only in Europe and in adjacent parts of the former Soviet Union. Despite its name, the reservoir hosts of cowpox virus are rodents, from which it can occasionally spread to cats, cows, humans, and zoo animals, including large cats and elephants. Transmission to humans has traditionally occurred via contact with the infected teats of milking cows.
• However, currently, infection is seen more commonly among domestic cats, from which it can be transmitted to humans. Milkers and milking machines are the main means of spread. Insects may also serve as mechanical vectors for the virus. Cowpox virus produces what is usually a benign infection of the udder and teats.
• Papules are first seen, followed by vesicles, which rupture leading to scab formation. Scabs drop off in about two weeks. Losses in milk production result from the soreness of affected teats and also from secondary bacterial infection, which may complicate the disease and contribute to development of mastitis.