diseases of animals caused by fleas of the genus Wermipsylla. The parasites affect the skin and hair. Wermipsylloses are usually observed in autumn and winter; they generally spread throughout the entire farm. Severe itching, formation of bare patches on the skin, and emaciation is observed in the animals. Treatment consists in treating the animals with disinfectant dusts and solutions. Prophylaxis consists in isolating and treating the affected animals and cleaning the premises and implements by machine, followed by the use of insecticides.