Dermatitis nodularis bovum- papilla of skin of cattle, nodular rash of cattle, the infectious disease which is characterized by fever and education on skin of specific small knots (hillocks). Proceeds in the form of an epizooty. The disease was observed in the countries of South and East Africa, Europe (Romania, Hungary, Germany), Asia and in Australia; in the USSR it is not registered. Lethality is 4 — 95%.
Etiology. The causative agent of a nodular dermatitis of cattle — not classified virus. Assume that the disease is caused by 3 types of viruses which differ from each other in pathogenicity for cattle and laboratory animals, to cytopathogenic action and probably immunological.
The main infecting agent — a nitling virus which is more often than others is allocated from pathological material. The virus is sensitive to air, warming up and well remains in the dried-up state (more than 5 years). Disinfectants (3% solution of alkali, 1% solution of phenol, 3 — licked 5% solutions, lactic acid, etc.) and sunlight inactivate a virus within several hours. Cattle, sheep, goats, rabbits, guinea pigs and newborn mice are susceptible to a virus. The virus is grown up in chicken embryos, the cultures of cells of a kidney of calfs and embryos of sheep, testicles of calfs, fibroblast of a chicken embryo. Epizootology is not studied. Immunity, the Had animals gain immunity to repeated infection within 8 — 12 months.
Symptoms and treatment. The disease proceeds chronically. Incubation interval from 3 to 13 days. The disease begins when the temperature is up to 40 °C and above; then there are watery expirations from eyes, slackness, refusal of a forage, hypersalivation, the held-down gait and the progressing emaciation. On skin (is more often than legs and a stomach) hillocks with a flat surface with a diameter of 0.5 — 0.7 cm, 0.5 cm high are formed. In 1 — 3 weeks from the moment of emergence of hillocks fabric sequesters are formed.
At a favorable outcome they are filled with granulyation fabric and the animal recovers also a current of 4 — 6 weeks. At a severe form small knots find in a mouth, in lungs, digestive organs. From a mouth dense viscous saliva, from a nose — slime with a fetid smell is emitted. At the lactating cows the struck udder is increased, in it there are small knots; milk becomes dense with a pinkish shade, when heating forms gel. At bulls at damage of testicles the virus is allocated with sperm more than 2 months after recovery.
Pathoanatomical changes. Find damage of lymph nodes; star-shaped hemorrhages under a visceral pleura of the nasal courses, a spleen, a liver, a hem; fluid lungs; nodules in the majority of internals; phenomena of the general intoxication.
The diagnosis is made on the basis of epizootological data, a clinical picture, pathoanatomical changes and results of a laboratory research (allocation of the activator and a biological test). The disease is differentiated from a skin form of tuberculosis, a small tortoiseshell, a streptotrichosis, a dermatofilyoz, an epizootic lymphangitis, smallpox, a demodicosis and also damages of skin after stings of insects.
Treatment. The opened small knots process solutions of disinfectants. Appoint streptocides and antibiotics for prevention of consecutive infection.
Prevention and measures of fight. Specific prevention is developed not completely. Against a nodular dermatitis of cattle caused by a nitling virus apply virus strains of smallpox of sheep to immunization. Unsuccessful farms are karantined. Export of animal raw materials is allowed only after its special processing.
Дата редактирования: 17 June 2019