Naudan pälvisilsa ‒ kirjallisuuskatsaus ja tutkimus pälvisilsan tartuntalähteistä Suomessa

Bovine ringworm is a contagious and superficial cutaneous infection usually caused by the dermatophyte Trichophyton verrucosum. New ringworm infections are found on 20‒30 Finnish farms annually. The skin lesions do not annoy the animal, but they damage the hide. The disease is zoonotic. The infection is spread by both direct and indirect contacts. Indirect contacts are probably the more significant route for the infecting a herd. The conidia remain infectious for months or even years in a dry and cool environment. Eradication relies on immunizing the cattle by a vaccination program lasting several years as well and cleaning measures to reduce the infectious pressure. In our descriptive study we surveyed 19 cattle herds where the infection was diagnosed since July 2016. In young animals the signs are hairless non-pruritic circular patches on the head and neck. In older animals the skin lesions are more often in the rear part of the body. Potential routes for the infection include introduced animals, visitors such as A.I. technicians, veterinarians, farm relief workers, repairmen, contacts through animal transport as well as contacts with neighboring farms contaminated with ringworm (neighbouring pastures, runaway animals). Since there are numerous unforeseeable routes for the infection to reach a farm, the disease prevention relies on prompt eradication of the infection. If the farm followed the existing eradication program, the signs disappeared quickly.