A Study of Outbreaks of Aujeszky’s Disease in Cattle

Abstract

Twenty-nine outbreaks of Aujeszky’s disease in cattle, involving 54 animals, were studied virologically and epidemiologically. The outbreaks could be divided into two distinct groups, viz., such with pruritus on the anterior (Group I) and such with pruritus on the posterior part of the body (Group II). Though low, the average number of affected animals per outbreak was twice as high in Group I as in Group II. Besides in the tissue of the central nervous system, virus was demonstrated in the oral, pharyngeal, and nasal mucous membranes of eight out of 12 animals from Group I outbreaks, which was thought to be indicative of respiratory infection, and in the vagina of the three animals with perineal pruritus from which such material was examined. It is concluded that the site of pruritus need not be identical with the site of virus entry. The probable routes of infection in the outbreaks examined will be discussed in detail in a subsequent paper.

Sammendrag

Niogtyve udbrud af Aujeszky’s sygdom hos kvæg med 54 angrebne dyr undersøgtes virologisk og epidemiologisk. Udbruddene kunne inddeles i to grupper, nemlig udbrud med kløe på forparten (Gruppe I) og udbrud med kløe på bagparten (Gruppe II). Antallet af angrebne dyr pr. udbrud var lavt, men gennemsnitligt dobbelt sa højt i Gruppe I som i Gruppe II. Virus påvistes i prøver fra mund-, næse- og svælgslimhinden hos otte af 12 dyr fra Gruppe I udbrud, hvilket antydede en respiratorisk infektion i disse tilfælde. Endvidere påvistes virus i vagina hos tre dyr med perineal kløe. Det konkluderedes, at kløestedet ikke nødvendigvis er identisk med det primære infektionssted. De sandsynlige smitteveje behandles særskilt i en efterfølgende artikel.