SEASONAL-VARIATION IN THE INCIDENCE OF SUBCLINICAL HORIZONTALLY TRANSMITTED INFECTION WITH CHICKEN ANEMIA VIRUS IN DANISH BROILERS AND BROILER BREEDERS

A significant reduction during the period 1991 to 1993 in the incidenc e of subclinical, horizontally transmitted infection with chicken anem ia virus in broiler breeders was observed. A similar reduction was obs erved in broilers from 1989-90 to 1992-93. The reduction coincided wit h improvement in housing and hygiene as parts of an eradication progra mme for Salmonella enterica. In addition, a seasonal variation in the incidence of subclinical infection with chicken anemia virus in broile rs and broiler breeders was observed. The lowest incidence was found i n poultry sampled during May-July compared to the rest of the year. It is concluded that the incidence of the subclinical CAV infection can be reduced by conventional hygienic measures.