SEROEPIDEMIOLOGIC SURVEY FOR ADENOVIRUS INFECTION IN LAMBS

A serologic survey was conducted to determine the prevalence and seroc onversion rates for ovine adenovirus (OAV) serotypes 1-4 and bovine ad enovirus (BAV) serotypes 2, 3, and 7 in sheep in Iowa and in surroundi ng states. For 2 consecutive years, paired serum samples were obtained from 1- to 2-month-old lambs as they entered a ram test station and, again, 2 months later. Sera were tested for adenovirus antibodies by u se of a microtitration serum virus-neutralization test. At the time of entry, high prevalence of antibody (titer greater-than-or-equal-to 2) was detected to all tested adenoviruses except BAV-3. All adenoviruse s were active in the ram test station both years, as indicated by grea ter-than-or-equal-to fourfold increase in adenovirus antibody titer (s eroconversion) in some of the lambs. The prevalence and seroconversion rate for OAV-1 was 94.0 and 7.2%, respectively; for OAV-2, 98.6 and 1 5.1%; for OAV-3, 86.5 and 11.0%; for OAV-4, 98.4 and 13.2%; for BAV-2, 97.6 and 22.4%; for BAV-3,11.4 and 3.8%; and for BAV-7, 81.6 and 4.5%. The results indicate that adenovirus infections were widespread in th e sheep population and that the prevalence of active infection based o n seroconversion rates was approximately 45%.