A RETROSPECTIVE SEROLOGIC SURVEY FOR ANAPLASMA SPP INFECTION IN 3 BIGHORN SHEEP (OVIS-CANADENSIS) POPULATIONS IN CALIFORNIA

Using an indirect immunofluorescence assay, we determined the prevalen ce of Anaplasma-reactive antibody in three herds of bighorn sheep, eac h a different subspecies and occupying a different habitat in Californ ia (USA). Antibodies to Anaplasma spp. were identified in none of twen ty California bighorn (ovis canadensis californiana) sampled from the Mt. Baxter herd, 11 of 17 peninsular bighorn (O. canadensis cremnobate s) sampled in the Santa Rosa Mountains, and all 20 desert bighorn (O. canadensis nelsoni) sampled at Old Dad Peak/Kelso Mountains. Based on an assay and an adsorption technique, the titers most likely were due to Anaplasma ovis. The presence and species of tick vectors in each of the habitats, and the presence or absence of deer or livestock were i dentified as factors potentially influencing seroprevalence of antibod ies.