Madigan J E, Hietala S, Chalmers S, DeRock E
Department of Medicine, School of Veterinary Medicine, University of California, Davis 05616.
J Am Vet Med Assoc. 1990 Jun 15;196(12):1962-4.
The prevalence of antibodies to Ehrlichia equi in horses from the foothill regions of northern California and from the Sacramento valley (non-foothill area) was determined, using an indirect fluorescent antibody test. Horses from foothill regions had a higher prevalence of seropositivity (10.4%) and higher titer (1:10 to 1:80) than did those from non-foothill regions (3.1%; titer less than or equal to 1:10). Fifty percent of healthy horses on a foothill farm enzootic for E equi had titer to E equi, suggesting that infection with E equi can be subclinical. Six veterinarians surveyed from northern California diagnosed clinical E equi infection in 38 horses during 1985-1986 based on clinical signs of infection and observation of E equi inclusion bodies in neutrophils on blood smears.
