Seroepidemiologic survey of antibodies to Ehrlichia equi in horses of northern California.
Abstract: 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.
Publication Date: 1990-06-15 PubMed ID: 2195000
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article investigated the prevalence of Ehrlichia equi antibodies in horses in northern California, finding higher rates and titers in those from foothill regions as compared to those from non-foothill areas. Researchers also suggested that E equi infection can be subclinical.
Investigation of Ehrlichia equi Antibodies in Horses
The primary objective of this research was to determine the prevalence of antibodies against Ehrlichia equi in horses located in northern California. Ehrlichia equi is a rickettsial agent that causes equine ehrlichiosis, a disease commonly known as Potomac horse fever. The prevalence of this bacterium in horses was tested in two distinct regions; the foothill regions and the Sacramento Valley, otherwise referred to as the non-foothill area.
- For determining the prevalence of these antibodies, the researchers used the indirect fluorescent antibody test, a common laboratory method to detect the presence of specific antibodies that bind to pathogens. This method allows for an accurate assessment of exposure to Ehrlichia equi.
- To evaluate the strength of the immune response against the pathogen, the researchers have measured the titer of antibodies. The titer is a measure of the concentration of antibodies in the blood. Higher titers indicate higher concentrations of antibodies, suggesting a stronger response by the immune system to the pathogen.
Results and Findings
The results showed a difference in seropositivity — the presence of antibodies — between horses from different regions.
- Horses from foothill regions exhibited a seropositivity rate of 10.4 percent and had a higher antibody titer, ranging between 1:10 and 1:80. So, a higher prevalence of Ehrlichia equi antibodies and immune response were identified in these horses.
- Contrarily, horses from the non-foothill region presented a lower seropositivity rate of 3.1 percent and a lower antibody titer that was less than or equal to 1:10, indicating lower exposure to Ehrlichia equi and a weaker immune response.
Furthermore, the study revealed that half of the healthy horses on a foothill farm endemic for E. equi showed a high titer against the pathogen, suggesting that infection with E. equi can occur without clinical signs.
Six vets from northern California reported clinically diagnosing E. equi infection in 38 horses from 1985 to 1986 based on observable signs of infection and the presence of E. equi inclusion bodies in neutrophils in blood smears, further indicating the occurrence of the disease in this region.
Cite This Article
APA
Madigan JE, Hietala S, Chalmers S, DeRock E.
(1990).
Seroepidemiologic survey of antibodies to Ehrlichia equi in horses of northern California.
J Am Vet Med Assoc, 196(12), 1962-1964.
Publication
Researcher Affiliations
- Department of Medicine, School of Veterinary Medicine, University of California, Davis 05616.
MeSH Terms
- Animals
- Antibodies, Bacterial / analysis
- California / epidemiology
- Ehrlichia / immunology
- Fluorescent Antibody Technique
- Horse Diseases / epidemiology
- Horses
- Prevalence
- Retrospective Studies
- Rickettsiaceae / immunology
- Rickettsiaceae Infections / epidemiology
- Rickettsiaceae Infections / veterinary
Citations
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