Experimentally induced infection of dogs, cats, and nonhuman primates with Ehrlichia equi, etiologic agent of equine ehrlichiosis.
Abstract: Dogs (German Shepherd Dogs and Beagles), cates, rhesus macaques (Macaca mulatta), and baboons (Papio anubis) were inoculated with Whrlichia equi, the etiologic agent of equine ehrlichiosis. Within 3 to 7 days after inoculation, morulae were observed in the eosinophils of cats, neurtrophils of macaques and baboons, and in both neutrophils and eosinophils of dogs. The severe disease produced in horses by this agent was not a feature of E equi infection in dogs, cats, macaques, and baboons. However, a susceptible horse, inoculated with the pooled blood of 2 infected macaques, developed severe clinical signs of equine ehrlichiosis. Infection with E equi did not alter the susceptibiltiy of dogs to infection with Ehrlichia canis and did not prevent development of signs of disease resulting from this infection. The broad experimental host range from this infection. The broad experimental host range of E equi distinguishes it from other ehrlichial agents which are characterized by a rather narrow host range. The susceptibiltiy of nonhuman primates to infection with E equi provides a basis for consideration of the potential transmission of ehrlichial agents to man.
Publication Date: 1975-01-11 PubMed ID: 1115421
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- Journal Article
Summary
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The research investigates the effects of Ehrlichia equi, the cause of equine ehrlichiosis, on different species such as dogs, cats, macaques, and baboons. The study found that while the severe disease is common in horses, it was not prominent in the other species tested, suggesting the differences in host responses to the pathogen.
Introduction to the Pathogen and Experiment
- Ehrlichia equi is the disease-causing organism for equine ehrlichiosis, a condition predominantly affecting horses. This bacterium is transmitted through ticks and causes various health complications in horses, including fever, weight loss, and anemia.
- In this study, various species including German Shepherd Dogs and Beagles, cats, rhesus macaques (Macaca mulatta), and baboons (Papio anubis) were experimentally inoculated with Ehrlichia equi to understand the disease’s cross-species behavior.
Observations and Findings
- Within a timeframe of 3 to 7 days post-inoculation, morulae (a type of bacterial aggregation) were observed in different white blood cells depending on the species, such as eosinophils of cats and neutrophils of macaques and baboons. In dogs, the morulae were found in both neutrophils and eosinophils.
- The severe disease typically seen in horses due to Ehrlichia equi was not seen in dogs, cats, macaques, or baboons. This potentially points out to variable susceptibility and response among different animal species to the same pathogen.
- Even after the infection, the susceptibility of dogs to another pathogen, Ehrlichia canis, was not affected, implying that infection with one Ehrlichia species does not confer protection against other species within the same genus.
Implications and Conclusion
- An infected horse showed severe symptoms of equine ehrlichiosis after receiving blood from two infected macaques. This further strengthens the theory of tick-borne transmission of the disease.
- The study concluded that E. equi infection has a broad host-range, distinguishing it from other Ehrlichia species, which usually have a narrow host-range.
- The successful infection of non-human primates presents the possibility of this bacterium’ potential risk to human health.
This exploration of the cross-species behavior of Ehrlichia equi provides a foundation for understanding how such pathogens can move beyond their typical host-species and potentially affect a wider range of animals, potentially including humans.
Cite This Article
APA
Lewis GE, Huxsoll DL, Ristic M, Johnson AJ.
(1975).
Experimentally induced infection of dogs, cats, and nonhuman primates with Ehrlichia equi, etiologic agent of equine ehrlichiosis.
Am J Vet Res, 36(1), 85-88.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Blood / microbiology
- Cat Diseases / etiology
- Cats
- Cricetinae
- Dog Diseases / etiology
- Dogs
- Ehrlichia / pathogenicity
- Female
- Guinea Pigs
- Horse Diseases / etiology
- Horses
- Macaca mulatta
- Male
- Mice
- Monkey Diseases / etiology
- Papio
- Rabbits
- Rats
- Rickettsiaceae / pathogenicity
- Rickettsiaceae Infections / veterinary
- Sepsis / veterinary
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