{"id":31756,"date":"2022-10-10T20:07:00","date_gmt":"2022-10-10T20:07:00","guid":{"rendered":"https:\/\/todaysveterinarypractice.com\/?p=31756"},"modified":"2022-11-16T21:08:26","modified_gmt":"2022-11-16T21:08:26","slug":"what-to-do-with-the-ehrlichia-positive-healthy-dog","status":"publish","type":"post","link":"https:\/\/navc.sitepreview.app\/todaysveterinarypractice.com\/parasitology\/what-to-do-with-the-ehrlichia-positive-healthy-dog\/","title":{"rendered":"What to Do With the Ehrlichia-Positive Healthy Dog"},"content":{"rendered":"

Ehrlichia<\/i> bacteria are obligate intracellular members of the family Anaplasmataceae, and several species are capable of causing infection, with or without illness, in dogs. The first species described was Ehrlichia canis<\/i>, which is still of enormous importance to the health of dogs worldwide.1<\/sup> Additionally, Ehrlichia ewingii<\/i> is a common cause of low-mortality, moderate-morbidity infection in much of the United States.2-4<\/sup> Ehrlichia chaffeensis<\/i> is the pathogen responsible for human monocytic ehrlichiosis, and while dogs can become infected and mount potentially cross-reactive antibody responses, it seems to cause very little disease in dogs.5,6<\/sup> Other species of Ehrlichia<\/i> infect dogs on occasion (e.g.,\u00a0Panola Mountain Ehrlichia<\/i>, Ehrlichia muris eauclairensis<\/i>).7,8<\/sup><\/span><\/p>\n

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When a routine screening test for Ehrlichia<\/i> returns a positive result in an apparently healthy dog, treatment with antimicrobials is not automatically the appropriate course of action. The decision of what course of action to pursue depends on several factors.<\/span><\/p>\n

Important Ehrlichia<\/em> Species<\/h2>\n

Three Ehrlichia <\/i>species are important for small animal veterinarians to understand (<\/span>TABLE 1<\/b><\/span>).<\/span><\/p>\n

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E canis<\/i> can cause an acute febrile illness, often followed by a prolonged phase of subclinical infection. Some chronically infected dogs eventually develop disease manifestations of canine monocytic ehrlichiosis, which can include pancytopenia, profound hyperglobulinemia, bleeding diathesis, and renal disease.1,9<\/sup> While tetracycline antimicrobial treatment is very effective for acute disease, chronic manifestations such as pancytopenia may respond poorly, and chronically ill dogs may die despite antimicrobial therapy.1<\/sup> Dogs can develop illness many years after initial infection.<\/span><\/p>\n

On the other hand, E ewingii<\/i> infection can be persistent but disease seems to be acute, although evidence exists that kidney disease, and especially proteinuria, might be a longer-term consequence of infection.3,10<\/sup> Febrile polyarthropathy and neurologic manifestations are described in the weeks after tick transmission.3,11,12<\/sup> The prevalence of antibodies to E\u00a0ewingii<\/i> in endemic regions can be very high, but clinical disease is not nearly as common. It seems that dogs with incidentally discovered antibodies to E\u00a0ewingii<\/i> but in apparent good health are unlikely to develop disease directly attributable to infection.<\/span><\/p>\n

The human pathogen E chaffeensis<\/i> causes a serious mononuclear infection in humans.13 <\/sup>Experimental infections of dogs have thus far resulted in mild thrombocytopenia but no clinical illness, although natural infections might cause disease signs.5<\/sup> Dogs in endemic regions (the same regions endemic for E\u00a0ewingii<\/i>) are commonly infected and develop potentially cross-reactive antibodies.2,14<\/sup><\/span><\/p>\n

Screening Tests<\/h2>\n

There are a handful of infectious agents for which routine screening is common in pet animals (e.g., retroviruses in cats, heartworms in dogs). In general, screening tests should be considered if the results will affect case management. For example, a positive heartworm test would lead to treatment of infection prior to development of heartworm disease with heart failure. Identification of feline immunodeficiency virus infection would lead to alterations in housing and management for the infected cat.<\/span><\/p>\n

When it comes to screening for Ehrlichia<\/i>, there are pros and cons to consider:<\/span><\/p>\n

Pros<\/b><\/span><\/p>\n