This article explores the diagnosis and treatment of ehrlichiosis, a tick borne illness. It is part two of a four part series “Four Tickborne Diseases: Lyme Disease, Ehrlichiosis, Anaplasmosis and Babesiosis” .
Diagnosis can be challenging, as the tick bite may not have been noticed, clinical symptoms may be non-specific, and laboratory confirmation of infection can be problematic, especially early in the course of these diseases. At times clinicians may need to treat on clinical suspicion alone.
Written for the Curious (Non-Medical) Reader
By Stuart M. Caplen, MD
Ehrlichiosis is caused by three bacteria, Ehrlichia chaffeensis, Ehrlichia ewingii, or Ehrlichia muriseauclairensis. The majority of reported cases are due to infection with E. chaffeensis. E. chaffeensis and E. ewingii are carried by the lone star tick, Amblyomma americanum, found primarily in the south-central and eastern United States. E. muris eauclairensis is carried by the blacklegged tick, Ixodes scapularis, but despite this tick’s wide distribution has only been reported in Wisconsin and Minnesota. In 2018, there were 1,799 cases of E. chaffeensis reported to the CDC. The other Ehrlichia infections are much rarer, with only 218 cases of E. ewingiiehrlichiosis reported to CDC from 2008–2018, and about 115 cases of ehrlichiosis caused by E. muris eauclairensis reported since its discovery in 2009.
Ehrlichia are small bacteria, round or ellipsoidal in shape. They preferentially invade white blood cells and form bacterial microcolonies known as morulae.
Ehrlichiosis should be considered in patients in endemic areas with a non-specific febrile illness of unknown origin, particularly during spring and summer months when ticks are most active. Ehrlichiosis can occur alone or as a co-infection with other tickborne illnesses such as Lyme disease.
Read more about:
Early Signs and Symptoms of Ehrlichiosis
Late Symptoms of Ehrlichiosis
Laboratory Findings in Ehrlichiosis
Testing for Ehrlichiosis
Treatment of Ehrlichiosis
The conclusion to Part 1-4 of this article is available in the FibonacciLIBRARY
The CME version of this article is available for the medical community with an online CME test in the APP.
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ABOUT THE AUTHOR
Stuart M. Caplen, MD, FACEP, MSM
Dr. Caplen is a retired emergency medicine physician and former emergency department medical director, who also has a Master of Science in Management degree, and green belt certification in Lean/Six Sigma.
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