Human monocytotropic ehrlichiosis

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Human monocytic ehrlichiosis
Ehrlichia chaffeensis
SpecialtyInfectious diseases Edit this on Wikidata

Human monocytotropic ehrlichiosis[1] is a form of ehrlichiosis associated with Ehrlichia chaffeensis.[2] This bacterium is an obligate intracellular pathogen affecting monocytes and macrophages.[3]

Symptom and signs[edit]

The most common symptoms are fever, headache, malaise, and muscle aches (myalgia). Compared to human granulocytic anaplasmosis, rash is more common.[4] Laboratory abnormalities include thrombocytopenia, leukopenia, and elevated liver tests.[citation needed]

The severity of the illness can range from minor or asymptomatic to life-threatening. CNS involvement may occur. A serious septic or toxic shock-like picture can also develop, especially in patients with impaired immunity.[5]


This disease is known to be caused by tick bites.[6]


Tick exposure is often overlooked. For patients living in high-prevalence areas who spend time outdoors, a high degree of clinical suspicion should be employed.[citation needed] Ehrlichia serologies can be negative in the acute period. Polymerase chain reaction is therefore the laboratory diagnostic tool of choice.[7]


If ehrlichiosis is suspected, treatment should not be delayed while waiting for a definitive laboratory confirmation, as prompt doxycycline therapy has been associated with improved outcomes.[8] Doxycycline is the treatment of choice.[citation needed]

Presentation during early pregnancy can complicate treatment.[9] Rifampin has been used in pregnancy and in patients allergic to doxycycline.[10]


In the US, human monocytotropic ehrlichiosis occurs across the south-central, southeastern, and mid-Atlantic states, regions where both the white-tailed deer (Odocoileus virginianus) and its ectoparasite, Lone Star ticks (Amblyomma americanum), thrive.[11][12][13]

Human monocytotropic ehrlichiosis occurs in California in Ixodes pacificus ticks and in Dermacentor variabilis ticks.[14] Nearly 600 cases were reported to the CDC in 2006. In 2001–2002, the incidence was highest in Missouri, Tennessee, and Oklahoma, as well as in people older than 60.[15]

See also[edit]


  1. ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology. Mosby. pp. 1130. ISBN 978-1-4160-2999-1.
  2. ^ Schutze GE, Buckingham SC, Marshall GS, et al. (June 2007). "Human monocytic ehrlichiosis in children". Pediatr. Infect. Dis. J. 26 (6): 475–9. doi:10.1097/INF.0b013e318042b66c. PMID 17529862. S2CID 1191660.
  3. ^ Zhang, Jian-zhi; Popov, Vsevolod L.; Gao, Si; Walker, David H.; Yu, Xue-jie (March 2007). "The developmental cycle of Ehrlichia chaffeensis in vertebrate cells". Cellular Microbiology. 9 (3): 610–618. doi:10.1111/j.1462-5822.2006.00812.x. PMID 16987329. S2CID 11384349.
  4. ^ Dumler JS, Choi KS, Garcia-Garcia JC, et al. (December 2005). "Human granulocytic anaplasmosis and Anaplasma phagocytophilum". Emerging Infectious Diseases. 11 (12): 1828–34. doi:10.3201/eid1112.050898. PMC 3367650. PMID 16485466.
  5. ^ Paddock CD, Folk SM, Shore GM, et al. (November 2001). "Infections with Ehrlichia chaffeensis and Ehrlichia ewingii in persons coinfected with human immunodeficiency virus". Clinical Infectious Diseases. 33 (9): 1586–94. doi:10.1086/323981. PMID 11568857.
  6. ^ "Ehrlichiosis – Transmission". United States Center for Disease Control. 17 January 2019. Retrieved November 23, 2020.
  7. ^ Prince LK, Shah AA, Martinez LJ, Moran KA (August 2007). "Ehrlichiosis: making the diagnosis in the acute setting". Southern Medical Journal. 100 (8): 825–8. doi:10.1097/smj.0b013e31804aa1ad. PMID 17713310. S2CID 31487400.
  8. ^ Hamburg BJ, Storch GA, Micek ST, Kollef MH (March 2008). "The importance of early treatment with doxycycline in human ehrlichiosis". Medicine. 87 (2): 53–60. doi:10.1097/MD.0b013e318168da1d. PMID 18344803. S2CID 2632346.
  9. ^ Muffly T, McCormick TC, Cook C, Wall J (2008). "Human granulocytic ehrlichiosis complicating early pregnancy". Infect Dis Obstet Gynecol. 2008: 1–3. doi:10.1155/2008/359172. PMC 2396214. PMID 18509484.
  10. ^ Krause PJ, Corrow CL, Bakken JS (September 2003). "Successful treatment of human granulocytic ehrlichiosis in children using rifampin". Pediatrics. 112 (3 Pt 1): e252–3. doi:10.1542/peds.112.3.e252. PMID 12949322.
  11. ^ Kennedy AC, Marshall E (2021). "Lone Star Ticks (Amblyomma americanum): An Emerging Health Threat in Delaware". Delaware Journal of Public Health. 7 (1): 66–71. doi:10.32481/djph.2021.01.013 (inactive 18 April 2024). PMC 8352541. PMID 34467183.{{cite journal}}: CS1 maint: DOI inactive as of April 2024 (link)
  12. ^ "Ehrlichiosis: Transmission". Centers for Disease Control and Prevention. 17 January 2019. Retrieved 18 April 2024.
  13. ^ "Tickborne Diseases of the United States: Ehrlichiosis". Centers for Disease Control and Prevention. 15 December 2023. Retrieved 18 April 2024.
  14. ^ Holden K, Boothby JT, Anand S, Massung RF (July 2003). "Detection of Borrelia burgdorferi, Ehrlichia chaffeensis, and Anaplasma phagocytophilum in ticks (Acari: Ixodidae) from a coastal region of California". J. Med. Entomol. 40 (4): 534–9. doi:10.1603/0022-2585-40.4.534. PMID 14680123.
  15. ^ "Statistics and Epidemiology: Annual Cases of Ehrlichiosis in the United States". Ehrlichiosis. Division of Vector-Borne Diseases (DVBD), National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Centers for Disease Control and Prevention. 5 September 2013.

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