Ehrlichiosis in Southern Ohio: Two case reports and a review of the literature




Ehrlichiosis Ehrlichia chaffeensis Amblyomma americanum Tick-borne disease Ohio


Tick-borne disease is becoming more commonplace as humans encroach on endemic regions with high tick preponderance. The incidence of ehrlichiosis is rising in conjunction with the increasing prevalence of its associated vector, Amblyomma americanum. In Ohio, populations of A. americanum have been expanding their range and growing in abundance and distribution. Southern Ohio in particular, has been identified as having a expanding population of E. chaffeensis infected ticks. The initial symptoms of ehrlichiosis are frequently vague and ill-defined. Often patients are not aware of having sustained a tick bite. Successful diagnosis and treatment of ehrlichiosis requires an index of suspicion, an awareness of local epidemiology, and prompt recognition of characteristic laboratory abnormalities consistent with E. chaffeensis infection. Patients in regions where these infections are known to exist, who present during tick season with fever, leukopenia and/or thrombocytopenia, and increased serum transaminase levels, should have ehrlichiosis included in the differential diagnosis. Left untreated, patients with ehrlichiosis can develop severe complications, including death. Doxycyline is the drug of choice for ehrlichiosis and should be initiated in symptomatic patients with a history of tick bite; it should not be withheld while awaiting lab results.


1. Dumler JS, Madigan JE, Pusteria N, Bakken JS. Ehrlichiosis in humans: epidemiology, clinical presentation, diagnosis, and treatment. Clin Infect Dis. 2007:45(Suppl1);S45-S51.

2. Ismail N, McBride JW. Tick-Borne Emerging Infections Ehrlichiosis and Anaplasmosis. Clin Lab Med. 2017 Jun;37(2):317-340.

3. Madison-Antenucci S, Kramer LD, Gebhardt LL, Kaufman E. Emerging tick-borne diseases. Clin Microbiol Rev. 2020;50(3):903-8.

4. Ganguly S, Mukhopadhayay SK. Tick-borne ehrlichiosis in human beings. J Vector Borne Dis. 2008 Dec;45(4):273-80.

5. Heitman KN, Dahlgren FS, Drexler NA, Massung RF, Behravesh CB. Increasing Incidence of Ehrlichiosis in the United States: A Summary of National Surveillance of Ehrlichia chaffeensis and Ehrlichia ewingii in the United States, 2009-2012. Am J Trop Med Hyg. 2016; 94(1):52-60.

6. Paddock CD, Childs JE. Ehrlichias chaffeensis: a prototypical emerging pathogen. Clin Microbiol Rev. 2003 Jan;16(1):37-64.

7. Fitak, RR, Kelly, DJ, Daniels, MK, Jiang J, Richards, AL, Fuerst, PA. The prevalence of rickettsial and ehrlichial organisms in Amblyomma americanum ticks collected from Ohio and surrounding areas between 2000 and 2010. Ticks Tick Borne Dis. 2014;5(6):797-800.

8. Tick-borne Diseases Ohio Summary, 2011. Accessed March 12, 2020.

9. Schutze GE. Ehrlichiosis. Pediatr Infect Dis J. 2006 Jan;25(1):71-72.

10. Biggs HM, Behravesh CB, Bradley KK, Dahlgren FS, et al. Diagnosis and management of tickborne rickettsial diseases: rocky mountain spotted fever, and other spotted fever group rickettsioses, ehrlichiosis, and anaplasmosis – United States. MMWR Recomm Rep. 2016;65(2):1-44.

11. Council of state and territorial epidemiologists 2009. Position Statement 07- ID – 03: revision of the national surveillance case definition for ehrlichiosis (ehrlichiosis/anaplasmosis). Accessed March 25, 2020.

12. Huntington MK, Allison J. Emerging Vector-Borne Diseases. Am Fam Physician. 2016;94(7):551-557.

13. Olano JP, Masters E, Hogrefe W, Walker DH. Human monocytotropic ehrlichiosis, Missouri. Emerg Infect Dis. 2003;9(12):1579-1586.

14. Krause PJ, Corrow CL, Bakken JS. Successful treat of human granulocytic ehrlichiosis in children using rifampin. Pediatrics. 2003;112:e252-253.

15. Anderson BE, Dawson JE, Jones DC, Wilson KH. Ehrlichia chaffeensis, a new species associated with human ehrlichiosis. J Clin Microbiol. 1991;29:2838-2842.

16. Ehrlichiosis Statistics and Epidemiology. Updated March 26, 2020. Accessed March 12, 2020.

17. Dahlgren FS, Mandel EJ, Krebs JW, et al. Increasing incidence of Ehrlichia chaffeensis and Anaplasma phagocyophilum in the United States, 2000- 2007. Am J Trop Med Hyg. 2011;85(1):124-131.

18. National Notifiable Diseases Surveillance System, Ehrlichiosis and Anaplasmosis 2008 Case Definition. Accessed March 8, 2020.




How to Cite

Gotfried, R. (2023). Ehrlichiosis in Southern Ohio: Two case reports and a review of the literature. Translation: The University of Toledo Journal of Medical Sciences, 11(2).