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Media Gallery

Female Lone Star tick, Amblyomma americanum, found in the southeastern and Midatlantic United States. It is a vector of several zoonotic diseases, including human monocytic ehrlichiosis and Rocky Mountain spotted fever. Courtesy of the CDC/Michael L. Levin, PhD.
Map of the United States showing the distribution of the Lone Star Tick, which is the principle vector for ehrlichiosis.
Established and reported distribution of anaplasmosis vectors Ixodes scapularis and Ixodes pacificus, by county, in the United States from 1907-1996. Courtesy of the Division of Vector-Borne Infectious Diseases at the Centers for Disease Control and Prevention.
Anaplasmosis incidence by age. Courtesy of the Centers for Disease Control and Prevention.
Ehrlichiosis incidence by age. Courtesy of the Centers for Disease Control and Prevention.
This graph displays the number of human cases of ehrlichiosis caused by Ehrlichia chaffeensis reported to the Centers for Disease Control and Prevention (CDC) annually from 2000 through 2016. *From 2000 to 2008, ehrlichiosis was included in the reporting category “human monocytic ehrlichiosis” in reports to the National Notifiable Diseases Surveillance System (NNDSS). **Since 2008, ehrlichiosis has been reported to the NNDSS under the categories “Ehrlichia chaffeensis infections,” “Ehrlichia ewingii infections,” and “Undetermined ehrlichiosis/anaplasmosis infections”, which include infections caused by Ehrlichia muris eauclairensis. Only E chaffeensis infections are shown above. Courtesy of the CDC (https://www.cdc.gov/ehrlichiosis/stats/index.html).
This graph shows the number of ehrlichiosis cases caused by Ehrlichia chaffeensis reported from 2000 through 2016 by month of onset to illustrate the seasonal trends. Cases are reported in each month of the year, although most are reported in June and July. Courtesy of the CDC (https://www.cdc.gov/ehrlichiosis/stats/index.html).
This graph shows the number of US ehrlichiosis cases caused by Ehrlichia chaffeensis and reported to the CDC from 2000 to 2018. Courtesy of the CDC (https://www.cdc.gov/ehrlichiosis/stats/).

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Author

Chinelo N Animalu, MD, MPH, FIDSA Associate Professor, Division of Infectious Diseases, Department of Internal Medicine, University of Tennessee Health Science Center College of Medicine; Physician, Department of Infectious Disease, University of Tennessee Methodist Physicians (UTMP), Methodist University Hospital

Chinelo N Animalu, MD, MPH, FIDSA is a member of the following medical societies: American College of Physicians, American Medical Association, Infectious Diseases Society of America, Memphis Medical Society, Tennessee Medical Association

Disclosure: Nothing to disclose.

Coauthor(s)

Spandana Vuyyuru, BS MD Candidate, University of Tennessee Graduate School of Medicine

Spandana Vuyyuru, BS is a member of the following medical societies: American Medical Association, Emergency Medicine Residents' Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Jon Mark Hirshon, MD, MPH, PhD, FACEP Professor, Department of Emergency Medicine, Professor, Department of Epidemiology and Public Health, University of Maryland School of Medicine; Chief, Emergency Department, Baltimore VA Medical Center

Jon Mark Hirshon, MD, MPH, PhD, FACEP is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Public Health Association, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Michael Stuart Bronze, MD David Ross Boyd Professor and Chairman, Department of Medicine, Stewart G Wolf Endowed Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center; Master of the American College of Physicians; Fellow, Infectious Diseases Society of America; Fellow of the Royal College of Physicians, London

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Medical Association, Association of Professors of Medicine, Infectious Diseases Society of America, Oklahoma State Medical Association, Southern Society for Clinical Investigation

Disclosure: Nothing to disclose.

Additional Contributors

Joseph Domachowske, MD Professor of Pediatrics, Microbiology and Immunology, Department of Pediatrics, Division of Infectious Diseases, State University of New York Upstate Medical University

Joseph Domachowske, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Society for Microbiology, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa

Disclosure: Received research grant from: Pfizer;GlaxoSmithKline;AstraZeneca;Merck;American Academy of Pediatrics, Novavax, Regeneron, Diassess, Actelion<br/>Received income in an amount equal to or greater than $250 from: Sanofi Pasteur.

Burke A Cunha, MD Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital

Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Samuel M Keim, MD, MS Professor and Chair, Department of Emergency Medicine, University of Arizona College of Medicine

Samuel M Keim, MD, MS is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Public Health Association, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Walid Abuhammour, MD, MBA, CIC, FAAP, FIDSA Professor of Pediatrics, Michigan State University College of Human Medicine; Adjunct Professor, Department of Pediatrics, Hashemite University, Jordan; Head of Pediatric Infectious Diseases, Department of Pediatrics, Al Jalila Children's Hospital, UAE

Walid Abuhammour, MD, MBA, CIC, FAAP, FIDSA is a member of the following medical societies: American Academy of Pediatrics, International Society for Infectious Diseases, International Society for Infectious Diseases, Jordan Medical Association, Jordan Pediatric Society, Michigan Infectious Disease Society, Michigan State Medical Society, National Arab American Medical Association, Pediatric Infectious Diseases Society

Disclosure: Nothing to disclose.

Thomas J Marrie, MD Dean of Faculty of Medicine, Dalhousie University Faculty of Medicine, Canada

Thomas J Marrie, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Society for Microbiology, Association of Medical Microbiology and Infectious Disease Canada, Royal College of Physicians and Surgeons of Canada

Disclosure: Nothing to disclose.

Nicholas John Bennett, MBBCh, PhD, FAAP, MA(Cantab) Assistant Professor of Pediatrics, Co-Director of Antimicrobial Stewardship, Medical Director, Division of Pediatric Infectious Diseases and Immunology, Connecticut Children's Medical Center

Nicholas John Bennett, MBBCh, PhD, FAAP, MA(Cantab) is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics

Disclosure: Received research grant from: Cubist<br/>Received income in an amount equal to or greater than $250 from: Horizon Pharmaceuticals, Shire<br/>Medico legal consulting for: Various.

Acknowledgements

Geofrey Nochimson, MD Consulting Staff, Department of Emergency Medicine, Sentara Careplex Hospital

Geofrey Nochimson, MD is a member of the following medical societies: American College of Emergency Physicians

Disclosure: Nothing to disclose.

	Human monocytic ehrlichiosis (HME)	Human granulocytic anaplasmosis (HGA)
Cell type Affected	Monocytes	Granulocytes
Organism	E chaffeensis	A phagocytophilum
Vector	Amblyomma americanum (Lone Star tick)	Ixodes scapularis (black-legged tick), Ixodes pacificus (Western black-legged tick) in California, Ixodes ricinus in Europe, and probably Ixodes persulcatus in parts of Asia
Location	Southeastern and south-central United States	Wisconsin and Minnesota, less active in New York and Connecticut, also California
Rash	30% of adults, 60% of children	Rare
Prognosis	~3% mortality	< 1% mortality

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