Photo Source: Microbiology and Immunology Online

Ehrlichiosis is an infectious disease transmitted by the bite of a tick. It is caused by bacteria that belong to the family called Rickettsiae. Rickettsialbacteria cause a number of serious diseases, including Rocky Mountain spotted fever and typhus. All of these diseases are spread to humans by a tick, flea, or bites from mites. Scientists first described ehrlichiosis in 1990, and have identified two types in the United States.

Human granulocytic ehrlichiosis (HGE) is also called human granulocytic anaplasmosis (HGA). It is caused by the rickettsial bacteria called Anaplasma phagocytophilum.


The incubation time between the tick bite and when symptoms occur is about a week. Symptoms of Ehrlichia are flu like symptoms, chills, fever, elevated liver enzymes, headaches, myalgias, fatigue, persistent leukopenia, thrombocytopenia, petechia (pin head size red dots), and a flat rash.

Signs and Tests

The test for Erlichiosis is a blood test;

The antibiotics most often used are tetracycline or doxycycline are used to treat the disease.

Ehrlichiosis is rarely deadly. With antibiotics, patients usually improve within 24 – 48 hours. Recovery takes 3 weeks.

Severe complications include kidney or lung damage, seizures, coma, or rarely death.

Articles on Erlichiosis

First Missouri death this year from tick-borne disease reported

Illinois State Department talks about Erlichiosis in Illinois

New Bacterium Found Causing Tick-Borne Illness Ehrlichiosis in Wisconsin and Minnesota

Human Monocytic Ehrlichiosis

Anaplasmosis/Erlichiosis in Wisconsin Fact Sheet


Pub Med Health

One thought on “Ehrlichiosis”

  1. My son and I both tested positive for Rocky Mountain Spotted Fever. We got it along with a couple of other co-infections, plus ‘Lyme’ (bb)- as ticks can and often do carry a bounty of infections.
    We did not get diagnosed ’till after the acute stage of infection was over, several years later, like too many.
    Good article- thank you:)

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