Ehrlichiosis is caused by various types of Ehrlichia and Anaplasmosis is caused by Anaplasma phagocytophilum.
Ehrlichiosis was formerly called HME, human monocytic ehrlichiosis and Anaplasmosis used to be called HGE, human granulocytic ehrlichiosis.
Some studies suggest that, in endemic areas, as many as 15 – 36% of the human population has been infected, although many people may not be aware that they are infected.
The clinical manifestations of ehrlichiosis and anaplasmosis are the same. Each is often characterized by sudden high fever, fatigue, muscle aches, headache. Rash is uncommon but has been reported. The disease can be mild or life-threatening. Severely ill patients can have low white blood cell count, low platelet count, anemia, elevated liver enzymes, kidney failure and respiratory insufficiency. Older people or people with immune suppression are more likely to require hospitalization. Deaths have occurred.
Compared with HME, HGA appears less likely to involve the central nervous system, but peripheral neuropathies are more common and can last weeks to months. Among the neurologic findings reported in the medical literature are facial palsy, demyelinating polyneuropathy and brachial plexopathy. Respiratory distress syndrome and a septic or toxic shock-like syndrome have been reported, but appear to be less common than in HME. Diagnosis is limited by our current ability to test for only two species. Ehrlichia parasites multiply inside host cells, forming large mulberry-shaped clusters called morulae that doctors can sometimes see on blood smears. The infection still can easily be missed. The doctor may suspect Ehrlichiosis or Anaplasmosis in a patient who does not respond well to treatment for Lyme disease.
Ehrlichia and Anaplasmosis