Anaplasmosis and Ehrlichiosis

Rickettsial infections are caused by a variety of bacteria, and are most often transmitted to humans by  infected fleas, lice, mites, and ticks. Rickettsial infections include anaplasmosis, ehrlichiosis, Rocky Mountain spotted fever, and typhus fever group. 

Ixodes scapularis

Anaplasmosis
(Anaplasma phagocytophilum infection)

Anaplasmosis, previously known as human granulocytic ehrlichiosis (HGE), is an illness caused by the bacterium Anaplasma phagocytophilum. Anaplasmosis is transmitted to humans through the bite of an infected blacklegged or deer tick (Ixodes scapularis), the same tick that causes Lyme disease and other tickborne diseases in Wisconsin. Illness occurs within 1-3 weeks after exposure to an infected tick. Symptoms may include fever, chills, muscle pain, severe headache, and fatigue. Clinical laboratory findings may include thrombocytopenia, lymphopenia, leucopenia, and elevated liver enzymes. If not treated, anaplasmosis can lead to serious and occasionally fatal illness. Anaplasmosis is the second most reported tickborne disease in Wisconsin.

Ehrlichiosis
(Ehrlichia chaffeensis, Ehrlichia ewingii and Ehrlichia muris-like infection)

Ehrlichiosis is an illness caused by several species of Ehrlichia (E. chaffeensis, E. ewingii and Ehrlichia muris-like). In Wisconsin, ehrlichiosis is transmitted to humans through the bite of an infected blacklegged or deer tick (Ixodes scapularis), the same tick that causes other tickborne diseases. Since 2008, there has been an increase in reported cases of ehrlichiosis in Wisconsin. A new Ehrlichia species (Ehrlichia muris-like) was discovered in Wisconsin and Minnesota in 2009. Illness usually occurs 5-10 days after exposure to an infected tick. Symptoms may include fever, chills, muscle pain, severe headache, and fatigue. Less common signs and symptoms may include nausea, vomiting, diarrhea, joint pain, confusion, and rash. Clinical laboratory findings may include thrombocytopenia, lymphopenia, leucopenia, and elevated liver enzymes. Severe symptoms, including respiratory and renal complications can occur in the elderly or immune-compromised people. The number of reported ehrlichiosis cases is much lower than anaplasmosis in Wisconsin.

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Additional Info Group

Last Revised: May 4, 2015