Human Granulocytic Anaplasmosis, which was formerly known as human granulocytic ehrlichiosis, is a disease caused by an active infection from the bacterium Anaplasma phagocytophilum. Exposure to Anaplasma phagocytophilum occurs when an animal is bitten primarily by a black-legged tick also known as a deer tick (Ixodes scapularis) or a western black-legged tick (Ixodes pacificus), that is infected with the bacteria. Recent research has also shown that this bacterium can be transmitted by the American dog tick (Dermacentor variablis) as well as the lone-star tick (Amblyomma americanum). The tick bite is not felt by the host and some people may not be able to recall a tick bite when being diagnosed. Out of the four stages in a tick’s life cycle, the nymph and adult tick are the most commonly known to transmit the bacterium Anaplasma phagocytophilum to humans. The northeast and upper midwest regions are reported most frequently in the United States for the transmission of Anaplasma phagocytophilum by ticks. Once these bacteria enter the body, they infect a special type of white blood cells of the immune system and will multiply inside these cells. Since the bacteria will hide in the cells of the immune system, it is very difficult for the body to rid itself of the infection.
Anaplasmosis is usually diagnosed based on the following symptoms: fever, chills, malaise, muscle pain, headache, nausea, cough, confusion, and a rash. These symptoms typically develop within 7-14 days after being bitten by an infected tick. Since the symptoms of Anaplasmosis are not unique, and are quite similar to Lyme disease, properly diagnosing Human Granulocytic Anaplasmosis can be difficult. After longer periods of time, infection can be fatal causing kidney failure, difficult time breathing, hemorrhaging, and neurological problems. Human Granulocytic Anaplasmosis is a potentially serious disease that can become fatal if it is not treated properly. Once diagnosed, treatment from a health care physician will prescribe children and adults Doxycycline, and the infection should clear up within 7-14 days of antibiotic usage. The disease is normally diagnosed by the symptoms shown and will then be tested in a laboratory. Occasionally, black-legged ticks have been found to contain co-infections of Anaplasma phagocytophilum and Borrelia burgdorferi (the bacterium that causes Lyme disease).
Info. from: http://www.cdc.gov/anaplasmosis/index.html