Ehrlichiosis (HME) was originally thought to be only an animal disease. It was described in humans in 1987 and is now found in 30 states, predominately in the southeast, south-central, and mid-Atlantic states, Europe and Africa. Anaplasmosis (HGE)in humans was first identified in 1990 in a Wisconsin man. Before that it was known to infect horses, sheep, cattle, dogs and cats. It occurs in the upper midwest, northeast, the mid-Atlantic states, northern California, and many parts of Europe. Studies suggest that in endemic areas as much as 15% to 36% of the population has been infected, though often it is not recognized. (1)
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 which doctors can sometimes see on blood smears. The infection still can easily be missed. The doctor may suspect ehrlichiosis/anaplasmosis in a patient who does not respond well to treatment for Lyme disease. (1)
Ehrlichiosis is caused by bacteria that belong to the family called Rickettsiae. Rickettsial bacteria cause a number of serious diseases worldwide, including Rocky Mountain spotted fever and typhus. All of these diseases are spread to humans by a tick, flea, or mite bite.
Ehrlichia bacteria can be carried by the Lone Star tick, the American dog tick, and the deer tick, which can also cause Lyme disease. (2)
There are two kinds of ehrlichiosis, both of which are caused by tick-borne rickettsial parasites called Ehrlichia that infect different kinds of white blood cells. In HME (human monocytic ehrlichiosis), they infect monocytes. In HGE (human granulocytic ehrlichiosis), they infect granulocytes. HGE was renamed anaplasmosis in 2003. Ticks carry many Ehrlichia-like parasites that have not been identified yet. It is likely that the lone star tick transmits HME and that the deer tick transmits HGE. (1)
Not every individual tick is infected with the bacteria, so a tick bite does not automatically result in illness. It usually takes 24 to 36 hours for an infected feeding tick to transmit the ehrlichiosis-causing bacteria to its host. (3)
The symptoms of ehrlichiosis usually appear about a week after someone has been bitten by an infected tick. However, it is also common for ehrlichiosis to have very mild symptoms or even no symptoms at all. The only way to conclusively diagnose ehrlichiosis is through a blood test. The good news is that this disease is usually resolved by the immune system and requires no medical treatment. (3)
For people who have compromised or weak immune systems, such as very young children, the elderly or those with autoimmune deficiency diseases, ehrlichiosis can become very serious or fatal if left untreated. When the immune system is unable to effectively fight bacteria, the bacteria are able to multiply quickly and overwhelm the body. (3)
Treatments include-
Doxycycline, minocycline, tetracycline, rifampin and zithromax
Symptoms include-
profound fatigue
sever muscle pain
high liver enzymes
low white blood cell count
fevers
severe headaches
nausea
malaise
flat red rash
diarrhea
joint pain
confusion
low platelet count
anemia
kidney failure
respiratory insufficiency
SOURCES-
1. http://www.lymedisease.org/lyme101/coinfections/ehrlichia.html
2. https://www.google.com/health/ref/Ehrlichiosis
3. http://www.wisegeek.com/what-is-ehrlichiosis.htm
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