Coinfections of Lyme Disease Babesiosis Babesiosis is an infection caused by a malaria-like parasite, also called a “piroplasm,” that infects red blood cells. Babesia microti is believed to be the most common piroplasm infecting humans, but scientists have identified over twenty piroplasms carried by ticks. Ticks may carry only Babesia or they may be infected with both Babesia and Lyme spirochetes. People can also get babesiosis from a contaminated blood transfusion. Ehrlichiosis 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. 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. Bartonella Bartonella are bacteria that live inside cells; they can infect humans, mammals, and a wide range of wild animals. Not all Bartonella species cause disease in humans. Bartonella henselae causes an important emerging infection first reported in 1990 and described as a new species in 1992. It is mainly carried by cats and causes cat-scratch disease, endocarditis, and several other serious diseases in humans. Bartonella bacteria are known to be carried by fleas, body lice and ticks. Scientists suspect that ticks are a source of infection in some human cases of bartonellosis. People with tick bites and no known exposure to cats have acquired the disease. People who recall being bitten by ticks have been co-infected with Lyme and Bartonella. More research needs to be done to establish the role of ticks in spreading the disease. Colorado Tick Fever Colorado tick fever is caused by a virus carried by Rocky Mountain wood ticks. Symptoms are acute high fever, severe headache, chills, fatigue, and muscle pain. Mycoplasma Mycoplasma species have been identified in ticks. Smaller than bacteria, they invade human cells and disrupt the immune system, causing fatigue, musculoskeletal symptoms, and cognitive problems. Mycoplasmas can be treated with antibiotics. Powassan virus Powassan virus causes tick-borne encephalitis (TBE). Symptoms may include fever, convulsions, headache, disorientation, lethargy, partial coma and paralysis. Ten percent of patients die and survivors may have permanent damage. Q Fever Q fever is caused by Coxiella burnetii, a kind of bacteria carried by cattle, sheep, and goats. Symptoms are similar to those of Lyme disease. Q fever is likely to start with a high fever. Pneumonia and abnormal liver function also suggest Q fever. Doxycycline is the treatment of choice. Rocky Mountain Spotted Fever Rocky Mountain spotted fever is caused by bacteria called Rickettsia rickettsii that are transmitted by the bite of a tick. Patients develop high fever, rash, headache and bleeding problems. Thirty percent of untreated patients die. It is treatable with antibiotics, often doxycycline. Tick Paralysis Certain ticks secrete a toxin that causes a progressive paralysis, which is reversed when the tick is removed. Tickborne Relapsing Fever The agent of tickborne relapsing fever, Borrelia hermsi, is carried by soft ticks of the western United States. It is characterized by cycles of high fever and is treated with antibiotics. Tularemia Tularemia, or rabbit fever, occurs throughout the United States. It is caused by the bacterium Francisella tularensis. Symptoms may include skin ulcers, swollen and painful lymph glands, inflamed eyes, sore throat, mouth sores, pneumonia, diarrhea and vomiting. The most effective treatment is with fluorinated quinolones.
Posted on: Mon, 19 Aug 2013 23:17:08 +0000
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