Tickborne Illnesses

The deer tick, Ixodes scapularis, spreads Lyme disease to animals and humans it bites. The first sign of infection is often a rash at or near the bite. This rash may be bull’s-eye-shaped (called erythema migrans), or it can look like a red streak or blotch. The rash is almost always more than three inches wide, so a smaller rash usually isn’t a sign of Lyme disease. In addition to the rash, the first stage of Lyme disease infection often includes fever and chills. Treatment in this stage includes antibiotics, usually doxycycline. No blood testing is needed, as tests are often negative early in the disease process. If Lyme disease isn’t diagnosed and treated early, it can progress to the next phase. At this stage, the bacterium that causes the disease, called Borrelia burgdorferi, gets into the bloodstream. This can cause a variety of problems, such as:

• Achiness and fever
• Blockage of electrical circuits in the heart, which leads to a slow heart rate and sometimes loss of consciousness
• Headache
• Meningitis, a swelling of the membranes that cover the brain and spinal cord
• Multiple areas of rash
• Nerve problems, such as facial paralysis (Bell’s palsy)

In this phase of the illness, patients usually test positive for the disease. Treatment includes antibiotics, either by mouth or intravenously (IV). Without treatment, Lyme disease can cause joint pain or swelling, usually in the knees or other large joints. Patients’ blood tests are always positive in this stage, and treatment includes antibiotics for two to four weeks.

Anaplasmosis is also transmitted by the deer tick and caused by a bacterium. This illness resembles the flu but without the usual hoarseness, cough, and stuffiness that accompany the flu. The main symptom of anaplasmosis is fever, which can be accompanied by:

• Chills
• General terrible feeling
• Headache

Symptoms of anaplasmosis can come on suddenly. We diagnose anaplasmosis with various blood tests, but the results can take a few days to come back, so we often treat the illness with antibiotics up front and then adjust our treatment as we receive lab results. Our main treatment is the antibiotic doxycycline. Some alternative antibiotics that are effective against Lyme disease, such as amoxicillin and cefuroxime, aren’t effective for treating anaplasmosis. Without treatment, anaplasmosis can be a severe illness, although deaths from the disease are rare.

Babesiosis is also transmitted by the deer tick. However, unlike Lyme disease and anaplasmosis, babesiosis is caused by a parasite that infects red blood cells. The main symptom of babesiosis is fever with chills, along with:

• Achiness
• Feeling awful
• Headache

This infection can be particularly severe in people whose spleens have been removed surgically or do not work well, as well as people with impaired immune systems (e.g., because of infections or infection with HIV). We diagnose babesiosis with a lab analysis of blood smears under a microscope and by DNA detection. Possible complications of babesiosis can include rupture of the spleen and severe anemia. There are several effective treatments for this condition, but they are different than those used for Lyme disease and anaplasmosis, so your doctor needs to think specifically of babesiosis when creating your treatment plan.

Despite the name of this disease, Rocky Mountain spotted fever has been present in Massachusetts for many years, especially on Cape Cod and the islands. However, it is rare. We have seen very few cases of this condition at Newton-Wellesley Hospital. Rocky Mountain spotted fever is transmitted by the dog tick. Symptoms often include a blotchy rash, and it has a high fatality rate. We treat this disease with the antibiotic doxycycline.

This infection is caused by an organism similar to the one that causes Lyme disease. However, the condition itself more closely resembles anaplasmosis. As with both of those conditions, Borrelia miyamotoi is transmitted by the deer tick. It was recognized in our area only a few years ago, and we are still learning about how frequent it is. Special tests are needed to diagnose Borrelia miyamotoi infection. However, treatment with the antibiotic doxycycline is very effective, so we often start patients on this medication before we have definitively diagnosed the illness.

Powassan virus is another emerging infection in our area. We diagnosed Massachusetts’ first case of Powassan in 2013, and only eight cases have been diagnosed so far in the state. The infection seems to mainly cause encephalitis, an inflammation of the brain tissue, which can be severe. Testing for Powassan is usually done at the CDC in Atlanta, and there is no known treatment at this time.