While most tick bites are harmless, several species can cause life-threatening diseases. Tickborne diseases include anaplasmosis, babesiosis, Colorado tick fever, and Powassan encephalitis. Two of the most well-known diseases are Rocky Mountain Spotted Fever and Lyme disease. Ticks can also transmit tularemia (a plague-like disease in rodents that can be transmitted to man), relapsing fever, and ehrlichiosis (an abrupt illness consisting of fever, rash, nausea, vomiting, and weight loss).
Lyme disease (LD) is a multistage, multisystem bacterial infection caused by the spirochete Borrelia burgdorferi, a spiral shaped bacterium that is most commonly transmitted by a tick bite. The disease takes its name from Lyme, Connecticut, where the illness was first identified in the United States in 1975.
According to the CDC, Lyme disease continues to be a rapidly emerging infectious disease, and is the leading cause of all insect-borne illness in the U.S. According to the CDC, over 22,500 cases were reported in 2010, and there were 7,500 probable cases of LD.
What types of ticks transmit LD?
Ixodes scapularis (northeastern, mid-Atlantic, and north-central U.S., black-legged deer tick)
Ixodes pacificus (Pacific coastal U.S., Western black-legged tick)
Ticks prefer to live in wooded areas, low-growing grasslands, and yards. Depending on the location, anywhere from less than 1 percent to more than 50 percent of the ticks are infected with spirochetes.
Although Lyme disease is a year-round problem, April through October is considered tick season. Cases of Lyme disease have been reported in nearly all states in the U.S. and in large areas in Europe and Asia.
The list of possible symptoms is long, and symptoms can affect every part of the body. The following are the most common symptoms of Lyme disease. However, each individual may experience symptoms differently.
The primary symptom is a red rash that:
Can appear several days after infection, or not at all.
Can last up to several weeks.
Can be very small or very large (up to 12 inches across), and may resemble a "bulls-eye."
Can mimic such skin problems as hives, eczema, sunburn, poison ivy, and flea bites.
Can itch or feel hot, or may not be felt at all.
Can disappear and return several weeks later.
Several days or weeks after a bite from an infected tick, a patient usually experiences flu-like symptoms such as the following:
Aches and pains in muscles and joints
Low-grade fever and chills
Weeks to months after the bite, the following symptoms may develop:
Neurological symptoms, including inflammation of the nervous system (meningitis) and weakness and paralysis of the facial muscles (Bell's palsy)
Heart problems, including inflammation of the heart (myopericarditis) and problems with heart rate
Eye problems, including inflammation (for example, red eye)
Months to a few years after a bite, the following symptoms may include:
Inflammation of the joints (arthritis)
Neurological symptoms including:
Tingling and pain
Difficulties with speech, memory, and concentration
Some people may develop post-Lyme disease syndrome (PLDS). A condition also known as chronic Lyme disease includes PLDS, but also other syndromes. Usually, these are characterized by persistent musculoskeletal and peripheral nerve pain, fatigue, and memory impairment.
Lyme disease is difficult to diagnose because symptoms are not consistent and may imitate other conditions. The primary symptom is a rash, but it may not be present in up to 20 percent of cases.
Diagnosis for Lyme disease is a clinical one and must be made by a doctor experienced in recognizing LD. Diagnosis is usually based on symptoms and a history of a tick bite. Testing is generally done to eliminate other conditions and may be supported through blood and laboratory tests, although these tests are not absolutely reliable for diagnosing LD.
Research is underway to develop and improve methods for diagnosing LD.
The symptoms of Lyme disease may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.
Specific treatment for Lyme disease will be determined by your doctor based on:
Your age, overall health, and medical history
Extent of the symptoms
Your tolerance for specific medications, procedures, or therapies
Expectations for the course of the condition
Your opinion or preference
Lyme disease in the earliest stage is usually treated with antibiotics for three weeks.
Treatment will also be considered based on these and other factors:
If you are bitten by a tick that tests positive for spirochetes.
If you are bitten by a tick and have any of the symptoms.
If you are bitten by a tick and are pregnant.
If you are bitten by a tick and live in an endemic, high-risk area.
Relapse and incomplete treatment responses occur. Complications of untreated early-stage disease include: joint disease, neurologic disease, carditis, and frequent hospitalizations to manage the disease. Some of these complications result in chronic, debilitating conditions.
Humans do not develop immunity to LD and reinfection is possible. In 1998, the FDA had approved a new vaccine against Lyme disease called LYMErix. The vaccine was not 100 percent effective, however, and the FDA still recommended using other preventive measures. In 2002, the manufacturer of LYMErix announced that the vaccine would no longer be available commercially.
Some general guidelines for preventing LD include the following:
Dress appropriately by wearing:
Socks and closed-toe shoes
Long pants with legs tucked into socks
Frequently check for ticks on:
All parts of the body that bend: behind the knees, between fingers and toes, and underarms
Other areas where ticks are commonly found: belly button, in and behind the ears, neck, hairline, and top of the head
Areas of pressure points, including:
Where underwear elastic touches the skin
Where bands from pants or skirts touch the skin
Anywhere else where clothing presses on the skin
Visually check all other areas of the body, and run fingers gently over skin.
Shower after all outdoor activities are over for the day.
Consider using repellents:
Products that contain DEET are tick repellents, but do not kill the tick and are not 100 percent effective in discouraging a tick from feeding on you.
Products that contain permethrin are known to kill ticks; however, they should not be sprayed on the skin but on clothing.
Check pets and children for ticks.
Do not touch the tick with your bare hand.
Use a pair of tweezers to remove the tick. Grab the tick firmly by its mouth or head as close to your skin as possible.
Pull up slowly and steadily without twisting until it lets go. Do not squeeze the tick, and do not use petroleum jelly, solvents, knives, or a lit match to kill the tick.
Save the tick and place it in a plastic container or bag so it can be tested for disease, if necessary.
Thoroughly wash the bite area with soap and water and apply an antiseptic lotion or cream.
Call your doctor to find out about follow-up care and testing of the tick for spirochetes (organisms that may be carried by the tick).