Warmer weather means we have to start thinking about ticks and Lyme Disease. Most people are aware of the association between tick bites and Lyme disease, but few know exactly what Lyme disease is or what causes it. The number of cases in Indiana has varied over the years, but generally has increased since around 2013. The most recent statistics from 2019 showed an incidence of 1.5 cases per 100,000 population in Indiana. The highest incidence state that year was 121 cases per 100,000.
Lyme disease received its name in the late 1970s when a number of children around Lyme, Connecticut developed arthritis. The actual disease has been described since the early 1900s. It is mostly found from Virginia up through Maine on the east coast as well as Wisconsin and Minnesota. When a case does occur in Indiana, the news spreads rapidly, sometimes inciting panic. Most infections (85 percent) are seen in the spring and summer with the remainder in the fall.
Ticks do not actually cause the disease, though they do carry the organism that does, the spirochete Borrelia burgdorferi. Spirochetes are bacteria that have a corkscrew shape. Another common misconception is that any tick can spread B. burgdorferi infection, when in fact only Ixodes (deer) ticks carry the organism. The accompanying photo shows a deer tick on a fingernail – they are very small.
The B. burgdorferi organism primarily infects field mice and white tailed deer during its life cycle. Humans are innocent bystanders when we wander into deer habitat. The ticks lie in wait on the tips of grasses and shrubs and crawl onto us as we brush by. They then crawl about until they find a nice tender spot where they attach and begin to feed on the host’s blood.
The risk of contracting B. burgdorferi is very small unless the tick has been attached and feeding for two to three days. Not everyone will develop clinically significant Lyme disease if they are infected.
Lyme Disease has three stages. The first two stages are termed “early infection” and the third is called “late infection.” The signs and symptoms are quite different during each stage.
Stage 1 consists of signs near the point of attachment of the tick. A characteristic rash usually develops called erythema chronicum migrans (ECM). The rash is red (erythema), lasts for a few weeks (chronicum) and tends to enlarge or migrate with time (migrans). Patients may also have fever, fatigue and headache.
Stage 2 involves more systemic signs and symptoms. This stage can involve virtually any tissue, but signs and symptoms are usually found in the joints, nervous system and heart. Two-thirds of people develop arthritis that can occur in various joints and may migrate from joint to joint. Weakness as well as numbness and tingling may occur in the nerves of the face and elsewhere. Infection of the heart can cause rhythm problems.
Step 3, or late infection, can present up to a year after the organism invades the body. Approximately ten percent of people develop chronic arthritis, usually of the knee. They can also develop infections of the brain and spinal cord and severe chronic malaise and fatigue can also occur.
Testing for Lyme is not always straightforward. Antibodies against the organism may be found in the bloodstream but can be be falsely positive or negative. Therefore, it’s important to not test persons who don’t have signs or symptoms of Lyme Disease. The CDC recommends that anyone with a positive test have it confirmed with a more specific antibody test called a western blot. People with neurologic symptoms may require a spinal tap to look for infection.
Treatment for Lyme disease is fairly straightforward. Most people are prescribed the antibiotic doxycycline. The length of treatment varies based on the stage and extent of infection. Some people with severe involvement may require hospitalization. This is most common if a person develops heart problems.
Simple steps can be taken to reduce your risk of contracting Lyme disease. Even though Lyme disease is rare in Indiana you should consider covering up when you’re in the woods. This includes wearing a long shirt and pants as well as a hat.
You should do a full body check for ticks after you’ve been in the woods and apply insect repellent with at least 30 percent DEET when going outdoors. Always be on the lookout for the signs and symptoms of Lyme disease if you have found a tick attached to your body
Removal of ticks can be tricky. You need to get a fine pair of tweezers and grasp the tick’s head as close to the skin surface as possible and pull slowly and gently upward until the tick lets go. You should then wash the skin with alcohol or soap and water. You should save the tick in alcohol in case it’s needed for identification. If you can’t remove the tick, call your health professional.
Dr. John Roberts is a member of the Franciscan Physician Network specializing in Family Medicine.