Lyme disease

     Spring is here and that means ticks will soon be on the prowl. The most common tick-carried infection in both the U.S. and Europe is Lyme disease.

     95% of Lyme disease is reported from 13 states – those along the upper east coast and the mid-western states of Wisconsin and Minnesota. These states have the perfect combination of lots of white-tailed deer and lots of leaf-litter on the forest floor that favors the ticks that carry Lyme disease.

     Lyme disease is transmitted by the deer tick (also called the black-legged tick). It is not transmitted by the larger and more commonly known wood tick (dog tick). The deer tick’s life cycle involves the adult biting any mammal (deer are preferred), taking a blood meal and dropping off to lay eggs. The next spring, those eggs hatch into the nymph stage. This young form of the tick stays on the underside of leaves of low-lying shrubs or grass and is sensitive to both heat and C02 emission. This early nymph phase is actually the more common cause of transmission to humans for two reasons: first, it feeds on anything that passes by, and second, it is very small – the size of a pin-head – making it hard to detect. This increases the risk of transmission of Lyme disease because the tick needs to be attached and actively feeding for 48 hours in order to transmit the disease. A tick walking on the skin looking for a place to attach is not a risk for Lyme disease.

     The sign of early Lyme disease is a “bull’s eye” rash at the site of the bite. This rash is called erythema migrans. It is a ring of red coloration that gradually expands with clearing in the center. It is common to have fever, weakness and general aches during this early phase. Later, more rashes can develop along with weakness of the facial muscles, especially those controlling the upper eyelid causing a “drooping’ lid. Headache and vomiting can also occur. Late symptoms of Lyme disease can involve multiple joint pains and neurological problems.

     Blood tests can be used to diagnose Lyme disease but it is very hard to interpret the results, especially early in the disease. They sometimes cause more confusion and worry than they give useful information. Some laboratories advertise Lyme disease testing that is not standardized or approved and can cost hundreds of dollars for nothing.

     Antibiotics are used to treat Lyme disease. Under age 7, amoxicillin is used and over age 7, tetracycline-type drugs are used. IV antibiotics are only used rarely and then only for late disease. It is common to still have symptoms after the 2 to 3 week course of antibiotics, but it is not necessary to continue the treatment. The symptoms gradually resolve.