In the late 1970s, Dr. Allen Steere and other physicians saw a large number of children and adults around the town of Lyme, CT, suffering from arthritis symptoms such as joint pain and stiffness. Recognizing that the symptoms were similar to cases in Europe that were in fact infections caused by insect bites, Steere treated patients with antibiotics, and they soon recovered. That was the first time Lyme disease was identified in the United States. It wasn't until the early '80s that researchers discovered the condition was caused by a bacteria found in ticks of the Ixodes scapularis type – better known as deer ticks — and transmitted by the bite of these ticks.

Today, Lyme disease is recognized as the most common tick-borne illness in the United States. Symptoms often include a large, bull's eye-shaped rash at the site of the bite followed by fatigue, chills, fever, headaches, stiff neck, muscle aches, and painful, swollen joints. Feelings of illness and fatigue may last for weeks, and sometimes more serious symptoms stemming from meningitis and Bell palsy (a paralysis of part of the face) develop.

As individuals and families prepare to spend more time outdoors this summer, here are four critical points about Lyme disease to keep in mind.

1. Lyme Disease is Increasing in the United States

The number of people in the United States being diagnosed with Lyme disease has increased in recent years. One reason is that doctors are more aware of the condition and are testing for it more often. But researchers believe that more people actually are getting infected because of several other factors. The deer, mice, and ticks that carry the bacteria responsible for Lyme disease have interdependent relationships. They live in wooded areas and are most active during the spring and summer months. Construction and development in these areas, as well as shifting weather patterns impacts the behavior of the deer, mice, and ticks, which has increased and prolonged humans' exposure to the ticks.

The vast majority of Lyme disease cases today occur on the northeastern coast from Maine to Virginia and in the Midwest in Wisconsin, Minnesota, and Michigan. On the West Coast, most cases occur in northern California and Oregon. However, areas where Lyme disease is found are increasing. As incidence increases around the country, it's important for patients — and physicians — to consider Lyme disease when they're experiencing symptoms, even if they don't live in areas where it's traditionally been found in the past.

2. Not Everyone With Lyme Disease Gets the Bull's Eye Rash

Most people associate Lyme disease with the tell-tale bull's eye rash that appears at the site of the tick bite. In reality, only about three out of four people ever develop or spot the rash, depending on the location of the bite. In addition to watching for the rash to appear, people should also be alert for symptoms suggestive of Lyme disease that appear within the first few days or weeks after being bitten -- fatigue, chills, fever, headaches, stiff neck, muscle aches, and painful, swollen joints.

It's important to remember that only deer ticks carry Lyme, and the tick must be attached for at least 36 hours in order to transmit the disease. Deer ticks are quite small and often difficult to notice. If you live in an area where Lyme is prevalent and you do see a small, engorged tick on you or if you begin to experience symptoms listed above even if you don’t remember having a tick bite, it's best to consult with a medical professional.

3. Early Treatment of Lyme Disease is Critical

If you suspect you might have Lyme disease, the earlier you see a doctor, the better. Often, if a patient lives in a Lyme disease-prone area, has recently spent time outdoors, and has that typical bull’s eye rash, a doctor will assume it's Lyme disease and begin treatment. Treatment consists of antibiotics and starting the course of medication early enough after the bite has been shown to actually prevent people from contracting Lyme disease at all. Make it a habit to check yourself and children for bites after spending time in wooded areas or where deer tick are prevalent.

Identifying Lyme disease early gives people a better chance of avoiding the early disseminated and late stages of the disease, when more significant and long-lasting symptoms are common. Treatment for these stages involves longer courses of antibiotics, often delivered intravenously.

Some people who have received a full course of treatment for Lyme disease have symptoms like fatigue and cognitive problems over extended periods, which can be referred to as post-treatment Lyme disease syndrome. It’s not clear how these symptoms are caused by Lyme disease but researchers have no evidence that such people have live Lyme disease bacteria in their body. And researchers have consistently found that prolonged antibiotic use is not an effective treatment – and may actually be harmful.

4. Lyme Disease is Preventable

The best way to avoid contracting Lyme disease is to avoid being bitten by a deer tick. If you plan to be outdoors in an area where Lyme disease is common, take some commonsense steps to protect yourself:

• Stay on paths and trails when walking in wooded areas
• Wear long-sleeved shirts
• Wear long pants and tuck them into boots or socks
• Wear light-colored clothing to make ticks easier to see
• Apply an insect repellent containing diethyltoluamide (DEET) to the skin

For more tips on preventing tick bites and to learn more about Lyme disease, visit the Manuals page or the Quick Facts page on the topic.