First identified in a group of children in Lyme, Connecticut, Lyme disease has now been found in nearly all states and 18 other countries. Most cases -- more than 90% -- are reported in three regions of the U.S.:
Northeast, from Massachusetts to Maryland
North Central States, mostly in Minnesota and Wisconsin
West Coast, particularly Northern California
Because the symptoms are random and vague (aside from a bull's-eye rash), Lyme disease can be hard to diagnose. Unfortunately, unless Lyme disease is treated promptly, it can also be difficult to cure. For these reasons, people living in high-risk areas can have considerable anxiety about Lyme disease, and doctors tend to over-diagnose and over-treat it.
The bull's-eye rash of Lyme disease is distinctive. If you have been exposed to a tick and have the rash, this is enough to make the diagnosis. But if you have no such rash, Lyme disease is hard to diagnose. It mimics other diseases, such as the flu and arthritis, and there is often a long time lapse between symptoms.
Your doctor will check for flu-like symptoms and take a sample of blood to check for a high antibody response to Lyme disease. However, blood testing is not completely reliable. It...
Lyme disease is caused by bacteria transmitted through the bite of the tiny black-legged, or deer, tick found in the Eastern and Central U.S. and the western black-legged tick in the Pacific West. The riskiest months for Lyme disease are from May through September, when young ticks are likely to be biting.
In humans, the bacteria may cause flu-like symptoms. It invades many tissues -- including the heart and nervous system -- and triggers an immune response that leads to Lyme arthritis.