Lyme disease is a potentially serious tick-borne illness that can be tricky to diagnose. And the number of cases in the United States may be vastly underreported, according to the Centers for Disease Control and Prevention (CDC).
A report published in the September 2015 issue of Emerging Infectious Diseasesestimates that 329,000 cases of Lyme disease occur in this country each year — more than 10 times the 30,000 confirmed and probable cases typically reported to the CDC.
As the CDC points out, onset of Lyme disease is most common in June, July, and August, when ticks are more active and people spend more time outdoors. But these ticks also feed in the spring, as well as during the summer months. A bacterial infection caused by a bite from the black-legged tick (also called the deer tick), Lyme disease is prevalent in the Northeast and upper Midwest.
It was previously believed that Borrelia burgdorferi was the only species of bacteria that causes Lyme disease in North America. But according to a study published earlier this year in The Lancet Infectious Diseases, researchers have discovered another species of bacteria, Borrelia mayonii, that can cause the disease.
So how do you know if you have Lyme disease? The first sign is usually a rash with a bull’s-eye shape that appears within weeks of being bitten by an infected tick. The rash may be accompanied by flu-like symptoms such as body aches, fatigue, and fever.
But not everyone develops a rash, according to Penelope Dennehy, MD, director of pediatric infectious diseases at Hasbro Children’s Hospital in Providence, Rhode Island. In those cases, “it’s difficult to sort out Lyme symptoms from whatever garden variety illness or virus is going around,” Dr. Dennehy says.
If left untreated, Lyme disease can cause arthritis or neurological problems. Though most cases can be treated with antibiotics, a small percentage of patients report lingering symptoms of fatigue and pain — a condition known as post-treatment Lyme disease syndrome.