Pennsylvania has reported the most Lyme disease cases for ten consecutive years and in 2016, while not over yet, has topped 12,000 cases, according to Centers for Disease Control and Prevention (CDC) data.

Black-legged tick
Ixodes scapularis, a Black-legged tick/CDC

Through Dec. 24, the Keystone State has seen 12,092 cases (provisional), the most reported.

Nationally, 31,926 provisional cases have been reported to CDC. Following Pennsylvania is  New York and NYC with 4,002 cases, New Jersey (3,850), Wisconsin (1,868) and Maryland (1,717).

Each year, more than 30,000 cases of Lyme disease are reported to CDC, making it the most commonly reported tick-borne illness in the United States.

However, CDC estimates indicate that the number of Americans diagnosed with Lyme disease each year is around 300,000, ten times higher than the yearly reported number.

According to the Pennsylvania Department of Health, Lyme disease is caused by the bacterium Borrelia burgdorferi and is often transmitted through the bite of an infected blacklegged tick, also known as a deer tick.

Symptoms include fever, fatigue, headache, muscle aches, joint pain, a bull’s eye rash may appear, and other symptoms that can be mistaken for viral infections, such as influenza or infectious mononucleosis. Joint pain can be mistaken for other types of arthritis, such as juvenile rheumatoid arthritis (JRA), and neurologic signs of Lyme disease can mimic those caused by other conditions, such as multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS).

When detected early, Lyme disease can be treated with antibiotics. Left untreated, the disease can spread to the joints, heart and nervous system.