For the 10th year in a row, Pennsylvania has reported more Lyme disease cases than any other state. And 2016 saw a new record for cases as the Keystone state saw in excess of 12000, nearly 40 percent of the country’s total.

Erythema migrans (EM) rash/CDC

Senior Associate at the UPMC Center for Health Security, Amesh Adalja, MD joined me on the Outbreak News This Week Radio Show to discuss the situation in Pennsylvania.

When asked how and why Pennsylvania has become such a hotbed for Lyme, Dr Adalja reminds us that Pennsylvania is not just Pittsburgh and Philadelphia, in fact, it is a very rural state and people take part in a lot of outdoor activities.

The tick is endemic in all 67 counties of Pennsylvania and is “something you can’t completely avoid”.

Adalja also notes, “We are very aggressive at testing here, it’s something that’s routinely done now. For example, in an emergency department, someone comes in with an undifferentiated cluster of symptoms, a Lyme disease test is often sent.

Several years ago, the Centers for Disease Control and Prevention (CDC) reported estimates that indicated that the number of Americans diagnosed with Lyme disease each year is around 300,000, about ten times the reported number. 

Does that mean Pennsylvania saw 120,000 Lyme cases in 2016?

“It’s hard to put the exact number on the number of cases that were undiagnosed, but we know that the number that are reported are gross underestimates in every jurisdiction, Adalja said. What were really seeing is a subset when you see what’s reported to the CDC.

“I’m not sure if it’s 120,000 that we have, but I’m sure that there are more cases than what is captured by the data. Which is the norm for almost every infectious disease reporting system.”

Dr Adalja also discussed what you can do to prevent tick bites and the early symptoms of Lyme disease.

LISTEN to the interview below:

The Outbreak News This Week Radio Show, the first and only radio program dedicated to infectious disease and health news and information, airs every Sunday at 8 pm ET in the Tampa Bay area on AM 1380 The Biz and online at