Cases of Lyme disease on upward trend locally
The number of confirmed cases of Lyme disease in Indiana County has more than tripled over the past three years, and Pennsylvania is now seeing the highest numbers of confirmed cases in the country, according to a specialist at Indiana’s hospital.
Indiana Regional Medical Center in 2013 reported 293 confirmed cases to the state’s Department of Health, up from just 82 in 2011, infection control coordinator David McDevitt said. That’s an increase of about 250 percent. In 2012, the hospital reported 154 cases.
This year seems to be roughly following this trend, with 129 cases already reported through the first half of the year, he said.
Although Lyme disease is more prevalent in southeastern Pennsylvania, which has reported about 500 cases so far this year, McDevitt said Pennsylvania has surpassed Connecticut in the total number of cases statewide. A report from the Centers for Disease Control confirms that Pennsylvania had the highest number of confirmed cases of Lyme disease in the country in 2011 and 2012.
“We just have the right conditions” for such an increase, McDevitt said, such as increasing deer herds and milder winters.
Lyme disease is a tick-borne disease of humans and some domestic animals caused by bacteria transmitted through the bite of an infected black-legged tick, also known as a deer tick. When conditions are favorable for these ticks, the rates of Lyme disease generally increase.
The bacteria that cause the disease enter a tick in either its larval or nymph stage when it feeds on the blood of a small rodent, usually a white-footed mouse or an eastern chipmunk, according to the Pennsylvania Game Commission.
Almost all infections are reported between May and September, McDevitt said, which is the time when ticks are present in all three stages: larval, nymph and adult. Once September arrives, only adults are present, so the number of cases drops off.
Nymphs are the real problem “because they’re so tiny and hard to spot,” he said. In this stage, a tick is roughly the size of a poppy seed, whereas an adult tick is about the size of a sesame seed, according to the CDC.
A common first symptom of Lyme disease is a bull’s-eye rash around the site of the bite, which appears one to two weeks after a bite from an infected tick. The rash is present in about 80 percent of infected patients and may remain for several weeks. In that time, the bacteria spread to other parts of the body and enters the bloodstream.
Some patients do not get a rash or have other symptoms including headaches and muscle aches, fever and fatigue. If left untreated, Lyme disease can progress to problems involving the joints, heart and nervous system. Early treatment with antibiotics is usually effective in preventing such complications, though. A vaccine against the disease was marketed in 1999 but was discontinued three years later due to insufficient demand, and no vaccine has been developed since.
Household pets can be infected, too, McDevitt noted.
“Often you can’t see the rash very well, so you’re usually looking for a tick bite” on the pet, he said. “You want to look: Is the tick engorged, and is it a black-legged tick?”
READ MORE: How to prevent and treat tick bites