Lyme disease on the rise in Pennsylvania



"Lyme disease is here; it's the new normal," says Karen Hacker, newly appointed director of the Allegheny County Health Department. Pennsylvania has long had one of the highest rates of Lyme disease in the nation, but most cases were concentrated in the southeastern part of the state, leaving Allegheny and its surrounding counties relatively unscathed. Those were the good old days.

"It has definitely increased dramatically in the last three years. ... In our hospital we're seeing almost a twofold increase every year," says Andrew Nowalk, assistant professor of pediatrics at Children's Hospital of Pittsburgh of UPMC and University of Pittsburgh School of Medicine. "And we think that Allegheny County has been seeing it, too."

Lyme Disease

Lyme Disease is transmitted by bites from blacklegged ticks, which are commonly called deer ticks. Blacklegged ticks, like spiders, have eight legs and are in the arachnid class of arthropods. They feed on blood and pick up the bacterium that causes Lyme disease, Borrelia burgdorferi, from infected animals -- often deer and white-footed mice. Once a tick is infected with Lyme disease, it can transmit it to every subsequent human or animal it bites.

Blacklegged ticks are often difficult for their human hosts to spot. They often attach in hard-to-see places such as the armpits, groin and scalp. Plus, the ticks are tiny. According to the U.S. Centers for Disease Control and Prevention, most humans are infected by nymphal ticks that have not yet reached adulthood. While adult blacklegged ticks are sesame-seed sized, nymphs are only about the size of a poppy seed.

After attaching to a host, a blacklegged tick will spend days slowly sucking the host's blood. The good news is that it generally takes 36-48 hours for B. burgdorferi to be transmitted from a tick to a host. Thus, removing a blacklegged tick within 24 hours of being bitten greatly reduces the odds of contracting Lyme disease.

Lyme disease is only transmitted through a bite from an infected blacklegged tick. The CDC notes that it is not transmitted from other ticks, through sexual contact or in breast milk. B. burgdorferi can infect dogs and cats, but the pets cannot transmit it to their owners. Fido and Fifi can, however, unwittingly give ticks a lift into the home. Owners can protect their pets from infection with various tick control products.

The actual number of people infected with Lyme disease any given year is unknown. The Pennsylvania Department of Health recognized only 10 confirmed or probable cases in Allegheny County in 2012. However, that number is based on what the U.S. Centers for Disease Control and Prevention defines as confirmed or probable, and experts acknowledge that such surveillance numbers are useful for observing trends but underestimate the actual number of cases.

"Certainly there are a substantial number of cases -- maybe even up to 50 or 100 -- that are not reported for every case that is reported," says Alison Galdys, infectious diseases physician and assistant medical director of infection prevention at UPMC.

While experts cannot pinpoint the number of cases, they agree that the rate of Lyme disease is increasing. "Lyme has spread certainly over the Northeast, and it's spreading westward as well," Dr. Hacker says. In 2009, Allegheny County had 32 reported cases, whereas so far in 2013 there have been 370 reported cases -- more than a tenfold increase.

Several factors likely account for the increased rate of infection, notes Dr. Galdys. First, there are more ticks in the area that carry the bacteria that spread Lyme disease. Second, health care providers are becoming more aware of the disease and testing more patients for it. And third, the CDC changed the case definition of Lyme disease, loosening requirements for the laboratory data "in order to be less conservative with regards to what is called Lyme disease and what is not."

Children are particularly at risk of becoming infected. Boys age 5-9 have the highest rate of Lyme disease nationwide, likely because their outdoor play leads them into tick-infested areas. "We are seeing just an amazing number of cases in children," Dr. Nowalk says. Last year, Children's Hospital treated more than 300 cases, and the numbers have not eased up this year.

Lyme disease is often misunderstood. "We run into a lot of myths when I'm seeing patients in the clinic or in the hospital," says Dr. Nowalk. The most common myth is that Lyme disease is not curable. "Believe it or not, a lot of people think that that's the case. They read on the Internet that the infection can't be fully cured with the antibiotic therapy, and you have it for the rest of your life. That's completely untrue." Another myth is that the diagnostic test can't detect people who've been infected for several years; it is "actually quite good at detecting people who've been infected for some time."

"And then the last myth," Nowalk continues, "is that every single tick bite you get is going to transmit Lyme disease. ... It's actually a really small minority of tick bites that might transmit Lyme."

To prevent contracting Lyme disease, "The best strategy is to try to avoid or prevent tick bites to begin with," says Dr. Hacker. The carriers of the bacteria that cause the disease, blacklegged ticks usually lie in wait for hosts in leaf litter or on long grasses. Avoid ticks by staying in the center of trails, using repellent containing DEET, and treating clothes and gear with permethrin, a neurotoxin that both kills and repels ticks. Dr. Hacker advises that city dwellers take the same precautions as residents in rural areas.

The American Lyme Disease Foundation also recommends wearing light-colored clothing to make it easy to spot ticks and checking clothing and exposed skin for ticks regularly. Possibly the most important method of prevention, according to the foundation, is to perform a full-body tick check before bed if you have taken part in any outdoor activities during the day. Children, especially, should be checked; parents can make a nightly tick check part of the bedtime ritual.

Remove a tick by grabbing it with tweezers as close to the skin's surface as possible and pulling upward. If the mouthparts break off, try to remove them with the tweezers as well. Then clean the bite with alcohol or soap and water and monitor the area for signs of infection.

PG graphic: Lyme disease transmission
(Click image for larger version)

"After you get that tick bite there are different possibilities," Dr. Hacker says. "Lyme is a very interesting condition in that it affects different parts of our bodies. Not everybody gets the same symptoms."

The first symptoms of Lyme disease tend to appear three to 30 days after a tick bite, according to the CDC. About 70 percent to 80 percent of those infected will develop a rash at the site of the bite called erythema migrans (EM) that gradually expands and can grow to resemble a bull's eye. Other symptoms can include fatigue, fever, chills, muscle and joint aches, headaches and swollen lymph nodes. Patients who seek treatment early take a course of antibiotics and almost always recover quickly and fully.

If the infection isn't treated, other symptoms can develop, including more EM lesions on other areas of the body, facial palsy, stiffness in the neck, severe fatigue, migrating joint aches, heart palpitations and dizziness. While some of those symptoms are likely to go away on their own, failing to get treatment can lead to further complications, including arthritis and neurological problems such as failing short-term memory and numbness in the hands and feet.

At Children's Hospital, Dr. Nowalk says, "We've been seeing a ton of [kids] come in not just with rashes in the early stages of the disease but lots of kids who've developed the Bell's palsy, a weakness of the face, with the infection. And a number of kids with arthritis as well."

Children tend to react differently to infection than adults. Adults are more likely to suffer from chronic arthritis, whereas children tend to experience acute arthritis, or bursts of severe joint pain that come and go for brief periods. "And children are much more likely to get nervous system infections," says Dr. Nowalk. Such neurologic complications include Bell's palsy and meningitis.

One fact that might be feeding the myth that Lyme disease is incurable is that a minority of patients (10 percent to 20 percent, according to the CDC) receive treatment but continue to experience symptoms, a condition known as post-treatment Lyme disease syndrome. It is similar to other chronic syndromes like chronic fatigue syndrome and fibromyalgia; its origin is unclear, treatment can be hit-or-miss, and symptoms can vary for patients.

"It can be a very challenging diagnosis for many of those patients because there's no easy answer and no quick cure for the symptoms that they experience once they're done with the antibiotic," says Dr. Nowalk. Although researchers are uncertain about what causes the post-treatment syndrome, Dr. Nowalk says, "We certainly know that it seems to be more associated with people who had a long period of infection before diagnosis." Fortunately for parents, the syndrome is rare in children.

As colder weather approaches, the season for infection is coming to an end. But while two-legged humans think about hot apple cider and holiday parties, eight-legged nymphal ticks -- potentially infected with B. burgdorferi -- will be lying dormant under leaf litter, waiting for warmer temperatures and unsuspecting hosts to come along. Welcome to southwestern Pennsylvania's new reality.

state - health

Kathryn Sterling: kkaasa@post-gazette.com. First Published September 30, 2013 4:00 AM


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