Lyme disease continues to spread this season

Working in the emergency room at Children's Hospital Pittsburgh earlier this month, some very worried parents had brought in their a 6-year-old son—where they had removed a tick from his left groin 10 days ago was a red rash with a clearing center. We all knew that he had contracted Lyme disease. But I thought to myself, why am I seeing Lyme disease? This was Pittsburgh not Philadelphia, and it was still winter.

Lyme disease used to be rare west of the Alleghenies and usually seen in the summer. But the area where Lyme disease is prominent has spread and it has been extraordinarily warm winter in most of the eastern United States

Fifteen years ago Lyme disease was primarily seen in the United States intercoastal patch from Southern Maine to northern Virginia just outside Washington DC and in western Wisconsin. Now the entire area of the Atlantic Coast from central Maine through Virginia and going as far west as the Great Lakes, all of Wisconsin, and parts of Illinois and Minnesota have large amounts of Lyme disease. The animal vector that directly transmits the bacterial infection to humans is the black or deer tick, but the tick becomes infected from warm blooded animals such as mice and deer. This can spread the ticks over a wider area.

The animals that carry Lyme disease have increased because more rodents thrive due to the the decreased numbers of killing frosts during our winters. The decrease in hunting has not culled the deer herds the way it used to as well. Felicia Keesing, an ecologist from Bard College, said in an interview with National Public Radio that 2017 will be a banner year for Lyme disease because the mild weather has markedly increased rodents especially field mice, highly efficient transmitters of Lyme, and this in turn has increased ticks. A field mouse can have up to 50 ticks living on its ears and face at one time.

Where we build homes has also increased our chances of getting Lyme disease. Before the Europeans came, the entire Northeast was one continuous forest full of predators like foxes that ate mice. But the forest now is in patches too small to support animals that keep rodent numbers in check. People love to live in a Sylvan setting where their houses are surrounded by tall trees. However, the incidence of Lyme disease infected ticks is so high in the Northeast that you don't have to live in the forest to get Lyme disease. I live in Center City Philadelphia and two of my children when they were young got Lyme disease near my house in the park along the Schuykill.

To protect against Lyme disease:

  • After walking in parkland or in wooded areas, take off clothes and check under the arms, in the groin, and on the back of the neck for ticks when you get home. They prefer these areas, but can be anywhere on the body.
  • Wear long sleeves and full length slacks outside, avoid walking in very high grasses
  • Check pets, especially dogs, when they come inside.

The most effective way of taking ticks off is to pull them upwards with steady pressure using tweezers. The quicker you take them off, the less likely they are to transmit disease.

Unfortunately, there is no good blood test for Lyme disease since most people in endemic areas such as Philadelphia already have developed positive blood titers from previous subclinical disease. (Titers are blood tests that check your immune status to vaccinations or diseases you may have received in the past. If you’re titers results are positive, it means that you have adequate immunity to a particular infectious disease.)

The Centers for Disease Control and Prevention does not recommend treating with antibiotics just for being bit by a tick, but in many who will develop disease, a characteristic rash erythema migrans as described in the boy above develops in one to 30 days after the bite and in the area of the bite.

If the child has the rash or clinical symptoms, they can be treated with 14 days of antibiotics.  Late manifestations of the disease include swollen large joints, weakness of the facial muscles and even very severe headache. So starting now, not this summer, look for ticks and follow the advice above. Lyme disease ticks are waiting for you and your family.


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