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Reminder - Watch for Ticks!

Posted: April 7, 2014

If you are in an area of Pennsylvania where ticks and Lyme disease are a way of life, it’s already time to be on alert.
Photo: adult female blacklegged ticks. Unengorged female encircled by partially engorged females. (Photo: James Occi, MA, MS). From the Lyme Disease Association website.

Photo: adult female blacklegged ticks. Unengorged female encircled by partially engorged females. (Photo: James Occi, MA, MS). From the Lyme Disease Association website.

Blacklegged ticks Ixodes scapularis (aka “deer ticks”) are the vector for Lyme disease. Adults have been on the move since the snow started to melt in mid-March in SE Pennsylvania.

According to the Center for Disease Control (CDC), Lyme disease is the #1 arthropod-transmitted disease in the US. There were over 4,000 cases reported in Pennsylvania last year and the CDC estimates there could be as many as 10 times more than the reported number. For many in the green industry, it is an occupational hazard.

The adults are active now. They are a bit easier to spot than the nymphs that will come later this spring. Dogs and cats that are outside are extremely effective scouting tools for ticks - usually bringing them inside to you. For the last few weeks I’ve been collecting two or three after every walk with my dog, probably aided by her nose-to-ground posture.

The tick has a two year life-cycle. Adults that are active now will feed and mate on deer, dogs, humans, or other animals. Eggs are laid on the ground where they hatch in early summer. The larva must feed (usually on white footed mice, birds, squirrels or other small animals) in order to grow and molt into the nymph. If the larva feeds on an infected host, it can transmit the Lyme disease spirochete to hosts it feeds on during later life stages.

This summer’s larvae will become nymphs next spring, after a dormant period and molt. In late spring and summer of the second year, nymphs feed and have another chance to become infected (if they aren’t already). During the fall of the second year nymphs molt into adults. Adult females can feed and lay eggs in fall or very early the next spring. The adults have had two chances to tank up on the blood of an infected host, which raises the odds that their bite can infect you.

It takes about 3-5 days for the tick to feed until engorged. It takes about 24-36 hours for an infected tick to transmit the Lyme disease spirochete. So the longer the tick remains attached to you, the higher the chances are for infection.

Remember that white footed mice are a major host and source of infection for blacklegged ticks. Mouse habitat is tick habitat. Cover exposed skin with light-colored clothing, use repellents, and check yourself often throughout the day and especially after coming in from outdoors. Look for adult ticks now, and nymphs a little later this spring. Even though it seems very early, check with your vet about ways to protect your pets.

References

Center for Disease Control, Map of reported cases of Lyme Disease - 2012

Penn State Extension Lyme Disease Facts 

Lyme Disease Association, Inc.

Tick Management Handbook. Kirby C. Stafford III, Chief Scientist. The Connecticut Agricultural Experiment Station, New Haven.