Beware of the ticks of summer

By Bev Johnson | The Daily Journal

Published 10:55 a.m., May 26, 2009

Petunia found a wood tick on her jeans last week and freaked out. She just hates any kind of crawlers.

Melissa Kemperman, an epidemiologist with the University of Minnesota, predicts that this year will see an increase of deer ticks. Last year, she found one-third of them were positive for Lymes. In fact, there were 1,000 cases last year as opposed to 300 to 400 per year in the 1990s.

Ticks get on you when you walk through grass or shrubs. They perch on the edges of leaves with their front legs extended. Specialized organs on the tips of the tick’s front legs have nerve endings that automatically trigger “questing” behavior when they sense carbon dioxide and heat of a passing animal.

They even quest when a deer belches, as that means food is close. When they find a nice spot of bare skin, they plunge a needlelike hypostome into it to feed. This organ has barbed projections and a sticky substance that work together to anchor the tick in place since it will take several hours for it to give you a disease.

If you don’t discover the little monster, feeding can last for days. During that time, hundreds of proteins in the tick’s saliva act as painkillers, reducing chances of discovery. They have another neat trick to make you sick. The salivary proteins change daily, so even if you produce an antibody to today’s salvia, it will not work tomorrow.

The changing proteins also prevent blood clotting and inflammation in the host which could put an early end to the blood feast. Ticks transmit the widest variety of pathogens of any bloodsucking arthropod, including mites, mosquitoes, flies and fleas.

An entomologist with an Agricultural Research Service, which service wasn’t indicated, found a live tick in his washing machine. He decided to test how tough they really were. Most of them lived through a cold or warm wash and some even through a hot cycle. An hour in the dryer on hot was uniformly lethal.

There is light on the end of that particular tunnel, however. Immunologists at the University of Massachusetts at Amherst are attempting to develop a vaccine that would cause an irritant reaction to the tick saliva. If you itch, you scratch. So you would scratch the bloodsucker off before they gave you Lymes or anything else.

Much of this information came from an article in the Discover Magazine authored by Amy Barth.

The moral for this week is, have your partner do a full body scan after you have been tromping through the brush, and don’t air dry clothes you were wearing.

Enjoy the summer.

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