Thursday 11 July 2013

Ticked Off


There is nothing quite like the creepy feeling as a tick crawls on your body looking for a place to set up its drilling rig. For the first time in two and a half decades of dealing with ticks, this year many of their bites resulted in welts.  We used to conduct 'tick checks" before the kids went to bed - they never seemed to get welts.

 It was time for me to do some research. The internet, of course. A review of literature revealed that there was very little good data about “our” local wood ticks, the Dermacentor variabilis or “Dog Tick”. So I tapped another resource, a listserv run by the Society of Rural Physicians of Canada. Thanks to my colleagues from across Canada and especially those from the prairie provinces, the answers here are a summary of what rural doctors had to say:

Q. WHAT IS THE BEST WAY TO REMOVE TICKS?

A. The quickest and surest is to hold the body of the tick between thumb and forefinger and perform a quick twist-pull with the wrist. Tweezers and needle-nose plyers are good second choices applying the same wrist movement. There is a little gadget on the market that can be slid under the tick to “pop” it off (I haven't seen it but I am told that it is sold in camping supplies).

Methods such as soaking an attached tick with vaseline, rubbing alcohol, or witch hazel work but take more time. Applying a lighted match or cigarette to the tick is probably more likely to cause damage to the victim although it will kill the tick (the theory that the “tick backs into the heat” is absurd).

Q. WHAT ABOUT THE MOUTH PARTS AND THE HEAD? WHAT if THEY ARE LEFT BEHIND?

A. Not one doctor reported heads being left behind after removal of the tick by any method. (In our house, we always check to see that there is a piece of skin in the jaws of the removed insect. A useless exercise because we don't do anything if we don't see skin.) The idea that the “heads migrate” is likely false; in spite of the widespread prevalence of the belief, no physician reported this finding.

To our knowledge, we have not had any mouth parts left behind. But if we did, a dermatologist stated that “Retained mouth parts would be very small and cause a minor irritation. The body would deal with them by literally dissolving them.”

Q. WHAT CAUSES THE ITCH AND WELT?

A. Ticks inject a local anaesthetic when they attach which is why we usually don't feel the attachment. They also inject a blood thinner so that the blood can be more easily sucked up. Either could cause a tissue reaction (like hives or mosquito bites) but the local anesthetic is probably the culprit. It is a neurotoxin and is injected in different amounts which explains the variability of the skin reactions.

It is not known whether the length of time that the tick was attached or the method of releasing the tick has any effect upon the development of a welt.

Q. WHAT DISEASES ARE TRANSMITTED BY TICKS?

A. Our local ticks are not disease vectors. Rocky Mountain Spotted Fever, and a Progressive Paralysis occur, as the name implied, largely in the Mountains. Lyme Disease is coming from Eastern Canada and the USA and is carried by the deer or black-legged tick which is about half the size of the dog tick. Know your ticks; know the signs of the disease.

Although no physician reported seeing an infected bite, the itch could cause such scratching that the broken skin could get infected.

Q. WHAT ABOUT PETS?

Ticks are very annoying to large animals like horses or cattle, especially when the tick is engorged. Cats usually clean them off by themselves. Dogs need a little help; the neurotoxic effect can result in centimetre wide denuded areas with fairly significant scabs. The scabs, even when they are piled up, are not mouth parts or heads and do not need to be removed.

ON A PERSONAL NOTE:

This spring for the month of June in the Touchwood Hills Southwest of Wynyard, we removed up to seven ticks a day using the “finger-pinch” method. Not all bites resulted in welts but, when they did, the itch was unbearable. One “bite” left a huge area on my lower leg looking and feeling much like an infection - reddened and hot (cellulitis). It was gone the next morning.

When we remove ticks, we put them in a small “tick jar” containing rubbing alcohol - notoriously hard shelled, they are otherwise difficult to kill. A hammer on a hard surface works, as does the judicious application of a pair of plyers.

Prevention is key. The following precautions work: wear long pants tucked into socks plus long- sleeved shirts, tight collars and cuffs. Wrap a scarf around your neck. For exposed skin, use DEET. Don't walk in tall grass.

There were a lot of myths and misinformation uncovered in looking for scientific research about the “dog tick” and I suspect they will continue to abound. With respect to the “migrated head” story, if anyone has or suspects that they might have a bonifide “migrated” head under his or her skin, please call me. To show my appreciation, I'll make a house call!

No comments:

Post a Comment