Beware danger of ticks

By BILL MCKELL,

Tick paralysis results from exposure to a neurotoxin released by tick salivary glands during a blood meal; it is the only tick-borne disease not caused by an infectious agent. The toxin appears to be produced exclusively by female, egg-laden ticks. The toxin is apparently not present in tick saliva during the early stages of feeding, so paralysis occurs only when the tick has fed for several days (the greatest amount of toxin is produced between the fifth and seventh day of attachment).

World-wide, more than 40 tick species have been associated with tick paralysis. It has killed thousands of animals, mainly cows and sheep, in other parts of the world. Although tick paralysis is of concern in domestic animals and livestock in the U.S. as well, human cases are uncommon and usually occur in children. Most North American cases occur in the spring and summer months.

Symptoms usually begin within 2-7 days after attachment (often on the scalp) with fatigue, weakness and numbness of legs, and muscle pains. Paralysis rapidly develops in both legs. It is a flaccid (as opposed to spastic), ascending (starts in the lower body and moves up) paralysis. It ascends to the truck, arms, and head within hours and may lead to respiratory failure and death in up to 12 percent of untreated patients.

Because of the inability of laboratory tests to indicate tick paralysis, diagnosis is based on symptoms and the rapid improvement of the patient once the engorged tick is removed.

Treatment involves simply removing the tick(s). The tick is best removed by grasping the head and mouthparts, with pointed tweezers, as close to the skin as possible and pulling in a firm steady manner.

No human vaccine is currently available.

 

Preventable measures, that we have listed often, include avoiding overgrown trails, wearing light-colored clothes (that allow one to see ticks more easily), and wearing long pants, socks, and enclosed shoes. For repellants, one should consider DEET-containing products for use on the skin and Permethrin for clothing. Permethrin is not a repellant but an insecticide; it causes ticks to curl up and fall off. One should perform daily self-examinations for ticks, particularly in body areas where ticks might not be readily apparent, such as scalp, hairline, ear canals, and pubic region.

Tick paralysis is a not uncommon cause of death in dogs, the symptoms and progression varying with the breed of the dog. Symptoms may be noticed after five days of tick attachment. Symptoms may vary, again depending on the breed, but can consist of a sudden change in the bark, frequent vomiting, weakness of the hind legs, loud breathing with excessive panting, and drooling. Should you become concerned, especially if you live in a tick-endemic area, you should consult your veterinarian at the earliest. You should check your pet’s skin on a daily basis for ticks, and if present, remove them. There are certain tick repellants on the market, and your vet may recommend one. In my research, I noted an oral medication for dogs and cats, Bravecto, which the manufacturers state will protect dogs and cats from fleas and ticks for 12 weeks. Being neither a veterinarian nor a tick, I have no experience with this product.

Dr. William McKell is a Northsider.