Folk wisdom has a whole repertory of techniques designed to force
the wee beastie to back off on its own-but
they don't seem to work and manual removal is all that's left
| Pleasant as it is to walk in the country with man's best friend as
company, man and beast may well bring back some uninvited hitchhikers from
their excursion. Sometimes, it's just a solitary tick that has grabbed a ride
but other times, biped skin and quadraped hide are quite polka-dotted with
ticks. Many or few, you want to warn your patients to get the ticks off as
quickly as possible-and to do it the only way that works. "Ticks are dirty creatures," says Dr. Glen R. Needham, associate professor of entomology at the College of Biological Sciences at Ohio State University in Columbus. "They carry all sorts of bacteria and viruses and spirochetes. Not all of them are pathogenic to humans but even if a tick doesn't transmit something like Lyme disease or Rocky Mountain spotted fever-and I should say that most ticks don't-it's still a dirty arthropod attached to the skin and if you don't pull it off correctly, the lesion might become infected." Infection is a distinct possibility not only because of the debris the ticks have on their bodies but because of the manner in which they attach them selves to man or animal. "Ticks find a good location on the host and for a tick, the best spots are those with the most vascularity and the highest temperature." Dr. Needham explains. "Once a site is selected, the tick uses its mouth-parts to excavate a hole in the skin. Having done that, the tick excretes an attachment cement that surrounds its mouth-parts like a collar and secures itself firmly to the host. The cement, incidentally, is what causes the itchiness many people experience with a tick |
bite.
It's incredibly strong, almost impossible to cut or tear apart with forceps. If
the tick is an adult female, it may remain on the skirt anywhere from six days
to two weeks, during which time it salivates continuously to maintain the
feeding lesion." There's no magic time period that it takes for the tick to do its damage. "You'd really have to put it on a disease-organism basis," says Dr. Needham. "For instance. it's been pretty well documented that the rickettsial organism that causes Rocky Mountain spotted fever has to be activated. Since it's the body temperature of the host that activates Rickettsia, that process might take some time, perhaps four to six hours. But an organism such as a virus or the spirochete that's responsible for Lyme disease can he transmitted immediately the first time the tick salivates into the lesion. So really, the bottom line is that since you don't know which tick is a carrier and which isn't, time is of the essence: the sooner you get the tick off, the more you reduce the chances of disease transmission." If prompt removal of the tick is accepted as essential, the proper method is less well established. Grandmothers and other traditional sources of folk wisdom have-a large repertory of recommended techniques. Using the back of a sheep as the test surface, Dr. Needham evaluated five of the most commonly advocated methods- petroleum jelly, fingernail polish, 70% isopropyl alcohol, a hot kitchen match, and forcible removal with forceps or protected fingers-and reports the results in Pediatrics (vol. 75. p 997). |
The
first four methods he labels "passive" techniques. "Since they don't involve
any mechanical force, they're intended to make the tick remove itself from the
host. Those techniques have clearly evolved from the basic phobia people have
about touching ticks. After all, they are not God's pretty creatures, so if
people can think of a substance to put on a tick to make it back out on its
own, that's what they'll use." The attitude may be understandable, says Dr. Need ham, but the techniques usually don't work. He applied generous amounts of petroleum jelly, clear fingernail polish, or 70% isopropyl alcohol to the dorsum and venter of the ticks, completely occluding their respiratory. openings. To use a match, he struck it, allowed it to burn until the tip was red hot, blew it out, and then held It against the dorsum of the tick for 5 to 10 seconds. After the allotted period of two hours, none of the ticks self-detached in response to any of the four techniques. "The presumed theory behind the petroleum jelly, fingernail polish, and alcohol," observes Dr. Needham, "is that those substances will impede a tick's breathing and it will gasp for air and let go. But that just doesn't happen. No one has recorded the respiratory rate of a tick while it's feeding but it's probably very slow, so blocking its air supply won't affect it. Furthermore, when nail polish is used, a tick couldn't back off even if it wanted to, because the polish hardens and virtually locks the tick into place." The hot-match method is the most commonly mentioned |
technique for tick removal. "Not only does it not work," Dr. Needham
told EM, "but it's fraught with potential problems. I'm concerned about people
taking red-hot matches and holding them against children's necks or sticking
them into dogs' ears and causing a lot of bad burns. There's also the
possibility that the heat will either burst the tick or cause it to regurgitate
and in either situation, infective fluids could enter the feeding lesion." In contrast to the failure of the passive methods, the use of forceps or protected fingers was completely successful in removing the American dog ticks, leaving neither the mouth-parts nor the attachment cement in the host's skin. Lone Star ticks and their mouth-parts were also easily removed mechanically but the attachment cement remained on the skin. The direction in which a tick is pulled off doesn't matter, says Dr. Needham, although another nugget of folk wisdom has it that only a counterclockwise motion will do. "One of the reasons I included electron micrographs of ticks in the study was to show that their mouth-parts aren't shaped like screws! Since they don't enter the skin like screws, you certainly don't have to 'unscrew' them." More important than the motion, he emphasizes, is where you grasp the tick. It's important to grasp the mouth-parts or head region- not the body of the tick-as close to the skin surface as possible in order to ensure that they don't break off and remain behind. |