The Tiny Unseen Enemy

[Guest guest]

NY Newsday

07/03/2001 - Tuesday - Page C 5

The Tiny 'Unseen Enemy'

by Ridgely Ochs

Staff Writer

'THE TICK you find is much less important than the one you don't find. "

That's the Lyme disease message from Durland Fish, a tick expert at Yale

University. He is one of the authors of a recently released study that

showed one dose of an antibiotic given soon after a deer tick is found and

removed is effective in preventing Lyme disease.

Though the study, released June 12 and to be published July 12 in the New

England Journal of Medicine, found that a small percentage-3.2 percent-of

those who found ticks actually got Lyme disease, Fish and others say most

people don't see the ticks to remove them in time-and thus are more likely

to get Lyme disease. me.

Fish pointed out in an interview that in the study only those

poppy-seed-size ticks in the nymph, or adolescent, stage were full of

blood-a sign they had been feeding on a human host and could transmit the

bacteria that cause Lyme. Adult ticks can also transmit Lyme disease, but

they reach two or three times the size of the nymph stage and are more

visible; thus, they are more likely to be plucked off before they can

cause damage, experts say.

" The whole problem is that this is an insidious, unseen enemy. We've been

exposed and we don't know it, " said Fish.

The bacteria Borrelia burgdorferi lives in the midgut of the tick until,

via blood transfer, it winds up in the host. Previous studies have shown

that the tick must be attached about 36 hours before it actually begins

taking a blood meal and transmits the bacteria.

If a tick is removed promptly-within that first 36 hours-there is little

chance it can transmit the disease. But, Fish said, most people don't know

a tick is present. In fact, he added, other studies have found that only

20 percent of people who develop Lyme disease remember getting bitten by a

tick.

In the New England Journal study, 28 of the 482 people in the trial-all

were from Westchester County, a highly endemic area, as is Long Island-had

more than one tick on them at the time they entered the study. And 18

percent had subsequent tick bites over the study's six-week period -a

short period of time given the six-month tick season, the authors note.

May to July, the nymph season, is the time when people are most at risk of

getting Lyme.

Dr. Dennis, another author of the study and coordinator of the Lyme

disease program at the U.S. Centers for Disease Control and Prevention,

said the " message is that we need to better educate people on looking for

and finding nymphal ticks. " " Because there's an easy treatment, " Dennis

said, referring to that one antibiotic dose, " doesn't mean we should be

complacent " about avoiding tick-infested areas or checking for them.

Dr. Ray Dattwyler, director of the Lyme Disease Center at SUNY Stony

Brook, agreed. While the low infection rate should be reassuring for those

who find a tick, the " majority don't recognize they've been bitten, " he

said.

The number of Lyme disease cases reported annually in the United States

has increased about 25-fold since national surveillance began in 1982,

with more than 128,000 cases reported from 1982 to 1999-although the CDC

said the incidence is probably underreported. New York has the highest

reported incidence rate, with 40,762 cases reported from 1982 to 1999,

according to the CDC. Areas like eastern Long Island and Westchester

County are especially infested with deer ticks.

People who live or work in residential areas surrounded by woods or

overgrown brush are at risk, as are people who participate in recreational

activities such as hiking, camping, fishing and hunting in areas likely to

be tick-infested, and those who engage in outdoor occupations such as

landscaping, brush clearing, forestry and wildlife and parks management.

Fish said that in his experience, most engorged adult ticks were found on

young children, usually in their scalp or in areas that might elude a

parent's notice. Dennis said he found one adult tick on the inside of his

young daughter's ear. " It's easily overlooked, " he said.

Even for experts, finding ticks can be daunting. " I can tell you that in

my career I had seven students doing field work and they all got Lyme,

although they knew everything about how to protect themselves and how to

look for ticks, " said Fish. " I can see how difficult it is, and I don't

like to see the situation taken lightly. " Here are tips from the Centers

for Disease Control and Prevention on avoiding Lyme disease: Avoid where

ticks live. Whenever possible, avoid entering areas that are likely to be

infested with ticks, particularly in spring and summer when nymphal ticks

feed. Ticks like a moist, shaded environment, especially that provided by

leaf litter and low-lying vegetation in wooded, brushy or overgrown grassy

habitats; both deer and rodents, the ticks' primary hosts, must be

abundant.

Wear the right clothes. Wear light-colored clothing so that ticks can be

spotted more easily and removed before becoming attached. Wearing

long-sleeved shirts and tucking pants into socks or boot tops may help

keep ticks from reaching the skin. Ticks are usually located close to the

ground, so high rubber boots may provide additional protection.

Application of insect repellents containing DEET to clothes and exposed

skin, and permethrin (which kills ticks on contact) to clothes, should

also reduce the risk of tick attachment. DEET can be used safely on

children and adults but should be applied according to Environmental

Protection Agency guidelines.

Check and remove ticks. Since transmission from an infected tick is

unlikely to occur before 36 hours of tick attachment, daily checks for

ticks and their prompt removal will help prevent infection. Embedded ticks

should be removed using fine-tipped tweezers. Do not use petroleum jelly,

a hot match, nail polish or other products. Grasp the tick firmly and as

closely to the skin as possible. With a steady motion, pull the tick's

body away from the skin.

Cleanse the area with an antiseptic.

After the tick bite. If you find a tick that is plump or looks full of

blood, call your health care provider. If you find an unexplained rash,

especially one shaped like a bull's-eye, or have unexplained fever or

muscle aches, see your doctor.

Strategies to reduce ticks. Remove leaf litter, heaps of brush and

woodpiles. Clear trees and brush to admit more sunlight and reduce the

amount of suitable habitats for deer, rodents and ticks. Tick populations

also have been suppressed through the application of pesticides.

Life Cycle of a Tick A tick may take less than a year or up to several

years to go through its four-stage life cycle. While ticks need a blood

meal at each stage after hatching, some species can survive years without

feeding.

Stage one: Some species of adult females lay about 100 eggs at a time.

Others can lay up to 6,000 per batch.

Stage two: 6-legged larvae hatch from the eggs Stage three: Larvae molt

into 8-legged nymphs after at least one blood meal.

Stage four: Nymphs molt into adutl male or female ticks with eight legs.

SOURCE: Food and Drug Administration

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