Ticks: Lifecycle, Removal and Lyme Disease

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A well-fed tick towers over its hungry neighbor.
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The lifecycle of a dog tick.

One of the best things about growing
up in the country is being able to go outside anytime you
want. One of the worst things is all the bugs you have to
put up with especially ticks. I remember as a boy how we’d
“look” ourselves for ticks after playing outside. Often,
we’d find one or two. Sometimes we’d be covered-on our
pants, down our shirts, in our ears. It was the kind of
thing that made you want to spit. And always there was the
fear you might get Rocky Mountain spotted fever.

The
experience raised a lot of questions for me: Where do ticks
come from? How can there he so many? (We found three in my
cousins ear once after collecting pop bottles from along
the road!) What should you do after a tick has latched on?
And how dangerous is Rock Mountain spotted fever. anyway?

Before jumping into these ticklish queries, a little
background, taxonomically speaking, is in order. First,
there’s, the animal kingdom that much is easy Then phylum:
for ticks it’s Arthropoda which in layman’s terms means
joint legged creature. Next is class: spiders, scorpions,
ticks and mites (all of which have eight legs and no
antennae) make up the Arachnida class. Ticks are then
singled out under the super family Ixodoidea and then
divided into two distinct subfamilies, Argasidae (soft
ticks) and Ixodidae (hard ticks) Distinctions within a
family are denoted by genus and species, with about 800
species described worldwide.

Both hard and soft ticks are
potential disease carriers, but hard ticks are the main
vectors in transmitting tick-borne diseases to man.

Lifecycle of the Tick

Where
do ticks come from? They come from eggs a one-time batch of
as many as 5,000 per female in hard-tick species. The
larvae that hatch out are called seed ticks. These are not
“worms.” as the stage name might suggest, but miniature
versions of adult ticks. Seed ticks have only six legs and
are unable to reproduce. Their top priority is getting
their first meal.

For a deer tick-the primary carrier of
Lyme disease-this is not what you’d call an exercise in
fine dining. Deer ticks prefer back-alley eateries like the
Rat’s Back or Mouse Far Lounge. The meals at these places
are enormous. Adult ticks can take on anywhere from 200 to
600 times their unfed body weight. But as it goes with
back-alley eateries, sanitation is sometimes a problem. And
so along with its meal, the larva may also ingest a spiral
shaped spirochete bacterium known as Borrelia burgdorferi,
the organism that causes Lyme disease.

After completing the
meal (and while .still hanging out at the Rat’s Back), the
larva molts. forming an eight legged nymph. Then it’s back
to the buffet for meal number two. When this engorgement is
complete, the nymph drops off the host and hides in leaf
litter to molt into an adult capable of
reproduction-capable, that is, after a third and final
feeding.

With this meal as its goal, the adult tick climbs
a blade of grass or a weed stem. Then. when it detects
movement, heat or the “smell” of CO2, it waves it,,
forelegs in the air, hoping to catch a ride with some
unsuspecting traveler in this case, usually a deer. Tick
and mite experts (acarologists) call this behavior
“questing.”

It can take several months for a tick to make
contact with a suitable host. As one writer puts it. ticks
are “great exponents of the gentle an of waiting.” Just
how many die in the process is not known. What we do know
is that adult ticks can live up to five years without
feeding. And little wonder: According to Cynthia Mills, a
doctor of veterinary science from Salem, Oregon, ticks are
able to “suck water from the air, and [they] bother to
breathe [only] four times a day.” As one researcher puts
it. “Nothing’s on but the pilot light.”

That’s one reason
why ticks are sometimes so plentiful. Other factors include
El Nino winters and, of course. the number of eggs the
females lay. And as for those times when you end up with
three ticks in one ear, as my cousin did? Its possible that
You’ve stumbled into a nest of recently hatched larvae. But
a more likely explanation comes from a team of Ohio State
University- scientists: ticks, it seems, are drawn to
roadsides by simple vehicle activity-the aforementioned
movement, heat and CO, from exhaust.

So does all
of this mean that anyone taking a walk on a country road
may as well hang a sign around his neck, reading: “Tick
Bait?” No, but it does mean you should it go tromping in
ditches in the middle of summer, when ticks are most
active. Other ways to protect yourself are pretty much
common sense:

Keep the area around your home free of tall grass and
weeds.

Stay to the center of pathways when walking through places
you know to be tick-infested.

Wear light-colored clothing with long sleeves and tuck your
pants into your hoots.

Use a DEET-based repellent topically. DEET has come under
criticism recently, but no other topical treatment is more
effective.

Use a permethrin-based repellent on outer clothing.
Permethrin is a synthetic version of pyrethrum, a
chrysanthemum extract.

And don’t forget to look over yourself and your kids every
few hours; tick-borne diseases are not passed to a host
immediately, so removal of a tick, even three hours after
the initial bite, greatly reduces the chance of disease
transmission.

Best Way to Remove a Tick

What is the best way to remove a tick? First off, forget
using petroleum jelly, alcohol, fingernail polish or the
ever popular hot match. These methods don t work and may
even cause a tick to defecate or regurgitate fluid back
into the host.

The tried-and-true method is manual
tick-picking. Ticks secrete a kind of cement that bonds
their mouth pairs to a host, so removal ran be a challenge.
But there are tools on the market that will enhance your
success. These devices are designed to get a firm grip on
the head of the tick so that it’s not left behind.

If a
tick tool seems a bit much, then common tweezers and latex
gloves will work just fine. Take care not to squeeze the
tick’s body with the tweezers, as this can inject
spirochete laden gut juices into the bite. And afterward,
be sure to wash your hands thoroughly.

Some folks save a
tick once it’s been removed. This is not a bad idea. If you
or a pet has been infected, having the tick on hand (no pun
intended) will make it easier to test for a particular
disease. Keep the tick in an airtight vial or some similar
container. Putting a straight pin through the tick (as when
collecting insects) is a definite no-no; this can pierce
the gut region, which may contain dangerous pathogens.

How
dangerous? In some areas of the country Connecticut, Rhode
Island and New York State in particular-Lyme disease has
become a serious concern. Early diagnosis is the key to
treatment. Most people who are given antibiotics soon after
being infected recover rapidly and completely.
Unfortunately, however, cases of chronic Lyme disease are
not rare. The good news is that a vaccination has recently
been approved by the FDA and is now available by
prescription.

Though far less common than Lyme disease, Rocky
Mountain spotted fever is considerably more dangerous. Most
cases occur in the eastern United States, despite the
regional name. The American dog tick is the primary carrier
of the disease. Again, early diagnosis is key. Symptoms
include the sudden onset of fever, myalgia and severe
headache with or without the red-spotted rash. If treatment
occurs within five days of noticeable symptoms, the
mortality rate is 6.5%. After five days, it jumps to 22.9%.
Vaccinations are available.

So when you head outdoors this summer, enjoy yourself to
the top, but remember one thing: ticks the seas onto be
cautiousness.

New Vaccine May Lick Lyme Disease

During the last two decades, Lyme disease has emerged as
the most common tickborne illness in the United States,
with nearly 100,000 cases reported to the Centers for
Disease Control since 1982.

A multistage bacterial infection, Lyme disease can produce
a range of ailments from skin rash to flu-like symptoms to
arthritis to cardiac irregularities. But even more
frightening are those instances in which the disease
remains asymptomatic-for months or even years following the
initial tick bite-only to manifest itself in its very late
stages in the form of severe arthritis or potentially
debilitating neurological problems.

And since the vector for this insidious disease is the
so-minuscule-it’s-hard-to-spot deer tick, most folks will
never know they’ve been bitten unless or until symptoms
appear. That’s why prevention is vital.

Enter LYMErix(TM), the first-ever vaccine for Lyme disease.
In extensive clinical trials, LYMErixITM) was shown to be
both safe and effective in preventing symptomatic and
asymptomatic forms of the disease in individuals age 15 to
70. Approved by the FDA last December, LYMErix is now
available by prescription.

The vaccine is recommended for folks who live, work or play
in high-incidence areas, including the Northeast, upper
Midwest and Pacific coastal regions. It carries a small
risk of injection-site reaction, including redness,
swelling and possibly joint or muscle pains.
For more information about Lyme disease or the vaccine,
talk to your doctor, call the LYMErix toll-free hotline at
1-888-LYMErix ext. 500, or visit the Web at
www.lymerix.com/ . LYMErix is manufactured by SmithKline
Beecham Biologicals.

Need Help? Call 1-800-234-3368