Philly Inquirer: Lyme disease/tick life cycle
- Subject: [cg] Philly Inquirer: Lyme disease/tick life cycle
- From: Alliums firstname.lastname@example.org
- Date: Mon, 09 Jun 2003 10:45:49 -0400
Incredibly easy to read and understand article in today's Philadelphia
Inquirer on the interplay between Lyme disease and the tick/human/deer
cycle that keeps the disease among us! :-(
Dorene Pasekoff, Coordinator
St. John's United Church of Christ Organic Community Garden
A mission of
St. John's United Church of Christ, 315 Gay Street, Phoenixville,
Learn the facts of Lyme disease
Ticks and deer play misunderstood roles in the spread of the bacteria
By Jim Occi
I know this sounds as if I'm an apologist for criminal behavior, but
The tick that transmits the Lyme disease bacterium is
True, it's a blood-sucking parasite and sex fiend that wantonly spreads a
microbe that can bring illness and even death to humans. But disgusting
behavior aside, the tick has been wrongly stereotyped by both sides in
the deer debate in suburbia.
Hunters call this arachnid the deer tick and suggest that the increase in
Lyme disease is directly attributable to the growing deer population. The
deer have brought these parasites right to our doorsteps, the hunters
say, where it's only a short walk to our arms and legs.
Animal-rights activists snarl at the mention of the term deer
tick. They say the ticks' prey is not the white-tailed deer but
rather the white-footed mouse, and to suggest that deer play a role in
the spread of Lyme disease borders on slander.
Let's set things straight: You're both wrong. And you're both right. So
would you please put aside your taste for venison or your love for Bambi
for a moment and consider the facts?
Let's start with the deer tick, which, by the way, is a legitimate term.
It is born free of the Lyme bacterium. Many, however, may pick it up in
their larval stage by feeding off the blood of a white-footed mouse that
carries the bacterium. So we have Fact No. 1: In the vast majority of
cases, the bacterium originates in the white-footed mouse.
Ticks partake in only one feeding in each stage of their life cycle. When
a larval tick has pigged out on the mouse, it will fall off, retreat to a
moist area, and reemerge in late spring or early summer in the nymph
So now we're in the period during which humans are most likely to
contract Lyme disease. Why? Because in the vast majority of cases, the
Lyme bacterium is transmitted by the nymph tick during its one seasonal
feeding. Its target might be a mouse or other rodent, or it might choose
you or me for its meal. In only rare cases would it pick a deer; that
comes later in life.
Deer ticks are as brilliant as they are devious. In the forthcoming warm,
moist days, they'll perch in the low-lying vegetation of our yards, alert
to rustling vibration, the scent of carbon dioxide, and the sensation of
warmth - all signs of a passing human. Using their forearm hooks, they'll
climb aboard, then seek out a warm spot on our bodies, where they'll find
ample supply of red blood cells. As they begin to fill themselves with
nutrient-rich blood, they make space in their systems by expelling water,
which they do through their saliva, thus transmitting the Lyme bacteria
into their unsuspecting victims.
Unsuspecting is the key word here. These pinhead-size proletarians
are able to prevent our blood from clotting and our skin bite from
itching or becoming painful. All this allows them to keep feeding,
unnoticed, for days.
That is why it's essential to wear light clothing that covers your arms
and legs when you spend extended periods near vegetated areas in the
summer. It's also important to closely check your clothing - and your
body - for any sign of ticks once you're back inside. Keep in mind that
when you remove the nymph tick within one or two days of the bite, you're
less likely to contract Lyme disease.
Once the nymph tick is sated, its feeding is done for that cycle, and
it's back to the leaf litter. Come fall, the nymph graduates to
adulthood, becoming a boy or girl and discovering the joys of sex.
About this time, the deer-mating season is under way, which means bucks
and does are also out there looking for a good time. So if you're a deer
tick, where's the best spot for a romantic getaway? The flesh of a
In fact, deer provide both the bedroom and round-the-clock room service.
While boy and girl mate, girl feeds off the deer blood to nourish her
After lovemaking that can last a week, the guy may drop dead or go off to
find a new girlfriend. The female tick goes back to the leaf litter and
lays 1,000 to 3,000 eggs, which hatch in the summer, and the cycle starts
So we have Fact No. 2: The tick is not falling off the deer and onto you;
the one seasonal feeding is over with the mating on the deer.
And Fact No. 3: Without a plentiful deer population, Mr. and Ms. Tick
would lose their favorite venue for procreation, which would have severe
implications for the future of their species.
The verdict: The white-tailed deer and white-footed mouse are unwitting
coconspirators with the deer tick in the transmission of Lyme disease to
Jim Occi is a microbiologist whose master's thesis dealt with deer
ticks infected with the Lyme disease bacterium. He lives in Union County,