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TICKS
MAKE ME CROSS! - Wes Bancroft
It seems to me that one of the
unspoken rights of passage into bird banding is a little epidermal
irritation as handed out by sneaky little eight-legged parasites. Nobody
formally sits you down and informs you of this practice, for I'm sure that
it might sway the odd bander to choose a lifestyle free of itchiness.
Yes. Ticks make me cross. I
think, most of all, that's because they're sneaky.
They don't set out to wreck your
day's banding then and there, rather they climb into your socks and wait
for the drive home before they launch their all-out on any bit of skin
they can find. Then they can wreck your night's sleep and the subsequent
days, weeks or months of your life.
I guess, however, that ticks are
somewhat of a social lubricant; in as far as it doesn't matter who you are
talking to, you can always share a whinging session about how many tick
bites you have. Ticks are not sexist, racist, ageist or classist. They
just bite everyone.
But with the problems also come
bragging rights - I've heard some pretty impressive stories about ticks.
The most number of bites on a single person at a single time is 94. I
can't begin to imagine how itchy that'd be. As for the best 'location' of
a bite…well, lets just say that ticks can get where only your most
intimate associates may dare to venture. I won't go there.
So, fuelled by agitation towards
these Acari, I did a little research. If we understand the enemy, then
maybe we can beat them (or at least persuade them to bite someone or
something else).
Ticks - know your enemy!
Ticks belong to the order Acari
(mites and ticks) within the class Arachnida (spiders, scorpions, mites
and ticks) of the phylum Arthropoda (includes insects, millipedes,
centipedes, crabs and shrimp). They are blood-sucking ectoparasites and
pretty much any old blood-filled vertebrate host will do. Ticks have four
life stages: egg, larva, nymph, and adult. A larva only has six legs, but
gains an extra pair when it moults to the nymph stage. Nymphs have no sex
differentiation, this is only present in adult ticks, and it is the adult
female that requires a blood meal in order to lay eggs.
Ticks 'lurk' at, or just above,
ground level (often in the vegetation), where they wait for their next
meal to walk by. They use their forelimbs to feel for the host which can
also be detected using carbon dioxide, scent and body heat.
Ticks in Australia
There are some 59 species of
tick in Australia in two families, the Ixodidae (hard ticks) and Argasidae
(soft ticks). I tried to find the latin and/or common name (and some
general biological information) of the ticks that we encounter here in
Western Australia. Six library books and a search of the internet later I
still had no clue. If anyone can give me a lead as to where else to look
then I would appreciate it. The only tick that regularly popped up was the
Australian paralysis tick (Ixodes holocyclus) - an Eastern States species
that secretes a neurotoxin in its saliva that causes a progressive, and
occasionally fatal, paralysis.
Prevention is better than cure
It's simply easier to not to get
bitten, than to remove a tick and deal with the bite. I first met ticks in
Whiteman Park when I was working with Mike Bamford. Prior to throwing
ourselves into the Woollybush, Mike advised me to tuck my shirt into my
pants, and my pants into my socks. Which, being the image-conscious (and
naïve!) young biologist that I was, I promptly ignored. Six ticks later
that day I chose to heed the advice of my experienced elders, regardless
of how it makes you look.
The Lyme Disease Foundation (http://www.lyme.org/ticks/personal.html),
and The University of Sydney (http://medent.usyd.edu.au/fact/ticks.htm)
recommend the follow steps be taken to avoid tick encounters:
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Avoid tick infested areas,
when possible.
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Avoid short-cuts through
heavily wooded, tick-infested areas.
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Use caution when you are
entering tick-infected areas.
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Stay in the centre of paths.
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Avoid sitting on the ground.
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Wear light-coloured
clothing.
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Wear a long-sleeved shirt
and long pants.
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Tuck your shirt into your
pants and pants into your socks (i.e. listen to Mike Bamford).
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Use approved tick
repellents.
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Conduct frequent
tick-checks... "This includes a visual inspection of the clothing
and exposed skin, followed by a naked, full-body examination in a
private location. Be sure to check the scalp, behind and in the ears,
and behind any joints."
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I've heard that smothering
yourself in diesoline keeps the ticks at bay, but I certainly don't
recommend trying it.
Cure is better than lyme
disease!
OK, so you've done your best,
but you've still found a tick attached to you. What do you do? It seems
that there's a wide range of methods for extracting ticks.
Tick's mouthparts have reverse
harpoon-like barbs, designed to penetrate and attach to skin and they
secrete a cement-like substance that helps them adhere firmly to the host
(http://www.lyme.org/ticks/removal.html).
How do we combat this? I found the following at the Centre for Disease
Control and Prevention website under 'Lyme disease' (http://www.cdc.gov/ncidod/dvrd/rmsf/Prevention.htm):
"Folklore Remedies Don't
Work! Folklore remedies, such as the use of petroleum jelly or hot
matches, do little to encourage a tick to detach from skin. In fact, they
may make matters worse by irritating the tick and stimulating it to
release additional saliva or regurgitate gut contents, increasing the
chances of transmitting the pathogen. These methods of tick removal should
be avoided. A number of tick removal devices have been marketed, but none
are better than a plain set of fine tipped tweezers."
The University of Sydney agrees:
"Many people have sought means to induce them [ticks] to 'let go' by
themselves, or at least to cause them to 'relax their grip'. These have
included putting metho, turps, kero or similar on the tick, or spraying
with insecticide, or even touching the tick with a lighted match. Any of
these are potentially hazardous to the patient because they can induce
spasm in the tick and may cause it to inject more venom (as well as the
possibility of skin reactions or burns)…
These days most people recommend
gripping the tick as near to the head as possible with a very pointy pair
of tweezers or forceps… Never grip the sac and pull! This may squeeze
more venom in, or break it off and leave the head and 'torso' firmly
stuck, which is likely to get infected… Remember, DO NOT try to pull the
tick out by gripping the end part of the body! This almost always breaks
off and fails to remove the head and legs."
Lyme Disease
The following is paraphrased
from the Lyme Disease Foundation website, http://www.lyme.org/
(who SHOULD know all about it).
Lyme disease is a bacterial
infection caused by the spirochete Borrelia burgdoferi (named after its
discoverer Willy Burgdorfer, PhD, MD). These spirochetes are maintained in
nature in the bodies of wild animals and can be transmitted from one
animal to another through the bite of an infective tick.
Signs and symptoms of early
Local Lyme Disease often starts with flu-like feelings of headache, stiff
neck, fever, muscle aches, and fatigue. A rash usually appears as a small,
reddish bump and soon expands outward, often leaving a clearing (normal
flesh colour) in the centre. It can enlarge to the size of a thumb-print
or cover a person's back.
Some people do not notice these
early indicators of infection. Early manifestations usually disappear, and
disseminated (other organ system involvement) infection may occur.
Symptoms include (I picked out the most graphic!): nerve conduction
defects (weakness/paralysis of limbs, loss of reflexes, tingling
sensations of the extremities - peripheral neuropathy), meningitis,
stroke, abnormal brain waves or seizures, sleep disorders, cognitive
changes (memory problems, behavioral changes (depression, personality
changes), panic attacks, disorientation, hallucinations, extreme
agitation, impulsive violence, dementia, double vision, blindness,
irregular heartbeat, myocarditis, chest pain, mild liver function
abnormalities, difficulty breathing, pneumonia, nausea, vomiting,
miscarriage and premature birth. Whew!
References
http://www.cdc.gov/ncidod/dvrd/rmsf/Prevention.htm
http://www.lambiek.net/wang_s.htm
http://www.lyme.org/
http://medent.usyd.edu.au/fact/ticks.htm
Lee, D. C. and Southcott, R. V. 1980. Spiders and Other Arachnids of South
Australia. South Australian Museum, Adelaide, SA.
Roberts, F. H. S. 1970. Australian Ticks. CSIRO, Yeerongpilly, Queensland.
Ruppert, E. E. and Barnes, R. D. 1994. Invertebrate Zoology. Saunders
College Publishing, Orlando, Florida, USA.
Taylor, F. H. and Murray, R. E. 1946. Spiders, Ticks and Mites, Including
the Species Harmful to Man in Australia and New Guinea. School of Public
Health and Tropical Medicine, University of Sydney.
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