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| A TICKS |
Ticks
are small arachnids in the order Parasitiformes. Along with mites, they
constitute the subclass Acarina. Ticks are ectoparasites (external parasites),
living by hematophagy on the blood of mammals, birds, and sometimes reptiles
and amphibians. Ticks are vectors of a number of diseases, including
v Lyme disease
v Q fever (rare; more commonly transmitted by infected
excreta)
v Colorado tick fever
v Rocky Mountain spotted fever
v African tick bite fever
v Crimean Congo hemorrhagic fever
v Tularemia
v Tick-borne relapsing fever
v Babesiosis
v Ehrlichiosis
v Tick-borne meningoencephalitis, as well as bovine
anaplasmosis and
v probably the Heartland virus. Some species, notably
the Australian paralysis tick, are also intrinsically venomous and can cause
paralysis.
LIFE CYCLE OF TICKS
You
probably have a clear idea of what happens to a person or an animal if it
doesn't get food ,it starves to death. Ticks can also starve to death, but
often the process takes months or even years. However, without food, ticks
can't do much. Ticks are a clear illustration of how food works as an energy
source. Ticks need energy from blood in order to grow, develop and lay eggs.
Without blood, ticks can't do any of this.
A
tick begins its life as an egg. When the egg hatches, a six-legged larva
emerges. Aside from its missing set of legs, the larva looks a lot like an
adult tick. Its first host is usually a small mammal or a lizard, and it has to
find a host in order to grow. After feeding, the larva drops to the ground to
digest its food and begin to grow. After one to three weeks, the larva molts
and becomes a nymph.
A
tick nymph has eight legs and looks like a smaller version of an adult tick. It
has to find another meal, usually from another small mammal, bird or lizard,
before it can molt again. Once the nymph is finished eating, it drops to the
ground to continue its development. Some species of soft tick molt several
times, consuming a blood meal before each molt. After its final molt, the tick
is an adult.
An
adult tick has one job -- to reproduce. In hard ticks, the female tick attaches
to a host and feeds, often for more than 24 hours, before mating. The male tick
feeds before mating as well, but he's often a fraction of the size of the
engorged female when mating takes place. Often, the male dies after mating, and
the female dies after laying anywhere from 2,000 to 18,000 eggs. Soft ticks are
an exception. Many species of soft tick eat several smaller blood meals and lay
eggs several times. This is one reason soft ticks don't consume as much blood
in one sitting or swell to the extent that hard ticks do.
Hard
and soft ticks also have different methods for finding hosts, which we'll
examine in the next section.
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| A hard tick lays her eggs |
Types of Ticks
Of
the three families of ticks, one is Nuttalliellidae which is comprises a single
species, Nuttalliella namaqua. The remaining two families contain the hard
ticks (Ixodidae) and the soft ticks (Argasidae). Ticks are closely related to
the numerous families of mites, within the subclass Acarina .
The
Ixodidae include over 700 species. They are known as 'hard ticks' because they
differ from the Argasidae in having a scutum or hard shield. This shield
generally can resist the force of a human's soft-soled footwear, especially on
soft ground; it requires a hard sole on a hard surface to crush the tick.
However, stepping on an engorged tick, filled with blood, kills it easily,
though messily. In nymphs and adults of the Ixodidae, a prominent capitulum
(head) projects forwards from the body; in this they differ from the Argasidae.
They differ too, in their life cycle; Ixodidae that attach to a host will bite
painlessly and generally unnoticed, and they remain in place until they engorge
and are ready to change their skin; this process may take days or weeks. Some
species drop off the host to moult in a safe place, whereas others remain on
the same host and only drop off once they are ready to lay their eggs.
The
Argasidae are known regionally as 'soft ticks' or 'tampans'. The family
includes about 200 species, but the proper composition of the genera is under
review. The following genera were accepted in 2010:
v Antricola
v Argas
v Nothaspis
v Ornithodoros
v Otobius.
The
most obvious distinctions between the Argasidae and the Ixodidae are that:
They
have no scutum and the capitulum is concealed beneath the body.
The
Argasidae also differ from the Ixodidae in their habits and ecology. Many of
them feed primarily on birds, though some Ornithodoros for example feed on
mammals and are extremely harmful. Both groups feed rapidly, typically biting
painfully and gorging within minutes and none of the species will stick to the
host in the way that hard ticks do. Unlike the Ixodidae that have no fixed
dwelling place except on the host, they live in sand or in crevices or similar
shelters near animal dens or nests, or in human dwellings where they might come
out nightly to attack roosting birds, or emerge only when they smell carbon
dioxide in the breath of their hosts and emerge from the sand to attack them.
Species common in North America primarily parasitise birds, and very rarely attack
humans or other mammals.
Tick Appearance
Tick's
aren't actually insects -- they are arachnids, from the same family as spiders
and mites. Although different types of ticks vary in size, they all lack wings
and have a flat, oval body in some shade of brown. While adult and nymph-stage
ticks are eight-legged creatures, tick larvae have only six legs.
Hard
vs. Soft
If
you've ever found a tick on yourself or removed one from your cat or dog, it's
almost certainly a hard tick. These are the creatures who primarily feed on
larger mammals, reptiles and birds. Soft ticks usually feed on smaller prey,
such as bats, baby birds and mammals and little rodents. Soft ticks go through
additional molting stages compared to their hard brethren, along with feeding
more frequently.
Fed
vs. Unfed
If
the adult tick is still small and flat, it hasn't yet found a host whose blood
it will suck. Once ticks do find a host and burrow in, they start swelling as
they consume the blood meal. If not removed, the average tick takes a week to
12 days until it becomes engorged and drops off. Females feed for a longer
period than males. Ticks don't fly, so they crawl onto their hosts from below
or move among leaves, rocks and other objects until locating a suitable host.
If you or your pets don't want to become a "suitable host," stay out
of tick-infested areas. Examine yourself and your pet carefully when returning
from a trip through the woods or a field to ensure you aren't bringing home
ticks. Your pets can benefit from flea and tick preventatives available from
your veterinarian.
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| Hard Ticks and Soft Ticks |
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| The different between hard ticks and soft ticks |
Symptoms of Ticks infection
The
most important symptoms are :
v Itching at in the area of the bite
v Swelling and in severe cases
v Breathing problems
v Coordination problems
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| Ticks bite |
Prevention of Ticks
i)Personal
Protection
Tick
bites are usually painless, the ticks are tiny, and consequently many people
are unaware that they have been bitten. Ticks do not survive in hot, dry areas
as it causes their bodies to dry. They can be active when temperatures are
above 40F even in the winter.
GOOD
SENSE TIPS
v Wear light colored clothing, long sleeves and pants,
tuck pants into socks. Long loose hair should be covered, braided or tied when
venturing into areas where ticks are apt to be. Spray your clothing, etc.
(also, see Repellent Sprays section).
v When coming in from outside activities where you
might have encountered ticks, throw clothing into the dryer set on high heat.
This will ensure no ticks survive on your clothing. Remember to do a tick
check, take a shower and wash your hair.
v Keep pets that have outside exposure off furniture
especially bedding.
v Make certain that you have very fine pointed
tweezers available.
v Also, see the section on property protection and
repellent sprays.
TICK
CHECKS
v Thorough tick checks should be done, daily or when
coming in after outside activities when temperatures are warm and you have been
in areas that you may have encountered ticks (ticks can be active even on warm
winter days). Check dark, moist areas: hair, cracks behind ears, knees, elbows,
underarms, crotch etc. (also see: Tick Removal section).
v Check your pets for ticks when they come into the
house (also, see Protecting Animals section).
v Wear light colored clothing, long sleeves and pants,
tuck pants into socks. Long loose hair should be covered, braided or tied when
venturing into areas where ticks are apt to be. Spray your clothing, etc.
(also, see Repellent Sprays section).
TICK
REMOVAL
v Ticks should be removed promptly. The longer it is
attached the higher the chance of disease transmission. Remove it carefully to
prevent disease transmission:
v Using fine pointed tweezers, grasp the tick as close
to the skin as possible without squeezing the tick's body.
v Firmly pull it straight out (expect to feel some
resistance). Save the tick for future testing by placing it in a plastic bag or
in a small jar of alcohol. If a tick is to tested for spirochetes place it in a
small jar or vial with a blade of grass to keep it alive. Be sure to note the
date and site of the bite for future reference.
v NEVER: squeeze the tick, burn it, or cover it with
Vaseline or any other substance.
v Remember to disinfect the site of the bite, wash
your hands and disinfect your tweezers.
v Contact your doctor.
ii)Repellant
Sprays
DEET
products can be used for exposed skin. Several controlled release DEET
formulations have been developed which decrease skin absorbtion and increase
protection time. Extended duration products include 3M Ultrathon, Skedaddle,
and Sawyer's Controlled Release. Concentrations of DEET effective for
mosquitoes, especially for children may not be effective against ticks, so tick
checks are vital (see Repellent Sprays section). US EPA information on DEET can be located at:
http://www.epa.gov/pesticides/citizens/deet.htm
Permethrin
0.5% based sprays (on clothing only, not on skin, always follow manufacturers
directions) for clothing, especially: shoes, socks, pants cuffs or on other
fabrics such as mosquito netting, tents.
It is a synthetic pyrethroid insecticide rather than a true repellant,
and works primarily by killing ticks on contact with treated clothes. It lasts
up to 2 weeks and provides high levels of protection against ticks and
mosquitos.
These
products (Duranon Tick Repellent, Repell Permanone, Cutter Outdoorsman Gear
Guard, Permethrin Tick Repellent)
usually can be found at sporting goods or garden supply stores. Once
dry, Permethrin has a low level of mammalian toxicity, is poorly absorbed
through the skin and is rapidly inactivated by the body. Comment: to prevent exposure, do not spray
permethrin on clothing on a windy day. Hint: if you regularly do yardwork, you
might consider using a set of clothing that you have sprayed with permethrin.
Natural
or Herbal Repellents and other products are marketed for protection against
mosquitos, but are probably less effective against ticks. Applications of
plant-derived repellents that might reduce tick attachment are less likely to
deter a tick from walking across the skin to an untreated area.
If
venturing into tick habitat, a combination of both DEET for skin and permethrin
on clothing might be considered. Always follow guidelines for using repellant
sprays before applying.
Consumers
Report, June 2000, "Buzz-off!"
contains worthwhile information on insect repellants.
iii)Property
Management
Ticks
are most common in overgrown places where the ground is covered with leaf
litter, weeds, and high grass, etc. These are the areas where they are
protected from harsh drying effects of sun and wind, and are also where mice
and deer live. Ticks can be found in the ecotone that surrounds your lawn area
from the woods. Sometimes they can be found on well mowed lawns or in your
home, because they dropped off animals or pets that crossed over or entered
these areas.
The
following methods are suggested to minimize ticks on your property:
v Create tick free zones around your home by cutting
back wooded areas and increasing the size of open lawn.
v Keep grass mowed to 3 inches or less. This lowers
humidity at ground level, making it difficult for ticks to survive.
v Place play areas in sunshine.
v Remove leaf litter, moist plant litter, brush, weeds
and other debris that attract ticks.
v Eliminate dense plant beds close to your home such
as ivy and pachysandra.
v Create borders (pebbles, cedar chips) to separate
your lawn from the wooded area surrounding it.
v Rock walls, woodpiles, and birdfeeders attract mice
and chipmunks which hide, nest and eat spilled food from these sources. Do your
best to keep these far from your home.
v Keep garbage in tightly closed cans and don't leave
pet food outside or purposely attract and feed wild animals.
v Reduce plants that attract deer and plant those that
they do not eat.
v Scare tactics can be used to keep deer away.
v Soap such as Irish Spring can be used to keep deer
from eating plants.
v Ten foot high deer fences can be used to keep them
out of property.
v See Tick control section for information about
arcaricides and insecticides.
v See Research section for the multiple other exciting
methods under development.
iv)Tick
Control
There
are many methodologies to control ticks. Most of these are covered under the
topics of Property Management or under Research.
Host
reduction and exclusion: We have built homes in wooded areas, farmlands have
decreased; the result of this is an increase in deer and mouse populations and
an increase of human contact with ticks.
The
deer are responsible for increasing the tick population. The mouse, followed by
the chipmunk are responsible for the spread of many tick-borne pathogens, as
they are the reservoirs for the disease organisms (as an example for the Lyme
disease spirochete). Therefore, reducing exposure to these animals and reducing
ticks on them seem a reasonable approach and are incorporated into much of the
research and recommendations in the other sections.
Insecticidal
soaps and Diatomaceous earth (silicon dioxide) due to its desiccation (drying)
properties work against ticks.
Arcaricides
are another approach that is quite controversial, use only those that are
labeled for the control of ticks in residential landscape. They can be quite
effective against nymphal ticks if application is done at the optimum date of
mid-May to early June in the Northeast. A fall application may be used to
control the adult I.scapularis. Comment: most people acquire Lyme disease from
the nymphal ticks, due to their small size. Always read and follow EPA approved
label on the product containers.
Cyfluthrin
(Tempo). Chemical class: pyrethroid. For licensed applicator use only, is one
of the most commonly used commercial products for tick control.
v)Protecting
Animals
PETS
Check
with your veterinarian for tick control products and/or a Lyme disease vaccine
that they consider safe for your animal. Remember that exposing your pet to
more than one type of treatment (collars, dips, baths or powders) within a
short period of time might seriously harm your pet. For pets that go outdoors,
check them carefully when they return inside.
Designate
specific sleeping areas for your pets and check their bedding routinely for
ticks (if they get on your furniture check it also). It is wise to vacuum their
bedding, carpeting, and furniture they frequent, then dispose of the vacuum bag
contents in outdoor trash can.
DEER
For
information about "4 poster" feeder stations which reduce ticks on
deer, see Research section.
MICE
& CHIPMUNKS
Keep
small animals, such as mice outside of your home by sealing small gaps. For
information about bait boxes that reduce ticks on mice and chipmunks, see
Research section.
You
may also use Damminix, tubes stuffed with cotton balls treated with the
pesticide permethrin. Mice make nesting materials from the cotton, thus
reducing the ticks on the mice.
References
:
i)
http://en.wikipedia.org/wiki/Tick
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