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Magnitude of problem
In the Spokane area this problem has not been of much note in recent
years, but once in a while there will be so many ticks on
tree branches and in rocky areas that you won't be able to avoid their presence
in your hair, clothing, or car. Remove them as
soon as you recognize any presence of them and you should not have any disease
manifestation problems at all.
Description
Ticks are in the phylum of animals called Arthropoda (jointedappendage). This
phylum of animals is the largest in the animal kingdom. There are over 850 different
species of ticks, and they parasitize every class of terrestrial vertebrate animal,
including amphibians. Ticks are small rounded arachnids that cling to one spot and do not
move. They have inserted their head under the skin and are engorging themselves on the
blood. Diseases carried by ticks means that you should have yourself or your pets checked
after you find ticks. On the one hand, ticks are a little easier to deal with since they
remain outdoors, and do not infest houses the way fleas do; on the otherhand, they carry
more dangerous diseases and are harder to find.
Role in diseases
Ticks are the most important arthropod in transmitting diseases to domestic animals
and run a close second to mosquitoes in arthropod borne human diseases. They transmit a
greater variety of infectious agents than any other type of arthropod. Ticks can cause
disease and illness directly. They are responsible for anemia due to blood loss,dermatosis
due to salivary secretions, and ascending tick paralysis due to neurotoxins in the
salivary secretions. They also can be the vector of other diseases. Some of the more noted
tick borne diseasesare babesiosis, anaplasmosis, East Coast fever, relapsing fever, rocky
mountain spotted fever and, of course, Lyme disease.
Kinds of ticks
There are two basic types of ticks. Soft ticks, the argasids, are distinguished by
their soft, leathery cuticle and lack of scutum. They can be recognized easily by their
subterminal mouthparts that are on the underside of the tick. Soft ticks when engorged
with blood blow up like a balloon. Soft ticks are fast feeders, being able to tank up in a
matter of hours. Hard ticks, the Ixodids, have a hard plate on the dorsal surface and have
terminal mouthparts. When attaching, a tick will slice open the skin with the mouthparts
and then attach itself. They also secrete a cement that hardens and holds the tick onto
the host. Hard ticks are slow feeders, taking several days to finish their blood meal.
During feeding a tick may extract up to 8 ml of blood, they can take 100X their body
weight in blood. Interestingly, they concentrate the blood during feeding and will return
much of the water to the host while losing some by transpiration through the cuticle.
Lifecycle
All ticks have four life cycle stages. Adult ticks, produce eggs. A female tick can
produce up to 20,000 eggs. Mating usually occurs on a host, after which the female must
have a blood meal in order for the eggs to develop. Ixodid ticks are unusual in that
mating does notoccur on the host. The eggs are laid in the soil or leaf litter after the
female drops off the host. These eggs hatch into a stage known as the larva. The larva is
the smallest stage and can be recognized by having only 3 pairs of legs. These "seed
ticks" are produced in great numbers. They must find a host and take a blood meal in
order to molt to the next stage called the nymph. If the nymph can feed on a host, it will
develop into the adult tick. Ticks vary greatly in how long this cycle takes and the
number of hosts involved. Some ticks are one host ticks; the entire cycle occurs on that
one host. Others use two hosts, some three and some of the soft ticks are multi-host
ticks. Ticks require high humidity and moderate temperature. Juvenile ticks usually live
in the soil or at ground level. They will then climb up onto a blade of grass or the leaf
of a plant to await a potential host. They will sense the presence of a host and begin the
questing behavior, standing up and waving their front legs. They are able to sense a
vibration, a shadow, a change in CO2 level, or temperature change. When unsuccessful in
their "quest" they become dehydrated and will climb back down the plant to the
ground to become rehydrated. Then back up the plant, etc., until they are successful or
they die. Some ticks have been known to live for over 20 years and they can live for a
very long time without food. Their favored habitat is old field-forest ecozone. One way to
cut down the number of ticks is to keep the area mowed.
Removing a tick
When you find a tick, use tweezers to pick up the body and pull s-l-o-w-l-y and
gently, and the mouthparts will release. You should see a small crator in your dog's skin,
if you see what looks like black lines, you've left the head of the tick in. At this
point, if your dog is mellow enough, you should try and pick it out. Otherwise, you may
need to take your pet into the vet, as the head parts will lead to an infection. Ticks
carry a lot of rickettsial diseases, including Lyme disease and Rocky Mountain Spotted
Fever, so you should wash your hands thoroughly with soap after handling a tick. Some
veterinarians will put on gloves, smear one finger with a bit of mineral oil and massage
the protruding part of the tick for a minute or so. The tick will back out.
Tips:
* Don't use any of the folklore remedies (matches, cigarettes, pins, gasoline) that
will irritate the tick. They increase the likelihood that the tick will "spit
up" in you, which increases the risk of disease. * Oil is not effective because the
breathing requirements of the tick are so small it could last hours covered with oil. *
The mouthpiece is barbed rather than spiralled, so trying to rotate the tick out doesn't
provide any advantage. * The preferred method is to use special tweezers designed for that
purpose, and pull straight out. Lyme disease (see below) is usually carried by tiny deer
ticks (two other kinds of ticks have also been identified as carriers) , which are the
size of the head of a pin. You must look yourself or your pet over very carefully to find
these kind of ticks. Other ticks can be as large as peppercorns. This can vary depending
on whether or not the tick has yet engorged itself -- the deer tick can be as large as the
more familiar Dog Tick if it has had time to feed. So if you are in doubt, preserve the
tick in rubbing alcohol and have your vet take a look at it.
Infections or abscesses
If you have left the head of the tick in your pet's skin, chances are there will be
an infection or an abscess in a week or so. Try disinfecting the area thoroughly with 70%
alcohol (it takes about 5 minutes for alcohol to sterilize an area). Ethyl alcohol is less
toxic than rubbing alcohol; vodka or any high-proof liquor will work. Betadine or iodine
is recommended. Then apply a combination antibiotic ointment. If an infection occurs
anyway, take your pet in to the vet to have it drained.
Disposing of ticks
To dispose of the tick, drop it into alcohol to kill it, then dispose of it.
Flushing them down the toilet WILL NOT KILL THEM. Squishing them with a thumbnail is not
recommended, and is not easy anyway. You might save the tick in a jar of alcohol for
identification, to help decide whether possible infection has occurred.
Where you pick up ticks
Adult ticks can remain on deer and other mammals through the fall and winter. If
you spend a lot of time outdoors during this period, be sure to check yourself, your
family and your pets daily for ticks. If you hunt or trap, check areas where you cache
your game for ticks that may have fallen off during handling. A helpful practice is to
wear long pants tucked into white socks; this way they crawl up the *outside* of your
pants and you can spot them in the field. Also wear a hat: they can drop from trees onto
your head. Ticks like long grass on the edges of woods (especially deer ticks) They crawl
up onto the grass blades and cling to you as you walk past. If you comb your pet with a
wide tooth flea comb right after taking a walk, chances are you will find unattached ticks
crawling around. Ticks don't attach themselves right away: they look around for good real
estate. It's much easier to remove ticks before they attach, and easier to remove newly
attached ticks than ones that have been feeding for a while.
Combatting ticks
If you have heavy infestations of ticks in your area, spraying your backyard
against ticks may be a good idea, especially if your pet is indoor/outdoors. If you have a
dog, a new product called Preventic appears to be highly effective. It is a tick collar
that kills ticks shortly after they attach to your dog. The active agent is Amitraz, which
prevents attachment and kills but does not affect fleas. Amitraz is not an insecticide
(flea killer) but an "arachnicide" (8-legged bug killer - ticks and spiders are
in the same class.) The collar works best if it is kept dry. Rain is OK, but swimming is
out as exposure to water reduces its effectiveness. Removing the collar is apparently
non-trivial. You don't need a prescription, although the only place you might find it is
at the vet's or in a mail-order catalogue. Twenty-four hours after putting it on, your dog
is protected from ticks. Many people have written about how effective it was for their
dog. It is NOT recommended for cats, however, and some dogs appear to have individual
sensitivity to it. If your dog becomes lethargic or irritable, remove the collar. NOTE
THAT THE COLLAR IS TOXIC -- if your pet eats any part of the Preventic collar, take him in
to the vet immediately. Symptoms include vomiting, white gums and unsteadiness. There is
an antidote for it, called Yobine. There is a product, called Tiguvon (chemical
composition) that is a systemic, administered monthly. Its drawbacks seem to be that it is
expensive and that the tick needs to fully engorge itself to be poisoned by the systemic.
Ticks don't typically infest houses, unless you have a pet that had an overlooked tick
that dropped off and hatched its eggs. In the Northeast US and other temperate climates
the tick _Rhipicephalus sanguineus_ is almost exclusively limited to domestic habitats,
particularly kennels. Becasue the entire life cycle occurs inside, control strategies
become similar to that of controlling fleas. You will have to spray your house in this
case as ticks hatch an unbelievable number of eggs. Your local hardware store can give you
tips on what is best to spray with. You are not too likely to find "natural" or
low-toxic sprays for ticks. On the other hand, one spraying is likely all you need to
clear them out of your house. They are not tenacious the way fleas are. Common
recommendations for reducing ticks in your backyard are to keep the weeds or grass
well-mowed. There are commercial sprays effective against ticks. If you live in
tick-infested areas, always examine your dog (and yourself!) after being outside. Control
vermin around your house and discourage deer and other wild or feral animals from your
property, as they are often vectors for ticks (as well as a slew of other nasties).
Lyme disease
Lyme disease is a complex illness that affects wild and domestic animals, including
dogs, as well as humans. It is caused by a corkscrew-shaped bacterium called borrelia
burgdoferi. First noted in 1977, the disease has rapidly spread throughout the
contintental US and Canada. Studies have shown that migrating birds have helped disperse
infected ticks to new areas. Hunting dogs, or any dog that runs in tick-infested fields,
can bring the problem home with them. And so do people who move from place to place with
infected pets. It is expected that Lyme disease will soon be a problem in all 48
contiguous US states. You should note that Lyme disease is fairly easily treatable with
antibiotics. Problems occur when it is left untreated. Lyme disease appears to affect
humans a bit differently and is more complex to treat. Sources for additional information
on Lyme disease: * State and local health departments * Your veterinarian or family
physician * Local Lyme Disease support and informational groups can be found in many areas
* Lyme Disease Foundation, Inc. P.O. Box 462 Tolland, Connecticut 06084 (203) 871-2900
(800) 886-LYME * The Lyme Disease Electronic Mail Network publishes the "LymeNet
Newsletter" once every 10-15 days. The Newsletter contains timely news about the Lyme
disease epidemic. Medical abstracts, treatment protocols, prevention information, and
political happenings are all included. In addition, subscribers may ask questions to the
patients, doctors and researchers on the net. To subscribe, send email to
listserv@Lehigh.EDU, with subscribe LymeNet-L in the body of the message. Problem reports
only should be sent to mcg2@lehigh.edu, the owner of the list.
Transmission
When a tick bites, the bacterium is transferred into the blood of the host. The
deer tick (Ixodes dammini) is found in the Northeast and upper Midwest; the black-legged
tick (I. scapularis) is found in the Midwest and Southeast; and the Western black-legged
tick (I. pacificus) is found mainly in the coastal areas of California, Oregon, and
Washington. Hosts include deer, migratory birds, rabbits, mice, raccoons and skunks ...
plus dogs, cats, cattle, horses and humans. Besides tick bites, Lyme disease may be spread
by contact with infected body fluids. Studies indicate that transmission may occur in his
manner from dog to dog, and possibly from cow to cow and horse to horse. Transmission from
animal to human *may* be possible. In utero transmission has been observed. Animals may be
reinfected with Lyme disease. The major vector for the deer tick is the mouse; deer have
relatively little to do with it. Deer simply act as a home for the overwintering adults.
Removing deer from an area has little long term effect on the tick population since the
adults simply find another animal to act as a winter host.
Symptoms
The symptoms of this illness have now been separated into three stages. If caught
before the end of the first stage, the illness is usually easily treated by antibiotics.
In general, a high fever combined with stiffness or arthritic symptoms (in both people and
animals) can indicate Lyme disease. The next two stages represent greater systematic
involvement and include the nervous system and the heart. If still untreated, the third
stage involves the musculoskeletal system. The erythema migrans (small round rash at the
site of the bite) is the best early sign of a problem. Unfortunately, the tick that bites
is usually a larva or nymph and so is seldom seen. The resulting rash is seen in
approximately 80% of adults but only about 50% of children. It is imperative that it be
diagnosed early since the more severe symptoms can begin quickly. Treatment consists of
several broad spectrum antibiotics -- including tetracycline, penicillin, and
erythromycin. This is effective, especially in the early stages. Consult with your
veterinarian or doctor.
Vaccination
There is a vaccination against Lyme disease for dogs that is now available. It is
Borrelia Burgdoferi Bacterin (Fort Dodge Laboratories). It is supposed to have a duration
of immunity that lasts through the tick season. One for people is coming out now as well.
An interesting discussion of what is happening in the veterinary community with regard to
Lyme disease is summarized in an easy-to-read letter titled "Questions 'push' for
vaccinations against Borrelia burgdoreri infection," in the Journal of the American
Veterinary
Association, 201(10), 11/15/92.
R. Sanguineus
They can carry various diseases including the protozoa Babesia canis and the
rickettsia Ehrlichia canis, both of which can cause serious illness in dogs if untreated.
Also unlike most other ticks R. sanguineus can cause *in house* infestations - that is,
like fleas you can have full life cycles occuring in the privacy of your very own home. In
house infestations of R. sanguineus in the northeast is apparently not that uncommon in
some kennels.
Cindy Tittle Moore, tittle@zmall.com |
