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Thread: Ticks Overview

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    Ticks Overview

    Ticks are the leading carriers of diseases to humans in the United States, second only to mosquitoes worldwide. It is not the tick bite but the toxins or organisms in the tick's saliva transmitted through the bite that cause disease.

    Ticks are arthropods, like spiders. There are more than 800 species of ticks throughout the world. They are responsible for carrying such diseases as Rocky Mountain spotted fever, Lyme disease , babesiosis (Texas fever), ehrlichiosis, and tularemia (also transmitted via rabbits), as well as Colorado tick fever and Powassan (a form of encephalitis).

    In addition to disease transmission, ticks can also cause tick paralysis. This condition occurs when neurotoxins in the tick saliva make you ill; cause paralysis of the body; and in extreme cases, can stop you from breathing in extreme cases.
    Two groups of ticks are important to humans because of the diseases they can transmit:

    [*]Hard ticks have a tough back plate or scutum that defines their appearance. The hard ticks tend to attach and feed for hours to days. Disease transmission usually occurs near the end of a meal, as the tick becomes full of blood.

    Some of the more common hard ticks are these:

    • American dog tick

    • Wood tick

    • Deer tick (they carry Lyme disease)

    • Lone star tick

    • Soft ticks have more rounded bodies and do not have the hard scutum found in hard ticks. These ticks usually feed for less than 1 hour. Disease transmission can occur in less than a minute. The bite of some of these ticks produces intensely painful reactions. Two common soft ticks found in the United States are the Pajaroello tick and spinose ear tick.

    • Outbreaks of tick-related illnesses follow seasonal patterns as ticks evolve from larvae to adults. They hide in low brush to hitch a ride on a potential host. Ticks require a "blood meal" to grow and survive, and they are not very particular upon whom or what they feed. If these freeloaders don't find a host, they may die.

    • Once a tick finds a host-such as you, your pet, a deer, a rabbit-and finds a suitable site for attachment, the tick begins to burrow with its mouthparts into exposed skin. Tick mouthparts are barbed, which helps to secure them to the host.

    • Often the tick secrets "cementum" to more firmly anchor its mouthparts and head to the host. Ticks may secrete or regurgitate small amounts of saliva that contain neurotoxins. These nerve poisons cleverly prevent you from feeling the pain and irritation of the bite. You may never notice the tick feeding on you. The saliva may contain a blood thinner to make it easier for the tick to get its blood meal.

    What is a tick?

    A tick is a small, blood-sucking mite. Normally it lives on blood from larger animals, like deer, but it may also attach itself to humans.

    The tick sits on tall grass and trees, waiting for a possible 'host' to walk by. If a tick attaches itself to someone, it will typically find its way to a warm, moist and dark place on the body (like the crotch or the armpit).

    It will then insert a probe into the skin and begin sucking blood. In most cases the tick will leave after a while, or the host will get rid of it without any harm having been done. But, occasionally, the tick carries a small bacterium called Borrelia burghdor feri in its stomach. This is what causes Lyme disease. The further under the skin it gets, the greater the risk of catching the disease.
    Why is it important to remove a tick?

    A tick on the body doesn't usually cause any pain, but it is still important to get rid of it because of the risk of Lyme disease. Every year about 300-500 cases are reported.
    How to remove the tick

    The tick presses its head into the skin so it is important to try and remove all of it: remnants in the skin could cause infection.

    Seize the tick with a pair of tweezers as close to the head as possible. Take care not to pull it apart. Pull slowly and consistently until it lets go. Don't pull too hard.

    If the above method fails, tie a cotton thread around the tick as close to the head as possible and pull slowly until it lets go.

    Do not attempt to remove the tick through burning or chemicals - this may cause more harm than good.
    What to do if the head gets stuck

    If the tick is accidentally pulled apart and the head stays in the skin, there is a risk of being infected with other microscopic organisms. This kind of infection has nothing to do with Lyme disease, but can still be dangerous and unpleasant. See a doctor if infection occurs.
    Do I need an antibiotic if I have been bitten by a tick?

    If you have been bitten by a tick and have removed it, the risk of getting Lyme disease is so small that there is no reason to use an antibiotic.

    It is, however, important to watch out for symptoms that may indicate Lyme disease, especially a red spot close to the tick bite. The spot gradually gets bigger and, eventually, a pale area will appear in the middle. This is often accompanied by headache and fever, which will usually appear between 3 and 30 days after the bite. If this happens, see a doctor immediately.
    Ticks generally are not born with disease agents but rather acquire them during various feedings. They then pass the disease on to other animals and mankind during subsequent feedings. When an infection moves from an animal host to a human it is called zoonosise. Lyme disease, babiosisos, erlichiosious and tularemia are examples of such diseases.

    Ticks have life cycles that involve three distinct life stages of development- larval (infant), nymph (immature) and adult (mature). The ticks known for the greatest quantity of disease infections are the Ixodes group. The group consists of many ticks but the ones of most concern are ixodes scapolarius, ixodes pacificus, ixodes damini, and ixodes ricionoiuse.

    Even experts find it difficult to distinguish the ixodes ticks based on physical characteristics alone since a large part of identification relies on the geographical location they inhabit. When the female tick engorges on blood, her body change of both size and color is so significant that she is unrecognizable when compared to her pre-engorgement appearance. Look at the below sequence of a Lone Star tick as she engorges . . . is this hard to believe? In an attempt to simplify identification we are providing photographs showing various stages of the tick during the feeding process. Regardless of the difficulty in identifying specific tick species within a group it is quite easy (with the aid of our photographs) to identify ticks belonging to the group. That is the purpose of this website!

    Besides the body types associated to different tick species, each has a distinguishing characteristic called the shield. It is an area just behind the mouthpart and is the key part of this tick identification method. You'll see in the photographs that the shield remains constant in size and in relationship to the mouthparts. The only difference you will note is that the shield pivots forward in relation to the mouthparts as the tick becomes more and more engorged. By using this system and knowing where the tick specimen originated, you will be able to identify the tick with reasonable certainty.

    If the ticks origin is from an area known to have incidence of tick-borne disease and if the specimen is of a species of tick known to carry and transmit that disease, you can consider that the possibility of infection exists. Ticks can be tested reliably at the state-of-the-art facility run by Igenix.


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    Last edited by trimurtulu; 02-20-2009 at 01:12 PM.

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