Rocky Mountain Wood Ticks

The Rocky Mountain wood tick (Dermacentor andersoni) is found in the Rocky Mountains states and southwestern Canada. Its habitat consists of brushy areas that provide food and protection for wild mammals, which serve as the tick’s usual hosts. This tick must feed on three different hosts during its life cycle. After feeding for 4 – 17 days, the mated female descends from the host and seeks a protected area to lay eggs. In the spring, she lays a single cluster of usually 3,000 – 5,500 yellowish brown ellipsoidal eggs over a period of 10 – 33 days. During the next 7 – 38 days, the eggs will hatch if the temperature is 72 F. The young six-legged larvae begin crawling in search of a small rodent°-90 host (such as mice, voles, and chipmunks), dying within 30 days if unsuccessful. The larvae, if successful in finding a host will feed for 2 – 8 days to engorgement, and then drop to the ground to molt within 6 – 21 days. In this eight-legged nymph stage, it may survive for more than 300 days if unfed. After finding a suitable small to medium size host (such as rabbits, ground squirrels, marmots, and skunks), the nymph will feed to engorgement in 3 – 11 days. After completing engorgement, the nymph will drop off again and molt into the adult stage in 14 -15 days (can be as long as 120 days). The eight-legged adult can survive more that a year (usually about 600 days) without feeding. But after finding a suitable medium to large-sized host (such as dogs, deer, and humans), they will feed, then mate on the host, and when they are finished feeding, they will descend to lay eggs and the life cycle will start over again. The life cycle can take 1 – 3 years (typically 20 months), depending primarily on host availability and various environmental stresses and conditions.

Ticks are highly sensitive to carbon dioxide, exhaled by animals as they breathe, and seek it out. Ticks will travel up the stems of grasses and low shrubs to wait for a passing mammal to brush against them. The ticks will then cling to the new host and attach itself by secreting a cement-like substance around its mouthparts and insert it into the host. If the tick has not found a host by the time that hot summer temperatures arrive, it seeks cover under leaves and remains dormant until the next year. Peak periods of tick activity can begin as early as March during warm seasons. They usually subside by mid-July.

Ticks produce a toxin that can cause paralysis in animals. This systemic toxic reaction is reversible when feeding ticks are removed from the victim soon after the onset of symptoms. If the paralysis is allowed to progress too long, death can result from respiratory paralysis. Symptoms of tick paralysis occur only after the female tick has been feeding for about five days. The victim may feel perfectly well one day, but on the next day they may complain of numbness in the feet and legs, and have problems walking. Following these complaints and difficulties, the patient may find it impossible to stand. Hands and arms are usually affected next. There is frequently a partial paralysis of the throat muscles, with an accompanying difficulty in swallowing. Loss of control over the tongue may occur; with the result that speech becomes difficult. Pain and fever do not usually accompany the other symptoms. Although the nature of the toxin is unknown, it is generally believed that tick paralysis is caused by a substance produced in the tick’s salivary glands. One theory suggests that the host’s tissues react in response to tick saliva to produce a metabolic toxemia. Still another theory postulates that symbiotic microorganisms living in the salivary glands of the tick produce the toxin while the tick feeds.

A person suspected of having tick paralysis should be stripped and examined carefully for the presence of feeding ticks. Particular attention should be paid to the armpits, neck nape, crotch and groin areas. Remove any ticks with forceps, eyebrow tweezers, or tissue or cotton held the fingers. Do not use bare fingers. Avoid folklore remedies, such as the use of petroleum jelly or hot matches. These do little to encourage a tick to detach from skin, and 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. After the tick has been removed from the patient, the wound should be examined to establish that head and mouthparts have been extracted with the tick body. If left embedded in the skin, these can cause infection. The wound should then be painted with an antiseptic. Following these procedures, get the patient to a physician as soon as possible and inform the doctor that you suspect tick paralysis.

Precautions to minimize tick bites:
When walking in tick-infested areas during the spring and summer months, take the following precautions:
1. Wear protective, light-colored clothing, such as long pants tucked into socks and long sleeved shirts buttoned at the neck and sleeves.
2. Apply an arthropod repellent containing DEET to exposed flesh and to shirt collars, shirt cuffs, beltline, and trouser cuffs.
3. Ask your veterinarian for advice on effective tick repellents for your pets.
4. Check both yourself and your pets for ticks on a regular basis, at lease twice per day and remove ticks as soon as found.

To safely remove a tick:
1. Grasp the tick with tweezers as closely to the head of the tick as possible. (The ticks head can remain imbedded in the skin if the tick is not removed properly.)
2. Slowly turn the tick over, in a lifting and twisting motion. This will cause the mouth of the tick to release its hold.
3. Wash the area with soap and water.

DO NOT burn or smother the tick to remove it! These methods increase the risk of infection and should not be used.

Although most tick bites are harmless, some can cause serious illnesses. If you have flu-like symptoms or develop a rash after being bitten by a tick, see your doctor immediately because you may have a tick-borne illness such as Colorado Tick Fever, Rocky Mountain Spotted Fever, Relapsing Fever, tularemia, Lyme Disease, hemorrhagic fever, Tick Typhus or Tick-borne Encephalitis. Different types of ticks may carry some of these diseases.

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