Tick

From ArticleWorld

Along with mites, the order ‘’Acarina’’ includes the commonly named tick. The tick is an arachnid and an ectoparasite (external parasite), living on the blood of animals. Ticks can be dangerous transmitters of disease. There are two types of tick, hard ticks and soft ticks. Hard ticks have a thick outer shell, while soft ticks have a membranous outer surface. Feeding methods for the two types are different as well. Hard ticks attach themselves to the skin of animlas and humans for long periods of time, dropping off when full. Soft ticks emerge only briefly to feed, then return to the crevices in which they live.

Disease vectors

Many diseases are transmitted by ticks. The two types of tick, hard and soft, tend to transmit different diseases to their hosts. Diseases like HIV/AIDS and malaria are transmitted by soft ticks. Lyme disease and Rocky Mountain spotted fever are two well known diseases that are transmitted, by hard ticks, to humans. Hard ticks also transmit several different livestock diseases.

Myths

It is a common misconception that ticks can jump from a plant to their hosts. In truth, ticks tend to position themselves at the tip of a blade of grass, or leaf, and attach themselves to their host as it passes by. Once attached, pulling a tick out by force may do more harm than good. There is a tendency for some of the contents of the tick to be squeezed back into the wound, and often the mouthpiece is left behind, causing infection.

Facts

• The lifecycle of a tick consists of three growth stages, larva, nymph and adult, and spans approximately two years. A blood meal is required to progress to each stage.
• Mating can take place while attached to the host, and is necessary for the female to complete her final blood meal. After mating, the female dops off her host, lays approximately 3000 eggs, and dies.
• The most well known hard tick is the American dog tick, ‘’Dermacentor variabilis’’.
• In the eastern U.S., the deer tick, ‘’Ixodes dammini’’, is responsible for the spread of Lyme disease.
• In the western part of North America, ‘’I. Pacificus’’ spreads the deadly Rocky Mountain spotted fever.

• In australia, there is a 20 kilometer band along the eastern coastline that is home to ‘’Ixodes holocyclus’’, the Paralysis tick.