Ixodes scapularis

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Deer tick
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Class: Arachnida Order: Acari Family: Ixodidae Genus: Ixodes Species: I. scapularis
Binomial name
Ixodes scapularis Say, 1821

This article is about the parasitic arachnid. For the folk-rock singer-songwriter please see Deer Tick (band).

Ixodes scapularis, commonly known as the deer tick or blacklegged tick (although some people reserve the latter term for Ixodes pacificus, which is found on the West Coast of the USA), and in some parts of the USA as the bear tick,^[1] is a hard-bodied tick (family Ixodidae) of the eastern and northern Midwestern United States. It is a vector for several diseases of animals and humans (e.g., Lyme disease, babesiosis, anaplasmosis, etc). They are known as the deer tick due to their habit of parasitizing the white-tailed deer.

The images shown to the left and to the right -- and in fact, most images of Ixodes scapularis that are commonly available -- show an adult that is unengorged, that is, an adult that has not had a blood meal. This is natural, since the ticks are generally removed immediately upon discovery to minimize the chance of disease. However, the "sack" that holds blood is so much larger when engorged and looks so different from the rest of the tick that it would be easy to assume that an engorged specimen of Ixodes scapularis is an entirely different tick (see photo on lower left). The "sack" is of a light grayish-blue color, whereas the tick itself is chiefly black. In identifying an engorged tick, it is helpful to concentrate on the legs and upper part of the body.

Deer tick females latch onto a host and drink its blood for four to five days. After it is engorged, the tick drops off and overwinters in the leaf litter of the forest floor. The following spring, the female lays several hundred to a few thousand eggs in clusters.^[2]

Contents 1 Disease vector 2 See also 3 References 4 External links

[edit] Disease vector

Ixodes scapularis is the main vector of Lyme disease in North America.^[3]

Ticks that transmit B. burgorferi to humans can also carry and transmit several other parasites such as Theileria microti and Anaplasma phagocytophilum, which cause the diseases babesiosis and human granulocytic anaplasmosis (HGA), respectively.^[4] Among early Lyme disease patients, depending on their location, 2-12% will also have HGA and 2-40% will have babesiosis.^[5] Cat scratch fever is another common co-infection, although there is debate among experts on this topic on tick-to-human transmission.^{[citation needed]}

Co-infections complicate Lyme symptoms, especially diagnosis and treatment. It is possible for a tick to carry and transmit one of the co-infections and not Borrelia, making diagnosis difficult and often elusive. The Centers for Disease Control (CDC)'s emerging infections diseases department did a study in rural New Jersey of 100 ticks and found that 55% of the ticks were infected with at least one of the pathogens.^[6]

[edit] See also

• Tick
• Deer

[edit] References

[edit] External links

• blacklegged tick, Ixodes scapularis on the UF / IFAS Featured Creatures Web site
• Ixodes scapularis, black-legged tick, deer tick overview as a vector for Lyme disease, developmental stages at MetaPathogen
• Ixodes scapularis genome sequence at VectorBase

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