Deer+Ticks

=Deer Ticks (//Ixodes scapularis)//=

Introduction[[image:fieldzoologyuvm/phoca_thumb_l_b1.jpg width="369" height="256" align="right" caption="Fig2: Unengorged female surrounded by females partially engorged."]]
The commonly known deer tick is endemic to the Eastern United States (though it is becoming increasingly common north of the border) [ 1 ]. It is just one of 13 tick species present in Vermont [ 2 ]. //I. scapularis// is a parasite, aside from parasitizing white tail deer, (where the tick gets its name) it can also parasitize small mammals, lizards, and birds [ 3-6 ]. The small creature is particularly troublesome because of the diseases it vectors. Aside from lymes disease the tick also vectors babesiosis and anaplasmosis [ 7 ]. If these diseases are not caught and treated they can causes severe sickness of the host.

Identification[[image:fieldzoologyuvm/Blausen_0291_DeerTicks.png width="335" height="254" align="right" caption="Fig3: A computer rendered drawing of adult male and female deer ticks."]]
Deer Ticks, also called black legged ticks, are relatives to spiders. Unlike spiders they have only one body segment. This is a synapomorphy of the subclass Acari. Deer Ticks are about 3mm long and are reddish brown, similar in many ways to other ticks in the North East. They can be distinguished from other ticks by their black legs [ 2 ]. This is the only way to identify to Deer Tick to species that I’ve found. Like their cousins, the spiders, ticks have eight legs. Like other ticks in the Ixodidae family Deer Ticks have a hard shell called a scutum [ 8 ]. Deer Ticks heads project forward out of the body [ 8 ]. When actually identifying Deer Ticks it is easiest to bring them to family by the presence of a scutum then to species by looking at the legs.

Deer Ticks live in shaded and sheltered areas where they can avoid drying out [ 2 ]. Their native habitat ranges from Texas up the Appalachian Mountains to a few hundred miles north of the great lakes in Ontario east to the sea coast [ 1 ]. They have a two year life cycle with three distinct stages, larva, nymph, and adult. Like levels in a video game the tick must feed before maturing to the next stage. Once a tick is attached to its host it will feed for 3-5 days before dropping off and morphing to the next stage [ 6 ]. Adults can remain active even after a hard frost so long as temperatures rise sufficiently during the day, and so are active from early spring to late fall [ 2 ]. Once an adult female feeds it buries its self into leaf litter and over winters. In the spring it will emerge and up to a few thousand eggs [ 8 ].

Lymes Disease
Lymes Disease is caused by bacteria //Borrelia burgdorferi//. Symptons of lymes vary from the unmistakable bull’s-eye rash to headaches, joint stiffness, meningitis, and a variety of other uncomfortable things [ 5 ]. Many people believe Deer Ticks to be much smaller than other ticks in this area. This belief stems from the fact that nymphs often bite people in the spring and summer. Other species of tick, such as the American Dog Tick, the Wood Tick, and the Lone Star Tick don’t bite people until they are adults. Deer tick nymphs are much harder to spot than their full size cousin and therefor usually go unnoticed for long periods of time [ 2 ]. This is how the majority of people are infected with lymes disease [ 1, 5 ]. In the southern part of the species range the rate of ticks carrying diseases increases, in New Jersey 55% of all Deer Ticks carry one of the three aforementioned diseases [ 7 ].

Relevant Reading
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Figures
Fig1- By Scott Bauer from http://www.ars.usda.gov/is/graphics/photos/mar98/k8002-3.htm Fig2- By James Occi from www.lymediseaseassociation.org/index.php/about-lyme/tick-vectors/photos Fig3- By Bruce Blaus from en.wikipedia.org/wiki/Ixodes_scapularis Fig4- By unknown from www.cdc.gov/lyme/transmission/index.html Fig5- By unknown from www.cdc.gov/lyme/signs_symptoms/index.html