What is a tick?
Ticks belong to the arachnid family, which means they are related to spiders and scorpions. Therefore, they are not true insects.
Ticks are parasites that feed by latching on to an animal host, embedding their mouthparts (called a hypostome) into the host's skin and feeding on its blood. This method of feeding makes ticks the perfect vectors (organisms that harbor and transmit disease) for a variety of pathogenic agents. Ticks are responsible for at least 10 different diseases in humans in the United States, including Lyme disease, Rocky Mountain spotted fever, ehrlichiosis and babesiosis, and several other newly identified diseases.
What species of ticks can transmit Lyme disease to humans?
The deer tick (Ixodes scapularis) in the Eastern United States and its close relative the Western black-legged tick (Ixodes pacificus) on the Pacific Coast have been thought to be the only tick species currently known to transmit the Lyme disease spirochete (a type of bacterium) to humans. Recent studies have identified the Lone Star Tick (Amblyomma Americanum) also a vector in Lyme disease. Other tick species have been observed to harbor the spirochete but apparently cannot transmit it to their human hosts.
What does a deer tick look like?
The first thing to remember about deer ticks is that they come in three different sizes and color patterns, depending on which stage of their lifecycle you're looking at. Just as humans have successive life stages (e.g., child, adolescent, adult), a deer tick hatches from its egg as a light tan, translucent larva (about the size of a period in newsprint), molts into a blackish nymph (about the size of a poppy seed), and eventually molts a second time into a brick-red adult female (about the size of a sesame seed) or a black adult male (slightly smaller than the female).
