Black-legged Tick (a.k.a. Deer Tick)

Size:

Tiny in size with adults measuring 1/8-inch, while young nymphs may be pinhead-sized.

Color:

Dark brown to black body and darker legs.

Behavior:

Like all ticks, the black-legged tick is a bloodsucking ectoparacite. Ticks require a blood meal at each stage of life in order to grow and the female will engorge herself with blood to obtain the nourishment necessary to produce the thousands of eggs she will lay soon. Commonly known as the deer tick, black-legged ticks have a two-year cycle beginning in the spring when the female tick deposits her eggs. Despite the thousands of eggs produced, only a small percentage will survive to maturity. Black-legged ticks are the primary vector of Lyme Disease in the Eastern U.S. and are common in wooded areas and fields where mammalian hosts such as deer, rodents and humans live. The tiny larvae get their first blood meal from rodents, mainly the white-footed mouse, Peromyscus leucopus. Ticks imbed their mouthparts, not their entire head, as some commonly believe, into their host. They inject an anti-clogging agent to keep the blood from clotting so they can feed. During feeding, black-legged ticks may inject the spirochete bacterium, Borrelia burgdorferi, which causes Lyme Disease. Due to the small size of this tick, its presence can go unnoticed for several days if the tick is attached in an inconspicuous area of the body, such as on the back or under the hair on the head. This increases the potential for transmission of disease if the tick itself is infected. Lyme Disease — Lyme disease was first detected in 1976 in Lyme, Connecticut when an unusually large number of children suffering from similar symptoms came down with an unidentified illness later found to be transmitted by the black-legged tick, Ixodes scapularis. In 1981 the causative pathogen, a spirochete named Borrelia burgdorferi, was isolated and confirmed as the cause. Studies have shown that 90 percent of the black-legged ticks may be infected with B. burgdorferi in parts of northeastern states. Lyme Disease most often begins with the appearance of a spreading rash at the site of the bite. This rash, called erthema chronicum migrans or ECM, is seen in about 60 percent of patients. Most victims of Lyme Disease report a flu-like illness at first, and often dismiss the symptoms as a “24 hour bug,” overexertion or lack of rest. Lyme Disease is very difficult to diagnose because each victim’s symptomatology can be different. Three distinct stages of Lyme Disease have been described, but these stages may not appear in all patients, may overlap, or often may occur out-of-sequence. The different stages may mimic the symptomatology of other diseases further conflicting correct diagnosis. Stage One involves the ECM rash and the flu-like illness. Stage Two involve neurological and cardiac problems. The disease can cause malfunctions in the electrical signals to the heart and has caused doctors to install pacemakers in some patients. Stage Three results in arthritic conditions in various joints. Unlike typical arthritis, Lyme Disease may only affect one side of the body or only one or two joints. Black-legged ticks are also carriers of a disease called human granulocytic erlichiosus or HGE. Some persons infected with Lyme Disease have also contracted HGE, possibly as the result of the same tick bite. For more information regarding tick-bourne diseases, visit the website of the Centers for Disease Control.