Ticks and Tick-Borne Diseases

Ticks have long been pests of humans and animals in North Carolina. From the larval to the adult stages, ticks attach to a living host and feed on the host’s blood. In doing so, they may transmit germs that cause Rocky Mountain spotted fever or Lyme disease, both of which can have serious consequences for humans. This publication will help you identify the several species of ticks found in North Carolina and the diseases they transmit. It also describes ways you can protect yourself from ticks outdoors and control ticks in your home.

Ticks are related to mites and spiders. They have four stages of development — the egg, larval, nymph, and adult stages. After hatching from the egg, the tick must take a blood meal to complete each stage in its life cycle. Each stage of the tick usually takes a blood meal from a different host. For most ticks, each blood meal is taken from a different type of host.

Ticks are usually active in the spring, summer, and fall; however, the adults of some species are active in the winter. When seeking a blood meal, ticks move from leaf litter, from a crack or crevice along a building foundation, or from another secluded place to grass or shrubs where they attach themselves to an animal as it passes. If a host is not found by fall, most species of ticks move into sheltered sites where they become inactive until spring. Once it is on a host, a tick crawls upward in search of a place on the skin where it can attach to take a blood meal. The tick’s mouth parts are barbed, making it difficult to remove the tick from the skin. In addition, the tick manufactures a glue to hold the mouthparts in place. The female mates while attached to a host and usually feeds for 8 to 12 days until it is full. By the time it finishes feeding, the female may increase in weight by 100 times. A male tick may attach, but it does not feed as long as the female. The male tick may mate several times before dying. The female, after mating and feeding, drops to the ground where it lays a mass of eggs in a secluded place such as in a crevice or under leaf litter. Shortly after laying an egg mass, which may contain thousands of eggs, the female dies. The eggs hatch in about two weeks, and the life cycle begins again. Depending upon the species of tick, the life cycle may take as little as a few months or as much as two years.

The American Dog Tick

The adult American dog tick, Dermacentor variabilis, is active in the spring, summer, and fall. It lives
along woodland paths, in recreational parks, farm pastures, wastelands, and other shrubby habitats in rural and suburban areas of North Carolina. In each stage of its life cycle, this tick may feed on a different animal. For example, the larvae feed only on white-footed field mice and meadow voles or pine voles, whereas nymphs prefer medium-sized mammals such as opossum or raccoons. Adults prefer humans and dogs as hosts. In North Carolina and throughout the southeastern United States, the American dog tick is the vector of Rocky Mountain spotted fever. However, this species does not transmit Lyme disease. The American dog tick is found throughout North Carolina, but it is most common in the piedmont area.

The Brown Dog Tick

Rhipicephalus sanguineous, the brown dog tick occurs throughout North Carolina and may be active year round. In all stages, it feeds almost exclusively on dogs and rarely attacks people. Brown dog tick females may lay egg masses in cracks and crevices along building foundations, in pet kennels, and in homes. After a few weeks, you may find several thousand larvae climbing on walls, draperies, or furniture. When uncontrolled in kennels, populations of the brown dog tick may grow to extremely high levels.

The Lone Star Tick

All stages of Amblyomma americanum, the lone star tick , readily feed on man and large wild or domestic animals such as deer and dogs. Adults and nymphs are abundant in the spring and summer months. The mite-like larvae of this species, commonly called seed ticks, are abundant in the fall. In this stage, the lone star tick readily attacks humans. This tick is found in habitats similar to those of the American dog tick. It transmits a form of Lyme disease called STARI (Southern Tick Associated Rash Infection) caused by the spirochete, Borrelia lonestari. The lone star tick also transmits bacteria that cause erhlichiosis and Rocky Mountain spotted fever. It occurs predominantly in the coastal plain, but it may be found in the North Carolina piedmont.

The Black-Legged Tick

Larvae and nymphs of Ixodes scapularis, the black-legged tick , feed on snakes and lizards. The adults attack large mammals such as dogs, deer, and humans. Adults are active in late fall, in early spring, and in winter when temperatures rise above freezing. The black-legged tick is found in the same habitats and regions of North Carolina as the lone star tick.

Rocky Mountain Spotted Fever

Lyme Disease

Lyme disease is caused by a spiral-shaped bacterium (called a spirochete), Borrelia burgdorferi. The bacterium is transmitted through the bite of an infected tick. Lyme disease was recognized as a distinct disease in 1975 after several children, living close to each other in the town of Old Lyme, Connecticut, developed arthritis. In the northeastern United States where the disease is prevalent, the black-legged tick, lxodes scapularis (formerly called the deer tick, Ixodes damnini) is the vector of the Lyme disease spirochete. The black-legged tick in the Southeast does not tend to bite humans and as a result many fewer cases of Lyme disease are found. The lone star tick does readily attack humans, but only a small number of spirochete-infected ticks have been collected in the Southeast. Like Rocky Mountain spotted fever, Lyme disease is indigenous to wild animals. Lyme disease has been divided into three clinical stages.

Stage I involves a rash and flu-like symptoms. Within 30 days of infection, a characteristic rash (erythema migrans) occurs at the site of the tick bite. Twenty to 50 percent of Lyme disease patients do not exhibit the rash, which often delays diagnosis of the disease. Erythema migrans may occur as an irregular-shaped red blotch or it may consist of a bright red ring around the bite that gradually expands over several days and clears in the center to form a bull’s-eye pattern. The rash can vary in size from 1 to 18 inches. Later, secondary blotchlike skin lesions may occur away from the site of the bite when the spirochete spreads. The rash is usually accompanied by fatigue, a headache, a stiff neck, muscle aches and pains, and a general feeling of discomfort.

Stage II, which occurs during the next several weeks, includes cardiac and neurological symptoms. Neurological complications occur in about 15 percent of the patients and can involve encephalitis (inflammation of the brain), radiculitis (inflammation of the nerve roots), and Bell’s palsy (transitory facial paralysis). In most instances, these symptoms completely disappear after lasting several months. Cardiac abnormalities occur in about 8 percent of patients. The symptoms include dizziness, shortness of breath, and heartbeat irregularities that may require installation of a pacemaker. Within several weeks these symptoms usually disappear.

Stage III is distinguished by arthritic problems that may appear as long as two years after the rash. Patients may experience pain, swelling, and elevated temperature in one or more joints. Some patients may also exhibit sleepwalking, loss of memory, mood changes, and inability to concentrate. Lyme disease and its complications can be effectively treated with antibiotics. Physicians use different antibiotics against each stage of the disease. With early treatment, the course of Lyme disease is shortened and the occurrence of late complications, such as arthritis, is reduced. Therefore, it is important to diagnose Lyme disease and administer antibiotic therapy quickly.

Ehrlichiosis

Pets may transport ticks into the family living area, so inspect them frequently for ticks. Remove attached ticks from pets
using the same procedures described for people. Control ticks on pets using flea-tick collars and powder or liquid formulations of pesticides. In addition, several safe and effective pesticides can control ticks in pet quarters. Contact your county Cooperative Extension Service agent for advice on pesticides or you can check the NC Agricultural Chemicals Manual .

Ticks and Tick-Borne Diseases in North Carolina

Insect Note - AG-426