|Ticks and Tick-Borne Diseases in North Carolina||Insect Note - AG-426 /th>|
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 hosts 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.
Biological Characteristics of Ticks
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 ticks 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 TickThe 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.
American dog tick - male (right) and female (left)
The Brown Dog TickRhipicephalus 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. Bites from the lonestar tick can result in an illness called STARI (Southern Tick Associated Rash Infection) which exhibits a rash similar in appearance to that seen with Lyme Disease. However, this disease is not caused by the same organism that causes Lyme Disease nor has it been linked to the same arthritic, neurological, or chronic symptoms associated with Lyme Disease. The lone star tick also transmits bacteria that cause erhlichiosis. 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 lizards and small mammals. The nymphs and adults attack small and larger mammals including dogs and deer. 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.
For more information about tick identification, CLICK HERE.
Black-legged tick - male (left) and female (right)
Diseases Transmitted by Ticks
Rocky Mountain Spotted FeverAlso known as tick typhus, Rocky Mountain spotted fever is caused by a bacteria-like microorganism, Rickettsia rickettsii. Rocky Mountain spotted fever rickettsiae are acquired by an American dog tick when it takes a blood meal from an infected animal. These bacteria are not harmful to most wild and domestic animals, but they are extremely pathogenic to humans and dogs. Rocky Mountain spotted fever is normally a disease of wild animals, but people can be infected while camping or hiking in tick-infested areas if they are bitten by an infected tick. In addition, pets may carry an infected tick into the family living area. The disease organisms can also be passed through the egg of an infected tick and from stage to stage in the life cycle. Fortunately, only a small percentage of American dog ticks found in nature are infected. Symptoms of Rocky Mountain spotted fever include headache, fever, chills, aches, pains, and sometimes nausea. These symptoms are usually accompanied by a rash that starts on the wrists and ankles. Because Rocky Mountain spotted fever is easily cured with antibiotics, a person exhibiting any of these symptoms 2 to 14 days after a tick bite should consult a physician at once. If left untreated, Rocky Mountain spotted fever can cause death.
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 bulls-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 Bells 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.
EhrlichiosisEhrlichiosis is caused by several bacterial species in the genus Ehrlichia (pronounced err-lick-ee-uh) which have been recognized since 1935. Human ehrlichiosis due to Ehrlichia chaffeensis was first described in 1987. The disease occurs primarily in the southeastern and south central regions of the country and is primarily transmitted by the lone star tick, Amblyomma americanum. Human granulocytic ehrlichiosis (HGE) represents the second recognized ehrlichial infection of humans in the United States, and was first described in 1994. The name for the species that causes HGE has not been formally proposed, but this species is closely related or identical to the veterinary pathogens Ehrlichia equi and Ehrlichia phagocytophila. HGE is transmitted by the blacklegged tick (Ixodes scapularis) and the western blacklegged tick (Ixodes pacificus) in the United States. Symptoms of Ehrlichiosis are somewhat similar to Rocky Mountain Spotted Fever. For more information about Ehrlichiosis, CLICK HERE.
How to Protect Yourself from Ticks
Procedure for Removing Ticks
Ticks and Pets
Pest information and control recommendations presented here were developed for North Carolina and may not be appropriate for other states or regions. Any recommendations for the use of chemicals are included solely as a convenience to the reader and do not imply that insecticides are necessarily the sole or most appropriate method of control. Any mention of brand names or listing of commercial products or services in the publication does not imply endorsements by North Carolina Cooperative Extension nor discrimination against similar products or services. All recommendations for pesticide use were legal at the time of publication, but the status of pesticide registrations and use patterns are subject to change by actions of state and federal regulatory agencies. Individuals who use chemicals are responsible for using these products according to the regulations in their state and to the guidelines on the product label. Before applying any chemical, always obtain current information about its use and read the product label carefully. For assistance, contact the Cooperative Extension Center in your county.
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