There are two families of ticks, the Ixodidae (hard ticks) and Argasidae (soft ticks). Those that are of importance to hikers, campers, and pet owners are in the family Ixodidae. Several species of hard ticks are important because they bite people and pets. Some can also transmit diseases. Therefore, this article will cover only some species of hard ticks, so you can learn what they look like, how they live, and how to protect yourself from tick-borne diseases.

The American dog tick, Dermacentor variabilis, is the most frequently encountered tick here in New Hampshire. It is about 1/8" (4—5mm) long, brown and tan, with an obvious mottled pattern. It is a "three-host tick," so-named because it must find and feed on an animal three times to complete its life cycle.

It begins life as an egg, one of hundreds laid in a mass on the ground by a female tick. The egg hatches into a larva, which has six legs. Larvae remain on the ground or vegetation while waiting for a small mammal (usually rodent) to brush by. It attaches to the animal and feeds for several days. Then it drops off and molts to the nymph stage, which has eight legs. Again it waits for a host (usually a rodent) to brush by. When that happens, the tick attaches and feeds on it for several days. When fully fed it drops off and molts to the adult stage.

Adults wait on shrubs or tall grass and attach to larger mammals such as people, deer, or pets. They also take several days to fully engorge (feed). A fully engorged female can be almost the size of a dime, and appears smooth and shiny. Mating takes place on the host, and when fully fed the females drop off and lay eggs. The cycle can be as short as three months or as long as two or more years. American dog ticks can survive a very long time without feeding. This species can transmit Rocky Mountain Spotted fever, which is rare in New England but more common farther south.

Stories in the press have confused many people about the relationship of this tick and Lyme Disease. Despite the fact that the Lyme Disease spirochete has been found in American dog ticks, tests have revealed that the tick can’t transmit the organism to its hosts. Therefore it isn’t involved in the spread of Lyme Disease.

The winter tick, Dermacentor albipictus, is similar in size and appearance to the American dog tick. Unlike that species, the winter tick isn’t active in the summer and it completes its entire development on one host. It is often found on moose, deer, or horses during the fall, winter, or spring. It doesn’t commonly bite people. Eggs of this species hatch in the spring, but the larvae remain bunched together in a torpor all summer long. They don’t become active until cold weather returns in fall. After finding a suitable host, this species remains on the animal, feeding and molting until it has fully grown. Then it drops off, and eggs are laid on the ground in the spring.

The brown dog tick, Rhipicephalus sanguineus, is slightly smaller and different in shape than the American dog tick. It is reddish-brown in color and lacks the mottling that the Dermacentor species have. It has a life cycle very similar to other three-host ticks. It can be a problem in kennels and zoos, but rarely bites people. It has a strong tendency to climb upwards, and hides in cracks in kennel roofs or in ceilings and porches. In heated buildings, it occurs at any time of the year. It is unlikely this tick would be found anywhere but in or adjacent to kennels or houses where dogs are kept.

Ixodes scapularis is the blacklegged tick. Until 1993, northern specimens were considered a different species, called the deer tick (Ixodes dammini). It looks similar to the other tick species mentioned, but is smaller and more rounded. It lacks the mottling of Dermacentor species. Adult males are very dark brown, almost black. Adult females are two-toned: dark chestnut brown on head, legs, and scutum; and orange-red on the rear half of the body. Nymphs are about the size of a pinhead (1—2mm), and adults are just over 1/16" (2—3mm) long. This species has received much attention because it is the vector of (the organism that spreads) Lyme Disease. Survey results from New Hampshire, Maine, and Massachusetts have shown that this species is most abundant along coastal regions.

The life history is typical of other three-host ticks. Larvae prefer mice, other small rodents, and birds. Nymphs commonly bite these hosts plus medium sized animals and people. The life cycle takes two years. Adults most commonly attach to large animals, such as white-tailed deer. They are most active from mid-September to mid-November, but activity continues in mild weather when there is little or no snow covering. Some adults are found in the spring. This species will readily bite people. Scientists have shown that high populations of deer are necessary for this tick to be abundant. In Massachusetts, the incidence of Lyme Disease is strongly linked with high deer populations.

Others ticks similar to the blacklegged tick include: Ixodes cookei, which bite people, dogs, cats, woodchucks, porcupines, and other animals; Ixodes banksi, which primarily attacks beavers and muskrats; Ixodes muris, which bites mice and sometimes cats and people; and Ixodes marxi, which typically attacks squirrels.

Ticks can spread several diseases, including Lyme, Rocky Mountain Spotted Fever, Tularemia, Tick Paralysis, Powassan Encephalitis, Babesiosis, and Colorado Tick Fever. Incidences of each vary by region. Here in New England, for example, it is unlikely you’d encounter any of these diseases except Lyme.

This disease is caused by a small micro-organism, a Rickettsia. Until about 1930, it was thought to occur only in the Rocky Mountain region, hence its name. Today there are far more cases reported in the eastern states, especially in Virginia, North Carolina, northern Georgia, and nearby states. The disease usually appears in late spring, summer, or early fall. The American dog tick is the primary vector in the east. Symptoms usually appear 3—10 days after being bitten by an infected tick. Headache, backache, and fever are common symptoms. A spreading, spot-lie rash usually develops on wrists and ankles 2—5 days after symptoms begin. The disease can be fatal if not treated. It is treatable with antibiotics.

"Rabbit fever" is caused by a bacterium. It can be contracted from skinning and cleaning rabbits, or from being bitten by infected ticks. In the east, most cases occur in the fall and winter and are presumed to be associated with hunting rabbits or other small mammals. Fever and flu-like symptoms are typical, along with swollen lymph nodes. Certain antibiotics are effective in treating the disease. The American and brown dog ticks are among the species that can transmit the bacterium.

Tick paralysis is caused by toxic substances in the secretions of feeding ticks. In people, it occurs most frequently in children under the age of seven. Young girls are common victims, probable because it is difficult to detect ticks in long hair. The most frequent site of biting that causes "paralysis" is the back of the scalp. The difficulty in moving or controlling arms or legs rapidly disappears when the feeding tick is discovered and removed. In the U.S., it is most frequently seen in the Southeast and Northwest. The American dog tick has been known to cause Tick paralysis.

Lyme Disease was first identified in the U.S. in the mid 1970s near Lyme, Connecticut. It is caused by a spirochete, an elongated, corkscrew-shaped micro-organism. Since its discovery near Lyme and islands off Cape Cod, the number of cases has rapidly increased. The disease has been frequently reported from Connecticut, Rhode Island, Massachusetts, New York, Wisconsin, and New Jersey. Lyme Disease is now the most common vector-borne (transmitted by insects or ticks) disease in the U.S., and is becoming very common in parts of Europe.

Symptoms of Lyme Disease frequently (but not always) begin with a characteristic red zone around the site of the bite. This usually appears within 20 days of being bitten by an infected tick, and slowly expands in size. It is often ring-shaped and warm to the touch. People who have never been bitten by I. Scapularis are less likely to show the rash. Fatigue, fever, headaches, stiffness, and pain in muscles and joints may occur. If left untreated, the rash may disappear, and dizziness, irregular heartbeat, arthritis, and nervous system disorders can follow. Swelling and pain in the knees are common symptoms in untreated cases months or years later.

Since tick bites are painless, ticks are often discovered after they have begun to feed. Removal is fairly easy, provided it is done correctly. Tweezers are recommended to grasp the tick, since bare fingers may get contaminated by a disease organism. It is also much easier to get a firm grip of the head with tweezers.

The most obvious way to avoid contact with ticks is to stay away from tall grass and bushy areas that are prime tick habitat. May through August are prime months for the American dog tick. April through early July, and September through mid-November are periods when deer tick (blacklegged tick) nymphs or adults are most active.

If you do spend time in tick-infested areas, wear proper clothing. Start with good shoes (no sandals or bare feet) and long pants tucked into your socks. A long-sleeved shirt with snug collar and cuffs will also offer protection if it’s tucked in at the waist, and a hat is recommended as well. Dressing this way helps keep ticks on the outside of your clothing, where they can be brushed away when spotted. Light-colored clothing allows for easier detection. For added protection, you can treat your clothes with a tick repellent. Socks, ankles, legs, and pant legs are the best places to treat. You can even find specially made tick-proof or tick-resistant clothing.

If you have been in tick-infested fields or woods, monitor yourself, your children, and your pets every day. Inspect your clothes carefully, then undress and examine your body as well. Don’t neglect to check your head, especially if you have long hair. Ticks tend to crawl upward, and if they can’t get inside your clothing, they’ll end up on your head or neck.

If you find a tick that has already begun to feed, carefully remove it as described above. If you’re concerned it might be a type that transmits disease, place it in a jar and take it to a cooperative extension county office or state entomologist. Be sure to record the date and location of the bite. If a rash forms around the area of a tick bite, see your doctor. In some cases, reaction to a tick bite is from an allergy. If your pet develops joint disorders, see a veterinarian for advice.

You can reduce the chances of tick problems in and around your home by keeping the lawn mowed, and keeping a mowed strip between play areas and thick brush. Insecticides may also be of help in cases of severe infestation. Use pesticides with care and carefully follow the label.