What are ticks? Although ticks are commonly thought of as insects, they are actually arachnids similar to scorpions, spiders, and mites. All adult ticks have eight legs and have no antennae. Adult insects, by comparison, have six legs and one pair of antennae. Ticks are parasites that feed on the blood of their host, which can include pets and people. Ticks are efficient carriers of disease because they attach firmly when sucking blood, feed slowly, and may go unnoticed for a considerable time while feeding. Ticks take several days to complete feeding. Ticks wait for host animals on the tips of grasses and shrubs. When a moving animal or person brushes the plant, the tick quickly lets go of the vegetation and climbs onto the host. This process is known as questing. Ticks can only crawl; they cannot jump or fly. Some species of ticks will crawl several feet toward a host. Some tick species can be active on winter days if the ground temperatures are above 32°F (0°C).
There are two groups of ticks, sometimes called hard ticks and soft ticks. Hard ticks, like the common American dog tick, have a hard shield just behind the mouth parts (sometimes incorrectly called the head); unfed hard ticks are shaped like a flat seed. Soft ticks do not have the hard shield and they are shaped like a raisin. Soft ticks prefer to feed on birds or bats and are seldom found on dogs or cats.
Are there certain ticks that I should be concerned about? Although there are at least 15 species of ticks in North America, only a few of these species are likely to be encountered by your dog. They include American dog tick, lone star tick, deer or black-legged tick, and brown dog tick. Other tick species may be encountered in various regions. Ask your veterinarian if you need additional information about a specific species.
American Dog Tick
The American dog tick feeds on a wide variety of hosts, including humans and dogs, but rarely infests homes. Adults are chestnut brown with white spots or streaks on their backs.
Engorged females become slate gray and may expand to a length of 1/2” (10-12 mm). Larvae and nymphs feed mostly on small rodents, while adults feed on dogs, cattle, other animals, and humans. These ticks are widely distributed throughout the Midwest. They are attracted by the scent of animals, and humans most often encounter them near roads, paths, trails, and recreational areas. Although present all year round, American dog ticks are most numerous in the spring.
Lone Star Tick
Adult lone star ticks are various shades of brown or tan. Females have single silvery-white spots on their backs and males have scattered white spots. After feeding, females may be 1/2” (10-12 mm) long. Larvae and nymphs parasitize small wild animals, birds, and rodents, while adults feed on larger animals such as dogs and cattle. All three stages of the lone star tick will bite dogs and humans. These ticks live in wooded and brushy areas and are most numerous near animal resting places and in the underbrush along creeks and river bottoms. Lone star ticks are present throughout the year, but peak populations may occur from March to July. Regionally, they can be found in the Midwest. The range of the lone star tick may be expanding with the re-introduction and increased populations of white-tailed deer in many areas of the eastern US. It has also been reported in Ontario and Quebec in Canada.
Deer Tick or Blacklegged Tick
All three active stages of the deer or blacklegged tick feed on a variety of hosts, including dogs and people. After the eggs hatch in the spring, the tiny larvae feed primarily on white-footed mice or other small mammals. The following spring, the larvae molt into pinhead-sized, brown nymphs that feed on mice, larger warm-blooded animals, and people. In the fall, they molt into adults that feed primarily on deer, with the females laying up to 2,000 eggs the following spring. Adults are reddish-brown and have a dark brown or black shield-like shape between their mouth parts and body. These ticks are usually found in wooded areas along trails. They are distributed throughout the Midwest and eastern United States, as well as throughout Canada, with the highest proportion in Ontario. The larvae and nymphs are active in the spring and early summer; adults may be active in both the spring and fall. The deer or blacklegged tick can transmit Lyme disease and possibly ehrlichiosis and anaplasmosis to dogs and people. Powassan virus can also be transmitted by the blacklegged tick to people.
Brown Dog Tick
The brown dog tick (also known as the kennel tick) is found throughout most of the United States and Canada and can transmit Ehrlichia. This tick feeds on dogs, but rarely bites people. Unlike the other species of ticks, its life cycle allows it to survive and develop indoors, which means it can establish itself in colder climates. The brown dog tick is found primarily in kennels or homes with dogs, where it may be found hiding in cracks, behind radiators, under rugs and furniture, and on draperies and walls.
The adult is reddish-brown and usually attaches around the ears or between the toes of a dog to feed. After feeding, a female may engorge to 1/2” (10-12 mm) long. She then drops off the dog and crawls into a hiding place where she may lay as many as 5,000 eggs. This tick is tropical in origin and does not survive long, cold winters outdoors.
Longhorned Tick
The longhorned tick was first detected in 2017 in New Jersey, and as of 2023, these ticks have been found in Arkansas, Connecticut, Delaware, Georgia, Indiana, Kentucky, Maryland, Massachusetts, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, and West Virginia. These ticks have been found on cats, dogs, livestock, and people. While it is not clear if these ticks carry bacteria and viruses that could cause disease in North America, in other countries, longhorned ticks transmit severe fever and thrombocytopenia syndrome virus (SFTSV) to people. What can I do to prevent my dog from getting ticks? There are many tick preventatives available commercially. Some products are available over-the-counter, while others are only available through your veterinarian. There are effective monthly preventatives that are typically applied to the skin at the back of the neck and represent a convenient method of control for these external parasites. Proper grooming can aid in keeping ticks at bay as well as finding any sneaky ticks that may have already found their way to your dog.
This useful information was provided by Malcolm Weir, DVM, MSc, MPH; Ryan Llera, BSc, DVM; Ernest Ward, DVM