Ticks are parasitic arachnids (spider-like) that are part of the mite family. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and fullness. Ticks are external parasites, living by feeding on the blood of mammals, birds, and sometimes reptiles and amphibians. The timing of the origin of ticks is uncertain, though the oldest known tick fossils are from the Cretaceous period, around 100 million years old. Ticks are widely distributed around the world, especially in warm, humid climates.
What are the types of ticks?
There are two broad families of ticks found in the United States: Ixodidae (hard ticks) and Argasidae (soft ticks). There are about 700 species of hard ticks and 200 species of soft ticks currently found throughout the world. Very few of these are known to bite and transmit disease to humans. The ticks are usually named based on their host organisms. They include the American dog tick, the black legged deer tick, the ground hog tick, the lone star tick, the rocky mountain wood tick, the pacific coast tick and several other species of tick. The three main tick species that are of concern to human health are Three tick species are a human health concern are the blacklegged tick (deer tick), the lone star tick, and the American dog tick.
How do ticks live?
Ticks love moist and humid environments, but they can adapt to any number of different areas. In general, ticks tend to live close to their hosts. This includes dog, cats, rodents, birds, deer and unfortunately, humans. Ticks do not live on their hosts. They are typically found outdoors, in wooded or grassy areas, where they attach to their host and begin to feed on blood just like the lice. After taking in a blood meal, the tick detaches itself from its host. It then goes on to either find a suitable spot to molt, or another host. It is not common for most species of ticks to infest a structure, though the brown dog tick does reproduce indoors. Other species, such as the American dog tick and the lone star tick, prefer to lay their eggs on ground soil, so these ticks don’t typically live in the home – they live outdoors.
How do ticks spread disease?
According to the CDC, Ticks transmit pathogens that cause disease through the process of feeding.
- Depending on the tick species and its stage of life, preparing to feed can take from 10 minutes to 2 hours. When the tick finds a feeding spot, it grasps the skin and cuts into the surface.
- The tick then inserts its feeding tube. Many species also secrete a cement-like substance that keeps them firmly attached during the meal. The feeding tube can have barbs which help keep the tick in place.
- Ticks also can secrete small amounts of saliva with anesthetic properties so that the animal or person can’t feel that the tick has attached itself. If the tick is in a sheltered spot, it can go unnoticed.
- A tick will suck the blood slowly for several days. If the host animal has a bloodborne infection, the tick will ingest the pathogens with the blood.
- Small amounts of saliva from the tick may also enter the skin of the host animal during the feeding process. If the tick contains a pathogen, the organism may be transmitted to the host animal in this way.
- After feeding, most ticks will drop off and prepare for the next life stage. At its next feeding, it can then transmit an acquired disease to the new host.
What diseases do ticks transmit?
Even though most species of ticks do not transmit diseases in human beings, the species that do so have been associated with several diseases which can be potentially life threatening if not identified on time and treated.
Blacklegged ticks are vectors of anaplasmosis, Lyme disease and human babesiosis. Symptoms of Lyme disease include fever, headache, fatigue and a bull’s eye-shaped skin rash around the bite sight. If untreated, Lyme disease can affect the joints, heart and nervous system.
The American dog ticks are carriers of the bacteria that causes Rocky Mountain spotted fever, a serious tick-borne illness with a mortality rate of over 20 percent if not treated early. Symptoms include high fever, chills, muscle aches, headaches, and sometimes a rash spread across the extremities 2-4 days after the fever begins. These ticks are also known vectors of tularemia, a disease transmitted from rabbits, mice, squirrels and other small animals. Symptoms include an ulcer at the bite site, fever, chills and tender lymph nodes.
Lone star ticks are known vectors of many diseases, including tularemia, Heartland virus, Bourbon virus and Southern tick-associated rash illness (STARI). As with all ticks, early detection and removal is crucial, but lone star ticks have long mouthparts that can make removal especially difficult, as their mouthparts oftentimes break off while being extracted, resulting in further infection in the host.
What do ticks look like?
The appearance of ticks varies depending on the specie or type of tick, the stage in their life cycle, the species, and even time of last meal. Ticks are arachnids, meaning they are closely related to mites and spiders. Unfed ticks are flattened, and their abdomens expand after feeding, making identification difficult for most people. The typical tick has four life stages: the egg, six-legged larva, eight-legged nymph, and adult. Larval ticks have six legs, while nymph and adult ticks have eight legs.
Based on the species, for the blacklegged and lone star ticks, the larvae are about the size of a grain of sand, nymphs about the size of a poppy seed, and adults about the size of a sesame seed. When fully fed, an adult female blacklegged and/or lone star tick can be as large as a raisin. American dog ticks are larger than blacklegged and lone star ticks.
Blacklegged adult ticks are a flat, broad oval shape and are typically orange-brown in color with darker legs; while American dog ticks are flat and oval in shape, and usually brown with whitish-gray markings. The brown dog ticks are oval shaped, flat, and typically brown in color, but can become a gray and blue color when engorged, just like the Rocky mountain wood tick. The Lone star ticks are reddish brown and become dark gray once engorged.
How to avoid tick bites and infestation?
To avoid tick bites, it is important to avoid tick-infected places and to keep pets clean and tick free. Experts give the following tips as a guide.
- Use a chemical repellent with DEET, permethrin or picaridin.
- Wear light-colored protective clothing that covers the arms and legs, and makes it easy to see if a tick is on an individual.
- Tuck pant legs into socks.
- Put tape around openings in clothing so ticks have no access to the skin
- Avoid tick-infested areas.
- When in the woods, keep to the center of the trail, where ticks are less likely to be (ticks tend to stay in shrubs and bushes).
- Check yourself, your children, and your pets daily for ticks and carefully remove any ticks.
- Use a fine-tooth comb through the hair and check folds of the skin.
- Shower and wash your clothes at a high heat so any ticks on you are killed.
- Remove a tick on the body as early as possible to avoid infection like Lyme disease. To do this, use appropriate forceps like tweezers, grab it, and pull it out!