In the coming months, some experts predict that ticks and the diseases they cause will be more abundant due to warmer winter temperatures. Worry, though, is unnecessary since prevention is possible.
Here's a simple guide to all things tick:
What are ticks?
Ticks are not insects, said Goudarz Molaei, a research scientist at the Connecticut Agricultural Experiment Station. They are arachnids, and like their relative the spider, they have eight legs when they reach adulthood. Life begins as an egg, and then ticks develop through larval and nymphal stages before reaching maturity.
"People should realize that ticks do not jump. They do not fly, and they do not drop from trees," Molaei said.
To survive, ticks must eat the blood of mammals, birds, reptiles or amphibians. If infected with bacteria, viruses or parasites, a biting tick poses a risk to human health.
According to Durland Fish, professor emeritus of epidemiology (microbial diseases) at the Yale School of Public Health, ticks have three feeding stages. The larval black-legged tick, recently hatched from an egg, is "about the size of a period at the end of the sentence." These tend to feed on birds and rodents.
Nymphs, which are "about the size of a poppy seed," and adults, which are "about the size of apple seed," also feed. Only infected ticks in either of these two stages pose a risk to humans, according to Molaei.
Lone star ticks are the exception. They sometimes bite humans in the larval stage, according to the Centers for Disease Control and Prevention.
Where are ticks found?
Ticks can be found in our backyards, under leaves, on ground cover, around walls and near structures and woodpiles where rodents and other small mammals are active, Molaei said.
"They are mainly active outdoors in wooded areas amongst shrubs, trees and tall grasses," he said.
There are several tick species in the United States, though three are most plentiful. Black-legged ticks (also called deer ticks) make their home throughout the Northeast and upper Midwest.
"Nearly 90% of ticks in the Northeast and upper Midwestern US are black-legged ticks," Molaei said. A related tick, the Western black-legged tick, can be found in the Pacific and Western regions of the country.
Dog ticks are common in the Midwest and Eastern US, with limited numbers on the Pacific Coast. This tick also inhabits the Northeast, but "it's not very common," said Molaei.
Finally, there's the lone star tick, which can be found throughout Southeastern and Eastern states.
What Illnesses are caused by infected tick bites?
"Illness depends on where you are and what kind of tick is biting you," Fish said. "And what kind of tick is biting you depends on where you are and what time of year it is."
According to Molaei, just three species -- black-legged (deer), dog and lone star ticks -- can transmit up to 15 diseases.
"However, the most important of these ticks is the black-legged tick," he said, explaining that it "is involved in transmission of at least five important disease agents": babesiosis, anaplasmosis, Borrelia miyamotoi infection, Powassan virus and Lyme disease.
Babesiosis is rare and does not usually have symptoms, though some people develop fever, chills, sweats, headache, body aches, loss of appetite, nausea or fatigue, according to the Centers for Disease Control and Prevention. Anaplasmosis is similarly rare and causes similar symptoms.
Borrelia miyamotoi "was discovered 10 to 15 years ago in the US, and it causes relapsing fever," according to Molaei.
Powassan virus, which was discovered in Ontario in 1958, is also rare, with the CDC reporting only 75 cases over the past decade in the northeastern states, the Great Lakes region and Canada.
Dr. Jennifer Lyons, chief of the Division of Neurological Infections and Inflammatory Diseases at Brigham and Women's Hospital in Boston, said most infected people will never show symptoms, but some develop fever and headache.
"About 15% of patients who are infected and have symptoms are not going survive," she said. "Of the survivors, at least 50% will have long-term neurological damage that is not going to resolve."
"You basically feel nonspecific flu-like stuff," Lyons said, including "muscle aches and pains; maybe you have a little rash on your skin."
And then there's Lyme disease.
According to Fish, Lyme is the most common tick-borne disease by far. Each year, the CDC receives reports of nearly 30,000 cases of this illness, which can cause fever, headache, fatigue and a bulls-eye rash known as erythema migrans. If left untreated, infection can spread to joints, the heart and the nervous system.
Lyme disease is most prevalent in the Northeast and the upper Midwest, with "probably 95% of the cases" occurring in these regions, though California sees some cases as well.
What about dog ticks and lone star ticks?
Dog ticks cause illnesses including Rocky Mountain spotted fever, which at 500 cases per year is probably the next most common disease spread by ticks, Fish said. Symptoms include fever, malaise and a rash.
It can be fatal and, of all the tick-borne infections, is most frequently so.
"All of those fatalities are really needless, because it's easily treatable with antibiotics," Fish said. The issue is that physicians don't always recognize it, and people don't always get treatment.
Most prevalent in the Appalachians, the Carolinas and Georgia, this fever was discovered in Montana, hence the name.
"If you get symptoms of fever, malaise after a tick bite, and with Rocky Mountain spotted fever you see rashes on your body, then you should seek immediate treatment."
An emerging illness transmitted by the lone star tick is Southern tick-associated rash illness, or STARI. Symptoms include fatigue, headache, fever, muscle pains and a rash similar to that of Lyme disease. It is important to remember that the lone star tick bites people at all three of its life stages; the smaller the bug, the less likely it will be noticed and felt.
Can you feel a tick bite? Where might it bite?
Dr. Sunil Sood, an infectious disease specialist and chairman of pediatrics at Northwell Health's Southside Hospital in Bay Shore, New York, said tick bites are usually painless.
"Generally, people cannot feel the tick bite, but after a day or two, they sense a mild itching," he said.
Although ticks can bite anywhere, they tend to migrate to moist, "warmer parts of the body," including the groin, armpits and scalp, which are the "three major areas where we find them attached."
Ticks are also often found behind the ears, behind the knees and around the waist.
Geoffrey Wall, an expert in tick-borne illness and professor of clinical sciences at the Drake University College of Pharmacy and Health Science, said ticks are often found in the hair, on their way to the scalp.
"Especially in men or women with long hair, you've got to really look carefully on the whole scalp. It's hard to see. You've got to be thorough," he said.
"If, at the end of the day, you bathe or shower with a washcloth, you pretty much dislodge any tick that is not yet attached," Sood said, explaining that "it takes a bit of a while" for a tick that has settled on the skin to "set up shop."
It may take a full day or even 36 hours before they burrow into your skin and begin sucking blood, according to Sood.
What do I do when a tick bites?
First things first: Remove the tick.
As Wall noted, "there's all sorts of different means and methods that people have been taught."
Some recommend poking an attached tick with a hot match, while others say to immerse it in alcohol or put Vaseline on it to smother it.
"Some of this stuff may or may not work," Wall said, adding that the CDC's recommendation is to use fine-tipped tweezers and pull the tick straight out with steady pressure. "Do not jerk it up," he said, work slowly, and then "thoroughly clean the bite area with alcohol and then soap and water."
There's no need to visit a doctor immediately.
"Don't visit your doctor until symptoms appear," Wall said, noting that it can take days, weeks or even several weeks. "Fever and a rash, in particular, if you have either or both of those, it's time to go see your doctor."
If you do visit a doctor after pulling off a tick, Sood said, "don't flush it down the toilet or squish it with your foot." He explained that a doctor would want to identify send it off to a lab for identification. "Save the tick."
A doctor will not necessarily test for Lyme disease. A false negative or false positive is possible, and even if the tick is infected with Lyme disease, that "doesn't mean it transferred to you," Sood said, noting that even having lots of tick bites doesn't necessarily mean a person would be more likely to get a disease.
"Don't panic. Don't destroy the tick; don't think you have to go on antibiotics right away," Sood said. "People overreact a lot."
When and where are people likely to get bit by ticks?
"There's a definite peak season for Lyme disease," Fish said, adding that 95% of cases are acquired in June, July and August.
Three-quarters of people get bit on their own property, he said. Even though "there are certainly more ticks in the woods than there are in the lawn," people spend more time on their lawns.
As Wall observed, "as we move into the woods more and we're putting more houses in and farther and farther out, I think we're probably likely to see more tick-borne illnesses becoming common."
"Studies have shown that 75% of the cases of Lyme disease, people don't recall having been bitten by a tick," Fish said, adding that's possibly the most important thing to know: In most cases, you won't know.
"The adult stage of the tick can theoretically cause Lyme disease, but it's big, and people usually find it and remove it before they get sick," Fish said. "But if you don't find it, you cannot remove it."
How do I defend myself?
"We say use tick repellents," Sood advised.
Deet, recommended by the Environmental Protection Agency, is the primary ingredient to look for in skin repellent products (often labeled "insect repellents").
"You don't need to go 200%, and 5% won't last long," Sood said; within the range of 25% to 50% works well.
"And the underutilized second repellent for people who are outdoors a lot" is another EPA-recommended chemical, permethrin, which is used on clothing, outerwear and gear.
"It's highly effective against ticks and mosquitoes," Sood said, so you'd be protecting yourself from mosquito-borne illnesses as well.
You can soak clothes in permethrin, which stays in the fabric for four to six weeks, even withstanding multiple laundry cycles, he said.
This combination skin and clothing repellent strategy is your best defense.
Another preventative measure: Once you've returned from a jaunt outside, inspect yourself and your clothing for ticks. Wall suggests carefully going through your hair; thoroughness is key.
"Drying clothes in a dryer is very effective for killing ticks," Sood said, noting that the dehydration kills them. Do all you can to keep ticks out of your household. Though they cannot survive long there, they pose a danger, especially to children.
What about pets?
"Pets, in particular dogs, can carry some of the same ticks humans can carry," Wall said. A tick collar can help with some ticks, but it will probably not destroy all of them.
"The Lyme disease tick actually can be carried by dogs," he said, though animals don't get the disease. "The dog doesn't transmit the disease to humans."
Because animals have their own set of tick-borne illnesses, they should see a veterinarian for vaccinations or treatment.