Creepy crawlies (ticks) did not mind the snowy winter

This past winter was bothersome to many, and Minnesota residents may be sad to learn the seemingly never-ending snow did little or nothing to hamper Minnesota's tick population.

While many Minnesotans were stuck indoors throughout the long, snowy 2022-2023 winter, ticks were tucked comfortably under a blanket of insulative snow — protected, not harmed, by the many inches of white stuff.

Well-known as vectors for various illnesses, the various tick species that bug outdoors enthusiasts are surprisingly adapted, resilient and complex with a life that progresses through three stages from larval to reproduction and death.

Uninterrupted, a female tick typically lives two years. It all starts when ticks hatch in the summer, emerging from batches of thousands of eggs as larvae.

"Generally ticks lay eggs in the springtime," said Elizabeth Schiffman, epidemiologist supervisor with the Minnesota Department of Health. "Those eggs hatch into little tiny larvae."

At this stage, larvae are often the size of a grain of sand, though varieties like deer ticks (which are smaller) are as small as flecks of pepper. This is only the first of a three-part lifespan.

The first feeding is the catalyst for graduating from the larval stage to the nymph stage. These larvae start hunting young, but they primarily parasitize small prey.

"They'll take a blood meal on a mouse or a bird or some small thing, and then they basically lay low all the way until the following spring, when they emerge as nymphs," Schiffman said.

Many tick species at this stage are the size of a poppy seed, still fairly difficult to spot.

Travis Grimler / Echo Journal

Because ticks have their first feeding as larvae, they do not transmit diseases until the nymph stage. Deer ticks appear to become hosts to bacteria like Lyme disease and human anaplasmosis and the parasite that causes babesiosis from their contact with rodents like mice, moles, chipmunks and gophers as larvae.

Older ticks may still contract the organisms from contact with larger mammals that had been previously infected, like deer.

Once they reach the nymph stage, deer ticks could potentially be disease vectors. For some reason, other species of ticks do not appear to carry these three diseases.

"So it's the same with other vector species, like mosquitoes and things, where pathogens and vectors kind of evolved together," Schiffman said. "They usually have kind of a specific relationship between which types of pathogen, a particular species of tick, or mosquito can can transmit successfully."

Schiffman said the biology of other ticks such as dog ticks may not be perfectly suitable to either carrying or spreading babesiosis, Lyme or human anaplasmosis.

"The mechanics of the bacteria that happened inside of the tick, that helps the transmission happen," Schiffman said. "It doesn't all line up, basically."

According to "STARI or Lyme?" an article by the Centers for Disease Control, some tick species, including the infamous lone star tick, can actually have saliva that kills Borrelia burgdorferi, the pathogen responsible for Lyme disease.

The lone star tick, however, can host its own list of pathogens like ehrlichiosis, heartland virus disease, bourbon virus disease and a molecule that causes "alpha-gal syndrome," a food allergy to red meat.

Many of those tick-borne illnesses familiar to Minnesotans aren't a risk until ticks become nymphs seeking their second blood meal and next stage of growth.

"They'll have another blood meal and then those nymphs in the fall will be adults," Schiffman said. "And then the adults we see in the spring are kind of the leftovers of those adults."

Adults overwinter under the snow where they wait for the coming spring thaw. Though it may pose a major inconvenience to humans, the more snow, the better for these diminutive pests.

In years when the winter draws out, it can seem like ticks are more numerous than usual. This is because the emergence of the adult ticks may be delayed by the late spring thaw.

When this happens, the adults emerge close to the same time as the nymphs, rather than the two populations emerging at separate times through the summer.

"All the snow does is kind of provide a nice blanket to keep the temperatures and conditions pretty consistent under the snow cover right at ground level," Schiffman said. "As long as the ticks don't freeze solid, they're able to make it through the winter without too much of a problem.

"A winter that would actually be worse for ticks would be one where we don't have very much snow cover and where we have a lot of really cold temperatures, because then they wouldn't have that protection," she said.

Those that weather the winter conditions emerge with food and reproduction in mind. Like the other life stages, mating and egg laying cannot occur until after yet another blood meal.

Like the larvae, adult deer ticks may be disease vectors, with exception of male ticks. According to an article by Alice Park in Time magazine called "Here's everything you need to know about Ticks," males latch onto hosts, but do not feed during their shorter lifespan, therefore being unable to contract parasites or bacteria from their hosts, much less to transmit them.

These males exist only to mate in the spring after adult females emerge.

To lay eggs, adult ticks must finish feeding and engorging on their host. They are unable to lay eggs on a host, and therefore must finish feeding and detach first.

They are not very selective about where they will deposit their eggs. Females can lay anywhere from a few thousand to 18,000 eggs. They may lay eggs in coat linings, carpeting, furniture, leaf duff and other warm, soft places, though they often lay them in the path of animals that the larvae might latch onto upon hatching.

The adult ticks then die.

Eggs are in clusters that are semi-translucent, shiny brown balls, often bigger than the pest that laid them. They hatch approximately a month after being laid, and the life cycle continues.

Life in the outdoors will almost certainly lead humans and ticks to cross paths, possibly multiple times in a single outdoor trip. That being the case, there are things a person can do to make them less likely to contract a disease carried by ticks.

Most people are familiar with citronella and DEET as popular insect repellents. Another, less-known option is permethrin, a chemical that is sprayed as a pre-treatment on clothing and shoes and allowed to dry.

This application lasts for several washes, unlike DEET, which must be re-applied almost like sunscreen to remain effective. Those ticks and other insects that come in contact with permethrin-treated clothing die from having their nervous system overexcited.

Prevention can also include lawn grooming and staying on paths.

"The biggest thing we talk about is knowing when and where you're at risk," Schiffman said. "Mowing the lawn and putting wood chips or something as a barrier between the lawn and high grass can give you a clue that you should be extra aware of ticks."

This is especially true for deer ticks, which are more sensitive to weather conditions than the larger dog ticks.

"Black legged ticks (commonly known as deer ticks) are prone to drying out if they have too much exposure," Schiffman said. "We tend to find them more frequently in wooded and brushy areas, sometimes in tall grass or those transition spots where woods become lawn or trail."

Dog ticks are a little less picky about habitat, and while shorter grass or clear paths may reduce encounters, it's always important to perform tick checks after being outdoors.

Finding and removing ticks is the most important preventative measure, above use of repellents or landscaping.

Schiffman said ticks must typically be connected to a host for a specific amount of time before transmitting a disease. This is because of the way they feed.

Ticks have developed saliva and a feeding method specifically to improve their chance of completing feeding, including regurgitating saliva that modulates defense responses.

Ticks feed by scraping an area of skin until a pool of blood forms, then they dig their mouth parts, equipped with two sets of hook-like features, into the wound and feed.

After a certain amount of time, any pathogens in the tick may have an opportunity to migrate from the tick's gut, out of its mouth and into the host through its saliva.

"When that feeding process starts, that kicks off sort of a host of chemical reactions and things both within the tick and within the pathogen," Schiffman said. "So the pathogen has to move out of the mid gut into kind of the broader innards of the tick and then from there, into the salivary glands, and then into the saliva that it's spitting out."

This takes time.

"It varies a bit by pathogen," Schiffman said. "For Lyme disease we say it has to be attached for 24-36 hours. For anaplasmosis and babesiosis it's more like 12-24. When it's only been on you for a short time, your risks are much, much lower."

It is for this reason that simple, instantaneous removal is vital to prevention. No special tools or chemicals are necessary, and can often draw out the exposure time.

Schiffman suggests simply using tweezers to grasp the tick by the head and quickly remove it. Whether the tick appears to have become bloated at all can be an indicator of how long it has been attached.

Symptoms for these illnesses can include fever, headache and fatigue. Each illness comes with a variety of additional symptoms, including a bull's-eye shaped skin discoloration or rash, joint pain, heart and nervous system issues.

Patients who suspect they may have contracted a tick-borne illness should seek the opinion of their physician. The physician will typically do a blood draw for a smear test. Some may prescribe a round of antibiotic doxycycline before the test has been complete out of caution.

Bringing the suspected tick for examination is not typically required.

Tick bites may also sometimes get infected with more typical wound related infections, which can cause inflammation that resembles the other more specific pathogens.

Travis Grimler is a staff writer for the Pineandlakes Echo Journal weekly newspaper in Pequot Lakes/Pine River. He may be reached at 218-855-5853 or travis.grimler@pineandlakes.com.