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Centers for Disease Control
Ticks
Don’t panic – the images of these ticks are much enlarged, as you can tell by the comparison to the dime at top. The blacklegged – or “deer” – tick can carry Lyme disease and other maladies, which it acquires by feeding on infected animals. Dog ticks, found in much of North America, do not carry Lyme.
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Mapping the Blacklegged Tick
The range of the blacklegged tick (deer tick) in our region as mapped by the U.S. Centers for Disease Control. Ontario also has the ticks.
In our North Woods, ticks and mosquitoes are an unfortunate – and all too abundant – part of the outdoor experience. These blood-sucking creepy-crawlies may even carry diseases, but a few simple precautions can keep them at bay.
“Primarily we just see the tick-borne illnesses,” says Sarah Waby, infection preventionist at Memorial Medical Center in Ashland, Wisconsin. She adds that most common is Lyme disease, carried by Ixodes scapularis, the blacklegged tick, popularly called a “deer tick.”
After a 3- to 30-day incubation period, Lyme disease manifests as the characteristic “bull’s-eye rash,” Sarah says, “or often just a red area where a tick was implanted.” Symptoms include fatigue, fever, headache, joint and muscle pain, and swollen lymph nodes. Ehrlichiosis, anaplasmosis and babesiosis share many of the same symptoms and are often co-transmitted with Lyme. All four diseases can be debilitating – even fatal – if not treated with antibiotics.
“A vaccine is something they’re looking at,” Sarah says, “but nothing is available. It would be nice to not have the threat of the Lyme when enjoying the outdoors.”
But preventive measures work almost as well. Avoid thick brush and high grass, wear long pants and long-sleeved shirts, and use bug repellent with DEET. After returning from the outdoors, thoroughly inspect yourself – and any pets that accompanied you – for ticks. The risk of human infection is greatest in late spring and summer, according to the Centers for Disease Control and Prevention.
A tick must be attached to a human host for 36-48 hours before it transmits a disease. So long as the tick is removed promptly, the risk of contracting an infection is minute. Use a set of tweezers to “grasp the tick as close to the skin’s surface as possible” and “pull upward with steady, even pressure,” according to the CDC.
In Minnesota, tick-borne disease is less common on the North Shore than other parts of the state. In all, Minnesota reported 1,185 confirmed cases in 2011, the latest year of data. Northwestern Wisconsin is one of the highest-risk areas in the state, and Wisconsin reported 2,408 cases statewide in 2011. Michigan had just 89 confirmed cases in 2011. On the Ontario side of the Lake, no Lyme cases were reported that year.
Neither Rocky Mountain spotted fever nor tularemia, both carried by American dog ticks in other U.S. regions, have reached the Big Lake. Dogs ticks do not carry Lyme disease or the other maladies transmitted by blacklegged ticks.
The Lake Superior region sees only a handful of West Nile virus cases annually. The illness, carried by mosquitoes and widespread in other parts of the United States and Canada, results in flu-like symptoms that can be dangerous for the young and elderly, but 80 percent of people bitten by an infected mosquito never develop symptoms, according to the Minnesota Department of Health.
Tests in the Thunder Bay district in 2008 found that a mere 0.6 percent of the district’s mosquitoes were of a species capable of transmitting the virus. No cases were reported in northwestern Ontario in 2011.
Protecting Pets against Lyme Disease
Our furry friends are vulnerable to bug-borne diseases, too, and they’re especially vulnerable to deer ticks, which can carry Lyme disease and anaplasmosis.
At the Duluth Veterinary Hospital, owner Steve Schuder says he sees more than 200 cases of Lyme disease in dogs every year. “We see almost as much anaplasmosis as Lyme,” he adds. “We’re seeing more and more tick-borne diseases.”
Like humans, dogs pick up ticks in wooded, brushy areas, often from low-lying vegetation and shrubs.
Dogs infected with Lyme disease can experience a painful swelling of the joints and sudden lameness, says Steve. An infected dog might have a low-grade fever and stop eating. Antibiotics are usually effective. Kidney failure and heart block can occur in late-stage cases.
Anaplasmosis, a disease that affects blood cells and platelets, is marked by a high fever, lethargy and swollen joints. It’s frequently transmitted along with Lyme disease and responds to similar antibiotic treatments.
As a preventive measure, Steve recommends once-a-month products like Frontline or Vectra, which repel and kill ticks before they can infect the animal. Ticks need at least 12 hours attached to a dog to transmit anaplasmosis, and twice that for Lyme. A Lyme disease vaccine is available for dogs.
Cats rarely contract tick-borne diseases, but outdoor cats – like dogs – can pick up ticks and bring them into the home. After an outing in the woods, remember to take a few minutes and inspect your pet before you cuddle up. You’ll both be thankful for it.