Deer ticks have become common in Wisconsin in the past two decades. Unlike the wood aka dog tick, these critters are very small, a half mm to a mm in size. They also are active whenever the temperature is over 40ºF so the season extends from March through November. They tend to inhabit grasses rather than brush. Dogs or cats are common collectors of deer ticks and can pass them on to humans.
I have several friends who have become seriously ill from deer tick borne Lyme disease. Lyme disease is a first cousin to syphilis and in advanced stages can cause very serious problems. The current medical belief is that if a tick has not fed for more than 36 hours, the bacteria will not have entered the host. If treated early (within several days after being infected), dioxycycline will prevent the disease from developing. Longer delays require more aggressive treatment. Additionally, once the disease develops, it tends to be chronic.
I get a tick bite requiring treatment about once a year on average. In those cases, the tick has been so embedded that it cannot be completely removed. Interestingly, I had requested that the urgent care physician surgically remove the remnant but was refused. He said, as had others before him, that the tick remnants would slough of in two weeks. In every case that I have had, it took a full six months for the bite to clear up. (the bite that I got on May 5th is still raised after five months.) If there is any possibility that a tick bite has gone unnoticed and not received immediate treatment or any of the common symptoms appear, I would strongly recommend having the test.
The medical profession in Wisconsin is very naive concerning deer ticks and Lyme disease. They are improving but there is still no real consensus as to best practices. For example, the current practice for a recent bite is a single 200 mg dose of dioxycycline whereas the doctor of my friend with the chronic disease recommends 200 mg of dioxycycline for 20 days. The current practice also recommends treatment only if the patient was bitten by a tick from an area known to have Lyme disease and the tick was positively identified as a deer tick, and the tick had been embedded for mor than 36 hours. Getting your health care provider to provide treatment is like pulling teeth but it is in your best interest to insist on it.
Best prevention is to avoid collecting ticks in the first place. I make every effort to stay out of woods and fields. Repellents are recommended. DEET based are used although I don't personally know how effective they are. Permethrin repellents are more effective as they are toxic to the tick but they should be in direct contact with skin. There is a vaccine for dogs but none for humans. Best practices would be to change clothing when in from the field and if practical also examine yourself for ticks. They usually make contact low on the body and work their way up to a feeding site. Sheltered area are preferred although I have had bites on my buttock, in my navel, and in the crook of my arm. An unnoticed bite can result in a bullseye rash although not always. If left untreated, other symptoms include joint pain and headaches. Our dog is on a prophylactic treatment which has so far been effective at keeping him safe. As I recall, we have only found one tick bite in two years and that one was fresh. He is apparently toxic to ticks and fleas.
.Anaplasmosis is another disease which has recently made the scene. It is carried by both the wood tick and deer tick. Our neighbor has contracted that disease, along with Lyme disease and is virtually crippled and undergoing long and expensive antibiotic treatment. Additionally, there have been a few instances of other tick borne diseases lately. I believe that Rocky Mountain Spotted fever has been found in Wisconsin as has the Heartland disease carried by the Lone Star tick.