May 14, 2020 at 8:29 p.m.
Springtime is tick time in the Northwoods
Springtime is tick time in the Northwoods
These creepy crawlers were the topic of PJ Liesch's recent presentation "Wisconsin Ticks." Liesch is the director of the UW Insect Diagnostic Laboratory.
According to Liesch, there are three main types of ticks in Wisconsin, all of which are arthropods, not insects. This means they are in the same family as spiders, centipedes and millipedes. They are invertebrates with a hard exoskeleton. They have eight legs at most life stages, although they emerge with only six.
Ticks follow a three-host life cycle. In their larval stage, they attach to a small host such as a rodent. They take one blood meal from that host, then drop off. Their second feeding is from a larger mammal, and the third from a mammal such as humans, pets, deer and larger animals. Ticks, he said, only take in three blood meals over the course of their two-year life cycle.
He also debunked some common myths about ticks.
For instance, ticks cannot jump or fly and they do not climb trees. Climbing high into a tree would likely be suicide for tick, he said.
One of the big issues for ticks far away from the ground would be the possibility of drying out. This is call desiccation. Ticks, he said, do move up onto low-growing shrubs and grasses, waiting for a host to happen by and brush against that vegetation. If a tick starts to dry out at that low height, he said, it can simply drop to the ground and find moisture to keep itself from drying out.
Ticks will wait on that low hanging vegetation until a likely host brushes by them. From there, Liesch said, it takes a tick minutes to hours to actually attach to the host. Then the tick typically remains attached for up to a week.
Ticks, he said, do not actually bury themselves in their host, but do attach only by their mouth parts.
While most residents see ticks in spring, they can be found in the state year round. Ticks overwinter in the leaf duff beneath the snow where they are insulated from the harsh winter conditions. Even in January, Liesch said, ticks can be encountered. If temperatures are above freezing and there is a lack of snow, ticks can and do emerge.
Ticks of Wisconsin
Although there are a total of 20 tick species in Wisconsin, there are three that are of main concern to humans. These species are the American Dog Tick (wood tick), the Lone Star Tick and the deer tick. Lone star ticks, Liesch said, are fairly rare in Wisconsin and tend to be a southern tick. It is unclear how these ticks make their way this far north, but one hypothesis is they hitch a ride on migrating birds.
While rare, the Lone Star Tick can cause some health concerns. One of the diseases carried by Lone Star ticks is Ehrlichiosis. This is treated in the same way Lyme disease is treated. These ticks can also cause a person to have an allergic reaction to red meat. In some people the reaction is small, and may not last a lifetime. In others it may last a lifetime. It may also cause anaphylaxis in some individuals upon consumption of red meat.
The wood tick, or American Dog tick, Liesch said, is the tick he would chose to get bitten by, if he had his druthers. They are most active during the warmer months of May to August, as are more ticks. They are not associated with any major diseases in Wisconsin, or in most of the upper Midwest. They have been known to carry Rocky Mountain Spotted Fever and Tularemia, however there have been no cases of either of these diseases linked to wood ticks in the Upper Midwest.
The tick of main concern, of course, is the deer tick. These ticks are very minute, making them hard to spot. They can carry Lyme disease, which is a major health concern for humans. Liesch said 20% of juvenile deer ticks and 40% of adult deer ticks carry Lyme disease. In some areas of the state, such as the western portion near Eau Claire and Chippewa Falls, that percentage can be as high as 60%.
Deer ticks do not have Lyme disease from the larval stage, he said, but instead must take a blood meal from an infected host to become infected. In Wisconsin 70 of our 72 counties have documented deer ticks within the county. Liesch said it is likely the other two counties also have deer ticks, but none have been confirmed.
The first case of symptoms of Lyme disease, he said, was found by a dermatologist, Dr. Scrimenti, in Medford in 1969. However a cluster of juvenile arthritis cases in Old Lyme Connecticut in the 1970s gave the disease its name. The cause was eventually identified in 1982 as being the deer tick.
Deer ticks have been known to carry other diseases as well. Besides Lyme disease, Anaplasmosis, Babesiosis, Powassan virus, and other diseases are known to be carried by deer ticks. Liesch said it is likely there are other diseases that are carried by these ticks, but links have yet to be firmly made.
Peak tick activity periods include spring as well as late summer and fall. At this time of the year ticks are in the larval stage. They will be in the adult stage in fall.
Lyme disease is getting more attention as more is learned about it. More people, as well as medical professionals, have Lyme disease at the top of their minds when they encounter the symptoms. Those symptoms can include aches, joint pain and fever. In approximately 75% of cases, the telltale "bull's-eye rash" is also present. In those cases where the rash is not present, he said, diagnosis is not as quick or easy. Liesch said many people, especially as they age, experience aches and joint pain and may not equate that to a tick bite.
The good news, if there is any, about Lyme disease, is that it takes approximately 36 hours or more for an attached tick to transmit the disease. This makes checking for ticks after outdoor adventures very important.
Prevention
Liesch listed several things people can do to reduce their chances of being bit by a tick. First, clothing choices can be important when going outside. Long sleeves and long pants tucked into boots can help a person spot a tick before it gets a chance to attach itself. Light colored clothing can help in this respect also.
Repellents are a good idea, Liesch said, but people should be sure to follow the manufacturer directions. Some repellents are made to be in contact with skin while others are meant to be applied to clothing. He also said that while homemade repellents are becoming more popular, they are not recommended. Many have no effect at all while others wear off almost as soon as they are applied. The best advice is to purchase an EPA-registered repellent. Repellents such as DEET, Picaridin, IR3535 and Oil of Lemon Eucalyptus are most common. Users should be sure to know how long the protection from any repellent will last and when to reapply.
Another repellent, Permethrin, is a clothing treatment that does a very good job repelling ticks. If ticks come into contact with it for too long, it will kill them. There are some types of clothing, that come with Permethrin woven into the fabric. These were originally developed for military use, but are popular with hunters and other outdoorsmen as well. Regular tick checks after outdoor activity, as well as bathing or showering, accompanied by washing all clothing worn outdoors, is a main line of defense for protection against ticks.
Liesch said not to forget companion animals when it comes to ticks. Dogs and cats can both be susceptible to tick bites. For dogs, there is a Lyme vaccination available, and for both cats and dogs repellents are available. Pet owners should be sure to consult their veterinarian when choosing the correct tick repellent.
Landscape management, too, can help control ticks. Ticks need a moist environment and will not do well in drier, open areas. For instance, they will not do well in turf grass of a common lawn. They tend to collect around the edges of the lawn in thicker vegetation.
Invasive vegetation, Liesch said, should be eliminated especially. Invasive terrestrial species such as honeysuckle thickets and Japanese barberry tend to provide thick habitat for smaller mammals, which are important to the tick life cycle. While these invasive species are detrimental to the environment in many ways, they can also contribute to increased tick activity, he said.
For many, limiting animal habitat is not part of their landscape management plan. In fact, many people look to enhance the number of wildlife in and around their yard. However, Liesch warns, this can increase tick activity as well. Reducing rodent habitat and excluding or discouraging deer, such as by fencing in a garden, can help to reduce ticks on a property as well. This can require a delicate balance for some. For others, with a stronger aversion to ticks, the decision may be more cut and dried.
There are also tick treatments available for landscapes and yards. These are broad spectrum lawn and landscape insecticides. They are generally applied in an 8-10 foot swath at the edge of a lawn near a wooded area. There are many companies that apply these insecticides and usually one treatment in the spring is recommended.
There is also an app called The Tick App, that can be found in cellphone app stores. This app includes not only identification help, but also an opportunity to become involved in a citizen science project, tracking ticks during daily activities. There is also a project specific to pet owners, which can be found at www.thetickapp.org/midwest/pets. For more information, Liesch's full article regarding ticks can be found on the Wiscontext website at www.wiscontext.org/abcs-tick-season-wisconsin.
Beckie Gaskill may be reached via email at [email protected].
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