As the weather warms up and the grass gets greener, inviting residents of Cavalier County out to play, a threat looms on the blades of grass and on branches.
By Melissa Anderson
Tick season has officially started, and residents are encouraged to be aware of a new tick-bourne disease that can be deadly.
Powassan or POW virus is transmitted to humans by infected ticks. Approximately 75 cases of POW virus disease were reported in the United States over the past 10 years with most cases occurring in the Northeast and Great Lakes regions. From 2006 through 2015, Powassan virus neuroinvasive disease cases have been reported in neighboring states of Minnesota and Wisconsin, with 20 cases occurring in Minn. and 16 in Wisc. The North Dakota Department of Health (NDDH) has had the Powassan Virus listed as a mandatory reportable condition since 2011.
“There are different species of ticks that can carry various tick-borne pathogens present throughout North Dakota, I recommend that all North Dakotans take precautions against tick bites. For the same reason, those who travel to Minnesota should also take precautions against tick bites,” Laura Cronquist, an Epidemiologist with the NDDH, advised.
Three species of ticks are found in North Dakota: American dog tick, Rocky Mountain wood tick, and winter tick. Of these, American dog tick is the most common species. Lyme disease and Powassan virus are typically carried by the black-legged tick, also known as deer ticks. Fortunately, the black-legged tick does not occur naturally in North Dakota, but during a 2010 study conducted in nine counties across the state, six of the counties including Grand Forks, Pembina, Eddy, Ramsey, Steele, and Rolette had the species.
“We know that there are established populations of black legged tick, the carrier for Powassan virus, in northeastern North Dakota,” Cronquist said.
The NDDH is currently working with veterinarians and zoos throughout the state to collect ticks for their Tick Surveillance Program. The ticks will be tested for various tick-borne pathogens, including Powassan virus.
“Regardless of whether or not we find evidence that the deer ticks in North Dakota are infected with Powassan virus, it’s important to keep in mind that ticks can also transmit other serious, sometimes potentially fatal, diseases,” Cronquist stated.
Powassan (POW) virus is related to West Nile, St. Louis encephalitis, and tick-borne encephalitis viruses. Humans become infected with POW virus from the bite of an infected tick. One aspect of this disease that is good news is that humans do not develop high enough concentrations of POW virus in their bloodstreams to infect feeding ticks. Humans are, therefore, considered to be “dead-end” hosts of the virus.
POW virus is maintained in a cycle between ticks and small-to-medium-sized rodents. While the three species of ticks that carry the disease feed on an assortment of small animals, it is the black-legged tick feeding on infected white-footed mice that is the primary means of humans becoming infected.
There are no vaccines or medications to treat or prevent POW virus infection. Many people who become infected with Powassan (POW) virus do not develop any symptoms. The incubation period (time from tick bite to onset of illness) ranges from about one week to one month.
Signs and symptoms of infection can include fever, headache, vomiting, weakness, confusion, seizures, and memory loss. Of those who develop symptoms, approximately half will have permanent neurological symptoms, such as recurrent headaches, muscle wasting and memory problems. In the extreme cases of POW infection, 10 percent of POW virus encephalitis cases are fatal.
There is no specific treatment, but people with severe POW virus illnesses often need to be hospitalized to receive respiratory support, intravenous fluids, or medications to reduce swelling in the brain.
This summer and every summer, it is important to remember to practice personal protective measures against ticks.
• Use Environmental Protection Agency (EPA)-registered insect repellent and always follow label directions.
• Use products that contain permethrin on clothing and gear such as boots, backpacks and tents.
• Wear light-colored clothing to make the ticks easier to see.
• Wear long pants, and tuck the legs into your socks or boots.
• Keep your shirt tucked in.
• Carefully examine gear and pets for ticks.
• Place clothes in a dryer on high heat for 10 minutes to kill ticks on dry clothing after you come indoors.
• Be sure to check your clothing and body carefully for ticks when you’ve been outdoors.
• Bathe or shower as soon as possible after coming indoors (preferably within two hours) to wash off and more easily find ticks that are crawling on you.
“The key to preventing tick-borne diseases, such as Lyme disease, anaplasmosis and Rocky Mountain spotted fever, is to avoid tick bites and find and remove ticks promptly,” Cronquist said. “Areas that are heavily wooded or have tall grass or brush are more likely to be infested with ticks, especially between April and September, with the highest risk of disease transmission occurring during the warmer months.”
The best way to prevent tick infestations around the home is by keeping lawns mowed at a height of 3 inches or less and removing high grass, weeds, leaf litter, and undergrowth near the home. Property that borders woodlots typically presents the most risk, with tick numbers generally declining as you move farther from the woods.
Wild animals such as deer, birds, and mice along with domesticated animals can transport ticks long distances and bring them into your yard or home. It is important to thoroughly check your pets after time spent outdoors.
To remove an imbedded tick properly, use fine forceps and grasp the capitulum (head) as close to the wounds as possible, and then apply a steady upward force until the tick is free. If part or all of the mouthparts (hypostome) remain in the wound, it can be treated as a sliver.
Do not use petroleum products to remove a tick, squeeze the body, or heat the tick with a match as this can cause the tick to release the contents of its stomach into the bite point and increase chances of infection in the host.
If you think you or a family member may have POW virus disease, it is important to consult your healthcare provider.