Mosquito bites are nothing unusual for Minnesotans. The pesky insects simply come with the territory.
However, a small number of those mosquitos carry dangerous viruses, and after a frightening sequence of events late this summer, Justin Wirth of French Lake Township learned from the Minnesota Department of Health last week that his 3-year-old son Emery had experienced a bout with the rare La Crosse Encephalitis.
The family had been boating in the Whitefish chain of lakes area when Justin noticed that something was wrong.
"He starting having these very pinpoint seizures," said Justin. "I’m actually a Registered Nurse so I was able to identify them, but it was nothing more than some twitching of the eyes and kind of a glazed stare."
They quickly returned to shore, Emery was transported by ambulance to Nisswa, and doctors sent him on to Brainerd for an airlift to Children’s Hospital in the Twin Cities, where he remained for six days until his blood counts returned to normal.
Because of the incubation period for the virus, it is believed that Emery received the bite while at home in Wright County during the first week of August. Doctors have been running tests for the past several months – a process delayed by the government shutdown - and Justin was informed on Friday, Nov. 8, that La Crosse Encephalitis was behind the event.
Cause for concern?
Dave Neitzell from the Minnesota Department of Health said such cases are rare, with an average of just six reported each year around the state. Emery was the fifth reported La Crosse Encephalitis case in 2013.
The location of his probable infection in western Wright County is unusual, since the virus has traditionally been found along the Mississippi River valley in the upper Midwest, but it does continue a trend of slow westward expansion.
"It’s been a more recent phenomenon," said Neitzell. "There has been a hotspot around the Lake Minnetonka area, and in the past few years we’re starting to see cases out to the west a little bit. If this isn’t the farthest west we’ve seen it’s pretty close."
Neitzell didn’t believe this was the first Wright County case, but he did say area residents should take proper precautions starting this fall.
La Crosse Encephalitis is primarily carried by the tree hole mosquito, a breed that favors wooded areas and originates in hollow spots on trees or in man-made objects such as tires or buckets that contain stagnate water. Unlike most mosquitos that are most active in the morning and evening, tree-hole mosquitos are most active during the day, though they rarely venture much farther from their breeding ground than a few hundred yards.
"When people have these mosquitos they are pretty local, right around their homes," said Neitzell.
The Minnesota Department of Health visited the Wirth property to search for tree holes and any containers holding standing water, and recommended that hollow places be filled with sand.
"It’s uncommon, but it’s potentially severe and it’s easy to prevent, so we want to make sure people know that," said Neitzell. "Just real simple cleaning up of water holding containers can easily prevent this illness."
Potentially deadly
While chances of contracting the virus are rare, the potential effects, particularly for children, can be serious.
Neitzell said most infected adults can fight off the virus without experiencing symptoms, but about 1 percent of those infected will die. The risk is greater for children.
"This is a disease that mainly affects children," said Neitzell. "Our average case age is 6 years old. About one-third of the kids infected will have long-term nervous system problems after the infection. When you have swelling on the brain, depending on where the swelling is and how long it persists, you can have varying degrees of damage. Some kids make a complete recovery, but others have long-term problems related to that infection."
Fortunately, Justin said that Emery seems to be on the way to a full recovery.
"He’s back to his normal self. His immune system is not as good as it was, but it’s normal for the immune system to be taxed for about a year afterward until they can fully recuperate," said Justin. "As far as his mental status, I think he’s back to his usual self."
Neitzell said that children infected with the disease will display fairly obvious symptoms.
"It usually starts as a high fever and headache, and then rapidly progresses into disorientation and seizures. With severe cases you can tell that your child is in rough shape and needs to be seen by a doctor right away," he said.
Prevention can include the usual anti-mosquito measures such as spray with a DEET content of 30 or spray that contains picaridin, long sleeves, etc. But Neitzell said property owners can act now to prevent problems next summer.
"The mosquitos are pretty much gone for the year, but the breeding sites are still there. With all the leaves coming down and vegetation dying back, you can really see those containers and tree holes now," he said. "If you clean up your yard and your neighbors clean up theirs, the chances of this virus being around are pretty slim.
"The best prevention is just to make sure you’re not producing mosquitos in the first place."