Tick surveys in Minnesota show that those state residents, as well as North Dakotans, may face a higher risk of contracting Lyme disease and other tick-borne diseases this year.
The deluge of rain in many parts of the Midwest coupled with possible hot weather later in the summer can contribute to favorable conditions for ticks and mosquitoes.
“What we’ve seen so far is high numbers of black-legged ticks,” said Dave Neitzel, the supervisor of the vector-borne diseases unit of the Minnesota Department of Health. “Given the number of ticks we’re finding out in the field, we wouldn’t be surprised to see more cases of these diseases.”
Black-legged ticks, also known as deer ticks, are the primary carriers of Lyme disease. Adults come out as soon as the snow melts, and the nymphs, or young ticks, arrive in mid-May and early June. Most tick-borne diseases are transmitted by nymphs.
“If you’re able to find a tick on you quickly, you can prevent disease transmission. It takes one to two days for the tick to transfer the Lyme disease bacteria to its host,” Neitzel said. “But the nymphs are so small that they’re hard to see.”
Neitzel recommends using insect repellent that contains DEET and permethrin-treated clothing to deter ticks.
“Nothing’s 100%,” he said. “So we recommend people do a thorough tick check.”
These tick checks are most important after someone walks in wooded areas, especially in mid-June through mid-July, which is when the peak of tick season occurs.
The most distinctive symptom of Lyme disease is a rash that is usually bull’s-eye-shaped, though not every patient will have the rash. Other common symptoms in the early stages of the disease include fatigue, headache, fever, stiff neck and sore muscles and joints. If left untreated, the disease can progress. The rash can spread, and the patient may face complications, such as meningitis, partial paralysis of the facial muscles and heart problems.
The CDC estimates that more than 300,000 people are diagnosed and treated for Lyme disease every year and the total cost for testing for Lyme disease is $492 million.
While the black-legged tick is the Department of Health’s main concern, the American dog tick, or wood tick, can transmit diseases, including Rocky Mountain spotted fever and tularemia, or rabbit fever.
Mosquito season begins at about the time the tick season ends. The population begins building in mid-June and peaks in July and August. Sometimes, mosquito season lasts until September.
“It’s too early to say how bad the mosquitoes will be,” Neitzel said. “If we have an extended stretch of hot weather, we are more concerned. Hot weather leads to the amplification of the mosquito population and the disease (West Nile virus).”
West Nile virus is Neitzel’s primary concern, and North Dakota and Minnesota are in one of the highest risk areas for the disease. But, Todd Hanson, the manager of Grand Forks Mosquito Control, said that Grand Forks has not identified West Nile virus in the area this year.
“More rain equals more mosquitoes, but we find hot and dry years have more cases of West Nile,” Hanson said. “The cooler spring has helped us out.”
Grand Forks runs a comprehensive mosquito control program, which includes the use of pesticides that target adult mosquitoes and larvae, surveillance of mosquitoes and testing specific mosquito species for West Nile.
The best way to prevent West Nile is to apply mosquito repellent with DEET, dump out or change standing water on property, wear proper clothing and avoid going outside in the evenings and early mornings, if possible, Hanson said.
“Mosquitoes can reproduce in containers as small as a bottle cap,” Hanson said.
Hanson warns that people older than 60 and those with other health issues or compromised immune systems should be extra wary, because they have a higher chance of contracting the more severe form of the virus.