MARQUETTE - Mosquitoes and ticks are more than just a nuisance; they also spread disease. In a year like this, avoiding these pervasive blood-suckers can be a challenge, but there are steps people can take to keep themselves, children and pets safe from the risks and the annoyance.
"This was probably a perfect year for mosquitoes in general, as a group of organisms," said Northern Michigan University professor and entomologist Roger (Mac) Strand. "The last two years have been really big years as a result of really wet springs...I've heard old-timers say this is the worst mosquito year they've ever experienced."
With no reported cases of West Nile Virus, disease-transmission is not a huge concern for mosquitoes in Michigan this year. But deer ticks have seen a population explosion, along with instances of Lyme disease.
Deer ticks, about the size of a sesame seed, live in grass and shrubs close to the ground, like what’s seen above. Wear clothing with plenty of coverage when spending time in tick habitats, and thoroughly inspect skin and clothes afterwards. (Journal photo by Mary Wardell)
A female mosquito takes her blood meal from the neck of Marquette resident Jonas Greenberg. After this single meal, female mosquitoes find a pool of standing water to lay their eggs. (Journal photo by Mary Wardell)
Strand said when he began studying deer ticks as a graduate student in 1989, they were limited to a fairly small population in Menominee County. Now, they've spread northward and are found across the Upper Peninsula in grassy, shrubby areas close to the ground.
"(The reason) is really hard to pin down, but it seems as though it might be a climate change story," he said. "They've also moved west, just expanding in very rapid fashion...In the early life stages - larval and nymph- they usually attach to little rodents, so they're not getting very far. But in the adult stage, it would be on something like a deer, something highly mobile, so it also has to be linked with their hosts."
According to the Centers for Disease Control, Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of infected black-legged ticks. Typical symptoms include fever, headache, fatigue and a characteristic skin rash called erythema migrans. If left untreated, infection can spread to joints, the heart and the nervous system. Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics.
Dr. Terry Frankovich, health department medical director for four U.P. districts including Marquette County, said recommended methods of prevention include avoiding high exposure times, which are dusk to dawn; wearing long, loose clothing; reducing habitats in yards; inspecting bodies and clothing for prompt removal and using insect repellant.
"We're talking about deer ticks, specifically. Wood ticks are much easier to see, but deer ticks are small - about the size of a sesame seed when not engorged," Frankovich said.
Ticks are often carried in on articles of clothing and pets, who should be inspected regularly, she said. Clothing can be put in the dryer on high for an hour to kill unseen ticks.
"Generally, if the tick is not attached for at least 24 hours, there's very little risk of transmitting Lyme disease," Frankovich said. "So identifying a tick early and removing it is very helpful."
When inspecting for ticks, she said to look in all the "nooks and crannies" - under arms, behind ears, in hair and between legs. To extract, use fine-tipped tweezers and pull straight out without rotating or turning. Monitor for symptoms of Lyme disease over subsequent weeks.
To reduce tick habitats around the home, she said to make sure grass is cut and play areas are away from shrubbery and greenery if possible.
Preventing mosquito populations, on the other hand, involves emptying or covering any and all standing water. This is where mosquito females lay - depending on the species - anywhere from dozens to hundreds of eggs at a time after their blood meal, Strand said.
"Warm days speed up their development. So the accommodation of warm and wet is going to make for really rapid population growth of the kind of mosquito you find in your backyard," he said. "Just a week or two weeks of warm weather could produce a new generation of mosquitoes."
Things like bird baths, wheel barrows, flower pots, tires and rain barrels need to be either covered or routinely dumped and sprayed to avoid stagnant water.
Insect repellant can be used for mosquitoes, flies and ticks, with varying degrees of efficacy, Frankovich said. For longer periods of exposure, products with a 20 percent concentration of Deet are recommended by the CDC to avoid the need for frequent reapplication. Other effective ingredients recommended by the CDC are picaridin, IR3535 and oil of lemon eucalyptus. For clothing only, a repellant called permethrin will last through several wash cycles, Frankovich said.
It is very important to read the labels and recommendations for all of these products to know how often to reapply and what ages are safe, she said. Avoid products that mix repellant with sunscreen, because they may need to be reapplied at differing intervals, and Deet can be harmful when applied too frequently.
A number of local retailers have actually reported difficulty keeping repellant on the shelves, so shoppers have had to wait or order it online. One store manager said demand has been so high, they have doubled and tripled their orders.
When all else fails, of course, there are predators that work on lowering mosquito populations naturally.
"Fish and aquatic insect predators will eat the larval mosquitoes," Strand said. "For adults, any insectivorous bird might eat mosquitoes...It's always a good sign if you have a lot of dragon flies - you can be sure that they're doing their part."
And, of course, spiders, especially the web-spinners.
Mary Wardell can be reached at 906-228-2500, ext. 248. Her email address is email@example.com.