Bugs bite. And when they do, they can make us miserable,
itchy, bumpy – and, occasionally, very sick.
With outdoor activity season in full swing, here's what you
need to know.
Insects can carry nasty diseases.
Most people who get a few mosquito or tick bites will not
get sick. But some mosquitoes and ticks can carry bacteria and viruses that
cause serious human illnesses – and some of those illnesses have recently
become more common in the United States.
Take West Nile Virus.
That mosquito-borne illness came to the United States in 1999. Since then, more
than 17,000 cases have been reported, says the federal Centers for Disease
Control and Prevention. While typical symptoms include headaches, joint pains
and rashes, a few people have serious neurologic symptoms and some die.
A newer threat: chikungunya, another viral disease spread by
mosquitoes. In 2014, nearly 2,500 cases were reported on the U.S. mainland,
mostly among people bitten while travelling. But 11 people were infected by
mosquitoes in Florida. While chikungunya rarely kills, it can cause severe
joint pain that lasts for months.
Then there's Lyme disease, caused
by a bacteria spread by ticks. The CDC has been tracking that disease since
1991, and says there are about 30,000 reported cases each year, but that the
real number is likely ten times bigger.
Your risk depends largely on where you live (or travel).
About 96% of confirmed Lyme cases occur in just 13 states,
clustered in the Northeast and Midwest, CDC says.
And the mosquitoes that carry chikungunya are tropical
species, meaning only southern areas need to watch for local outbreaks, says
Jonathan Day, a professor of medical entomology at the University of Florida.
The fact that people in the United States spend so much time inside, with air
conditioning and screened windows, may help prevent big outbreaks, he says.
Mosquitoes that can carry West Nile do live throughout the
United States. But local conditions determine where epidemics catch fire, Day
says. For example, a 2012 outbreak near Dallas was spurred by drought – which
caused virus-carrying mosquitoes and birds to cluster around scarce water
sources. Another outbreak in Arizona was linked to un-drained swimming pools in
foreclosed houses abandoned during the recession, he says.
Some people get bit more than others.
It's true: mosquitoes and ticks find some people especially
attractive. Scientists disagree on the reasons.
Day says he is convinced it's mostly about carbon dioxide:
mosquitoes and ticks find their victims by detecting it and some of us produce
more than others. That includes heavier people, pregnant women and exercisers.
"The amount of carbon dioxide you produce depends on your metabolic
rate," he says.
But Uli Bernier, a research chemist for the U.S. Department
of Agriculture, says he has seen evidence that other factors are at work over
many years of exposing people to mosquitoes in his Gainesville, Fla., lab. He's
seen different mosquitoes zero in on different people. He's also found that
some people (himself included) seem to become more attractive to mosquitoes
over time.
What you eat and drink may matter, Day and Bernier agree.
Alcohol, in particular, seems to attract mosquitoes, they say. At least one
study also suggested smokers were at higher risk – but probably because they
spend so much time smoking outside, Day says.
Several repellents work well.
CDC says you want one that includes DEET
(N,N-diethyl-meta-toluamide), picaridin, oil of lemon eucalyptus or a chemical
called IR3535.
While DEET products have long been thought the most
effective, recent tests by Consumer Reports gave the edge to picaridin and oil of lemon eucalyptus.
"It was really a surprise," and should be good
news to people uneasy with the possible side effects of DEET, says the
magazine's senior health and food editor, Sue Byrne.
DEET has been linked with seizures and other serious side
effects, mostly in people who swallowed it or applied heavy concentrations.
When used as directed, it's safe, Bernier says: "It's
been around 63 years and has a remarkable safety record."
Other strategies can help.
Wear long sleeves, pants, closed shoes and socks for a walk
in the woods. You also can also spray a repellent called permethrin on clothing
and gear. And check yourself for ticks when you go inside.
For an evening on your patio, try this: sit next to a fan
running at high speed. Consumer Reports found that helped repel mosquitoes, and
Day says it makes sense: "Mosquitoes do not have an ability to fly in wind
conditions much more than 1 mile an hour."
Here's what doesn't work.
Consumer Reports gave thumbs down to:
"Natural" repellent sprays made with plant oils,
such as citronella, lemongrass, and rosemary
Wrist bands containing citronella or geraniol oil
Citronella candles
- Garlic
- Vitamin B1 supplements
- Bug zappers (they may actually attract insects)
- Ultrasonic devices
FOLLOW US!
