The emergence of
the Zika virus means avoiding mosquito bites is
more important than ever. The Centers for Disease
Control recommends using an effective
insect repellent, such as DEET or Picaridin. But another option
they recommend is wearing clothing
that has been factory treated with the
insecticide Permethrin. The process was created
for the US military where Permethrin treated
combat uniforms have helped protect soldiers from
insect borne diseases, like malaria and West Nile
virus, since the early 1990s. But in recent months,
sales of Permethrin treated civilian
clothing has jumped as concern about Zika
carrying mosquitoes grows. One manufacturer has even
launched a line of Permethrin treated maternity clothing. But is Permethrin treated
clothing effective? We tested three different
Permethrin treated shirts from two different
manufacturers, an L.L. Bean crew shirt made by
Burlington and two ExOfficio shirts, the BugsAway
Breez’r and the Talisman, both made by Insect Shield. All three shirts come
embedded with 0.52% Permethrin and claim to
last through 70 washes. We wanted to see how
these products performed new and after being
washed 25 times. As a control, we also tested
three untreated shirts, and one we sprayed
ourself with 30% DEET. Testers put their arms into two
separate cages filled with 200 disease-free mosquitoes. The untreated shirts provided
almost no protection from bites by hungry mosquitoes. All of the Permethrin
treated clothing incapacitated or
killed mosquitoes that landed on the
shirts, but in some cases that knockdown didn’t
happen quickly enough to prevent all from biting. None of the testers were bitten
when wearing the new L.L. Bean shirt, but after the
shirt had been washed Aedes mosquitoes, the kind that
carry the Zika virus, bit three out of four testers. With the ExOfficio shirts,
both new and washed, all four testers received
bites from the Aedes mosquitoes as well as the kulaks mosquitoes
that can carry West Nile virus. Consumer Reports
contacted the companies that make the Permethrin
treatment, Insect Shield and Burlington. Both cited formal
studies and field testing data to underscore
the effectiveness of their products. But there’s another way
to keep bugs from biting. According to the
CDC, any repellent that works on your skin
should work for just as long when applied to clothing. With the DEET treated
shirt we tested, neither kind of mosquito
landed on the arm, and therefore there
were no bites. Ideally, clothes should be
sprayed before you put them on and allowed to dry
for 30 minutes. The best repellents will keep
you protected from mosquitoes for at least seven hours. To see all the results
of our most recent insect repellent testing, check
out www.consumerreports.org.