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Re: NPR: permethrin + DEET a bad idea



Josh and All,

I heard the NPR story. What it is very important to remember, when 
talking about using permethrin as a tick repellent, is that it IS NOT to 
be used on the skin! Permethrin as a tick repellent is applied to the 
field clothing and the spray allowed to dry. Once it has dried, the 
active insecticidal ingredient is bound to the fibers of the clothing 
and will not move to the skin, hence, no exposure. The specific use 
pattern the Duke researcher talked about was permethrin formulated for 
application to the hair and scalp for lice control; in this instance, 
you would be exposed directly to the active ingredient and would 
experience a "double exposure" if you then applied DEET. If you recall, 
the researcher also strongly advocated a personal "risk/benefit" 
assessment; he specifically said that the hazard posed by disease 
transmitting arthropods could well outweigh the small risk associated 
with occasional use of DEET or other materials.

Having once experienced the pleasures of Rocky Mountain Spotted Fever, I 
for one will continue  to treat my field clothes with permethrin, and 
when the skeeters are bad, I'm going to use DEET, too. It is still the 
only really effective mosquito repellent. The Duke researcher's other 
recommendations, to use lower strength DEET formulations and to avoid 
frequent reapplications, are prudent. As with all pesticides, it is 
critical to read the label and follow the directions!

On the bird front, I saw a Mississippi kite on 64 near Tarboro yesterday.

Take care,

Clyde Sorenson
Dept. of Entomology
NCSU and Calyton, NC
clyde_sorenson@ncsu.edu

Joshua Stuart Rose wrote:

>Hi Carolinabirders,
>
>When the first few ticks of the year appeared in the Piedmont tragically
>early this past spring, we had a brief discussion here on Carolinabirds
>about tick repellent. I seem to recall someone recommending permethrin.
>There was just a story on the local NPR affiliate, WUNC, today, "The State
>of Things", discussing mosquitoes, mosquito-borne diseases, and
>repellents. One strong recommendation from the expert who was being
>interviewed, a researcher from the Duke U. Medical Center who was working
>with the military, was that permethrin should ***NOT*** be combined with
>DEET! Apparently the two chemicals in combination have effects far more
>severe than either individually, and the Dr. hinted that this combo might
>even have been part of "Gulf War Syndrome". Just wanted to get that
>warning out there...
>
>No bird sightings to add, just a Phidippus audax (a really cool jumping
>spider, black with white spots and metallic green mouthparts) on our back
>door.
>
>Good birding,
>
>Josh
>
>
>Joshua S. Rose
>Duke University
>Department of Biology (Zoology, R.I.P.)
>
>jsr6@duke.edu
>http://www.duke.edu/~jsr6/
>
>  
>