Use Deet Carefully to Repel Mosquitos

Jun 14, 2024, 12:03 PM by Department of Pediatrics


It’s that time again.  After all the heavy rains to the north and the high tides, mosquitos are back. According to an article by Dr. Bonnie Wood, Director of the Houston Travel Clinic there are over 3700 types of mosquitos worldwide.  Over 200 types have been documented in the US.  Fortunately, only 12 are associated with transmitting disease.   It is hard to tell the difference between which one can carry a disease and which one does not, so it is better to prevent any bites. Unfortunately the ones that do carry disease are usually tiny, their sting goes unnoticed and they don’t have the warning buzz.

Transmitted diseases found here are the following.  West Nile Virus (WNV) has been found across North America and in every continent but Antarctica.  Less than 1% develop encephalitis which can lead to permanent neurologic disorders.  There is no vaccine or specific treatment.  Dengue is found across Asia, Africa and the Americas.  In the US it is primarily in Puerto Rico, the US Virgin Islands but has been reported in Texas.  Dengue symptoms can range from mild to hemorrhage and shock.  Treatment is supportive.  There is a vaccine Dengvaxia but its use is not available on mainland US.  Chikungunya (CHIKA) is another mosquito-transmitted disease which is prevalent in tropical Africa, Asia, Central and South America.  It has been reported in Florida and Texas.  It causes chronic or recurrent joint pain in almost ½ of the adults infected.  The care is supportive. There is a vaccine for those over 18 and traveling to places where there is an outbreak.

Climate change will affect where these diseases break out and change in their virulence.  The most important remedy is to prevent the disease from happening. The first step to prevent mosquito bites is to check the area around your home for cans, pails, or any container that may hold stagnant water. Dispose of all possible holders of stagnant water.  Keep children in during the early morning and evening hours. Dress children in light colored, long sleeve and long legged clothing.  Avoid floral scents, use unscented soaps, no perfumes or scented lotions.

DEET functions to produce a vapor layer distasteful to mosquitoes. The American Academy of Pediatrics recommends that DEET should not be used on babies under the age of two months.  Older children can use DEET concentrations up to 30%.  The higher the concentration the longer it last.  A percentage of 10% will last about 2 hours.  Apply only to exposed skin but never around eyes, lips or on toddler’s hands and only once a day.  Put repellant on your hands to apply to skin close to the face.  Avoid pressurized sprays to avoid inhaling it.  Do not use products that combine DEET and sunscreen.

Products containing permethrin can be sprayed on clothing, sleeping bags, and tents but never on skin.

Prevention, as always, is key.  At present these disease are rare.  Children are in more danger without protective gear on skates, bikes or scooters.

by Sally Robinson, MD Clinical Professor
Keeping Kids Healthy
Published 5/2023

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