Mosquito Update 2005
The bloodsuckers are back!
By Dean Traiger MD, aka Doc-Dean
But this year we have a few new tools in our armamentarium. Picaridin and oil of lemon eucalyptus have been recommended by the Centers for Disease Control and Prevention (CDC) for the prevention of mosquito bites. Along with diethyl toluamide, also known as DEET, they are the three agents are currently registered with the U.S. Environmental Protection Agency (EPA) as safe and effective.
For many years, the only CDC-approved agent as a mosquito repellant was DEET. The name "Picaridin" is approved by the World Health Organization, but there is no International Organization for Standardization common name for this substance. Picaridin's other names include KBR3023, Bayrepel, Hepidanin, and Autan Repel.
According to the Journal of Drugs in Dermatology, Picaridin is available in Europe and Australia, and will soon be sold in North America. It is sold in Australia in spray and lotion forms with 92.8 gm/L picaridin as the active ingredient. A formulation with 192 grams/liter is termed Autan Repel Army 20.
Products that contain Picaridin should be on shelves by the time you are reading this, include a 5% cream, a 5% non-aerosol pump spray, and a 10% aerosol spray They will be sold by S.G. Johnson and Sons and will join 200 different formulations of insect repellants (most including DEET) that are sold in the United States. Picaridin has been available outside North America since 1998. Spectrum Brands introduced a picaridin-based repellent in January -- Cutter Advanced. It is the only product that that is immediately available in North America. Others are sure to follow.
Picaridin appears to be less irritating than DEET and additionally DEET has limitations because its high potential to irritate eyes and mucous membranes which makes application to the face difficult.
"Since West Nile virus is present across the entire country (USA – ed. note) at this point and it's here to stay, we constantly need to be vigilant," said Dr. Lyle Petersen, director of the CDC's division of vector-borne infectious diseases. "It gives consumers a better option to protect themselves."
The CDC says picaridin is "often comparable with DEET products of similar concentration" and oil of lemon eucalyptus provides protection time "similar to low-concentration DEET products in two recent studies." At concentrations of 19%, picaridin provided protection for up to eight hours, similar to a 35% long-acting DEET product. Cutter Advanced with picaridin probably needs to be reapplied more often. Most products containing oil of lemon eucalyptus that are sold in the United States have not yet been standardized to determine the appropriate concentration for best and longest effectiveness against mosquito bites. Commercial products in Europe and Australia claim protection up to six hours with a single use.
Spectrum Brands has also been marketing a repellent with oil of lemon eucalyptus since 2002. The products claim four to six hours of protection.
DEET can be applied to young children over the age of two months. In general, weaker concentrations should be used unless the area is heavily infested, especially when there is concern about malaria, West Nile virus or other mosquito-borne infections.
Products containing oil of lemon eucalyptus have labels that state the product should not be used in children under 3 years of age. I could not find a specific problem with oil of lemon eucalyptus in children. The caution exists because its safety has not been studied.
I had difficulty locating any safety recommendations on Picaridin but this is from the product label of Bayrepel: “Special toxicology tests have shown that BAYREPEL®is safe to use during pregnancy and breast-feeding. BAYREPEL®was tested in collaboration with the EPA, so products containing BAYREPEL®are safe to use. The tests produced no negative results, so it can be assumed that BAYREPEL®is safe in toxicological terms.”
Consumers tend to like picaridin repellents because they are more pleasant to the skin and don't have the odor that DEET repellents have. And oil of lemon eucalyptus is a natural ingredient, which appeals to those who don't like the thought of putting chemicals on their skin, said Angela Proctor, a product manager for the Cutter line of insect repellents by Spectrum Brands.
Various levels of DEET appear in the popular Off! lines by S.C. Johnson & Son Inc., including Deep Woods and Skintastic. Other brands such as Repel and BugOff! have lately launched products without DEET.
Expect to see an explosion of new products containing picaridin and lemon oil of eucalyptus come to market during the next few years. Also, more studies will be performed to determine relative effectiveness of the three compounds, how often they need to be reapplied, and their safety in children.
Finally, I want to add: No product, even if applied correctly, will provide complete protection, so avoiding mosquitoes altogether is the best strategy.