All You Ever Wanted to Know About Insect Repellents
Mosquitoes are more than a nuisance! They excel in introducing and carrying various diseases. Malaria, Dengue Fever, West Nile Virus infection, Japanese encephalitis, and many other viruses are all carried and introduced into humans by the pesky mosquito. Wearing long clothing is not always a comfortable proposition in hot climates. Applying an Insect Repellent is a crucial part of protecting yourself and your children. But what are the most effective insect repellents? How to choose one among various that are available? And can they be used without harm to infants or small children?
DEET is an acronym for one insect repellent (not to be confused with DDT) and is one of the most common insect repellants in commercially available products. It repels a variety of mosquitoes and biting insects. It is available in formulations of 5%-40% and 100%. DEET products less than 20% effectively repel insects for only 1-3 hours, and then must be re-applied. Higher formulations can provide longer lasting protection, up to 12 hours, but duration of effect reaches a plateau at any concentration higher than 50%, therefore as a general standard all would have to be re-applied at least every 12 hours. The US Army developed a long acting DEET formulation, called Extended Duration Tropical Insect and Arthropod Repellent, and thus referred to as EDTIAR. It contains 25% and 33% DEET but is equivalent an application of 75% DEET and lasts for 12 hours. This product is commercially sold as Ultrathon. In Australia and Europe there is new product, Picaridin, sold as Autan Repel which has performed as well at the US Army EDTIAR. Many other Insect repellents are Citronella-based but provide less than one hour of protection (Skin So Soft Bug Guard). A recently marketed eucalyptus-oil based repellent called Repel Lemon Eucalyptus in a field trial provided 4 hours of effective protection. A soy bean oil based product called, Bite Blocker, was tested and gave only 95 minutes of protection.
Permethrin is a contact insecticide that can be used to apply to clothing, mosquito nets, tents and sleeping bags. It is very effective. Wearing Permethrin-coated clothing and applying a DEET-containing Insect Repellent to exposed skin areas may be the most highly effective way to prevent insect bites.
Safety has been demonstrated for DEET in young children and DEET has been safely used in the second and third trimester of pregnancy. Prolonged use of formulations above 50% or heavy application of DEET formulations onto young infants has been associated with some cases of toxicity (ingestion of the DEET repellent in some of these infants may have occurred; please consult your physician when considering your youngest infants). Rashes and Allergic skin reactions can occur with DEET but are uncommon High formulations of DEET can damage clothing made of synthetic fibers and plastic, eyeglasses, and watch crystals. There have been no serious adverse effects reported thus far with Picardin. Permethrin is toxic to the nervous system but poorly absorbed from the skin, therefore, it should be applied only to clothes, nets, and tents. It does not does not damage clothing.
Mark Siefring M.D. M.S.
Mosquitoes are more than a nuisance! They excel in introducing and carrying various diseases. Malaria, Dengue Fever, West Nile Virus infection, Japanese encephalitis, and many other viruses are all carried and introduced into humans by the pesky mosquito. Wearing long clothing is not always a comfortable proposition in hot climates. Applying an Insect Repellent is a crucial part of protecting yourself and your children. But what are the most effective insect repellents? How to choose one among various that are available? And can they be used without harm to infants or small children?
DEET is an acronym for one insect repellent (not to be confused with DDT) and is one of the most common insect repellants in commercially available products. It repels a variety of mosquitoes and biting insects. It is available in formulations of 5%-40% and 100%. DEET products less than 20% effectively repel insects for only 1-3 hours, and then must be re-applied. Higher formulations can provide longer lasting protection, up to 12 hours, but duration of effect reaches a plateau at any concentration higher than 50%, therefore as a general standard all would have to be re-applied at least every 12 hours. The US Army developed a long acting DEET formulation, called Extended Duration Tropical Insect and Arthropod Repellent, and thus referred to as EDTIAR. It contains 25% and 33% DEET but is equivalent an application of 75% DEET and lasts for 12 hours. This product is commercially sold as Ultrathon. In Australia and Europe there is new product, Picaridin, sold as Autan Repel which has performed as well at the US Army EDTIAR. Many other Insect repellents are Citronella-based but provide less than one hour of protection (Skin So Soft Bug Guard). A recently marketed eucalyptus-oil based repellent called Repel Lemon Eucalyptus in a field trial provided 4 hours of effective protection. A soy bean oil based product called, Bite Blocker, was tested and gave only 95 minutes of protection.
Permethrin is a contact insecticide that can be used to apply to clothing, mosquito nets, tents and sleeping bags. It is very effective. Wearing Permethrin-coated clothing and applying a DEET-containing Insect Repellent to exposed skin areas may be the most highly effective way to prevent insect bites.
Safety has been demonstrated for DEET in young children and DEET has been safely used in the second and third trimester of pregnancy. Prolonged use of formulations above 50% or heavy application of DEET formulations onto young infants has been associated with some cases of toxicity (ingestion of the DEET repellent in some of these infants may have occurred; please consult your physician when considering your youngest infants). Rashes and Allergic skin reactions can occur with DEET but are uncommon High formulations of DEET can damage clothing made of synthetic fibers and plastic, eyeglasses, and watch crystals. There have been no serious adverse effects reported thus far with Picardin. Permethrin is toxic to the nervous system but poorly absorbed from the skin, therefore, it should be applied only to clothes, nets, and tents. It does not does not damage clothing.
Mark Siefring M.D. M.S.