Protection Against Mosquitoes, Ticks, and Other Insects and Arthropods

Emily Zielinski-Gutierrez, Robert A. Wirtz, Roger S. Nasci
(from the CDC/Atlanta)

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Although vaccines or chemoprophylactic drugs are available to protect against some important vector-borne diseases such as yellow fever and malaria, travelers still should be advised to use repellents and other general protective measures against biting arthropods. The effectiveness of malaria chemoprophylaxis is variable, depending on patterns of drug resistance, bio-availability, and compliance with medication, and no similar preventive measures exist for other mosquito-borne diseases such as dengue or chikungunya.

CDC recommends the use of products containing active ingredients that have been registered by the U.S. Environmental Protection Agency (EPA) for use as repellents applied to skin and clothing (see below). EPA registration of active ingredients indicates the materials have been reviewed and approved for efficacy and human safety when applied according to the instructions on the label.

General Protective Measures

• Avoid outbreaks: To the extent possible, travelers should avoid known foci of epidemic disease transmission. The CDC Travelers’ Health webpage provides alerts and information on regional disease transmission patterns and outbreak alerts (www.cdc.gov/travel).

• Be aware of peak exposure times and places: Exposure to arthropod bites may be reduced if travelers modify their patterns of activity or behavior. Although mosquitoes may bite at any time of day, peak biting activity for vectors of some diseases (e.g., dengue, chikungunya) is during daylight hours. Vectors of other diseases (e.g., malaria) are most active in twilight periods (i.e., dawn and dusk) or in the evening after dark. Avoiding the outdoors or focusing preventive actions during peak hours may reduce risk. Place also matters; ticks are often found in grasses and other vegetated areas. Local health officials or guides may be able to point out areas with greater arthropod activity.

• Wear appropriate clothing: Travelers can minimize areas of exposed skin by wearing long-sleeved shirts, long pants, boots, and hats. Tucking in shirts and wearing socks and closed shoes instead of sandals may reduce risk. Repellents or insecticides such as permethrin can be applied to clothing and gear for added protection; this measure is discussed in detail below.

• Check for ticks: Travelers should be advised to inspect themselves and their clothing for ticks during outdoor activity and at the end of the day. Prompt removal of attached ticks can prevent some infections.

• Bed nets: When accommodations are not adequately screened or air conditioned, bed nets are essential to provide protection and to reduce discomfort caused by biting insects. If bed nets do not reach the floor, they should be tucked under mattresses. Bed nets are most effective when they are treated with an insecticide or repellent such as permethrin. Pretreated, long-lasting bed nets can be purchased prior to traveling, or nets can be treated after purchase. The permethrin will be effective for several months if the bed net is not washed. (Long-lasting pretreated nets may be effective for much longer.)

• Insecticides: Aerosol insecticides, vaporizing mats and mosquito coils can help to clear rooms or areas of mosquitoes; however, some products available internationally may contain pesticides that are not registered in the United States. Insecticides should always be used with caution, avoiding direct inhalation of spray or smoke.

• Optimum protection can be provided by applying the repellents described in the following sections to clothing and to exposed skin.

Repellants for Use on Skin and Clothing

CDC has evaluated information published in peer-reviewed scientific literature and data available from EPA to identify several EPA-registered products that provide repellent activity sufficient to help people avoid the bites of disease-carrying mosquitoes. Products containing the following active ingredients typically provide reasonably long-lasting protection:

*Note: This recommendation refers to EPA-registered repellent products containing the active ingredient oil of lemon eucalyptus (or PMD). “Pure” oil of lemon eucalyptus (e.g., essential oil) is not the same product and has not received similar, validated testing for safety and efficacy, is not registered with EPA as an insect repellent, and is not covered by this recommendation.

EPA characterizes the active ingredients DEET and picaridin as “conventional repellents” and oil of lemon eucalyptus, PMD, and IR3535 as “biopesticide repellents,” which are derived from natural materials.

Repellant Efficacy

Repellants and Sunscreens

Repellents that are applied according to label instructions may be used with sunscreen with no reduction in repellent activity. Products that combine sunscreen and repellent are not recommended, because sunscreen may need to be reapplied with greater frequency and in greater amounts than are needed to provide protection from biting insects. In general, the recommendation is to apply sunscreen first, before applying the repellent.

Repellents/Insecticides for Use On Clothing

Precautions when Using Insect Repellents

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