Supplement

Canadian Recommendations for the Prevention and Treatment of Malaria Among International Travellers

Appendix III

Instructions for Insecticide Treatment of Bed Nets and Clothing

How to Treat Mosquito Nets with Insecticides (adapted from PATH Canada)

Before travelling, individuals should inquire about the availability of insecticides and should plan to purchase and apply these products at their destination. Pre-impregnated mosquito nets are available from PATH Canada (www.pathcanada.org) and are found in some travel and mountain equipment stores in Canada and the United States. These products are not currently registered by the Pest Management Regulatory Agency (PMRA). For information regarding the availability of insecticides in subSaharan Africa for application onto clothing or nets, see the PATH Can-ada Website.

Always use metric measurements: centimetre (cm), metre (m), millimetre (mm) millilitre (mL) and litre (L). All nets should be clean and dry. Always wear protective gloves when soaking a net in insecticide.

1. Calculate the area of the net, in square metres. Consider a conical net as a triangle and a rectangular net as two rectangles.
   How to measure a mosquito net:
   Conical net
   • Lay the net flat:
   • Measure the total distance around the curved base of the net (m)
   • Measure the height (m)
   • Multiply base x height = area of net
   Rectangular net
   • Hang the net up:
   • Measure the area of the top = width x length
   • Measure the area around the sides = height x total distance around base of net
   • Add the two measurements together to find the total area of the net
2. Calculate the amount of water absorbed by the net, in millilitres or litres.
   Using a bucket and a measuring container, measure 2 L of water into the bucket. Soak the net until it is totally wet. Carefully wring out the net over the bucket. When the net has stopped dripping, measure the water remaining in the bucket. For example:
   • Original water in bucket (2 L) minus remaining water in bucket (1.3 L) = water absorbed by the net (0.7 L or 700 mL)
3. Calculate the amount of insecticide required
   • Obtain the highest quality product, in original packaging, specifically designed for use on mosquito netting. Avoid use of products that have not undergone meticulous quality control. Do not use substitute products.
   • Check the recommended dose of insecticide. Read the instructions on the bottle or check the following Table.
   • Check the concentration of the insecticide. This follows the name of the insecticide. For example, permethrin EC 50 contains 500 g of insecticide in each litre; this is also known as a 50% solution.
     
     

   Doses of commonly used insecticides (in mg of insecticide per square metre of material - polyester)
   Compound andformulation	Dose (mg of active ingredient/square metre)
   Permethrin EC	200-500
   Deltamethrin SC	15-25
   Deltamethrin tablet	1 tablet per net
   Lambda-cyhalothrin CS	10-15
   Cyfluthrin EW	30-50
   Alpha-cypermethrin SC	20

   
   To calculate the amount of insecticide use the following formula:

   • Dose (mg/unit metre) x area of net (in square metres) to determine the amount of insecticide required in mg (remember there are 1000 mg per gram, 1000 mL per litre, and 1 gram per mL).
   • Take amount of insecticide required divided by the amount in mg of insecticide per mL of product (for example, a product that contains 50% permethrin will contain 500 g permethrin/litre and therefore 500 mg permethrin/mL) = amount of insecticide required in mL.
   For example:
   If you want a dose of 200 mg/square metre on an 11 square metre net and you are using a product containing 50% permethrin w/w, you would calculate the amount required as follows:
   • 200 mg/square metre x 11 metres squared = 2200 mg permethrin required.
   • 50% permethrin = 500 mg permethrin/mL.
   • 2200 mg divided by 500 mg/mL = 4.4 mL of insecticide required to treat the net.
   If you have found that your net absorbs 0.7 litre (700 mL) of water, add this amount of water to the insecticide to make a final mixture.
4. Wear protective gloves when treating nets with insecticide.
5. Measure the amount of water and insecticide needed.
   Wide-mouth containers, such as an empty margarine container (1 kg = approximately 1 litre), are best for measuring large amounts of water. Insecticide can be measured using a 250 mL empty container, which can be scored inside at 50 mL intervals. For small amounts of insecticide a syringe could be used.
6. Add the insecticide to the water and mix well. Treatment should be performed out of doors or in a well-ventilated area. Alternatively, you can place the net in a plastic bag (making sure there are no holes in the bag), add the insecticide and water solution, knead well, and remove the treated net from the bag for drying.
7. Dip the net into the solution until it is thoroughly wet.
8. Wring the net out over a bowl and hang it up until it has stopped dripping.
9. Dry the net.
   Wet nets can be laid out flat to dry. Do not place them in direct sunlight for more than a few hours, as UV exposure may reduce the efficacy of the insecticide.
10. Wash your hands and all equipment with soap and water. Triple rinse any containers that will be reused, and punch holes in containers or equipment that will be discarded to prevent their reuse as drinking water containers.
11. Pour any waste insecticide down a pit latrine or into a pit dug into the ground and NOT into a river or pond, as pyrethroids are highly toxic to fish and aquatic invertebrates.

For more information regarding application of insecticides onto mosquito netting, see HealthBridge Canada Website at <http://www.healthbridge.ca/index_e.cfm>.

How to Treat Clothing with Insecticides (adapted from Sawyer Products)

Before travelling, individuals should inquire about the availability of insecticide and should plan to purchase and apply these products at their destination. These products are not currently registered by the PMRA.

1. Select an area that is well ventilated, but out of the wind. Do not spray in an enclosed area.
2. Lay clothing flat on the ground, pin clothes on a clothesline, drape over porch furniture and railings, or hang clothes on separate clothes hangers, so that each garment can be easily sprayed and allowed to thoroughly dry.
3. One treatment with permethrin spray will remain effective for 2 weeks, including weekly launderings. An amount of 100 mL (3 fluid ounces) of permethrin spray will treat one complete set of garments (a pair of long-legged trousers and a long-sleeved shirt). Jackets, windbreakers, and rain gear may be treated in the same manner (caution: permethrin does not adhere well to some synthetic fibres).
4. Wear protective gloves.
5. Spray one side of the garment for approximately 60 seconds holding the spray can or bottle upright and 15-20 cm away from the surface. Spray in a slow sweeping motion, similar to spraying paint, to evenly coat the entire surface. Turn the garment around to the other side and repeat by spraying the second side for 60 seconds. The surface of the clothing should be wetted but not completely saturated with spray.
6. Hang garments up and allow the permethrin treatment to dry for 2 hours, or 4 hours if conditions are very humid.
7. Treating other garments and gear (do not treat underwear):
   • Socks can be treated with permethrin spray. Lay socks on the ground or pin on a clothesline, and lightly spray the upper parts of socks. Allow to dry for 2 or more hours.
   • Polyurethane-coated nylon (synthetic) tent flaps and doors can be treated with permethrin spray. Erect tent outdoors and spray all tent flaps and doors until wetted. Leave standing for 2 or more hours to dry.
8. After garments have dried, pack them as you normally would for your trip. You may also want to roll up your treated clothes and store them in a plastic bag to keep them dry. Pack tents as you normally would.

For more information regarding application of insecticides onto clothing,
see <www.permethrin-repellent.com>.

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