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Policies and Procedures on Infection Control Ministry of Health Malaysia 188 • Biological control agents include toxins from the bacterium Bacillus thuringiensis var. israelensis Bti. These products can be applied in the same way as chemical insecticides. They are very specific, affecting only mosquitoes, black flies, and midges. • Insect growth regulators such as methroprene. Methoprene is specific to mosquitoes and can be applied in the same way as chemical insecticides. • Mosquito fish Gambusia affinis are effective in controlling mosquitoes in larger bodies of water. • Other potential biological control agents, such as fungi e.g., Laegenidium giganteum or mermithid nematodes e.g., Romanomermis culicivorax, are less efficient for mosquito control and are not widely used. 2. Avoidance from mosquito bite Specific measures on the avoidance from mosquito bite should be followed. Measures that have been described to avoid mosquito bites are: • insect repellents containing N,N-diethyl-3-methylbenzamide DEET, Adult-dose 95 DEET lasts as long as 10-12 hours, and 35 DEET lasts 4-6 hours. For children, use concentrations of less than 35 DEET. Use sparingly and only on exposed skin. Remove DEET when no longer exposed. Please refer to PROPER APPLICATION OF REPELLANT. • protective clothing the most effective is permethrin-impregnated. Avoid mosquitoes by limiting exposure during times of typical blood meals. Wearing long-sleeved clothing may also prevent infection. • insecticide-treated bed nets The usefulness of insecticide-treated bed nets at night is limited since Aedes mosquitoes bite during the day. • insecticides- “knockdown resistance” may occur in some locations. • Untreated bed nets form a protective barrier around persons using them. However, mosquitoes can feed on people through the nets, and nets with even a few small holes provide little, if any, protection. • Aedes mosquitoes bite during the day; hence, these measures must be taken during the day, particularly in the morning and late afternoon. • Fogging or area spraying is primarily reserved for emergency situations: halting epidemics or rapidly reducing adult mosquito populations when they have become severe pests. Fogging and area sprays must be properly timed to coincide with the time of peak adult activity, because resting mosquitoes are often found in areas that are difficult for the insecticide to reach. Policies and Procedures on Infection Control Ministry of Health Malaysia 189

13.6.1 Introduction

Humans are infected with Plasmodium protozoa when bitten by an infective female Anopheles mosquito vector. The mosquito larvae develop within a few days, escaping their aquatic environment before it dries out. It is difficult, if not impossible, to predict when and where the breeding sites will form, and to find and treat them before the adults emerge.

13.6.2 Patient’s Isolation

Malaria patient need not be nursed in isolation room. However, an air-conditioned or a naturally-ventilated room is preferred. If a naturally-ventilated room is used, it is suggested to put mosquito nets to all the windows in the room. If both facilities are not available, then the patients can be nursed in the general ward. Specific measures to avoid mosquito bites should be considered see under Prevention of vector transmission.

13.6.3 Prevention of vector transmission

1. Source eliminationreduction for Malaria fever Source elimination or reduction is the method of choice for mosquito control refer to Source eliminationreduction for Malaria fever. 2. Avoidance from mosquito bite Specific measures on the avoidance from mosquito bite should be followed. Measures that have been described to avoid mosquito bites are: • insect repellents containing N,N-diethyl-3-methylbenzamide DEET, Adult-dose 95 DEET lasts as long as 10-12 hours, and 35 DEET lasts 4-6 hours. For children, use concentrations of less than 35 DEET. Use sparingly and only on exposed skin. Remove DEET when no longer exposed. Please refer to PROPER APPLICATION OF REPELLANT. • protective clothing the most effective is permethrin-impregnated. Avoid mosquitoes by limiting exposure during times of typical blood meals. Wearing long-sleeved clothing may also prevent infection. • insecticide-treated bed nets The use of insecticide-treated bed nets at night is useful as Anopheles mosquitoes bite during dawn and dusk. • insecticides- “knockdown resistance” may occur in some locations.

13.6 Malaria