Page 199 - policy and procedure infection control

Policies and Procedures on Infection Control

• 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.

188 Ministry of Health Malaysia