As a result, the mosquito netting and pesticide industries developed so-called long-lasting insecticidal mosquito nets (LLINs), which also use pyrethroid insecticides. There are two types of LLINs, one which is polyester netting and the insecticide is bound to the external surface of the netting fiber using a resin and another which incorporates the insecticide into a polyethylene fiber which then releases the insecticide slowly over 5 years. Both types can be washed at least 20 times but physical durability will vary, a survey carried out in Tanzania concluded that effective life of polyester nets was 2 to 3 years (Erlanger et al., 2004, Med Vet Entomol 18: 153-160), with polyethylene LLINs there is data to support > 5 years life with trials in showing nets which were still effective after 7 years (Tami, A et al. Malaria Journal 2004, 3:19). When calculating the cost of LLINs for large scale malaria prevention campaigns the cost should be divided by the number of years of expected life, hence a slightly more expensive net may be cheaper over time. In addition the logistical costs of replacing nets should be added to the calculation.
Scientific trials of ITNs
A review of 22 randomized controlled trialRandomized controlled trialA randomized controlled trial is a type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services or health technologies . RCTs are also employed in other research areas, such as judicial, educational, and social research of ITNs found (for Plasmodium falciparumPlasmodium falciparumPlasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria in humans. It is transmitted by the female...malaria that ITNs can reduce deaths in children by one fifth and episodes of malaria by half.
More specifically, in areas of stable malaria "ITNs reduced the incidence of uncomplicated malarial episodes by 50% compared to no nets, and 39% compared to untreated nets" and in areas of unstable malaria "by 62% compared to no nets and 43% compared to untreated nets".
As such the review calculated that for every 1000 children protected by ITNs, 5.5 lives would be saved each year.
Mosquito nets do reduce air flow to an extent and sleeping under a net is hotter than sleeping without one, which can be uncomfortable in tropical areas without air-conditioning.
Another alternative is to apply an insect repellentInsect repellent An insect repellent is a substance applied to skin, clothing, or other surfaces which discourages insects from landing or climbing on that surface. There are also insect repellent products available based on sound production, particularly ultrasound to the skin; this also may be less effective (reducing rather than eliminating bites), more expensive, and may pose health risks with long-term use.
