Types of ITNs
Pyrethroids are the only family of insecticides used to treat bed nets, as they are safe to humans. Nets requiring re-treatment every six months are no longer used in malaria control programmes in Ethiopia or elsewhere. Therefore, the term ITN in the rest of this study session refers to LLINs.
There are two types of ITNs: conventionally treated nets and long-lasting insecticidal nets or LLINs. A conventionally treated net is a mosquito net that has been treated by dipping in a pyrethroid insecticide. Dipping is often done at the village level, by health workers or communities themselves. However, to ensure its continued insecticidal effect, the net needs to be re-treated after three washes, or at least every six months. A much better alternative is the long-lasting insecticidal net. LLINs are factory-treated mosquito nets made with a netting material that has insecticide incorporated into the fibres, or as a coating on the fibres. LLINs are effective against mosquitoes for at least 20 standard washes, or three to five years under field conditions. As the lifespan of most nets is three to four years, the insecticides in LLINs remain effective for the whole life of the net. Therefore, there is no need to re-treat LLINs.