Monheim.  Researchers from Bayer CropScience (BCS) are the first to have successfully incorporated deltamethrin, its WHO-recommended active ingredient, into polypropylene fiber. The result is a new textile fiber which can be used to manufacture mosquito nets that are softer, stronger and remain effective for longer. With these long-lasting insecticidal nets (LLINs), BCS wants to make an important contribution to vector control and thus help to stem the spread of tropical diseases such as malaria.