Parasitism is a relationship in which one organism (the parasite) benefits while the other(the host) is harmed. This is a positive, negative relationship. (Campbell)( Dionne L Rice Jr) The parasite usually lives on or inside the other organism. For example, mosquito is a parasite, feeding on a human while transferring the disease called Malaria.
Artificial brush fibres are most commonly made of nylon and polyethylene, though vinyl and steel wire are also used for certain applications. Nylon fibres are either tapered and split like hog bristles for use in paintbrushes or left untapered for making cleaning brushes, hair brushes, and toothbrushes.
Other designs in Europe used feathers. The first toothbrush of a more modern design was made by William Addis in England around 1780 â the handle was carved from cattle bone and the brush portion was still made from swine bristles. In 1844, the first 3-row bristle brush was designed. Natural bristles were the only source of bristles until Du Pont invented nylon. The invention of nylon started the development of the truly modern toothbrush in 1938, and by the 1950s softer nylon bristles were being made, as people preferred these. The first electric toothbrush was made in 1939 and the first electric toothbrush in the US was the Broxodent in 1960. Today, both manual and electric toothbrushes come in many shapes and sizes and are typically made of plastic molded handles and nylon bristles.