Modes of Action

Pathogens cause diseases by damaging cells, digesting and destroying living cells or producing toxins that interfere with the essential processes of cells stopping the cells from functioning correctly.Viruses take over the cell's metabolism and may insert their genetic material into the host cell's DNA. They use the host cell to make new viruses. The viruses then burst out of the cell destroying the cell and spreading to other cells.Some protoctists take over cells and digest the cell contents in order to gain nutrients to produce gametes or new organisms by asexual reproduction and break the cells open to release the new generation.Fungi digest and destroy living cells. The symptoms of disease are caused by the response of the body to infection.Some bacteria produce toxins which may break down the cell membrane, inactivate enzymes, interfere with the host cell genetic material, interfere with cell division. These toxins are normal products of the bacteria's metabolism but are detrimental to the host.Some fungi produce toxins that cause disease.