Some diseases such as influenza are contagious and infectious. The micro-organisms that cause these diseases are known as pathogens and include varieties of bacteria, viruses, protozoa and fungi. Infectious diseases can be transmitted by as, by hand-to-mouth contact with infectious material on surfaces, by bites of insects or other carriers of the disease, and from contaminated water or food (often via faecal contamination), etc. In addition, there are sexually transmitted diseases. In some cases, micro-organisms that are not readily spread from person to person play a role, while other diseases can be prevented or ameliorated with appropriate nutrition or other lifestyle changes.
Some diseases, such as most (but not all) forms of cancer, heart disease and mental disorders, are non-infectious diseases. Many non-infections diseases have a partly or completely genetic basis (see genetic disorder) and may thus be transmitted from one generation to another.
Disease transmission
Friday, October 16, 2009
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