communicable diseases

• pathogen are microorganisms that enter the body that cause diseases, they are communicable (infectious) diseases - that spread easily
• both plants and animals can be infected by pathogens
• pathogens can be - bacteria or viruses or protists or fungi
• bacteria cells are very small and make you feel ill by producing toxins that damage your cells and tissue
• viruses are not cells - they are much smaller. like bacteria the reproduce rapidly and can cause disease
• viruses live inside your cells and replicate themselves using your cell's machinery , the cells usually burst releasing all the new virus, the cell damge is what make you feel ill
• protists are eukaryotic cells that are not true cells, but are made up of a few cells that are joined together most of them are single-celled
• some protists are parasites, which live on or in other organisms and transferred through a vector
• fungi comes in different shapes - some a single-celled others have a body which is made up from a hyphae
• hyphae can grow and penetrate human skin and the surface of plants causing diseases. the hyphae can produce spores which can be spread to other organisms
• pathogens can be spread by water, air, direct contact
• some pathogen are spread through dirty water e.g cholera is a waterborne disease spread by contaminated water
• pathogens can be carried in air and can be breathed in e.g the flu is spread by droplets produced when you sneeze or cough
• some pathogen can be spread by touching a contaminated surface, including skin e.g athletes foot is a fungus that can be spread by touching contaminated surfaces like a shower floor