Causes and Spread of Infectious Diseases

Causes of Infectious DiseasesBacteria, fungi and parasites are all considered as ‘living’ things,. Bacteria are single celled microorganisms that can only been seen through a microscope, they collect their nutrition from their surrounding and unlike viruses, they do not need a living host to reproduce. Viruses are difficult to destroy because they are enclosed in a protein coating. Viruses are disease-producing agents, far smaller than bacteria. Viruses are not considered as living because they are unable to reproduce.Fungi are placed into the plant category although they are very different from green plants. The basic part of fungus is a hollow tube, which is known as ‘hypha’. Fungi spread by releasing spores into its surroundings. Parasites are an organism that feeds and is dependent of its host.Common illnesses and infections caused by bacteria include:Common illnesses and infections caused by viruses include:Common illnesses and infections caused by parasites include:Infection means that the body is being invaded by bacteria, viruses and parasites that are not usually there, these are known as microorganisms.Colonization is a bacterial infection manifesting on or in an individual, making the individual the carrier of the infection who may not necessarily have any signs or symptoms of the illness, however they do still have the potential to infect others.Systemic infection means the infection is in the blood stream, and is or has spread through the body. Lime Disease, AIDS, Tuberculosis and Septicemia are examples of Systemic infections. Localized infection means the infection is restricted to one area on the body i.e. small cut or ulcer that is infected. However if a localized infection becomes worse, and no medical treatment is given it could spread and become a systemic infection.Four key factors are needed to make the perfect environment for microorganisms to grow, these include; moisture, nutrients, warmth and time.Common sources of infection include food, water, sick people (colds and flu), animals and poor housing (invaded with pests such as rats and mice or damp and moldy), contaminated food, drinks, bodily fluids; vomit, tears, breast milk, urine, blood, mouth, nose, sweat and broken skin.The different ways that infective agents can be transmitted to a person include,The key factors that will make it more likely for infection to occur include:Conditions needed for the growth of micro-organisms