1.1 and 1.2 Bacteria - are micro-organisms that consist of only one cell. Bacteria multiply by splitting themselves in two, which is called a binary fission. Because of this they can increase in number rapidly. The majority are harmless, but some can be pathogenic which results in bacterial infection occuring. Bacterial infections can be treated by using antibiotics. Bacteria can evolve a resistance to antibiotic e.g. MRSA. Some diseases caused by bacteria include tuberculosis, pneumonia, salmonella, tetanus and syphilis.
Viruses - are extremely small particles made from protein and either DNA or RNA. They are not made up of cells instead they invade the living cells of other organisms and use them to produce many copies of…show more content… All pathogens need a source of food to provide them with a source of energy and nutrients they need to multiply. Often they get it from the body of the infected individual. All human pathogens require moisture to grow, that is why food is preserved by drying, which deprive mico-organisms of moisture. The pathogens that infect humans grow best at body temperature of 37*C. Higher temperatures inactivate and kill most of the micro-organisms, while low temperatures slow or stop their grow. That is why heat is used to steralize objects, while freezing is used to preserve food. It takes time for the pathogen to multiply to the point where it starts to cause symtomps of infection. This is called an incubation time.
2.2 There are four main ports of entry: - inhalation into the nose, throat and lungs (pathogens in the air or droplets, which can cause e.g. TB), - ingestion into the stomach and gut (pathogens ingested and swallowed, which can cause e.g. salmonella and norovirus), - sexual contact (pathogens transmitted in any sexual contact, which can cause e.g. HIV, gonorrhoea), - wounds and breaks in the skin (pathogens enter the body through mucus membranes, nose, mouth, gut, genital urinary track - catheters, or wounds like surgical incisions which can cause e.g. MRSA).
2.3 The sources of infection can be divided in two main groups. These are exogeneous and endogeneous sources. A source of the infection is