2.0 What is a Pathogen?
2.1 Major Categories of pathogens/micro-organism
Fig 2.3 Bacterial Shapes
Fig 2.5 Structure of a virus
3.0 Pathogenic Environment
4.0 What is disease?
4.1 How disease spreads
Pathogens and the spread of disease
“Health depends on the body maintaining its internal harmony.” (The U205 Course Team, 1985)
Health is a momentary condition of ones state of physical and mental well being. This is constantly compromised by the threat of disease. It is often hard to define exactly what disease is, however it is generally conceived as any undesirable bodily or mental condition which causes an organism to alter from its normal state of existence (Nesse, 2000).
Our concern is to discuss and explore the abnormal functions and structures of pathology which underlie in illness and disease. To do so we have to ask a few questions. Firstly we need to discuss what disease is any why it occurs; we then need to consider the definition of pathogens and the major categories of micro-organisms and their microbial environment. Furthermore we shall analyze the pathogenesis of infection which deals with how disease spreads and what role pathogens play in the advance of it.
2.0 What is a pathogen ?
Diseases in all humans, plants and other organisms are caused by micro-organisms called pathogens; these can be micro-organisms such as bacteria, viruses, fungi, helminths and protozoa (Inglis,1996). The term pathogen is most commonly used to describe an infectious organism which interrupts the usual physiology of a multi-cellular animal or plant (Wassenaar, 2009). There are many pathogens which have been responsible for massive outbreaks of disease, an example of this is Yersinia Pestis which was the bacteria responsible for the black plague (Harwood 1979).
Yersinia Pestis is an extracellular pathogen, once attached to a microphage, it activates a specialized type III secretion system that acts like a syringe, allowing the bacterium to inject a number of toxic proteins called the Yersinia outer membrane protines or Yops directly into the macrophage cytoplasm.
2.1 Major categories of pathogens/micro-organisms
There are four major variations of pathogens to exist. They are Bacteria, Viruses, Fungi and parasites. Discussed here is how to identify these pathogens and mention common examples in each category.
There are numerous types of bacteria that can invade the body. They are single celled organisms that come in many different shapes and sizes. Most bacteria are microscopic, hence being micro-organisms being under 0.01mm,they also share similarities within their cells. They are typically composed of a cell wall, cell membrane, cytoplasm and genetic...