Biological Incidents

For the purpose of clarity; when describing a biological incident involving specific pathogens, the term Biological Agent shall refer to any micro-organism, cell culture, or human endo-parasite, whether or not genetically modified that is capable of causing disease, infection, allergy, toxicity or otherwise create a hazard to the general good health of humans or animals and are categorised by the company into Risk Groups. Some chemical agents are also classed as biological hazards due to the effects they have upon living matter.

Biological agent is a generic term used to describe specific pathogenic micro-organisms which affect animals, plants, fungi, protozoa and even bacteria themselves (Bacteriophages). Pathogenic micro-organisms are categorised as follows;

• Prions: - Are considered to be an infectious agent that, according to current scientific consensus, is comprised entirely of a propagated mis-folded protein. The mis-folded form of the prion protein has been implicated in a number of diseases in a variety of mammals including bovine spongiform encephalopathy (BSE, also known as "mad cow disease") in cattle and Creutzfeldt-Jakob disease (CJD) in humans. All hypothesized prion diseases affect the structure of the brain or other neural tissue. All are currently untreatable and are always fatal.
• Viruses: - Are sub-microscopic infectious agents that are unable to grow or reproduce outside a host cell. Viruses infect all cellular life and consist of two or three parts: all viruses have
  genes comprising either DNA or RNA, (long molecules that carry genetic information). All have a protein coat that protects these genes; and some have an envelope of fat that surrounds
  them when they are outside a cell. Viruses vary in shape from simple helical and icosahedral shapes, to more complex structures. They are about 100 times smaller than bacteria.
• Bacteria: - are a large group of unicellular micro-organisms typically a few micrometers in length. Bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Bacteria
  are ubiquitous in every habitat on Earth growing in soil, acid hot springs, radioactive waste, water, and deep in the Earths crust, as well as in organic matter and the live bodies of plants and animals.
• Protozoa: - are microorganisms classified as unicellular eukaryotes. While there is no exact definition of the term "protozoan", most scientists use the word to refer to a unicellular heterotrophic protist such as an amoeba or a ciliate. The term algae is used for microorganisms that photosynthesize.
• Moulds: - include all species of microscopic fungi that grow in the form of multi-cellular filaments, called hyphae. In contrast, microscopic fungi that grow as single cells are called yeasts.
• Helminths: - Parasitic worms or helminths are a division of eukaroytic parasites that, unlike external parasites such as lice and fleas, live inside their host. They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient absorption, causing weakness and disease. Those that live inside the digestive tract are called internal parasites where humans and animals play host to such organisms.

The ability of pathogenic micro-organisms to colonise a wide diversity of environments, survive for long periods of time (as with bacterial Endospores resisting desiccation for 25 million years), rapidly expand their host range by genetic recombination (such as HIV) and overcome immune defence mechanisms (such as Streptococcus pyogenes activating plasminogen), signifies that newly emerging or resurgent infectious diseases will continue to be a threat.