Introduction to Biological Hazards

05/01/2022

Biological hazard can be defined as substances which pose a threat to the health of other living organisms, primarily humans. This could include microorganisms such as bacteria, viruses or toxins.

What are biological hazards?

Micro-organisms are abundant within our atmosphere and can be found anywhere with our natural environment. Often, these micro-organisms will be harmless and are often required to complete vital tasks, such as making medicine or support the production of other chemicals. They are also responsible for the production of approximately half of the oxygen we breathe. However, we also can recognise that certain micro-organisms can cause significant harm. In this instance they are considered a biological hazard

Micro-organisms can cause harm to a human being through three routes, these are:

being infected with the micro-organism
being exposed to toxins produced by the micro-organism
having an allergic reaction to the micro-organism or substances it produces.

Dependant on the nature of the biological hazard, the harm that they can cause can often be serious, and potentially fatal.

Whilst the UK rail industry does not conduct work specifically with microorganisms, many of its operations can result in employees being exposed to biological hazards which can adversely affect human health. Examples can include:

Blood borne viruses
Blood borne viruses (BBVs) are carried in the bloodstream. When transferred into a new bloodstream BBVs can cause severe disease in some and few or no symptoms in others.

Key BBVs include:

hepatitis B virus (HBV)

hepatitis C virus

hepatitis D virus, which causes hepatitis (a disease of the liver)

human immunodeficiency virus (HIV) which causes acquired immune deficiency syndrome (AIDS), affecting the immune system of the body.

Within the rail industry, individuals who are exposed to needlestick injuries whilst conducting tasks that involve syringes and waste handling and disposal, are at risk.

Other risks of BBV’s include when operators are working in locations or with equipment that is significantly contaminated with sewage or animal faeces. This contamination can lead to infection with E. coli, a bacterium which can cause stomach problems. The other significant risk is that sewage could also be contaminated with Hepatitis A.
Lyme disease
Bites from ticks that are infected with a certain strain of bacteria can result in individuals becoming affected by Lyme disease. Initial symptoms can include a rash around the bite point. However, some people also have flu-like symptoms in the early stages, such as:

a high temperature or feeling hot and shivery

headaches

muscle and joint pain

tiredness and loss of energy.

Individuals who suffer with Lyme disease can also develop more severe symptoms months or years later which is more likely if treatment is delayed.

These more severe symptoms may include:

pain and swelling in joints

nerve problems, such as pain or numbness

heart problems

trouble with memory or concentration.
Leptospirosis
The main form of leptospirosis is Weil’s disease which is a potentially life-threatening illness passed from rats via urine. The disease may be transmitted through contact with rat’s urine or watercourses contaminated with it. It may enter the body through abrasions, cuts in the skin and through the lining of the mouth, nose, and ocular mucous membranes.

Symptoms include flu-like symptoms such as:

fever

headache

vomiting

muscle pains

pneumonia

possible kidney failure and death.
Legionella
Legionellosis is a collective term for diseases caused by legionella bacteria. The bacterium Legionella pneumophila is a significant concern and can result in individuals suffering with Legionnaires' disease. This is a potentially fatal form of pneumonia, and everyone is susceptible to infection.

These are commonly found in natural water sources such as rivers, lakes, and reservoirs, but are usually experienced in very low numbers. However, Legionella can be a significant risk in water storage and treatment/transport systems where environmental conditions could be suitable for legionella bacteria growth.

This highlights dependant on the design on the water storage system and its application, the risk of Legionella bacteria within the rail industry is a real concern that must be suitably and sufficiently managed.

The symptoms of Legionnaires' disease are often found to be like symptoms of the flu:

high temperature, feverishness and chills

cough

muscle pains

headache

diarrhoea and signs of mental confusion.
Toxic plant saps
As trackside areas are not commonly maintained or controlled with regards to flora and fauna, there is the possibility that harmful plants may become established. The most notable is Giant Hogweed, the sap of which is phototoxic. Should skin encounter its sap, the skin will result in the skin being unable to protect itself from sunlight, which leads to Phytophotodermatitis, a serious skin inflammation.

Symptoms include:

large areas of blistering

itching

redness

inflammation

pain.