Page 258 - IGC BOOK

Hepatitis A is contracted orally by cross-contamination with faecal material containing the
hepatitis A virus, so sewage workers are at risk.

Hepatitis B is transmitted in body fluids, such as blood, so occupations at risk would include
healthcare workers (doctors and nurses), fire-fighters, police and waste- disposal workers.
The virus survives for long periods outside the body and can survive harsh treatment that
would kill other micro-organisms (such as boiling in water). Contaminated body fluids can
cause infection by contact with damaged skin, needle- stick injury and even splashing to the
eyes and mouth. Symptoms of the disease include jaundice and liver damage. Though many
people are able to make a full recovery other will become long-term sufferers and some
continue to carry the virus but do not display any symptoms of infection.
Typical controls include:

• Use of PPE (such as gloves and eye protection) when handling potentially contaminated
material.
• Correct disposal of potentially contaminated material (such as clinical waste).
• Prevention of needle-stick injuries by correct disposal of sharps in a sharps bin.
• Decontamination and disinfection procedures.
• Vaccination where appropriate.
• Procedures to deal with accidental exposures (e.g. needle-stick injuries).

Carbon Monoxide (CO)

A colourless, odourless gas usually encountered as a by-product of partial combustion (e.g.
poorly maintained heating boiler). It is hazardous by inhalation.

During normal respiration, oxygen from the atmosphere is absorbed by the red blood cells
in the blood and chemically bound to haemoglobin (a protein) so that it can be carried around
the circulatory system to body tissues. Carbon monoxide interferes with this oxygen carrying
process by binding onto the haemoglobin molecule at the same place where the oxygen
should be (forming a compound called carboxy-haemoglobin). This prevents oxygen
transportation and can lead to death by asphyxiation.

Low levels of CO (0.005%) will cause a progressively worsening headache. Levels of 1.3% will
cause immediate unconsciousness and death within three minutes. Note that this can occur
even though oxygen concentrations are normal at 21%.

ENSIGN| Unit IG2 – Element 7 – Chemical and Biological 53
Agents