Infectious diseases

Occupations that are exposed to the risk of infectious diseases include, but are not exclusive to:

• care workers for people with disabilities
• dentists and dental assistants
• emergency care providers of the police, fire brigade and ambulance services
• first aid providers
• garbage collectors
• health carers workers
• hospital cleaning and laundry staff
• maintenance plumbers and sanitation workers
• medical and forensic laboratory technicians
• medical practitioners
• nursing staff
• post-mortem technicians and other mortuary staff
• prison workers
• providers of sexual services
• operating theatre staff

HEPATITIS
Hepatitis is a viral liver disease with three main forms, A, B and C. Those at risk include healthcare workers, sewage workers, police and emergency services, morticians and embalmers and others who come into contact with bodily fluids and used injecting needles. Hepatitis A is easily contracted from close contact with infected individuals or ingesting contaminated food or faeces. Symptoms can range from virtually no effects through to fever, nausea, lack of appetite, diarrhoea, abdominal pain and jaundice to coma and death. Prevention is achieved by good sanitation, waste disposal and personal hygiene.

Hepatitis B is 100 times more infectious than HIV, and carried in blood, saliva, semen, urine and vaginal secretions. One third of those infected are without symptoms, one third suffer a mild flu-like illness and one third suffer severe illness for up to six months with nausea, vomiting, fever, pain, fatigue and jaundice. Most people fully recover from Hepatitis B however, 5 to 10 per cent of those infected remain chronic carriers of the virus. About 20 percent of chronic carriers of the disease die from liver cancer. Prevention can be achieved by vaccination, good personal hygiene and avoiding contact with bodily fluids.

Hepatitis C can cause chronic illness and ultimately death. It is also transmitted in body fluids though to a lesser extent than hepatitis B. When Hepatitis C infection first occurs most people do not experience any symptoms. It often takes ten or more years for symptoms to appear. The most common are stomach pain, nausea and tiredness. There is currently no preventative vaccine available for Hepatitis C. For all forms of Hepatitis, transmission in the workplace accounts for only a small percentage of those infected with the disease.

HIV/AIDS
Human Immunodeficiency Virus (HIV) is a type of RNA virus called a retrovirus. It enters the body, travels through the bloodstream and invades the lymph nodes, targeting certain types of white cells there that are involved in the immune system. People infected with HIV may be free from illness for months to years before symptoms appear. Most infected people will develop AIDS with 10 to 15 years. HIV is spread from person to person in the following body fluids:

• blood
• semen
• vaginal secretions
• breast milk

HIV is NOT spread through the environment; it is a very fragile blood-borne virus. HIV-infected persons do not pose a threat to co-workers or clients during casual, day-to-day activities and contacts. Healthcare workers and emergency personnel are at low risk (but possible) of acquiring HIV from workplace exposure to HIV (for example by needle stick injuries). A drug treatment regime called Post Exposure Prophylaxis (PEP) has been shown to be effective in preventing conversion to HIV in these circumstances.

Acquired immune deficiency syndrome (AIDS) is a collection of symptoms and infections  resulting from the specific damage to the immune system  caused by HIV. The late stage of the condition leaves individuals susceptible to opportunistic infections  and tumors. Although treatments for AIDS and HIV exist to decelerate the virus‘  progression, there is currently no known cure

LEGIONNAIRES’ DISEASE

Legionnaires’ disease is a serious and sometimes fatal form of pneumonia caused by the bacteria Legionella. Although not all cases of Legionnaires’ disease are severe, up to ten per cent of cases can be fatal. Symptoms are usually similar to a severe ‘flu’ infection and include: fever; headache (often severe); shortness of breath; muscle aches and pains and sometimes a dry cough. From the time of infection with the Legionella bacteria, it takes between two and 10 days for symptoms to appear. In most cases, symptoms begin after five or six days. People usually get Legionnaires’ disease by breathing in Legionella bacteria in very fine droplets of water called aerosols. It cannot be transferred through person to person contact. In the workplace, Legionnaires disease is usually contracted through the cooling towers associated with air conditioning and industrial cooling processes. The bacteria must be high in concentration in this environment before there is a significant risk of exposure. Most people exposed to Legionella bacteria do not become infected. The risk of disease increases with age, especially amongst smokers. People with long term medical conditions that weaken the body’s immune system (such as cancer, lung disease, diabetes, and transplant recipients) may be at increased risk of Legionnaires’ disease.

 Can legionnaires disease be prevented?

We must accept that many water systems are colonized with legionella and it will rarely be possible to completely and permanently prevent this. The task is to prevent multiplication, production of aerosol mists and therefore, the chance of inhalation of the water droplets. This can be achieved by:

• carrying out inspection of water systems and cooling towers every month for build-up of slimes and micro organisms and regularly treating them to keep them clean;
• eliminating the drift of potentially contaminated droplets from cooling towers with adequate shrouding;
• providing appropriate respiratory protection to workers inspecting or working in or on cooling towers where aerosols might be created and inhaled.

Examples of occupationally acquired diseases, their sources and workers at risk –

Source	Infection	Occupations at Risk
		Directly	Incidentally
Isolation/study of pathogens	Various	Lab and health services workers
Human tissue and body fluids	Hepatitis, tuberculosis, enteric infections, HIV infection, Childrens diseases such as rubella, cytomegalovirus (CMV), chicken pox, mumps	Health care workers, accident and emergency service workers, childrens services workers, mortuary workers, sex industry workers	teachers, institution staff, cleaners of all types, security staff, first aiders, people involved in accidents
Animals, animal products	Anthrax, avian flu, brucellosis, Q Fever, leptospirosis, chlamydial infections (psittacosis), salmonellosis, rabies, toxoplasmosis	Animal/bird handlers, vets, abattoir workers, processors of animal products	Agricultural workers
Ticks	Lyme disease	Game keepers, shepherds	Timber workers
Soil	Salmonellosis, shigellosis, hepatitis A, leptospirosis Tetanus and other clostridial infections		Sewerage and water workers Agricultural and construction workers, gardeners
Contaminated aerosols	Legionnaires disease	Air conditioning maintenance workers	Office workers, other maintenance workers

Table taken from Hazards at Work TUC Guide to Health and Safety

Risk Control Measures

• Ensure that workers are fully informed and trained about the risks of their job and appropriate prevention and control measures including vaccination. (Vaccinations are available for a number of infectious diseases such as Hepatitis A and B, Q fever etc).
• Ensure the employer has a disease reporting system in place, ensure employees are instructed in when and how to use it and ensure incidents are acted on by the employer and reported to the safety committee.
• Good housekeeping in workplaces to establish and maintain hygienic environments.
• Ensure the employer carries out a comprehensive risk assessment which covers prevention, control, protection, emergency procedures and monitoring and health surveillance.
• Isolation of the source of the infection through engineering controls.
• Where biological agents are being used, stored or transported ensure that the correct procedures are in force.
• Provision of one-use equipment to prevent reuse.
• Provision of equipment to dispose of all used equipment in workplaces (e.g. sharps containers).
• Where there is a serious and imminent risk of infection, employees are entitled to withdraw their labour in order to protect themselves until a safe system of work is applied.
• Reduction of hazardous procedures to a minimum (for example, use invasive procedures on patients only where essential).
• If any disease symptoms occur, ensure that employees report these immediately. Any other people who might be affected should be immediately tested for signs of illness.
• Provision of protective clothing and equipment (e.g. rubber gloves, latex gloves, masks, goggles and tongs) where necessary.
• Ensuring regular cleaning and maintenance of air-conditioning equipment.

Infections and Pregnant Women
A particular risk assessment needs to be carried out of the hazards to pregnant or breastfeeding women or women who have given birth within the previous six months. Suitable protective or preventive measures should be provided, working conditions altered or suitable alternative work provided. If none of these can be achieved, the woman should be suspended on full pay for as long as it is necessary to avoid the risk.
Some infections can cause miscarriages or affect a breastfeeding child: German measles, chickenpox, hepatitis, HIV, typhoid, tuberculosis, ovine Chlamydia, and toxoplasmosis, found in infected cat and dog faeces.

USEFUL LINKS

Infection Control
Follow the above link to a Safework SA fact sheet regarding infection control within the workplace.

 

Acknowledgements:
Safework SA www.safework.sa.gov.au
OHS Reps at Work Infectious Diseases
Health and Safety Executive UK – www.hse.gov.uk
HIV/AIDS Fact file ABC Health and Wellbeing
Quinlan Miller & Treston lawyers – Legionnaires Disease