|Occupational Health and Safety
Hazardous Substances: Tuberculosis (TB)
What is tuberculosis (TB)?
Tuberculosis is an infectious disease caused by a germ called Mycobacterium tuberculosis. The germ usually causes an infection in
the lungs, but sometimes it can affect other parts of the body.
What are the signs and symptoms of tuberculosis?
The signs or symptoms of tuberculosis are common to many other diseases. They are:
loss of weight
loss of energy
fever and wet cough
persistent cough lasting more than three weeks
How is tuberculosis transmitted?
Tuberculosis is transmitted through the air from exposure to germs in the saliva of infected persons and sputum coughed up from
their lungs. When an infected person coughs, sneezes, or speaks, tiny droplets which contain the germs are released and can be
inhaled by employees or anyone in the area. The germs inhaled through the nose and mouth reach the windpipe (trachea) and the
dividing air tubes (bronchi) that lead to the lungs. The germs can spread from the initial location in the lungs to other parts of the
body through the bloodstream. Within weeks from infection, the immune system which is the infection control mechanism of the
body, reacts to the germs and usually prevents them from multiplying and spreading. Not everyone infected develops the disease.
In fact, about 90% of infected persons remain infected for life without having any symptoms.
About 5% of infected persons develop the disease. A person infected with the germs who does not develop the disease cannot
infect others because no germs are discharged in the sputum or saliva.
How is tuberculosis recognized?
Medical tests such as skin tests, chest x-ray, and sputum tests can determine if a person was exposed to the germs and whether
the person has the disease.
Can tuberculosis be treated?
Tuberculosis can be treated very effectively through a combination of drugs. It is important to follow the physician's directions and
take the drugs exactly as recommended. If you forget to take your pills or if you take only one of them, the tuberculosis germs might
become resistant to the drugs and start growing again.
Should tuberculosis be an occupational concern?
In the workplace, employees of institutions or hospitals can contract tuberculosis from persons who have not yet been diagnosed.
Safe work procedures should include screening programs that will identify persons who have been exposed to the germs causing
tuberculosis. If you work at a long term care facility your employer should have a policy for screening all new residents before
admission, or within 14 days of admission with a two step tuberculin mantoux test. Health care workers who have been exposed to
an infected patient must be monitored for infection. Tuberculin mantoux testing is easiest to monitor in workers who previously skin
tested negative, but a doctor's order is required for this to be completed.
When an infectious person is identified universal precautions should be strictly enforced in addition to wearing a personal
respiratory device. All isolation precautions should be implemented. An infectious person should be placed in a private room.
Employees entering the room should wear a protective respiratory device. The isolation room should be at negative air pressure
and it should have adequate ventilation to dilute the concentration of contaminants within the room. The air from the isolation room
should be directly exhausted outside.
If you contract TB as a result of your work, report this to first aid and your employer and submit a workers' compensation claim.
Information in this fact sheet comes from the Canadian Occupational Health and Safety Centre.
Source: CAW Health, Safety & Environment Department