Canadian Centre for Occupational Health and Safety
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Health and Safety: Teaching Tools


Infectious Diseases

Biological hazards can be encountered at home, at school and in workplaces. Biological hazards are caused by animals, plants or "microbes", like bacteria and viruses, which impact on our health.

Shown are a tick, poison ivy and a virus (Rhinovirus) which causes the common cold. Ticks can come from animals or the outdoors, poison ivy can be found in forests, and cold viruses can come from other people, or surfaces that people with colds have touched.

Biological agents can be put into different categories by their type:


Bacteria, Viruses ? which we usually refer to as "germs" include Bacteria such as Salmonella and E.coli; Viruses include Influenza, Common cold virus

Plants, Pollens or Molds ? includes plants such as:

  • Jimsonweed seeds, Poison Ivy ? cause poisoning, skin irritation
  • Pollens such as ragweed, grass, tree pollen ? cause allergies
  • Molds such as Stachybotrysatra (black or toxic mould) have been found in some Ontario schools ? can cause lung infections

Different biological hazards can cause a range of health effects, some of which are minor and temporary in nature, others which are associated with lifethreatening reactions or disease.

Health Effects

Ragweed Pollens - can cause seasonal allergies or asthma (for sensitized people who have developed the allergy

Viruses ? can cause skin, eye and ear infections, as well as colds and the flu

Peanuts or Bee Stings ? can cause serious asthmatic or anaphylactic reactions (where breathing becomes very difficult)

The biological hazards or biohazards described above can be transmitted through various sources, namely:

Biological Hazards

People ? human to human

Animals ? from pets or wildlife (e.g. deer ticks carry Lyme disease)

Dirty food or water ? (eating, drinking, even swimming sometimes)

Dirty needles ? When we use the word "Dirty" we could say "contaminated". With respect to needles, any USED needle is considered dirty.

General Safety Tips

Here are some key ways to protect yourself in the workplace from infectious agents or biological hazards:

General Safety Tips

COVER cuts with bandages since these are a vulnerable source of potential infection.
THROW out dirty gloves. They can become contaminated with bacteria from handling meat or be torn during use.
STORE your lunch in a safe place is important (away from thawing meats, away from contaminated areas).


do not
NEVER EAT or DRINK near potentially contaminated areas (such as dirty cookwear, utensils, near sick patients, etc.)


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