138 Workplace Hygiene and Illness Prevention

Contagious Diseases

What are Pathogens?

Pathogens are organisms that cause infectious diseases. Pathogens are also known as infectious agents and germs. When a pathogen enters and attacks a host, symptoms begin to appear. A host is a human who can carry a pathogen and become ill.

There are five main types of pathogens:

1. Bacteria - Bacteria are microscopic, single-celled organisms having different shapes, such as rods, spirals, or spheres. Bacteria are usually larger than viruses and have a nucleus containing DNA. Most bacteria are harmless, but there are a few that can cause illness.
2. Virus - Viruses are infectious agents that are smaller than bacteria and require a living host to replicate and thrive. Once a virus invades the host cells, it uses the host cell to replicate, producing many new viruses that infect other cells. This process usually damages or destroys the infected cells.
3. Fungus - Fungi, which can be single-celled or multicellular organisms, can survive outside a host. Their cell contains a nucleus with cellular components enclosed within a thick cell wall.
4. Protozoa - Protozoa are single-celled organisms that can move through water and prey on other microorganisms. They feed off their hosts parasitically and multiply causing infections and illnesses.
5. Helminths - Helminths, or parasitic worms, are larger multicellular organisms that enter and inhabit many areas of the body, often causing illness by feeding on the host.

In the workplace, viruses and bacteria are the most common causes of illness. Examples of infectious diseases caused by pathogens:

• Common Cold: Many viruses can cause the common cold. It is a viral infection that affects the nose and throat.
• Influenza (flu): A contagious respiratory illness caused by influenza viruses. It affects the nose, throat, and sometimes the lungs.
• Coronavirus Disease 2019 (COVID-19): COVID-19 is a disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. This virus is related to the coronavirus responsible for the SARS outbreak of 2003. Cases have ranged from mild symptoms to severe respiratory illness and death.
• Norovirus: The norovirus is also known as the stomach flu. Norovirus is a common virus that is not related to the flu.
• Measles: A highly contagious, serious disease that is caused by a virus. About 1 in 5 (20%) unvaccinated people in the U.S. who get measles are hospitalized.
• Strep Throat: A mild bacterial infection that affects the throat and tonsils.
• E. coli: Escherichia coli (E. coli) are bacteria found in the environment, food, and intestines of people and animals. Most strains of E. coli are harmless, but others can make you sick.

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