What are pathogens?

If 2020 could teach us one thing, that thing would be protecting ourselves from pathogens.  While COVID-19 has dominated our daily lives for the better part of the year, we should also learn about other pathogens that are part of every day life.  So, what is a pathogen?  Bottom line up front, pathogens are organisms that cause disease to another living organism (Balloux and van Dorp, 2019). 

Going beyond the simple definition of a pathogen, we can break down the different types of pathogens.  Pathogens can be broken up into five types.  These types are viruses, bacteria, fungi, protozoa, and worms (Janeway et al., 2001).  You may have or have had a disease caused by each of pathogens.  If not you, perhaps someone you know has gotten a disease from these pathogens.

Pathogen Type

Example Disease Caused by Pathogen Type


Chicken Pox


Strep Throat


Ring Worm



Worm (also known as parasite)

Tape Worm


How do pathogens spread?

Now that we know about pathogens, the first step in protection is understanding how they spread.  There are a multitude of ways pathogens can spread.  It can depend on the pathogen type and environmental conditions.  Following segments of the information series will go in detail by pathogen type and therefore, we will provide the most common ways pathogens can spread.  The most common ways pathogens spread are exchanges of bodily fluids, skin-to-skin contact, droplets from sneezes and coughs, contaminated surfaces and inanimate objects, human or animal fecal consumption, and insect bites (National Geographic, n.d.). 

How to prevent the spread of pathogens?

Since we know how pathogens spread, we can take the appropriate counter measures.  This includes the following:

  • Stay away from others when you are sick
    • This includes other members inside your household
    • Quarantine yourself to one room or area of the house until medical resources have cleared you from the disease
  • Limit touching surfaces and inanimate objects while sick
    • Routinely clean and disinfect surfaces
    • Routinely clean and disinfect commonly used inanimate objects (TV remote, pens/pencils, keyboards, computer mouse)
  • Do not engage in high risk sexual activities
    • Avoid unprotected sex with a high volume of partners
    • Avoid unprotected sex with unknown partners
  • Thoroughly wash your hands
    • After you use the bathroom
    • After you touch high frequency surfaces (countertops, door knobs, desks, etc.)
  • Wear a mask and social distance if you absolutely have to be around people
    • When you are sick
    • When others are sick


Balloux, F. and van Dorp, L.  (2029, October 19).  Q&A: What are pathogens, and what have they done to and for us?  National Institutes of Health.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5648414/

Janeway, C., Travers, P., Walport, M., and Sclomchik, M. (2001).  Immunobiology: The Immune System in Health and Disease. 5th edition.  National Institutes of Health.  https://www.ncbi.nlm.nih.gov/books/NBK10757/

National Geographic.  (n.d.).  Methods of Disease Transmission.  National Geographic.  https://www.nationalgeographic.org/media/methods-disease-transmission/