Human Biology

(Sean Pound) #1

http://www.ck12.org Chapter 1. Human Biology


1.53 Pathogens



  • List common causes of infectious diseases and how they are spread.


What are germs?


You know germs can make you sick. They can live anywhere, from on your doorknob to in your food. A more
scientific word for germ is pathogen.


Pathogens


Has this ever happened to you? A student sitting next to you in class has a cold. The other student is coughing and
sneezing, but you feel fine. Two days later, you come down with a cold, too. Diseases like colds are contagious.
Contagious diseases are also called infectious diseases. Aninfectious diseaseis a disease that spreads from person
to person.


Infectious diseases are caused by pathogens. Apathogenis a living thing or virus that causes disease. Pathogens
are commonly called “germs.” They can travel from one person to another.


Types of Pathogens


Living things that cause human diseases include bacteria, fungi, and protozoa. Most infectious diseases caused by
these organisms can be cured with medicines. For example, medicines called antibiotics can cure most diseases
caused by bacteria. Bacteria are one-celled organisms without a nucleus. Although most bacteria are harmless,
some cause diseases.

Free download pdf