A variety of microorganisms can cause disease. Pathogenic organisms are of five main types: viruses, bacteria, fungi, protozoa, and worms.

Which microorganism does not cause disease?

Nonpathogenic organisms are those that do not cause disease, harm or death to another organism and is usually used to describe bacteria. It describes a property of a bacterium - its ability to cause disease. Most bacteria are nonpathogenic.

Why do microorganisms cause disease?

Microorganisms that cause disease are collectively called pathogens. Pathogens cause disease either by disrupting the bodies normal processes and/or stimulating the immune system to produce a defensive response, resulting in high fever, inflammation^? and other symptoms.