An infectious disease is one that is caused by?

Answer 1

Infectious Diseases are caused by:

Bacteria

Viruses.

Fungi (funguses)

Spirochetes

Protozoa (tiny animals that you can't see)

and others, like worms (no, not earthworms) such as heartworms, tapeworms, and so on.

Also there are prions. This word stands for "protein infection". They are misfolded bits of protein with no nucleus or DNA. If they get into the bloodstream, they cause normally-folded proteins to "misfold" by copying the first prion(s). The brain is simply not able to cope with these strange forms, so is then said to be infected. Prion disease is always in the brain and always fatal. A good example is 'mad cow disease'.

Answer 2

Can be passed onto another person or living creature.

Answer 3

Pathogens