Are Disease-Causing Agents Such as Bacteria and Viruses?

Infectious diseases are caused by microorganisms such as viruses^?, bacteria^?, fungi or parasites^?. Microorganisms that cause disease are collectively called pathogens.

Are all diseases are caused by a bacteria or a virus?

Many human illnesses are caused by infection with either bacteria or viruses. Most bacterial diseases can be treated with antibiotics, although antibiotic-resistant strains are starting to emerge. Viruses pose a challenge to the body's immune system because they hide inside cells.

Which term refers to a disease causing agent?

A pathogen or infectious agent is a biological agent that causes disease or illness to its host. The term is most often used for agents that disrupt the normal physiology of a multicellular animal or plant. However, pathogens can infect unicellular organisms from all of the biological kingdoms.