Which kinds of microorganisms can cause infectious diseases?

In the field of microbiology, infectious diseases are caused by several distinct categories of organisms and agents. These are primarily classified as bacteria, viruses, fungi, and parasites.12

• Bacteria: These are common causes of infectious disease, ranging from mild skin infections to severe conditions like tuberculosis and bubonic plague. They induce disease through the production of exotoxins, the release of endotoxins upon cell disintegration, or by triggering immune sensitivity in the host.3
• Viruses: These agents can cause both acute and chronic diseases. While many viruses are harmless, others cause illness by destroying host cells or by triggering damaging immune responses.4
• Fungi: Fungal diseases, or mycoses, can range from superficial infections like athlete’s foot to severe, systemic conditions that affect internal organs.56
• Prions: Distinct from the categories above, prions are abnormal, misfolded proteins that lack nucleic acid. They cause fatal neurodegenerative disorders, such as Creutzfeldt-Jakob disease, by inducing normal proteins to adopt their harmful shape.7