Germs

Germs is a common term used to refer to microorganisms that can cause disease in humans, animals, or plants. In scientific usage, the word encompasses bacteria, viruses, fungi, protozoa, and sometimes prions. Most microorganisms are harmless or beneficial, forming the normal flora or microbiome that supports digestion, immunity, and environmental processes.

Germs are invisible to the naked eye and vary greatly in size, structure, and life cycle. Bacteria are single-celled organisms that can reproduce on their own. Viruses are smaller particles that require a host cell to replicate. Fungi range from yeasts to molds. Protozoa are single-celled eukaryotes. Prions are misfolded proteins that can cause neurodegenerative diseases.

Germs spread through various routes, including direct contact, droplets in the air, contaminated food or water, vectors like insects, and medical or environmental surfaces. The presence of germs does not always lead to illness; many exposures are controlled by the immune system or do not cause disease due to low virulence or dose.

Prevention focuses on reducing transmission and exposure: hand hygiene, safe handling and cooking of food, clean water, sanitation, vaccination, and appropriate use of disinfectants and sterilization. Antibiotics treat bacterial infections but are ineffective against viruses; vaccines can prevent many viral diseases. The study of germs informs public health, microbiology, and medicine, and ongoing surveillance monitors emerging pathogens and antibiotic resistance.