Infection, disease and immunity (4)

Pathogen

A biological agent capable of causing disease.

Infectious disease

A disease caused by a pathogen that can potentially spread between people, animals, or through the environment.

Non-communicable disease

A disease that is not caused by an infectious pathogen and does not spread from person to person in the usual way.

Bacteria

Single-celled organisms; some are harmless or beneficial, while others can cause disease.

Virus

A microscopic infectious agent that must use a host cell to reproduce.

Fungus

An organism such as a yeast or mold; some fungi can cause infections.

Parasite

An organism that lives on or in a host and obtains resources from the host.

Direct transmission

Spread through direct physical contact or close interaction between an infected source and another person.

Respiratory transmission

Spread through respiratory particles released when an infected person breathes, talks, coughs, or sneezes.

Contaminated-source transmission

Spread through contaminated food, water, objects, or other sources.

Blood/body-fluid transmission

Spread through contact with infected blood or certain body fluids.

Vector transmission

Spread through another organism, such as a mosquito or tick, that carries a pathogen.

Immune response

The body’s coordinated response to recognize and defend against harmful foreign substances or pathogens.

Innate immunity

The body’s immediate, non-specific defence mechanisms.

Adaptive immunity

A more specific immune response that develops after exposure and can produce immune memory.

Antibodies

Proteins made by certain immune cells that specifically bind to foreign substances such as antigens.

Antigen

A molecule or structure recognized by the immune system that can trigger an immune response.

Vaccination

A method of preparing the immune system to recognize a pathogen or part of it and respond more effectively in the future.

Immune memory

The ability of the adaptive immune system to respond more rapidly and effectively after a previous exposure.

Antibiotics

Medications used to treat certain bacterial infections.

Why antibiotics do not treat viruses

Viruses reproduce using host cells and do not have the bacterial structures or processes targeted by antibiotics.

Antibiotic resistance

The ability of bacteria to survive antibiotics that would normally inhibit or kill them.