organisms that are too small to be seen without using a microscope

microbe

a condition that disrupts processes in the body

disease

parasites that can reproduce only inside the cells of plants, animals and bacteria. Many diseases like common cold, influenza, chickenpox and cold sores are caused by these

viruses

small single-celled prokaryotes that sometimes grow in or on human tissue and cause disease

bacteria

often found on rotting materials in a forest; they cannot move and therefore live on other dead and decaying materials

fungi

a single-celled or multi-celled organism with a simple biological structure

protist

an organism that lives on or in another organism, it takes nourishment from its victim

parasite

occurs when an infectious disease spreads to many people in one particular geographic area, in excess of the number of cases that might usually be expected

epidemic

occurs when an infectious disease spreads to millions of people around the world

pandemic

conditions and practices that help to maintain health and prevent the spread of diseases

hygiene

agent that causes illness or disease

pathogen

the cells in which another organisms lives or feeds

host cell

a chemical that kills or inhibits growth of bacteria

antibiotic

any substance which is used to stimulate the production of antibodies, in turn providing immunity against one or a few diseases

vaccine

the process whereby a person is made resistant to a disease, typically by the administration of a vaccine

immunization

can spread among a population in various ways, such as transfer of body fluids or contaminated food or water

infectious disease

the spread of disease from one person to another by close contact

contagion

any organism that can transmit a disease from one animal or plant to another (e.g. ticks)

vector

a person who has one copy of a mutated (changed) disease-causing gene but has no symptoms or mild symptoms

carrier

any cell or organism that possesses a clearly defined nucleus (e.g. plants and animals)

eukaryote

individual microscopic organism with no nucleus (e.g. bacteria)

prokaryote

A measure of how fast a new disease/illness spreads in a population over a period of time

rate of infection