Epidemiology is the study of the distribution and determinants of health-related states or events in a specified population.

The three main modes of transmission for infectious diseases are contact, droplet, and airborne; fomite, vector, and animal; and waterborne, foodborne, and sexually transmitted.

Hepatitis A is an example of a contact-transmitted disease, which is spread through direct contact with an infected person or through contact with contaminated objects.

Mumps is an example of a droplet-transmitted disease, which is spread through respiratory droplets produced when an infected person coughs, sneezes, or talks.

COVID-19 is an example of an airborne-transmitted disease, which is spread through tiny respiratory droplets that can remain suspended in the air for long periods of time.

A reservoir is the person or animal that harbors and transmits an infectious agent to another person or animal.

A carrier is a person or animal that is infected with an infectious agent but does not show any symptoms of the disease.

The incubation period is the period of time from when an infectious agent enters the body until the onset of symptoms.

The infectious period is the period of time during which an infected person is capable of transmitting the infection to others.

Control is the process of stopping the spread of an infectious disease.

Eradication is the complete absence of a disease in a population.

Elimination is the reduction of the incidence of a disease to a very low level, but not complete elimination.

Prevention is the measures taken to prevent the occurrence of a disease.

Vaccination is an example of a primary prevention measure, which is taken to prevent the occurrence of a disease before it has a chance to develop.

Antibiotics are an example of a secondary prevention measure, which is taken to treat a disease after it has developed.

Isolation is an example of a tertiary prevention measure, which is taken to prevent the spread of a disease after it has developed.