IMMUNOLOGY

Detailed explanation-1: -Epidemic refers to an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area. Outbreak carries the same definition of epidemic, but is often used for a more limited geographic area.

Detailed explanation-2: -A pandemic is the worldwide spread of a new disease. Viral respiratory diseases, such as those caused by a new influenza virus or the coronavirus COVID-19, are the most likely to turn into a pandemic. A pandemic is not the same as an epidemic.

Detailed explanation-3: -Examples include a national flu pandemic or the threat of water-borne diseases after natural disasters or other emergency situations.