A number of communicable diseases can constitute
significant threats at local, regional or global levels
leading to epidemics or pandemics. An epidemic
refers to an increase, often sudden, in the number
of cases of an infectious disease above what is
normally expected in a given population in a specific
area. Examples of major epidemics include cholera
and diarrhoeal diseases, measles, malaria, and
dengue fever. A pandemic is an epidemic of infec-
tious disease that spreads through human popula-
tions across a large region, multiple continents or
globally. These are diseases that infect humans
and can spread easily. Pandemics become disasters
when they cause large numbers of deaths, as well
as illness, and/or have severe social and economic
impacts. Concerns exist about potential pandemic
diseases including new strains of influenza, such as
severe acute respiratory syndrome (SARS), Middle
East respiratory syndrome (MERS) to which humans
may not have immunity. In the past, pandemics
have included cholera, smallpox, leprosy, measles,
polio and yellow fever.
• Epidemics and pandemics can be:
• Airborne: transmitted by air and droplets, for ex-
ample, flu, measles, SARS, MERS;
• blood and/or body fluids borne: transmitted
through contact, including blood transfusion,
mother to child in utero, and sexual activity, for
example, Ebola virus, HIV;
• waterborne: transmitted by water, for example,
cholera;
• zoonotic: transmitted between animals and peo-
ple, by direct and indirect contact, for example,
viruses, bacteria, parasites, and fungi;
• vector-borne: transmitted by being bitten by
mosquitos, fleas, ticks etc., for example, malaria,
dengue, plague; and
• food-borne: transmitted by preparing and eating
food, for example, salmonella, listeria and hepa-
titis A.
Epidemics and pandemics can be prevented and
mitigated through a range of household and commu-
nity measures, such as:
• good hygiene and sanitation
• access to clean water
• handwashing
• vaccination
• use of antiviral medications
• social distancing
• good clinical practice
• proactive surveillance
• early warning systems
• vector control
• access to safe food.
