With the constant media coverage of diseases like the zika virus, ebola, H1N1 and the yearly
flu, we keep hearing about the threat of epidemics and pandemics, but what do these really mean
when it comes to disease emergence and spread?
The baseline or endemic level of a disease, is the amount that is usually present in a
given community.
An epidemic is a drastic increase in the number of people infected with that disease, in that
same community.
A pandemic refers to an epidemic that has spread to several countries or continents,
affecting a large number of people.
So what can cause an epidemic?
Epidemics can be caused by a couple different factors including:
• An increase in the amount of a disease or its virulence
• Its appearance in a new location • An enhanced mode of transmission
• A change in the susceptibility of the host to being infected
and • Increased host exposure or a new method
of host infection
3 common ways epidemics can be spread are: • From a common-source, where a group of
people are all exposed to an infectious agent or toxin from the same source
• By propagated outbreak, with transmission from one person to another
Or • Using a vector or carrier (like mosquitoes)
that interact with humans and transmits the disease
To classify the spread of disease as a pandemic, there need to be community level outbreak
epidemics in at least one other country in a different world health organization defined
region, which means the disease is starting to spread around the world.
By this time the respective governments of outbreak-stricken countries should have taken
action to halt disease progression and implement national health strategies.
So next time you hear about epidemics and pandemics on the news, you don’t need to
prepare to flee to Antarctica. Take some time to learn more about the disease, how it’s
spread and where it is prevalent, to keep yourself safe.
For more information please visit the WHO’s website at www.who.int