Medically speaking on epidemic is defined as a widespread occurrence of a disease in a community of a particular time.

Key to this definition is the word occurrence.

On epidemic is an event in which a disease is actively spreading.

In contrast, the term pandemic relates to geographic spread and is used to describe a disease that affects the whole country or the entire world.

While casual use of epidemic may not require such nuance, it's important to know the differences between these two terms and similar ones, like outbreak and endemic when considering public health news.

In addition, from an epidemiologic standpoint, terms like these direct the public health response to better control and prevent a disease.

Common confusion.

While epidemic is typically used to describe matters of health, for example, the opiate crisis in America has grown to epidemic proportions.

It is sometimes used colloquial way to describe behavior.

There's an epidemic of tantrums among preschoolers or behavioral phenomena such as epidemic hysteria.

While the usages are not inappropriate in the modern context, they can cause confusion.

In addition, even when the word is used to define health issues, it may not accurately depict the scale or progression of the disease.

In some cases, terms like outbreak or endemic may be more appropriate in others.

Epidemic may fall short in describing the scale of the problem and be better defined as a pandemic disease Event Classifications Epidemiology is the branch of medicine that deals with the incidents, distribution and control of diseases in the United States.

The main body collecting and overseeing this data is the Centers for Disease Control and Prevention.

CDC.

Among its many functions, the CDC is tasked with directing the appropriate response to a disease occurrence.

While the level of disease occurrence can be described in many ways, it is primarily defined by two measurable factors.

The pattern and speed by which a disease moves known as the reproduction rate the size of the susceptible population.

Known as the critical community size definitions based on the disease prevalence incidents and the known or unknown disease pathways.

There are several ways an epidemiologist might describe a disease event.

Sporadic refers to a disease that occurs infrequently or irregularly, food burn pathogens such as salmonella or E.

Coli can often cause sporadic disease outbreaks.

Cluster refers to a disease that occurs in larger numbers, even though the actual number or cause may be uncertain.

An example is the cluster of cancer cases often reported after a chemical or nuclear plant.

Disaster endemic refers to the constant presence and or usual prevalence of a disease in a geographic population.

Hyper endemic refers to persistent high levels of disease well above what is seen in other populations.

For example, HIV is hyper endemic in parts of Africa, where as many as one in five adults has the disease and endemic in the United States, where roughly one in 300 is infected.

Epidemic refers to a sudden increase in the number of cases of a disease above what is normally expected outbreak.

Kerry is the same definition as an epidemic, but is often used to describe the more limited geographic event.

Pandemic refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people.

By contrast, a plague is not an epidemiologic term, but one that refers specifically to a contagious bacterial disease characterized by fever and delirium such as bubonic plague.

Epidemic versus Pandemic.

While the terms may suggest that there is a specific threshold by which an event is declared an outbreak, epidemic or pandemic, the distinction is often blurred, even among epidemiologists.

Part of the reason for this is that some diseases become more prevalent or lethal overtime, while others become less, forcing the CDC to regularly adjust its statistical models.

The CDC also recognizes that certain terms can incite undue panic.

One such example is the Zika outbreak of 2016 which triggered alarm in the United States when seven cases were identified in Florida and Texas.

Even with H I V, a disease spread across much of the planet, the term pandemic has been increasingly replaced by epidemic, given the widespread distribution of effective treatment and decreasing rates in some previously hyper prevalent regions.

On the other hand, as influenza becomes more virulent year after year, public health officials will commonly refer the seasonal outbreaks as pandemics, particularly given the 2009 H one and one outbreak in the United States in which over 60 million Americans were affected, resulting in 274,304 hospitalizations and 12,469 deaths.

This is not to suggest that pandemics are approached in the same way as a more constrained outbreak, given the need for international cooperation.

On the flip side, on Outbreak may be treated no less aggressively than a pandemic if it has the potential to expand beyond its borders, such as may occur with the Ebola virus.

Phases of a pandemic.

While there are procedural steps, the CDC will take to evaluate and classify a disease event, the actual staging of an epidemic essentially the outline as to when the spread of disease is severe enough to take specific actions can vary based on the pathogenesis pathway of a disease and numerous other epidemiological factors.

The one staging model used to direct the public health response specifically involves influenza the flu.

In 1999 the World Health Organization W H O released the very first influenza pandemic preparedness plan in which it outlined the appropriate response based on six clearly outlined phases.

The aim of the plan is to coordinate the global response by providing countries of blueprint from which to draw up their own national strategies based on available Resource is the United States released its first pandemic influence a plan in 2005.

The same basic model can be applied with variations to other epidemics such as tuberculosis, malaria and the Zika virus.

Phases one through three are designed to help public health officials know it is time to develop the tools and action plans to respond to an impending threat.

Phases four through six are when action plans are implemented in coordination with the w h o the W.

H O.

Revised the phases in 2009 to batter distinguish between preparedness and response.

The plan is solely intended to address influence of pandemics, given their high mutation rate on the viruses ability to jump from animals to humans.

W H o Stages of a flu pandemic.

Phase one is the period during which no animal viruses are reported to cause infection in humans.

Phase two is the first level of threat where in a virus is confirmed to have jumped from an animal to humans.

Phase three is when sporadic cases or small clusters of disease are confirmed.

But human to human transmission has either not occurred or is considered unlikely to sustain an outbreak.

Phase four is the point where either human to human transmission or human animal virus has caused a community wide outbreak.

Phase five is when human to human transmission of the virus has caused the spread of disease tau at least two countries.

Phase six is the point at which the disease is declared a pandemic, having spread to at least one other country.

The timeframe for each phase can vary significantly, ranging from months two decades.

Not all will progress to phase six, and some may even revert if a virus spontaneously weakens notable pandemics in history.

In addition to HIV, which has killed over 39 million people since 1982 there have been other, equally devastating pandemics in history.

The plague of Justinian of 5 41 a.

D.

Was attributed to the bubonic plague and wiped out half of the population of Europe.

25 million in one year.

The black plague, which stretched from Asia to Europe, killed more than 75 million people from 13 47 to 13 53.

The first cholera pandemic of 18 16 to 18 24 extended from India to Indonesia and Russia, killing over 40 million.

The Spanish flu pandemic of 1918 killed well over 50 million people in one year, including 675,000 Americans.

The smallpox pandemic of the 20th century claimed between 300 to 500 million lives and as many as 50 million per year until the development of the sock vaccine in 1955.

The ongoing tuberculosis pandemic continues to kill over 1.5 million people annually.

Despite the availability of the effective treatment, multidrug resistance has staved Jeffords to reverse the progression of the pandemic.