What are They? - Often, an epidemic will begin when a new disease is introduced to a population where that disease has never appeared before.
QUESTIONS: What are They? - They can also begin in areas where a natural disaster or a war has destroyed infrastructure, infected water, introduced a new disease, or lowered the disease resistance of the population.
Historical Pandemics - Another notable pandemic was the Spanish Flu, which killed between 50 million and 100 million people between 1918 and 1920 and made another 500 million or so sick. It got its name because people believed Spain was the hardest hit with the disease.
QUESTIONS: Historical Pandemics - In the 1800s and 1900s, there were seven cholera pandemics. Cholera, a bacterial infection of the small intestine, still kills over 100,000 people each year. Typhus, measles, tuberculosis, yellow fever, malaria, and HIV have also all caused pandemics.
What Is an Epidemic? - Infectious disease can spread if an area's food or water gets infected. Disease can also begin to spread rapidly because it has gotten more virulent (severe or harmful).
QUESTIONS: What Is an Epidemic? - Propagated outbreaks can also occur through the sharing of hypodermic needles. This is called vehicle-borne transmission because the shared item is acting as a vehicle to carry the disease from one person to another. Propagated outbreaks can also be vector-borne.
What Is A Pandemic? - According to the World Health Organization (WHO), pandemics generally unfold across six stages, beginning when a virus is found in animals, but not in humans, and officially becoming a pandemic when the virus has spread globally.
QUESTIONS: What Is A Pandemic? - Explain how the Black Death changed the course of European history.
The Black Death - The most up-to-date research on the pathogen suggests that it may have existed in Europe as much as 5,000 years ago. It was most common on ships. The situation became a pandemic because some rats would frequently find their way to shore in each port, bringing the disease to the population with them and eventually carrying the disease all over Europe and Asia.
QUESTIONS: The Black Death - The first major outbreak (the Plague of Justinian) was in 541 and 542 A.D., when it killed an estimated between 30 and 50 million people in Asia, North Africa, Arabia, and Europe.
The 1918 Flu - The flu made its first appearance in Europe, the United States, and parts of Asia in 1918 and swiftly spread around the world. It was called the Spanish Flu because people believed Spain was the hardest hit with the disease. But this was not true; Spain was just the only country accurately reporting on it.
QUESTIONS: The 1918 Flu - The flu is a type of virus called a coronavirus that attacks the respiratory system. It spreads from person to person through the respiratory droplets that leave a person's body when they cough or sneeze.
How to Stop Them! - An epidemic typically begins opportunistically by attacking the weakest and most susceptible people first. Those that survive develop an immunity. As the disease finds less and less hosts that it can easily attack, the epidemic eventually ends. Some illnesses are seasonal.
QUESTIONS: How to Stop Them! - A more modern-day example of a vector-borne disease is Malaria or the Zika virus, which are both transmitted by mosquitoes.
Pathogens and Biodiversity - According to scientists at Conservation International, the most important thing that we can do to prevent the next pandemic is to take better care of nature. Why? Because the appearance of nearly half of zoonotic pathogens since 1940 can be traced back to changes in land use, agriculture, or wildlife hunting.
QUESTIONS: Pathogens and Biodiversity - Biodiversity has the ability to restrain pathogens so that they don't make that leap, and preserving the biodiversity in one geographical location can prevent new pathogens from emerging and leaping into another.
Epidemiology - Epidemiology is the branch of medicine that studies the occurrence, spread, and possible control of disease. Englishman Jon Show is considered the Father of Epidemiology. Twenty years before the microscope was invented, Snow studied outbreaks of Cholera, a bacterial infection of the small intestine.
QUESTIONS: Epidemiology - Strangely, no cases of cholera appeared within a two-block area near the infected pump. His investigation into this anomaly found that this area was inhabited by workers at a local brewery who got their water from the Brewery's well rather than the pump, and who also drank a daily ration of malt liquor rather than water.
COVID-19 - The novel coronavirus COVID-19 first appeared in Wuhan, China at the end of 2019. The CO stands for corona, VI stands for virus, and D stands for disease. The 19 represents the year the virus first appeared.
QUESTIONS: COVID-19 - The virus affects different people in different ways. Some people only have very mild or moderate symptoms and are able to recover at home without any medical help, as if they simply had a bad cold. In these mild and moderate cases, symptoms may include fever, coughing, and shortness of breath. Some people have also reported having aches and pains, a sore throat, and (rarely) diarrhea, nausea, or a runny nose, similar to having the flu.