Public health is the study and practice of handling and managing any threats to the health of a community, with special attention to preventive measures. There is special attention paid to the social context of disease, health, and improving health through society-wide measures such as vaccination programs, the fluoridation of drinking water, testing for infectious diseases in humans in wildlife, for hazardous materials, and for pollutants in our water and air.
Public health can be divided into epidemiology, biostatistics, health services, environmental, social, behavioral, and occupational health.
Public Health in History:
In 1796, Edward Jenner created an experimental vaccination, an inoculation of a cow-pox virus to help build immunity against the deadly smallpox virus that was killing thousands of people. Interestingly, the term "vaccination" is a term that Jenner invented, derived from the Latin vacca, meaning a cow. The term vaccination was adopted by Pasteur for immunization against any disease.
In the 18th century, smallpox was a killer disease, more widespread than cancer and heart disease in the 20th century. The victims, however, were typically infants and young children.
The only way Jenner could have created such an impact on the world is by his observation that the deadly and common disease was a major cause of death in the 18th century. The process of vaccination was brought to England in 1721 from Turkey, a method that involved inoculating healthy people with substances from diseased people, however this often had deadly results. During the 1788 epidemic of smallpox in Gloucestershire, Jenner noticed that his patients who worked with cattle and had come down with a more mild disease called cowpox were never infected with smallpox. Such an observation gave rise to the cowpox vaccination that protected people from contracting smallpox.
Today, the world is essentially free of the scourge of smallpox due to Jenner's vaccination and the Public Health awareness of the need to vaccinate against smallpox throughout the world.
In 1980, as a result of Jenner's discovery, the World Health Assembly officially declared "the world and its peoples" free from endemic smallpox.
Definition of Terms:
Epidemic - affecting or tending to affect a disproportionately large number of individuals within a population, community, or region at the same time – Merriman Webster
Pandemic - occurring over a wide geographic area and affecting an exceptionally high proportion of the population – Merriman Webster
In terms of Public Health, contagious or communicable diseases that spread through a population at an alarming rate warrant attention. There have been epidemics throughout the world of different diseases, and while typically they are localized, they can cause many deaths. Public Health awareness as to the cause of the disease, how it is spread, and how to prevent it is paramount to the safety of a community.
According to the World Health Organization (WHO), a pandemic can start when three conditions have been met:
the emergence of a disease new to the population.
the agent infects humans, causing serious illness.
the agent spreads easily and sustainably among humans.
A disease or condition is not a pandemic merely because it is widespread or kills many people; it must also be infectious. Cancer is not considered a pandemic, even though it kills many people. It is not contagious.
There have been many pandemics recorded in human history, many of them are zoonoses, infections transmitted to humans from animals, such as tuberculosis and influenza.
- Peloponnesian War 430 BC. Typhoid fever killed 25% of the Athenian troops and population over four years. The disease weakened the dominance of Athens, but the disease burned itself out because it killed its hosts faster than they could spread it. Through evaluation of teeth of the victims it was discovered in 2006 that the scourge was due to typhoid.
- Antonine Plague 165 – 180. This was possibly due to smallpox brought to the Italian peninsula by returning solders, killing 25% of those infected, and taking the lives of over five million people. At the peak of the outbreak, over 5,000 people were dying every day in Rome.
- Plague of Justinian 541 to 750 is considered to be the first recorded outbreak of the Black Death, or bubonic plague. It is believed to have started in Egypt and reached Constantinople by the following spring. This plague killed 10,000 people a day at its peak, and killed over 30% of Europe's population.
- Black Death 1300 A return of the bubonic plague to Europe, started in Asia and reached the Mediterranean and western Europe in 1348. This plague killed between 20 and 30 million Europeans in six years.
- Cholera – First Pandemic 1816 – 1826 Began in Bengal then spread across India by 1820 reaching China and the Caspian Sea.
- Second Pandemic 1829 – 1851 was in Europe, Canada and the Pacific Coast of North America.
- Third Pandemic 1852 – 1860 affected mainly Russia killing over a million people.
- Fourth Pandemic 1863 – 1875 contained mostly in Europe and Africa.
- Fifth Pandemic 1866 – Contained mostly in North America.
- Sixth Pandemic 1892 – Contaminated a water supply in Hamburg, Germany, killing 8,606 people.
- Seventh Pandemic 1899 – 1923 Europe was spared because of advances in public health, but Russia was hit badly.
- Eighth Pandemic – Began in Indonesia in 1961 (El Tor strain), reached Bangladesh in 1963, India in 1964, and USSR in 1966.
- Influenza – First pandemic 1510 moving from Africa throughout Europe.
- Second Pandemic 1889 – 1890 Asiatic Flu Spread from Russia to North America in December 1889, South American, India, and Australia in 1890. Had a very high attack and mortality rate.
- Third Pandemic – Spanish Flu – 1918 – 1919 identified in Camp Funston, Kansas, and by October 1918 it had become pandemic throughout the entire world. This flu was very deadly, and killed over 50 million people worldwide.
- Fourth Pandemic – Asian Flu 1957 – 1958 an H2N2 causing 70,000 deaths in the U.S. after having spread from China in 1957.
- Fifth Pandemic – Hong Kong Flu 1968 – 1969 An H3N2 that caused about 34,000 deaths in the U.S. The virus was detected in Hong Kong in early 1968 and spread to the U.S.
- Typhus – Often called camp fever or jail fever due to its rapid spread in the cramped quarters of ships and jails. This was first recorded during the Crusades and has appeared throughout the world killing soldiers, prisoners, and citizens throughout the world.
- Colonization Diseases – When the European explorers discovered new worlds, they brought with them diseases that were very virulent. Disease killed the entire population of the Canary Islands in the 16th century. Smallpox killed half the native population in Hispaniola, Mexico, Peru, and Native Americans. Measles has killed millions of Mexican natives. It is believed that 90 to 95 percent of the Native American population of the New World is due to Old World diseases.
Other Lethal Diseases: