Pandemic

A pandemic is a disease that affects people or animals over an extensive
geographical area (from Greek pan+demos, all+people). Technically speaking
it should cover the whole globe and effect everyone. Fortunately there has
not been a pandemic on the true sense of the world.

Common killers and pandemics

Note that just because a disease kills a lot of people, it doesn't make it a
pandemic-a lot of diseases (for instance cancer) kill but they are a fact a
number of diseases lumped together for the sake of convenience.

Historical pandemics

There have been a number of significant pandemics in human history, all of
them generally zoonoses that came about with domestication of animals - such
as smallpox, diphtheria, influenza and tuberculosis. There have been a
number of particularly significant epidemics that deserve mention above the
'mere' destruction of cities:

   * Peloponnesian War, 430 BCE - An unknown agent killed a quarter of the
     Athenian troops and a quarter of the population over four years. This
     fatally weakened the dominance of Athens, but the sheer virulence of
     the disease prevented its wider spread.

   * Antonine Plague, 165-180 - Possibly smallpox brought back from the Near
     East; killed a quarter of those infected and up to five million in all.
     At the height of a second outbreak (251-266) 5,000 people a day were
     said to be dying in Rome.

   * Plague of Justinian, started 541 - The first recorded outbreak of the
     bubonic plague. It started in Egypt, reached Constantinople the
     following spring, killing (according to the Byzantine chronicler
     Procopius) 10,000 a day at its height and perhaps 40 per cent of the
     city's inhabitants, and went on to destroy up to a quarter of the
     population of the eastern Mediterranean.

   * The Black Death, started 1300s - eight hundred years after the last
     outbreak, the bubonic plague returned to Europe. Starting in Asia, the
     disease reached Mediterranean and western Europe in 1348 (possibly from
     Italian merchants fleeing fighting in the Crimea) and killed twenty
     million Europeans in six years, a quarter of the total population and
     up to a half in the worst-affected urban areas.

   * Cholera
        o first pandemic 1816-1826 - Previously restricted to the Indian
          subcontinent, the pandemic began in Bengal then spread across
          India by 1820. It extended as far as China and the Caspian Sea
          before receding.
        o The second pandemic (1829-1851) reached Europe, London in 1832,
          New York in the same year, and the Pacific coast of North America
          by 1834.
        o The third pandemic (1852-1860) mainly affected Russia, with over a
          million deaths.
        o The fourth pandemic (1863-1875) spread mostly in Europe and
          Africa.
        o The sixth pandemic (1899-1923) had little effect in Europe because
          of advances in public health, but Russia was badly affected again.
        o The seventh pandemic began in Indonesia in 1961, called El Tor
          after the strain, and reached Bangladesh in 1963, India in 1964,
          and the USSR in 1966.

   * The "Spanish Flu", 1918-1919 - Beginning in August 1918 in three
     disparate locations - Brest, Boston and Freetown - an unusually severe
     and deadly strain of Influenza spread world wide. The disease spread
     across the world killing twenty-five million in the course of six
     months; some estimates put the total of those killed worldwide at over
     twice that number. An estimated 17 million died in India, 500,000 in
     the USA and 200,000 in England. It vanished within eighteen months, and
     the actual strain was never determined.

The epidemic disease of wartime was typhus; because of this pattern it was
sometimes called Camp Fever. Emerging during the Crusades, it had its first
impact in Europe in 1489 in Spain. During fighting between the Christian
Spaniards and the Muslims in Granada, the Spanish lost 3,000 to war
casualties and 20,000 to typhus. In 1528 the French lost 18,000 troops in
Italy and lost supremacy in Italy to the Spanish. In 1542, 30,000 people
died of typhus while fighting the Ottomans in the Balkans. The disease also
played a major role in the destruction of Napoleon's grande armŽe in Russia
in 1811.

Encounters between European explorers and populations in the rest of the
world often introduced local epidemics of extraordinary virulence. Disease
killed the entire native (Guanches) population of the Canary Islands in the
16th century. Half the native population of Hispaniola in 1518 was killed by
smallpox. Smallpox also ravaged Mexico in the 1520s (killing 150,000
including the emperor in Tenochtitlan alone) and Peru in the 1530s, aiding
the European conquerors; measles killed a further two million Mexican
natives in the 1600s. As late as 1848-49 as many as 40,000 out of 150,000
Hawaiians are estimated to have died of measles, whooping cough and influenza.

There are also a number of unknown diseases that were extremely serious but
have now vanished and the etiology of the disease cannot be established.
Examples include the previously mentioned plague in 430 BCE Greece and the
English Sweat in sixteenth-century England which struck people down in an
instant and was more greatly feared even than the bubonic plague.

Concern about possible future pandemics

Diseases that may possibly attain pandemic proportions include Lassa fever,
Rift Valley fever, Marburg, Ebola and Bolivian haemorrhagic fever. As of
2002, however, the recent emergence of these diseases into the human
population means their virulence is such that they tend to 'burn out' in
geographically confined areas, or that their effect on humans is currently
limited.

AIDS can be considered a global pandemic but it is currently most extensive
in southern and eastern Africa and is restricted to a small proportion of
the population in other countries, and is only spreading slowly in those
countries. If there was to be a true destruction of life pandemic it would
be likely to be similar to AIDS, i.e. constantly evolving disease.

Antibiotic-resistant superbugs may also revive diseases previously regarded
as 'conquered'.

In 2003, there are concerns that SARS, a new highly contagious form of
pneumonia, may become pandemic.