Flu Pandemics in History

Influenza pandemics are believed to have occurred for at unpredictable intervals for many centuries. Since the first well-described pandemic of influenza-like disease occurred in 1580, 31 influenza pandemics have been documented.

In 412 BC Hippocrates, the father of medicine, described a flu-like disease for the first time at Perinthus in North Greece. Diodorus Siculus recorded an epidemic that swept through the Athenian army in Sicily. Some historians have speculated that influenza may have contributed to the demise of Athens in 404 BC.

The term, influenza, from the Italian word meaning "influence", was coined 1357 AD. Popular belief at that time blamed the development of flu on the influence of the stars.

In 1485 the "sweating sickness", a flu-like malady, sickened hundreds of thousands of people in Britain. The Lord Mayor of London, his successor, and six aldermen died. The Royal Navy could not leave port due to the sickness of sailors. Doctors prescribed tobacco juice, lime juice, emetics, cathartics, and bleeding in attempts to cure their patients.

The first recorded global spread of flu swept out of Asia in 1580, then infected Africa, Europe and ultimately America, where over 90 percent of the populace was afflicted. Mortality was extremely high, with doctors treating their patients by bleeding them.

During the 18th century at least three pandemics occurred (1729-1730, 1732-1733, and 1781-1782). The 1781 pandemic was a major outbreak that caused high mortality among the elderly that spread across Russia from Asia. Other major outbreaks occured in 1889-1890 and in 1900.

The Spanish Flu of 1918 is considered the most severe of all influenza outbreaks to date, but the pandemic of 1830 through 1832 was similarly severe - it simply occurred when the world's population was smaller. Four major influenza epidemics were recorded between 1830 and 1848. The 1830-1831 epidemic may have originated in China; and in 1833 influenza advanced westward out of Russia into Europe. In 1836-1837, influenza diffusion was largely north to south, and in 1847-1848 the disease swept through the Mediterranean to southern France and thence elsewhere in Western Europe. Each of the four epidemics spread rapidly and caused very high morbidity rates. Although case-mortality rates were always low, each epidemic killed thousands of people, with most deaths being among the elderly. Many writers have described all four outbreaks as pandemics, but true pandemics, presumably caused by major new viral types, are clearly identifiable only in 1830-1831 and 1833. The status of the 1836-1837 outbreak is unclear, but there was no pandemic in 1847-1848.

The 1889 pandemic was believed to have originated in China. It rapidly spread via Russia throughout Europe (known as the "Russian Flu"). It spread thence to North America and then Japan. It reached North America in December 1889 and spread to Latin America and Asia in February of 1890. Approximately 1 million people were known to have died as a result of this pandemic.

Recent Pandemic Flu Scares

The most recent pandemic "scares" was the Avian Flu Scare in 1997 and 1999. In 1997, at least a few hundred people became infected with the avian A/H5N1 flu virus in Hong Kong and 18 people were hospitalized. Six of the hospitalized persons died. This virus was different because it moved directly from chickens to people, rather than having been altered by infecting pigs as an intermediate host. In addition, many of the most severe illnesses occurred in young adults similar to illnesses caused by the 1918 Spanish flu virus. To prevent the spread of this virus, all chickens (approximately 1.5 million) in Hong Kong were slaughtered. The avian flu did not easily spread from one person to another, and after the poultry slaughter, no new human infections were found.

In 1999, another novel avian flu virus - A/H9N2 - was found that caused illnesses in two children in Hong Kong. Although both of these viruses have not gone on to start pandemics, their continued presence in birds, their ability to infect humans, and the ability of influenza viruses to change and become more transmissible among people is an ongoing concern.

Several novel virus alerts have been issued since 1977, none of which progressed to a pandemic. These include isolated cases and limited clusters of swine H1N1 influenza virus infections, avian H5N1 infections in 2003 (two persons hospitalized), avian H7N7 in 2003 (83 human illnesses, including one death), and avianH5N1 in 2004 (34 human illnesses, including 23 deaths as of May 2004). Control measures have included culling of poultry and protection of those who may have been exposed to the avian influenza virus, particularly those with high-level exposure (e.g., those doing the culling).

Very limited person-to-person transmission occurred during the 1976 Swine influenza outbreak in the US, the 1997 H5N1 avian influenza outbreak in Hong Kong, and also during the 2003 H7N7 avian influenza outbreak in the Netherlands. None of these outbreaks progressed to the next pandemic level possibly because none of these viruses were animal/human reassortants and, in case of the avian influenza outbreaks, aggressive efforts to eliminate the domestic animal reservoir were carried out.