Throughout history, pandemics have posed some of the greatest threats to mankind, claiming more lives than all wars and accidents put together. One well known pandemic is cholera, which was widespread in the 19th century and killed tens of millions of people. Another example is tuberculosis, which killed around one quarter of the European population, also in the 19th century.

Two more recent examples of pandemics include human immunodeficiency virus (HIV) and the H1N1 pandemic of 2009.

The 2009 influenza A pandemic

Influenza A H1N1 was a new strain of the influenza A virus that was responsible for most cases of human flu in 2009.

In the latter half of April that year, the World Health Organization upped its pandemic alert from a level three to a level five. On 11th June, the alert level was further raised, to a level six, which is the highest level for a pandemic. The virus spread globally and caused around 17,000 deaths by the beginning of 2010.

The pandemic was declared to be over in August 2010, as announced by the World Health Organization (WHO) who said that flu activity had returned to the usual seasonal patterns.

HIV and AIDS pandemic

HIV infection first began in Africa and then spread to Haiti. From there, it spread to the United States between 1966 and 1972 and then onto other nations of the world. HIV is now a pandemic and in southern and eastern Africa, around one in four individuals are infected.

In South Africa, the prevalence of this infection among pregnant women in 2006 was 29.1%. Public education campaigns about sexual health and infection prevention have helped to reduce infection rates in some African countries. In Asia and the Americas, however, the number of people infected is now on the rise again and AIDS is estimated to kill between 90 and 100 million people in Africa by the year 2025.