New Zealand and Israel confirmed cases of swine flu on Tuesday, the latest countries hit by a new strain that has killed up to 152 people in Mexico and threatens to become a pandemic. The World Health Organization (WHO) has raised its alert level to phase 4, indicating a significantly increased risk of pandemic. Here are details of the latest number of cases and some facts about previous influenza outbreaks: Influenza: Seasonal flu kills between 250,000 and 500,000 people globally in an average year. Here are some details of previous pandemics: Three worldwide (pandemic) outbreaks of influenza occurred in the 20th century, in 1918, 1957 and 1968. It is estimated that approximately 20 to 40 percent of the worldwide population became ill and more than 50 million people died in the earliest of the outbreaks. The most recent, between September 1968 and March 1969, killed 33,800 people. The three have been informally identified as Spanish, Asian, and Hong Kong influenza, respectively. They are now known to represent three different antigenic subtypes of influenza A virus: H1N1, H2N2, and H3N2, respectively. – ReutersCountry Death Suspected Confirmed Cases Cases Cases Mexico 152 1.600 20 US 0 51 68 Canada 0 6 13 Spain 0 25 2 Australia 0 16 3 New Zealand 0 43 11 Sweden 0 13 0 Britain 0 2 2 Germany 0 3 0 Israel 0 0 2 France 0 1 0 Norway 0 5 0 S. Korea 0 1 0 __
