Timeline: Swine Flu Outbreak

26 April

The New Zealand health minister, Tony Ryall, says 10 students who travelled to Mexico have tested positive for flu and it was "likely", though not definitely, swine flu.

25 April

Mexican health officials say there are now more than 1,300 suspected cases and 81 deaths "probably linked to the virus". The US Centers for Disease Control (CDC) reports it has so far confirmed 11 cases of swine flu: seven in California, two in Texas and two in Kansas. There are also eight suspected cases in New York City after 200 students at a high school fell ill, according to the city health commissioner, Dr Thomas Frieden. Meanwhile, Northwick Park Hospital in Harrow, north London, says tests for swine flu on a British Airways cabin crew member proved negative.

24 April

Mexican authorities say they have identified more than 900 suspected cases and 62 deaths linked to swine flu. These include 854 cases of pneumonia in Mexico City, of which 59 have proved fatal. In San Luis Potosi, 24 cases of flu-like illnesses have been detected, including three deaths. In Mexicali, near the border with the United States, there have been four cases of flu-like illnesses, with no fatalities.

23 April

Mexican health authorities say the outbreaks in the country and in the US appear to be linked. The US identifies another seven cases: five in southern California and two in a town close to San Antonio in Texas.

22 April

The Mexican Health ministry issues a nationwide alert after learning that 20 people across the country have died from a flu-like illness this year. Tests on Mexican samples in Canada confirm that the swine flu stain identified in those cases is the same as that in the Californian outbreak.

21 April

The US confirms two children in California have tested positive for swine flu. The 10-year-old boy and nine-year-old girl live in two adjacent counties of the state, around 210km apart.

16 April

The Mexican health department notifies the Pan-American Health Organization (PAHO), part of the WHO, of its swine flu outbreak.

12 April

A 39-year-old woman infected with swine flu dies of severe viral pneumonia in San Luis Potosi, a city in central Mexico.

18 March

Mexican health authorities begin picking up outbreaks of flu-like illnesses.