The following is a timeline of the spread of swine flu, officially known as influenza A(H1N1), since it was detected last month:

April 24

The World Health Organisation (WHO) announces that around 800 suspected cases of so-called swine flu have been recorded in Mexico, along with seven cases in the United States.

Schools, universities, theatres and museums are closed down in Mexico City and the centre of the country to prevent the spread of the virus.

April 25

WHO warns that the virus, identified as a member of the H1N1 family, has 'pandemic potential'. Mexico orders isolation of sick people.

April 26

The United States declares a health emergency after the confirmation of 20 cases in the country.

April 27

First three cases are confirmed in Europe.

WHO raises its alert level from three to four on a scale of six, signalling a "significant increase in risk of a pandemic". It warns that no region in the world is safe from the virus.

April 28

First cases confirmed in central America and the Middle East. Several countries suspend pork imports from infected regions.

April 29

A 23-month-old Mexican child is the first confirmed fatality in the United States.

WHO raises its alert level to five, calling on countries to prepare for an "imminent" pandemic.

The first cases involving people who had not visited Mexico are confirmed in the United States, Spain and Germany.

April 30

WHO adopts the term 'influenza A(H1N1)' after veterinary experts point out that the virus is not occurring among pigs.

May 1

Mexico begins a five-day shutdown over the holiday weekend in an attempt to contain the virus.

A Mexican man visiting Hong Kong becomes the first confirmed A(H1N1) case in Asia.

May 2

The WHO says there is no indication that A(H1N1) has begun to spread in a sustained manner anywhere outside North America.

May 3

Mexican authorities say the flu outbreak appears to be declining after having peaked last week, with fewer people now being admitted to hospital and with less severe symptoms.

May 4 The number of confirmed infections rises above 1000 and the WHO has so far confirmed 26 deaths — all but one of them in Mexico.

Mexico says it will begin to reopen schools, museums and theatres.

AFP