Swine fever spreads to New York and Canada

Europeans were advised today by the EU Health Commissioner against all non-essential travel to Mexico or the United States. The warning came as 103 people were reported to have died in Mexico from the outbreak of swine fever virus, most of them young adults. In Mexico City, the normally teeming streets were eerily quiet on Sunday as the majority of the 20 million population heeded government warnings to stay at home.

Further outbreaks have been confirmed in the United States and Canada, countries which supply the majority of tourists to Mexico, and a single case in Spain. The US, where 20 people are confirmed to have caught the virus, including eight high school students in New York, has declared a public health emergency.

There is as yet no report of an outbreak in Britain. The British Airways cabin attendant reported yesterday to have been taken ill on a return trip from Mexico City to Heathrow, and displaying flu-like symptoms, was later given the all-clear. There are unconfirmed cases being investigated in Scotland, France, Israel, Australia and New Zealand.

There have been no deaths reported outside Mexico: in most confirmed cases in the US and Canada, people have been only mildly ill and have made a full recovery.

The fear of the World Health Organisation, the UN's health agency, is that the virus might mutate into a more dangerous strain. For the moment, the WHO is not declaring an international pandemic. This will be reviewed on Tuesday in Geneva.

WHAT IS THE VIRUS?
It is a flu virus that affects pigs, often hitting farms in autumn and winter. It rarely spreads to humans. But when it does, the outbreak begins with someone being in contact with an infected pig. It can spread, human to human, through coughing and sneezing. It cannot be spread by eating pork or pork products. The new strain belongs to the most common influenza sub-type H1N1.

WHAT ARE THE SYMPTOMS?
The same as with normal flu: fever, coughing, sore throat, body aches. Some patients have also reported diarrhoea and vomiting. In Mexico, those who have died suffered from pneumonia and respiratory failure.

WHO IS CATCHING IT?
According to reports so far, the new strain is most lethal to those in the 25 to 45 age range. This is ominous because it was the hallmark of the Spanish 1918 flu pandemic that killed tens of millions worldwide. However, the circumstances were quite different: many thousands of victims were young men recovering from service in World War One.

CAN THE VIRUS BE CONTAINED?
Too late. There are no travel restrictions into or out of Mexico, though the EU Health Commissioner has advised Europeans to avoid Mexico and the Unites States. In Mexico itself, mass gatherings are banned as are handshakes and and kisses on the cheek. Schools and universities are currently closed.

IS THERE A VACCINE?
No. In Britain two drug companies have been contracted to develop vaccines. Scientists at the National Institute for Medical Research in north London are reported to have spent the weekend working on virus samples provided by the US. Diagnostic kits designed to detect the new virus should be ready this week.

HOW WILL BRITAIN DEAL WITH AN OUTBREAK?
Because of the recent bird flu scare, Britain has a stockpile of the antiviral drugs Tamiflu and Relenza, enough to treat half the population. These drugs will not cure swine flu, but they should reduce its severity and help limit its spread while a purpose-made vaccine is developed - though to make enough for the majority of the population would take months.