Mexico doesn't know origin of swine flu virus

Mexico City, April 30 (EFE) The origin of the swine flu outbreak provisionally blamed for 159 deaths in Mexico could be either Asia or the US, the chief epidemiologist of the Latin American country has said.

The virus's genome sequence 'corresponds to a Euro-Asiatic strain... (and) it's very likely that that strain is not found circulating in swine' in the Americas, Miguel Angel Lezana told reporters here Wednesday.

'The recombination of the virus could have occurred in Asia' and been carried to the Americas by a traveller, he added.

Lezana ruled out the idea that the virus had mutated in La Gloria, a highland town in the Mexican Gulf coast state of Veracruz, where the first case was detected.

He said the theory that a complex of 16 nearby pig farms was where the virus developed was not plausible because the installation is located 80 km away and because none of the residents of La Gloria work there.

According to Lezana, the agriculture secretariat 'did a very careful study' of the farm and 'did not find infected pigs' there.

Lezana said that 'the virus is incapable of reproducing by itself' and had to have had 'human transmission'.

He also stated that the first casualty of the flu, a 39-year-old woman in the neighbouring state of Oaxaca who died April 13, worked as a survey-taker for the Tax Administration Service, and 120 people with whom she had contact before dying have been tested for the flu.

In Mexico, the number of confirmed deaths from the virus was revised downward to seven from the 20 that had been counted before, and there have been 2,498 potential cases tallied.

Seven other countries have documented confirmed cases of infection with the A/H1N1 virus, while the United States has reported its first fatality from the current outbreak.

Authorities in Mexico City have intensified preventive health measures by closing leisure and entertainment locations along with part of the capital's 35,000 restaurants.

The new restrictions have practically paralyzed a metropolitan area that is home to nearly 20 million people.

Schools, colleges and day care centres across Mexico were ordered to close until at least May 4.

The effects of the swine flu outbreak on the Mexican economy are becoming quite evident in the tourist sector, for instance.

The 17 cruise ships that were supposed to arrive this week at the Cozumel and Mahahua ports of Mexico have now temporarily cancelled their stopovers. This will prevent about 35,000 passengers from travelling vacation spots along Mexico's Caribbean coast, causing a loss of an estimated 40 million pesos ($2.9 million) in revenue.