Having two dozen "astronauts" turn up on her front door at the weekend and a policeman guarding it ever since has not gone down well with Mexico's Rosy Whitehead.

But her American husband is more philosophical about China's response to the flu.

"They just want to keep everyone healthy," Neil Whitehead told China Daily by phone yesterday, his fourth day in house-bound quarantine in Shanghai.

"The government's primary concern is public safety. Sure we're inconvenienced, but it's keeping everyone healthy, and it's keeping people from panicking.

"This is a little boring for us, being in the house, but we'll do whatever they tell us to do," added Whitehead. The two language teachers have lived in Shanghai for seven years.

Rosy Whitehead and her husband are under observation because her brother-in-law, Celestino Alcala, flew to the city on Thursday on the same flight as a 25-year-old Mexican man who was subsequently diagnosed by Hong Kong authorities as having been infected by H1N1 influenza.

The Whiteheads are among dozens of foreigners, including Mexicans, Americans and Canadians, under a strict medical quarantine nationwide for fear the deadly virus could spread to China.

As of yesterday, there was no other confirmed case in the country, nor did anyone show symptoms in major cities.

The Mexican government criticized China over the weekend for quarantining Mexican nationals and suspending flights to the Central American country to help stem the spread of the flu.

The Foreign Ministry yesterday said China's quarantine measures were in line with the Law on the Prevention and Treatment of Infectious Diseases, and the Frontier Health and Quarantine Law of China.

Gabriela Johnson, a 35-year-old Mexican housewife, thought China was working "too hard" in following the example set by Western countries five years ago during SARS.

"But during SARS, Mexico didn't cancel flights to China," she said.

Her compatriot Guillermo Garcia said he was concerned by the amount of misinformation by various governments and the media.

"I think information has sometimes been exaggerated," he said. "At first they said there were almost 200 casualties in Mexico, then, a week later, it happened to be 17, so this is kind of strange. The image of Mexico has been very damaged."

Yet the majority of European and American expats interviewed by China Daily supported the government's response to the threat of yet another potential scourge in the wake of SARS, bird flu (2004) and recent reports of hand-foot-and-mouth disease in Anhui province.