An American schoolteacher in China who was infected with SARS -- Severe Acute Respiratory Syndrome -- has died from the flu-like illness that is sweeping across Asia. 52-year-old James Salisbury - an English teacher in Shenzhen - was brought across the border to Hong Kong where he was pronounced dead. Hong Kong health officials reported 42 new cases of SARS today, and two more deaths ? bringing the total of 27. Mainland China -- where the flu-like illness is believed to have started -- has reported 53 deaths out of nearly 1,300 cases. As David Cohler reports, experts from the World Health Organization want China to extend its measures to control the disease:

A letter from a Chinese military doctor obtained by Reuters news agency accuses the Chinese Health Ministry of covering up the true extent of the SARS outbreak. The ministry denies the accusation. But on Wednesday, the World Health Organization asked China to conduct an extensive investigation in the capital, Beijing.

In Hong Kong, the outbreak remained centered at a public housing project in Kowloon. Some officials speculated that cockroaches may have carried SARS-tainted waste through sewage pipes. Others speculated that the spread of the disease was facilitated by poor ventilation and poor hygiene.

In the United States, which has reported 150 SARS cases but no deaths so far, the head of the Centers for Disease Control, Dr. Julie Gerberding, told Congress her agency is taking the outbreak very seriously,

"We have to be prepared for this to continue to spread. And we are doing everything that we can across the public health system, the scientific system, as well as the research system, to be out in front of it."

In Singapore Wednesday, health officials reopened some of the schools that were closed in late March because of the SARS outbreak there. But health teams increased their presence at Changi Airport, to screen for possibly infected passengers from China and Hong Kong.