Hong Kong has reported a big jump in the number of deaths from Severe Acute Respiratory Syndrome, despite efforts to contain the disease. The increase in deaths is raising speculation that something may be making the disease deadlier.

Seven more patients have died in Hong Kong from Severe Acute Respiratory Syndrome, the highest number of deaths in a single day in the city.

Forty more SARS patients have been admitted to hospitals. The city has seen almost 1,200 SARS victims, 47 of whom have died.

Five people died of the illness Sunday in Hong Kong. Those deaths stirred alarm because some of the victims were apparently healthy and relatively young adults. Previously, most of those killed by SARS were either elderly or suffering from a chronic illness.

The victims during the past two days include five people aged 40-52.

Dr. Liu Shao-haei, an official with the Hong Kong Hospital Authority, said he is saddened to see younger and fitter patients lose their battle with SARS. He said it too early to tell if the disease is now hitting younger people harder for some reason.

"I do not have a sort of concrete figure to give you. I must say no age is immune, but then we are seeing fewer of these cases in the very young," Dr. Liu said. He added that some otherwise healthy adults who died from the disease had sought medical help late in the course of the illness. Experts have said early treatment seems to benefit SARS patients.

Hong Kong news media reported several theories that the disease might somehow have become more deadly. But health experts say it is not clear why deaths have risen.

The continued spread of the disease confounds Hong Kong's efforts to contain it with quarantines and strict infection controls in hospitals. The city's chief executive, Tung Chee-hwa has said the virus is not yet "under effective control."

Worldwide, at least 3,300 people have been sickened by SARS and about 140 have died.

Two more people have died in Singapore recently, bringing that city's total to 12 deaths and 151 cases. Experts note that the death rate in Singapore is double the worldwide average, but say this does not necessarily mean the disease is more deadly there.

On Sunday, four more people in Singapore showed the flu-like symptoms and atypical pneumonia associated with SARS. Singapore continues to see a trickle of new cases, despite having acted quickly to try to contain the outbreak by quarantining hundreds of people and suspending school classes.