WASHINGTON - THE H1N1 flu virus continued to spread in the United States on Monday, as a key health official said the 2,600 confirmed cases represented just the tip of the iceberg of actual infections.

The official number of confirmed cases of the new flu strain given by health officials in Mexico on Monday was 2,059 infections and 56 deaths. Even though the virus was showing none of the severity of the 1918 influenza pandemic, which killed 50 million people around the world, health officials will continue to monitor it, in particular in the southern hemisphere, which is just beginning its cool-weather flu season, Ms Schuchat said. ... more

'That's a little bit lower than previously stated because we have been able to rule out some probable cases,' she told a news conference.

Earlier on Monday, the CDC had said on its website that 2,618 people in 44 states have tested positive for (A)H1N1, up 86 from the previous day.

Although the rate at which confirmed cases rose on Monday marked a sharp slow-down compared with Friday and Saturday last week, when some 600 new cases were reported by US health officials, Ms Schuchat predicted a steep uptick in confirmed cases as the week wears on.

'Many states did not report over the weekend, so we expect a big jump in the number of cases tomorrow,' she said, adding that the number of cases being confirmed as (A)H1N1 were probably just 'the tip of the iceberg.' That was in part due to the fact that the influenza outbreak caused by the new strain of virus in the United States has been relatively mild, similar to seasonal flu, and not everyone is seeking medical help or testing.

'We have seen that most people who have become ill with this virus tend to recover in a way that is similar as what we see with seasonal flu. The vast majority recover ... The vast majority don't need to get laboratory confirmation,' Ms Schuchat said.

The statistics being supplied by the states are only of people who go to a laboratory for a test to diagnose H1N1 flu, she said.

Her message that the confirmed cases were only presenting a small snapshot of the whole picture was confirmed by a report that will be published on Thursday in the journal 'Science', which was made available online ahead of publication 'because it contains important public health information.'

The report, compiled by the World Health Organization (WHO) Rapid Pandemic Assessment Collaboration, which includes CDC scientists, estimated that 23,000 people had been infected by the (A)H1N1 virus in Mexico, where the WHO first reported a fast-spreading outbreak of influenza late last month. -- AFP