WHO reports 2,099 cases in 23 countries

The World Health Organisation says influenza A (H1N1) has infected 2,099 people in 23 countries, killing 44. According to WHO spokesman Keiji Fukuda, it is "reasonable" to estimate that a third of the world's population could catch the virus.The World Health Organisation on Thursday said that in a pandemic situation it was "reasonable" to estimate that a third of the world's population would catch the swine flu virus."If you look at past pandemics, it would be a reasonable estimate that a third of the population would be infected" if the current swine flu outbreak became a pandemic, said Keiji Fukuda, acting assistant director general of the UN health agency.Fukuda had made the point in response to mounting concerns that the WHO may have over reacted given that most swine flu cases have turned out to be mild.The WHO had raised its pandemic alert level to five out of six last week, signaling that a pandemic was "imminent" after the flu appeared to be spreading locally not just in Mexico but also in the United States.The move prompted countries to activate their pandemic alertness plans.Fukuda said when considering how to deal with such outbreaks, the WHO has to take into account the fact that in a full-blown pandemic, even if only a small percentage of people were to develop serious illness or die from the disease, it would translate into a large absolute number of people.