It is probable that a few tens of thousands had the flu but only the severely ill were admitted to hospital. Probably too late they identified the illness as a new flu and the appropriate medicine used.
That healthy adults were dying is also a worry and indicative of "cytokine storm" that causes many of the deaths associated with bird flues. It is hard to treat and doctors may not have seen it before. Why it is not showing up in patients in other countries is not known.
There is also conflicting information about the numbers that died. See