The World Health Organisation (WHO) on Monday said it was on maximum alert for the rapid spread of bird flu cases across the world.
Since last November, more than 40 countries have reported fresh cases of the virus, WHO Director-General Margaret Chan said.
"The rapidly expanding geographical distribution of these outbreaks and the number of virus strains currently co-circulating have put WHO on high alert," Chan told the executive board of the United Nations health organization in Geneva.
She called upon all countries to closely monitor bird flu outbreaks in poultry and potential human cases, Efe news reported.
Chan added it was not possible to rule out the possibility of human to human infection in two of the reported cases, but added that these examples were not serious strains of the virus.
Of the viral strains of bird flu that have transmitted to humans, Chan mentioned H7N9 - prevalent since 2013 in China with more than a thousand cases and a mortality rate of 38.5 per cent.
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New strains have also appeared recently, such as the H5N6 outbreak in Asia -- the product of a four-way genetic exchange with other bird flu strands.
Other countries which have recently been affected by bird flu outbreaks include Chile, Croatia, Japan and Taiwan.
There was an unforeseen uptick in bird flu cases, including potent strains, since December, said Chan, for which she asked the international community to fulfil its duty by reporting cases early so that human cases can be identified.
--IANS
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