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CAIRO, March 31 (Reuters) - Two Egyptian children have tested positive for the deadly H5N1 bird flu virus, bringing the total number of human cases in Egypt to 31, Egypt's Health Ministry said on Saturday.

The Health Ministry identified the children as 4-year-old Ibrahim Mahmoud Helmy of Qena province, around 670 kilometres (416 miles) south of Cairo, and 7-year-old Mahmoud Mohamed Shalaby of Sohag province, around 467 kilometres south of Cairo.

A World Health Organisation (WHO) official confirmed the two new cases.

Both cases were admitted to hospital on Thursday suffering from fevers after exposure to poultry, and both have been treated with the antiviral Tamiflu, the standard treatment for the symptoms of the disease, according to the statement.

Both were in stable condition and had been transferred to hospital in Cairo, it added.

Egypt has the highest number of confirmed human bird flu cases outside Asia.

Thirteen Egyptians have died from bird flu since it first surfaced in the country's poultry a year ago. Most of those who fell ill were reported to have had contact with sick or dead household birds, primarily in northern Egypt.

On Tuesday two children tested positive for bird flu, but are stable, according to the WHO official.

"They're all in stable condition and alive," said Hassan al-Bushra, regional adviser for communicable disease surveillance for WHO.

Health experts fear the H5N1 virus could mutate into a form that passes easily from human to human, sparking a pandemic that could kill millions.

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