Two people who died from H5N1 bird flu in Egypt last month had a strain of the virus that was resistant to the key anti-viral drug Tamiflu, the World Health Organization said last night.

The resistant strain, known as 294S, first emerged in Vietnam in 2005. However, events in Egypt have provided the first evidence of it spreading beyond Asia, WHO experts said. "What we've confirmed is that H5N1 viruses isolated from two patients in recent cases in Egypt both showed this so-called 294S change," Dr Keiji Fukuda, coordinator for the WHO's global influenza programme, told Reuters.

"But, based on what we see from laboratory tests, we expect any reduction in sensitivity or increase in resistance is going to be on the moderate side.”

As a result, the WHO said there were no immediate plans to change its recommendation to treat bird flu patients with Tamiflu (oseltamivir). The Roche drug is currently being stockpiled by governments worldwide for use in the event of an influenza pandemic.

However, Dr Anne Moscona, an expert on flu treatment at Weill Cornell Medical College, said that the development “is not a big surprise, but it certainly is disheartening." She told the New York Times that the latest development suggested that doctors might have to consider switching to a cocktail of drugs as first-line treatment, as is done with AIDS medications and sometimes with antibiotics.

The Tamiflu-resistant strain in Egypt was susceptible to Relenza, and also to amantadine, an older drug that is not normally used as a first-line treatment because many avian flu strains are resistant to it.

Questions raised over sole Tamiflu route

In the UK, some scientists and the House of Lords Science and Technology Committee have questioned the Government’s decision to stockpile only Tamiflu as a contingency against a flu pandemic, which many experts fear will arise if or when H5N1 mutates sufficiently to enable human-to-human transmission.

The UK Department of Health has already placed an order for 14.6m courses of Tamiflu to cover a quarter of the population in the event of such a pandemic. In the Egyptian cases a girl and her uncle died from the flu strain in late December. The death of the man’s 35-year-old sister is also though to be due to H5N1, although this has not yet been confirmed.

The three – who lived together in Gharbiyah province, 50 miles north-west of Cairo – fell ill within days of one another after exposure to sick ducks.

"Based on the information we have, we can’t yet rule out human-to-human transmission," said Dr Fred Hayden, a WHO bird flu and antivirals expert. "We need to better understand the dynamics of this outbreak."

Egypt, which announced on Wednesday it was treating another bird flu patient, has recorded 10 deaths among 19 confirmed human cases -- the largest toll outside Asia. Worldwide, there have been 161 fatalities among 267 known cases since 2003. By Michael Day

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