Bird flu remedy works on mice

Dubai: Scientists hailed a bird-flu breakthrough last night as mice were immunised against the H5N1 strain.

The successful immunisation resulted from antibodies taken from bird-flu survivors, an obvious but complex manoeuvre that has taken years to perfect.

"This is not the silver bullet but it is very promising,'' Thomas Brooks of the Swiss Institute for Research in Biomedicine, where the antibodies were isolated, told Gulf News last night.

Brooks, however, warned that a vaccine would not automatically follow on.

"Ten years ago, people were saying we would have a vaccine for malaria, that has not happened yet, but this has worked in mice, maybe it can work in humans."

The World Health Organisation (WHO) estimates that there had been 306 known cases of bird flu in humans up until mid-May. Of these, 185 were fatal, a death rate of about 60 per cent.

Guarded optimism

The WHO cautiously welcomed the news. "It is too early to tell, but it is interesting,'' spokesman Gregory Hartl said.

The breakthrough came, in part, from work carried out to tackle Severe Acute Respiratory Syndrome or SARS.

Between November 2002 and July 2003, there were 8,096 known cases of SARS, and 774 deaths (a mortality rate of 9.6 per cent). "We treated the blood of an Italian man who had been infected with SARS, and cured him," Brooks said.

"The techniques we used there were used for the immunisation. What we learnt from SARS helped us with bird-flu.''

Institute researchers found that the antibodies provided significant immunity to mice that were subsequently infected with the Vietnamese strain of H5N1. Viral infection was reduced in the lungs and the brain and spleen were clear.

The antibodies were found in the laboratory of Professor Antonio Lanzavecchia at the Swiss Institute for Research in Biomedicine.

But Lanzavecchia was adamant that this was not the end of the pandemic threat. "We do not know what a pandemic flu virus will look like. We have an idea, but we can't say for definite that it will resemble the H5N1 strain that we have been studying.''

The technique of taking blood from flu survivors is not new. It was used during the 1918-19 Spanish H1N1 flu pandemic. But it remains difficult to clear the blood of harmful products.

Different approach

Vaccines are of no use once the disease has struck. Antibodies, however, work immediately, and are relatively easy to manufacture on an industrial scale.

The downside is that the protection does not last for more than a few months. For bird-flu sufferers - who only seek treatment after infection - it could, however, offer a real hope of a cure.