Scientists call for more mutant bird flu experiments

Two scientists behind a controversial H5N1 avian flu publication last year, which deliberately modified the virus to become more transmissible to humans (see BioNews 662), hope to perform similar experiments on a new flu strain that has already killed more than 40 people in China.

The H7N9 flu strain had no history of infecting humans until March this year. Since then, at least 133 people in China have been infected.

Professor Ron Fouchier from the Erasmus Medical Center in the Netherlands, and Professor Yoshihiro Kawaoka from the University of Wisconsin-Madison, published an open letter in the journals Nature and Science to make their case for the controversial experiments. They say that gain-of-function (GOF) experiments are essential to mediate a potential pandemic threat with the H7N9 strain.

Scientists often ask two basic questions when investigating specific genes: what happens when this gene is gone, and what happens when it is extremely active? Genetic 'knock-outs' - where a gene is silenced - are known as loss-of-function experiments. GOF experiments seek the opposite effect, a gain in activity, resulting in over-production of a specific protein, for example. Over-activity from GOF experiments can produce effects in the whole organism that are considerably different to when the gene is functioning normally.

In the case of the H7N9 strain, GOF experiments might identify the steps needed for the flu to become airborne, where it would then pose a major threat to public health.

A supporter of the proposal, virologist Professor Wendy Barclay from Imperial College London, said: 'This type of work is like fitting glasses for someone who can't see well - without the glasses the vision is blurred and uncertain, with them you can focus on the world and deal with it a lot more easily'.

The scientists explain that by doing these experiments they can address, in advance, issues that might arise if such a strain naturally developed, including resistance to treatment.

But the proposal has been criticised by some senior scientists. Marc Lipsitch, professor of epidemiology at Harvard University told The Independent it was 'not clear how lives could be saved even if we knew the exact genetic mechanisms governing efficient human-to-human transmission'.

Similarly, Dr Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota told The Scientist: 'I have always maintained that Yoshi Kawaoka and Ron Fouchier could do this work safely. But my concern is that publishing their data would allow labs around the world, which won't adhere to the same safety requirements, to do the same'.

Currently, only one case of potential human-to-human transmission of the H7N9 strain, between father and daughter, is under investigation.