As scare stories go, bird flu seems very last year. But the threat hasn't gone away. A human pandemic from the virus H5N1 is still possible, and one recent study put the likely death toll at around 60m, slightly more than current total annual global mortality. Nearly all of these deaths would be in developing countries.
H5N1 is a strain of the H5 influenza virus, of which a human form exists—along with a vaccine. So in principle, an outbreak might be stymied by a rapid programme of anti-H5 vaccination. But these vaccines need more than one dose, and the question is whether the stuff can be made, distributed and used quickly enough and in sufficient quantities. Moreover, no flu vaccine guarantees full protection.
The World Health Organisation plans to stockpile H5 vaccines. With the use of additives that enhance the immune response and lower the amount of vaccine needed per dose, perhaps 5-6bn doses could be manufactured within a year. But for a vaccination campaign to succeed, it has to be finely tuned to ensure that the spread of the flu is slowed without encouraging the emergence of a new, vaccine-resistant strain. As experience with antibiotics and superbugs has shown, rapidly mutating pathogens have to be managed carefully—it's unrealistic to think they can simply be eliminated.
There are also economic obstacles. Who pays, and how can prices be made equable worldwide? The poorest nations will be hardest hit, and even with adequate stockpiles of vaccines they may lack the infrastructure to apply them.
Scientific challenges remain too, not least working out how to develop new drugs quickly as resistant strains of the virus emerge. An international team of scientists has just reported in Nature a new strategy for identifying the genes in a host organism that a virus hijacks to replicate itself. The method uses RNA interference, a technique that can selectively block specific genes from generating the protein enzymes they encode. If no protein is produced, the gene is effectively "switched off." The method allows an organism's genome to be screened to pick out the genes most vital to the life-cycle of the virus, thereby flagging up the most promising targets for new drugs. The technique has already been shown to work for fruit fly cells vulnerable to a modified "fly" form of H5N1.
Don't mention the war
Until late last year, nuclear physicist Moniem El-Ganayni was employed, as he had been for 18 years, at the Bettis Laboratory near Pittsburgh, which works on naval nuclear propulsion for the US department of energy (DoE). But the DoE has revoked El-Ganayni's security clearance, losing him his job—and the only reason for this appears to be that he is an Egyptian-born Muslim who has criticised the US government. El-Ganayni, who moved to the US in 1980 and became an American citizen in 1988, acts as an imam in Pennsylvania's prisons. A prominent member of his local Islamic community, he has condemned the Iraq war and denounced the FBI's attempts to recruit informers at mosques.
The lawsuit filed on his behalf by the American Civil Liberties Union demands to see the evidence on which the decision was made. The official reasons, stated in a letter in January from the DoE, are stock generalisations: that El-Ganayni "knowingly established or continued sympathetic association with a saboteur, spy, terrorist, traitor" whose interests "are inimical to the US." And, apparently, he is "not honest, reliable or trustworthy" and had "conflicting allegiances." The DoE won't expand further, calling it a "personnel security matter."
American twitchiness about security is not without foundation. In March, Chinese-born engineer Chi Mak received a 24-year prison sentence for sending plans of ships, submarines and weapons to China, knowledge he acquired while working under security clearance on defence contracts. Mak has allegedly admitted to being recruited to spy by Chinese intelligence services 20 years ago. But there seem to be no charges whatsoever against El-Ganayni.
Phoenix looks for life on Mars
Nasa's Phoenix, a robotic mini-laboratory scraping around in Martian soil, is the first real heir to the Viking missions of the 1970s, which set out to scour the planet's surface for signs of life. Although this is not Phoenix's mission—we now have more reason to doubt that Mars hosts life—it will chemically analyse the planet's soil to assess the chances that microbes could survive.
Phoenix's other goal is to provide information about the history of water in the Martian arctic. It's widely thought that the planet may once have had liquid water—essential for life—and a hydrological cycle like ours. Phoenix's robotic arm has already found ice under the soil surface after digging a trench. But in such frigid conditions, ice is very hard, and difficult to scrape for analysis.
The latest task is to stick a pronged probe into the soil to measure electrical conductivity and heat flow, which would reveal more about whether water or ice is present. So far, Phoenix has performed like a dream—more evidence that cheap robots are ideal cosmic explorers.
