Will influenza be the next bioweapon?

Marilynn Larkin

The use of influenza as a bioterrorist weapon is a “clear and present danger”, warns Mohammad Madjid (University of Texas Health Science Center, Houston, TX, USA). “Our work on the effects of influenza on cardiovascular mortality shows that many people die from influenza-related myocardial infarction, which is not reported as influenza mortality. Thus, mortality due to influenza in the USA alone is much more than previously estimated—probably 90 000 annually rather than the reported 20 000—once the effect on the heart is taken into account”.

The idea that influenza could be so lethal prompted Madjid and colleagues to consider the virus's potential as a bioweapon. They report their concerns—in particular, the soon-to-be-completed sequencing of the influenza genome from the 1918 epidemic that killed 40 million people—in the Journal of the Royal Society of Medicine (2003; 96: 345–46). “Unlike anthrax or smallpox, influenza is available, it can be aerosolised, the incubation period is short and inoculation doesn't protect you during this time”, explains Madjid. “Moreover, if an epidemic starts, it may look natural because flu happens every year. And, whether man-made or natural, it can rapidly overwhelm and paralyse the whole health-care system.”

Critics say that it would be hard to create an influenza strain that is virulent enough to pose a significant threat. But, counters Klaus Stohr, project leader for WHO's Global Influenza Programme, “the tools to create a virulent strain are readily available”. With reverse genetics—the same technology that was used to construct a vaccine against the H5N1 influenza strain (Drug Discovery Today 2003; 8: 518–19)—“we can readily produce the surface proteins and other proteins needed to assemble viruses on demand”, he says. “We could reproduce the 1918 virus or develop one that is completely new, put it together with other proteins necessary for the virus to function, and then release it”.

Stohr would prefer to use reverse genetics and other technologies to develop cross-subtype-specific vaccines. “We have the haemagglutinin genes H1-H15, and we should have vaccines that protect against H1 and H3, which are currently circulating, and any new or possibly emerging strains.” Because new vaccine development requires investments on the part of pharmaceutical companies, WHO is looking into “changing the environment in a way that is conducive” to commercial entities. Licensing mechanisms and respect for intellectual property rights are among the issues that need to be worked out.

Meanwhile, continues Stohr, “we can develop a library of influenza viruses, going around the world and getting all the different protein subtypes, and develop vaccine strains, put them in the refrigerator, and have something we can use in case we don't come to agreement”.

Governments can also prepare, add Madjid and colleagues, by providing better security for laboratories, vaccine manufacturers, and distributors; improved influenza immunisation programmes; expanded disease surveillance; and use of antiviral filters, biosensors, and inactivation mechanisms for ventilation systems. Stockpiling antivirals would also help, they suggest; however, Stohr points out that this approach is extremely expensive and is being done only in Japan.

Donald Henderson, founding director of Johns Hopkins University's Center for Civilian Biodefense Strategies (Baltimore, MD, USA), is skeptical about a weaponised flu. Influenza, he asserts “just isn't a good enough agent to be concerned about” from a bioterrorist perspective. “Something like Q-fever, which is a stable, aerosolisable agent, would be a much more effective bioweapon; it's well known in the biological weapons community that Q-fever will go a long distance and infect lots of people.” Influenza, by contrast, might put troops out of commission for a while, he says, “but that means the offending nation must have a protective vaccine to protect their own troops so it doesn't rebound”. Even if flu is of concern to the military, “for civilians it's not such a big deal because people will come down with the flu, but they won't spread it easily and most will recover.”

“I'm a little apprehensive about people fiddling with the influenza virus experimentally; but on the other hand, I feel we have as much to fear from nature as we do from man”, continues Henderson. “Do we need to be concerned about it? Yes; once a pandemic comes, it can move across the world within a year. Are we doing enough to be prepared? No. Producing vaccines against each strain is one approach. But shouldn't we be pursuing the idea of a live vaccine that can be developed with a recombinant capability, and permit growth in tissue cell culture, rather than the ancient system of growing the stuff in eggs, which limits the quantity? This concept has not been pursued as diligently as many of us feel it should be.”






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>작성자 : Gangster
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1. 사람뿐만 아니라 다른 생명체에도 치명적인가요?
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>2. 영화처럼 미사일안에 생화학탄이 구슬모양입니까?
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>3. 한국군보유하거나.. 만들 능력이 있습니까?
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>한국은 화학공업이 상당히 발전해서 화학무기는 얼마든지 대량생산 가능하다고 하는데.. 그 종류도 다양하고..
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>4. VX뿐만 아니라 보통.. 생,화학무기는 몇km내에 생명체가 다 죽나요?
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>5. 생,화학무기 강국은 미국,러시아,북한,한국,이스라엘.. 정도 인가요?
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>6. 영화에서 보면 막 피부가 녹던데.. 그런 화학무기도 있나요?;;
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>7. 생,화학무기가 핵처럼 지독한 무기라던데...
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>--- 질문 Q&A방은 사람들 발걸음이 드문것 같에서 여기다 올릴게요^^;;--
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>그리고 3번째 사진은 달러맨님 사진이구요.. 좀 북한군이 멋있어 보이네요..;
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