MUSIC: "Our World" theme
Straight ahead on "Our World" ... one avian flu mystery solved, while others remain ... the earth's biodiversity under threat ... and ancient tricks to build a fantastic memory.
FOER: "And I see Bill Clinton at the front door of my house. And then I walk into my house. And right behind the front door, I see the second card. Let's say it's the Queen of Diamonds, and it translates to a horse."
Those stories, the red planet on our website of the week, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
Scientists this week said they think they now understand why avian, or bird flu does not easily infect people or spread between them. Teams of scientists in the Netherlands and Japan, working independently, said the deadly H5N1 virus attaches to cells deep in the lungs. Dutch researcher Thijs Kuiken of Erasmus Medical Center in Rotterdam says that's in contrast to the ordinary seasonal flu, whose virus attaches to cells in the nose and throat.
KUIKEN: "Being able to attach higher up in the respiratory tract may mean, we're not sure, but it may mean that it comes more easy for such a person to become infected in the first place, and in the second place to transmit the virus to another person."
Understanding details of how the flu virus works could be key to understanding how to respond if this avian flu or a future strain mutates into a form capable of person-to-person infection. A lot of scientists are studying flu virus, but one of the best, Jeffery Taubenberger of the U.S. Armed Forces Institute of Pathology, admits big gaps remain in the knowledge.
TAUBENBERGER: "Pandemics are quite variable. 1918 was this horrible pandemic. 1968 was a relatively mild pandemic. And we don't understand the differences necessarily that led to that. We don't understand the genetic basis for why one virus is more virulent in one particular host than another. So there are a lot of things that we still don't know."
Taubenberger and his colleagues reconstructed the 1918 virus last year from bits of genetic material taken from some of the estimated 50 million people who died in the 1918 pandemic.
The largest and longest international study looking at the consequences of cigarette smoking concludes that those who quit dramatically reduce their risk of dying in middle age. The study also gives long-time smokers a good reason to quit. VOA's Jessica Berman reports.
BERMAN: According to the World Health Organization, smoking is the major preventable cause of death among adults, claiming about 5 million lives globally each year.
About half of the deaths occur in people under the age of 70, with 13 percent of those between the ages of 30 and 60, mostly from cancer or heart disease.
What's not really been known is the risk of dying prematurely, particularly in middle age, as a result of smoking. In the largest study of its kind to date, Norwegian researchers followed 50,000 rural men and women born between 1925 and 1941.
Ron Davis is a preventive medicine physician at the Henry Ford Health System in Detroit, Michigan.
DAVIS: "The key finding is that cigarette smokers are much more likely to die in middle age compared to people who have never smoked or compared to people who have smoked and have quit."
BERMAN: Writing in the journal "Annals of Internal Medicine," the authors report that 41 percent of men who smoked two or more packs of cigarettes a day during middle age died of lung cancer compared to 14 percent of non-smoking men.
Twenty-six percent of women who were heavy smokers developed lung cancer compared to only nine percent of non-smoking women. Cigarette smoking is considered the leading risk factor for lung cancer.
The Norwegian researchers found that mortalities related to cigarette smoking from any cause, including heart disease and alcoholism, were highest among those in their sixties.
But Davis, who wrote a commentary in Annals of Internal Medicine, notes the study also showed a significant reduction in the risk of dying the earlier that a smoker quit.
DAVIS: "In the forties and fifties. However, it's important to note that even people who quit at old ages will enjoy better health and a longer life expectancy."
BERMAN: The risk of death among smokers age 40 and and older was nearly double that of never-smokers or those who had stopped, prompting Davis to conclude that the study should provide a powerful incentive to quit. Jessica Berman, VOA News, Washington.
A U.N. report issued this week says that species are going extinct today at a rate not seen since the dinosaurs were wiped out 65 million years ago.