³Ô¹Ï²»´òìÈ

Scientists reported on Wednesday that they have recovered DNA from the oldest viruses known to have infected humans — and have succeeded in resurrecting some of them in the laboratory. The viruses were all strains of hepatitis B. Two teams of researchers independently discovered its DNA in 15 ancient skeletons, the oldest a farmer who lived 7,000 years ago in what is now Germany.Until now, the oldest viral DNA ever recovered from human remains was just 450 years old. (Zimmer, 5/9)

The hepatitis B virus has been infecting people since at least the Bronze Age, according to a new study published in the journal Nature by geneticists who teased the virus from 4,500-year-old human remains. Hepatitis B was discovered in the 1960s, and a vaccine (and Nobel Prize) came swiftly thereafter. Despite the vaccine, the virus still kills people, and chronic infections cannot be cured. Nearly 900,000 people with the virus died in 2015, mostly from liver complications, according to the World Health Organization. An estimated 257 million people carry the virus that targets the liver and can be a risk factor for cancer. (Guarino, 5/9)

Some earlier observational studies have suggested that children who are exclusively breast-fed have higher I.Q.s through adolescence, and even higher incomes at age 30. But a randomized trial, a more rigorous type of study that better controls for socioeconomic and family variables, found that breast-feeding in infancy had no discernible effect on cognitive function by the time children reached age 16. (Bakalar, 5/9)

A new coating for medical devices that are inserted into the body could help prevent infections, according to researchers in the University of Georgia’s College of Engineering. They developed a technology called LINOREL — or liquid-infusing nitric oxide-releasing silicone — that can coat devices such as catheters and surgical tools that sometimes carry infections. (Boss, 5/9)

A new study suggests that many first-time mothers might want to consider an alternative to the traditional "watch and wait" approach of allowing a pregnancy to run up to 41 weeks. For those who are healthy, inducing labor at 39 weeks lowers the risk of serious complications and cesarean delivery, according to a team of researchers led by Dr. Charles J. Lockwood, dean of the Morsani College of Medicine at the University of South Florida. (Griffin, 5/9)

In his final days, David Goodall spoke about his 104 years of life and the legacy he hopes to leave behind when he dies. The Australian scientist, who has traveled from his home in Perth to Switzerland to end his life by assisted suicide, answered questions Wednesday about why he wants to die and how he plans to do it. When asked what song he wanted played at his bedside, he said he has not chosen one but if he had to, it would be Beethoven’s 9th Symphony. (Bever, 5/9)

The Democratic Republic of the Congo declared an Ebola outbreak after two suspected cases tested positive for the Zaire strain of the virus, the World Health Organization reported Tuesday. The outbreak emerged in Bikoro, a town in the northwest area of the country, after local health officials reported 21 patients with symptoms of a suspected viral hemorrhagic fever — rare and life-threatening fevers caused by several families of viruses, according to the Centers for Disease Control and Prevention. (Villagomez, 5/9)