Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
Sixth Person Dies of H7N9 Bird Flu; U.S. Begins Work on Vaccine
A sixth death from the H7N9 bird flu strain was announced by Chinese officials Friday and authorities in the city of Shanghai have killed all poultry at a market where the virus was detected in pigeons being sold for meat.
The poultry slaughter is the first so far as the Chinese government tries to deal with the virus that has infected 16 people along the eastern seaboard. They are the first known H7N9 infections in people, the Associated Press reported.
Officials believe that people are being infected through direct contact with fowl and say there is no evidence that the virus is spreading between people.
In the United States, health officials have started to make a seed vaccine against the H7N9 bird flu strain. It is being made "only as a precaution," according to a Centers for Disease Control and Prevention spokesman, but a CDC virologist said the agency was "fairly worried" about the new virus, The New York Times reported.
It will take at least a month to create the seed vaccine. It will then be tested in ferrets. After receiving the vaccine and given time to produce antibodies, the ferrets will be infected with the H7N9 virus. It will then take a few days to see if they get sick.
"If everything works smoothly the first time, we could theoretically have it ready to send to manufacturers within four weeks," Michael Shaw, associate laboratory director for the CDC's influenza division, told The Times. "But some things, like ferrets, you can't speed up."
By the time the seed vaccine is ready, the CDC will have a better idea of how dangerous the new H7N9 virus is, according to agency spokesman Tom Skinner.
It is still not clear how deadly the virus is "because we may be seeing only the serious cases, the ones who go to hospitals," Shaw said. The number of mild cases that may have gone unreported will be known only by testing for antibodies in blood samples from a large number of people, he explained.
The fact that the virus has been found in pigeons is unusual.
"It's clearly not making the pigeons ill, since no one's seen large numbers of pigeons dying. Pigeons usually aren't tested. And this could make control harder. Chickens are easy to round up," Shaw told The Times.
Preliminary tests suggest that the H7N9 virus is susceptible to the antiviral drugs Tamiflu and Relenza, the World Health Organization said.
Roger Ebert Dies at Age 70
Pulitzer Prize-winning film critic Roger Ebert died Thursday, two days after he announced that he was undergoing radiation treatment for a recurrence of cancer.
He died at the Rehabilitation Institute of Chicago as he was preparing to go home for hospice care, according to a statement posted on his blog by his wife Chaz, the Associated Press reported.
Ebert, 70, was the film critic for the Chicago Sun-Times since 1967 and co-hosted two long-running TV shows.
Ebert underwent cancer surgeries in 2006 and lost portions of his jaw and the ability to eat, drink and speak. However, he returned to writing full time and eventually returned to television.
3 Million Lbs of Frozen Pizza, Other Snacks Recalled
Possible E. coli contamination has prompted Rich Products Corp. of Buffalo to expand a recall to include about 3 million pounds of frozen pizza, mozzarella bites, Philly cheese steaks and other snack products.
The recall involves all products made at the company's plant in Waycross, Ga. The products have best buy dates from Jan. 1, 2013 through Sept. 29, 2014, NBCNews.com reported.
The foods may be contaminated with E. coli O121, a strain that can be just as dangerous as the better-known E. coli O157:H7, which is frequently involved in outbreaks caused by hamburger.
This latest recall expands on a March 28 recall of about 196,000 pounds of Farm Rich brand frozen chicken quesadillas and other frozen mini meals and snack items that may have been contaminated with E. coli O121, NBCNews.com reported.
So far, 24 people in 15 states have become ill after eating those products, including 7 who have been hospitalized, according to the Centers for Disease Control and Prevention.