April 12, 2013 at 7:40 AM ET
A new report on three of the first patients in China to contract a novel strain of bird flu has U.S. officials worried about a grim scenario that includes severe illness with pneumonia, septic shock, brain damage and multi-organ failure.
All three of the patients died, according to a Thursday report by a group of Chinese scientists in the New England Journal of Medicine.
“It is possible that these severely ill patients represent the tip of the iceberg,” wrote Dr. Timothy Uyeki and Dr. Nancy Cox, both of the influenza division at the Centers for Disease Control and Prevention, in a perspective piece accompanying the article.
The reports chronicle the early days of an outbreak of a new influenza A virus, H7N9, which has never before been seen in humans. As of Friday, Chinese officials said it had infected at least 43 people in four Chinese provinces and killed 11 in the past two months.
On Saturday, China's center for disease control confirmed the first case of the new bird flu strain in Beijing: A seven-year-old girl whose parents work in the live poultry trade has been infected.
The patients described in the report included two men, ages 87 and 27, both from Shanghai, and a 35-year-old woman from Anhui. All had preexisting health conditions and two had been exposed to chickens at live poultry markets in the previous week. They became ill between Feb. 18 and March 13 and died between March 4 and April 9 of severe complications, the report said.
The virus, which has been traced to a reassortment of genes from wild birds in east Asia and chickens in east China, “raises many urgent questions and global public health concerns,” the U.S. researchers wrote.
It’s particularly concerning because the virus clearly has the potential to cause severe disease, it has genetic characteristics that suggest that it might be better adapted than other bird flu strains to infect mammals -- including humans -- and people have no resistance to it, the U.S. scientists reported.
The virus doesn’t make birds sick, so it may spread widely and remain undetected until people become ill.
In addition, previous vaccines developed to fight other H7 strains did not invoke strong immune responses in humans, the U.S. scientists wrote. Even so, researchers at the Centers for Disease Control and Prevention said they received an isolate of the virus from China on Thursday and were continuing to rush efforts to create a vaccine, a process that could take several months.
Scientists are expected to start growing more of the virus to share for use in several ways, including not only developing a vaccine, but also creating a blood test that can detect previous human immune system protection against the virus, and testing to see whether the virus remains susceptible to antiviral drugs.
CDC officials also will use it to create a diagnostic test that could be used to detect infection in travelers who return to the U.S. from China with symptoms of flu, or those who’ve been in contact with someone who’s been sick.
Officials with CDC and the Food and Drug Administration are working to quickly expedite approval and manufacture of the kits, said Mike Shaw, associate director of laboratory science for the CDC's flu division. About 400 diagnostic kits, which each can perform 1,000 tests, may be complete by Monday, he said. They could be shipped as early as next week to public health labs across the country.
The CDC has urged local public health officials to watch for signs of sick travelers from China. So far, about 10 people who recently traveled from China to the U.S. have been tested for the H7N9 virus because of suspicious symptoms, officials said.
"So far, everyone that has been tested in the U.S. has been negative," Shaw said.
The virus remains contained to China and there is no evidence of sustained person-to-person transmission, both good signs, scientists said.
But as the U.S. researchers concluded, vigilance remains high.
“We cannot rest our guard,” they wrote.