Reading the Atlanta Journal-Constitution has the occasional benefit beyond keeping me informed of the ups and downs of my favorite baseball team (they’re tied 1-1 with Houston in the first round of the playoffs). Atlanta is the home of the US Centers for Disease Control. And folks there have recreated the 1918 influenza virus in an effort to understand precisely why it was so deadly.
The work, hailed as a stunning scientific achievement, confirms what some scientists have long suspected: The lost 1918 virus was a bird flu that jumped species to attack humans, much like the avian flu strain that has killed at least 60 people in Asia since late 2003. It was conducted in three cities and completed in a high-security Atlanta laboratory.
They’re not kidding about the security; 1918 (I don’t know if it has an H#N# designation yet) is being treated like a bioweapon. And it appears the virus is as rough as the historic record suggests:
The group then used the recovered virus in experiments on mice, chicken eggs and cultures of human lung tissue. It killed all the mice within days, as well as chicken embryos normally used to produce quantities of virus for vaccines. And it reproduced rapidly in lung cells, even in cell cultures made to mimic certain body tissues where flu cannot normally grow.
Important insights have already been gained:
The group found that the virus was almost completely a bird-flu virus — not, as some had thought, a mixture of segments from both avian and human flus — and possessed a handful of mutations in each of its eight genes that probably occurred as the virus began to infect humans.
The Barry book talks about this phase. There was a wave of infections in the spring of 1918 that was not as deadly as the wave in the fall. Researchers’ thesis is that as the flu passed among humans and accumulated mutations, selection favored a more dangerous form of the virus. Passage through human populations is a relatively well-known phenomenon, while the random nature of mutations means that they can trend to less dangerous forms as well as more dangerous. In 1918, humanity drew the short straw.
Some of the news from Atlanta is good:
The experiments [with the recreated virus] pinpointed molecular terrain that drugs could be designed to attack, Tumpey said, adding: “I have already gotten messages from other scientists saying, ‘I have an idea for targeting this.’ “
Some of the news is a little more worrying:
And in a second analysis, they compared the 1918 sequence with the genetic sequence of the avian flu now circulating in Asia, finding that the current bird flu shares some of those same mutations.
“In a sense, [the current bird flu] might be going down a similar path to what ultimately led to 1918,” Taubenberger said. He suggested that with further research, virologists could provide an early-warning checklist of changes signalling what scientists fear most: bird flu’s shift from a hard-to-acquire infection in people to one easily transmitted.