This afternoon, Nature's Declan Butler has one of the more fascinating -- and ominous -- dispatches since the H7N9 outbreak in China occurred. Nature bills itself as the international weekly journal of science. It is one of the most respected publications of its kind in the world.
And Declan Butler is not one to go around sounding alarms. His articles are reasoned and insightful. SO it was with great concern that one of my IT people (shout-out Sean Nickerson) came into my office (my door is always open, insert Bob Newhart quip here). He had just gotten an email with a link to the Nature story.
Here is a snippet:
There is still no evidence of any sustained human-to-human spread of the H7N9 virus. But the World Health Organisation confirmed on Saturday that Chinese authorities are investigating two suspicious clusters of human cases. Though these can arise by infection from a common source, they can also signal that limited human-to-human transmission has occurred.
"I think we need to be very, very concerned" about the latest developments, says Jeremy Farrar, director of the Oxford University Clinical Research Unit in Ho Chi Minh City, Vietnam.
....The Beijing Municipal Health Bureau also announced today that a 4-year-old contact of a 7-year-old girl who had been hospitalized with the virus tested positive for the virus too, despite showing no symptoms. (bold mine) This is the first asymptomatic case. Along with several mild cases already reported, it suggests that the virus might be more widespread among humans than the numbers of reported cases suggest.
Perhaps counterintuitively, such mild cases are "very worrying", says Farrar. That is because reduced virulence can often point to further genetic adaptation of the virus to infection of human beings — and thus greater potential to spread.
Marc Lipsitch is an epidemiologist at the Harvard School of Public Health in Boston, Massachusetts. Declan quotes him:
"It's too soon to say how big a threat H7N9 poses because we don't know how many animals of which species have it, how genetically diverse it is, or what the geographic extent is," says Lipsitch, "It looks as though it will be at least as challenging as H5N1."