There is a small window of time during the 7 to 17-day incubation period in which the person becomes infectious before he has the easy-to-recognize, tell-tale smallpox lesions on his skin. That does not mean that he's totally asymptomatic, however.
During this 2-4 day prodromal period, he develops fever, body aches (especially backache), headache, and maybe severe abdominal pain and delirium. In other words, he wouldn't be walking around acting like a healthy and happy camper.
About this time, the lesions first appear inside the mouth and nose (this is still before they appear on the body), and it's at this point that the person becomes highly infectious. The lesions in the mouth have very high concentrations of the virus, and anyone standing downwind from or in the vicinity of a cough is likely to get sprayed with sputum droplets that contains the smallpox. Yum, yum. One or two days later, the rash is present on the skin for all to see.
I won't even get into the fomites. ;-)
As far as letting the passengers go, they've probably determined that the suspect passenger is not displaying any of the above symptoms, so therefore he's not contagious.
The real question now will be what they do with him. Under what grounds would they be able to hold him for 17 days? Is he a US citizen with constitutional rights? Will he be allowed to run loose among the population, possibly developing symptoms later, just because they can't legally hold him? Do we really want to start forcing people to be quarantined just because someone called in a phone prank?
I just saw some pretty inaccurate information being given and I wanted to correct it.
At the very least, they should take his photograph, ask him where he will be in the next three weeks, make sure that the names and whereabouts of all passengers and crew is known, cross their fingers and be hyper-alert to any smallpox-like prodromes in the next three weeks, especially in the passengers'and crew's communities..
Of course, this would take focus, commitment, and common sense
That was exactly my question--it sounded from that KomoTV news report as if they were simply letting him go as well, but they didn'specifically address him. That may have been updated by now--in fact, I'm sure it has, but they better not let him go free until they can determine for sure that he isn't carrying smallpox.
Thanks for the clarification--that's exactly what my pharmicist friend told me, that at that point in the infection when they are first contagious, even though the person doesn't have lesions, they're not going to be in any condition to go anywhere outside of their homes or even outside of their bedrooms...they're simply to sick to do so.
But I am wondering what they're doing with this guy who showed no symptoms but who was indicated in the tip.
-penny