"This kind of incubation period -- 17 months -- is quite unusual, " he said.
But even exit screening, he says, is unlikely to have much effect because of the virus' long incubation period.
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Therefore the first causality was probably at the beginning of March 2009 taking into account the incubation period.
During the incubation period of seven to 17 days, you look and feel healthy and can't infect others.
Another key number is the incubation period--how long it takes one person to become sick after being infected.
Following the incubation period, a sudden onset of flu-like signs and symptoms occurs.
Powys Council said it took up to two days to recover from the illness which had an incubation period of five days.
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By contrast, the 1918 flu pandemic that killed 50 million had an incubation period of two days (and an R of 2).
The incubation period and the prognosis both depend on the dose ingested.
SARS, says Longini, was contained partly because it has a relatively long incubation period of six days, giving authorities more time to respond.
The incubation period is usually about two weeks, and early symptoms are a raised temperature, cough, runny nose, and red and watery eyes.
And as the Director said, the notion that -- based on the incubation period that we're likely to see a greater severity is likely.
However, Dr McCormick said, although they were "confident" they had identified the source, because of its incubation period, more cases of Legionnaires' disease were expected.
The incubation period, the time from when you're first exposed to the time you express symptoms, is usually 1-5 days, but can be as long as 60 days.
French doctors estimated the disease's incubation period to be from 9 to 12 days for the second case, longer than the 7 to 10 days previously reported by others.
Professor Ironside added that the incubation period of the disease was significant and there had been a slight rise in the number of cases over the past 12 months.
It is now three weeks since restrictions were imposed on the movement of livestock - a period which is thought to be the maximum incubation period of the virus.
"Eventually the incubation period elapses and people begin to manifest cirrhosis and advanced liver failure and the death rate will undoubtedly increase over the next few years, " he added.
The problem is that the death toll is still too small, and far too little is known about the length of the incubation period, to rule out an epidemic.
"The organ transplantation occurred more than a year before the recipient developed symptoms and died of rabies, " the CDC said, adding such an incubation period is much longer than usual but not unheard of.
But another doctor, Duan Qing, explained at the briefing that would be impossible for there to be any such cases of AIDS, Hepatitis B, Hepatitis C, or syphilis because there is a lengthy incubation period.
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The researchers say that in this worst case scenario - if people with other gene variants are equally as susceptible as those in the original subgroup, but have a longer incubation period for vCJD - there could be a total of around 600 deaths from vCJD.
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