The comments below again raise the specter of asymptomatic SARS infected people as well as asymptomatic transfer. The palmed civets tested in the Science paper did not have symptoms, yet they were SARS CoV positive. In fact the level of virus allowed for SARS CoV isolation in several instances. Thus the animals appeared healthy, had isolatable virus at the time, and civet handlers in three separate markets in Guangdong frequently had antibody to the SARS CoV.
The virus isolated from the civets had the 29 nt and about two dozen loci which were altered in all human isolates and another two dozen altered in all human isolates linked to the Metropole Hotel. Thus the SARS CoV had a number of significant difference with the animal isolates, but there is evidence for a fairly broad spectrum of illness in humans, with the most severe cases showing up in older individuals and/or those with underlying disease.
These data suggest that there may be a significant amount of viral shedding in animals and there is little evidence against significant virus shedding in humans. The broad host range also suggests that humans could act as vectors to transmit virus to other domestic animals, including rats, cats, and dogs.
Suggesting that recurrences of SARS will be limited to links to wild animals in Guangdong Province seems premature.
>===== Original Message From "Henry L Niman, PhD" <henry_niman@hms.harvard.edu> =====
centredaily.com
Posted on Thu, Oct. 16, 2003
Study: High number of Chinese animal traders had SARS virus
BY MARILYNN MARCHIONE
Milwaukee Journal Sentinel
MILWAUKEE - (KRT) - A new study has found that a surprising number of Chinese
animal traders were infected with the virus that causes SARS, suggesting it
may have been far more common than believed and that many people may have had
it without showing symptoms.
The research also strengthens the likelihood that the new virus crossed to
humans from a yet-to-be-determined animal source.
The study, done by Chinese researchers and reported Thursday by the U.S.
Centers for Disease Control and Prevention, is the most extensive one yet
involving blood samples tested for severe acute respiratory syndrome.
Until now, health officials had thought the virus caused only the severe cases
of pneumonia that came to light during last spring's outbreak.
What's surprising about this study, said Dennis Maki, chief of infectious
diseases at the University of Wisconsin-Madison, is the high rate of infection
in people who weren't sick. |
