Looks like the wild animals are still causing problems:
It will be interesting to see what the HKU release says, but I suspect the following:
The civet sequences have 13 positions in the S gene that are changed in all human SARS CoV isolates, as well as 9 more that are in almost all human SARS CoVs except for the earliest Guangzhou isolates. However, the earliest sequences from last season came form patients infected in late January / early February. Thus, there were no isolates to represent what the virus looked like in humans between Nov 2002 and Feb 2003. My guess is that the latest isolate has several of the wild type nucleotides at these key positions, so when it is compared to the human SARS CoVs it has 22 changes, but the differences with the civets is less. Thus the novel isolate is closer to the animal version (and probably also has the 29 nt, although sequence data on that region may not be available yet) and the data further supports SARS originating from wild animals.
Since the patient had a SARS-like condition in March, that virus may still have looked like the present isolate, but may have been missed because these early versions don't grow well in culture or reach a high enough level in humans to be easily isolated. Thus more "early" SARS CoVs may be sequenced via PCR analysis of earlier patients from last year. In addition, testing the patient for neutralizing antibodies against the civet isolates will probably generate a significantly higher titer.
Thus, many of the questions surrounding this patient will remain open (is this a re-activation or another animal to human jump), but the sequence will further support the linkage between early human SARS CoVs and those SARS CoVs isolated from civet cats.
SARS-like virus found in wild animals
Keith Bradsher NYT
Monday, January 5, 2004
iht.com
HONG KONG Researchers here and in nearby cities of mainland China have found SARS-like viruses in many wild animals, and have found that a man who fell ill recently in Guangzhou was infected with a virus genetically similar to one of these wild animal viruses, Hong Kong University announced Sunday night.
Public health experts have warned that if the virus causing severe acute respiratory syndrome can survive in wild animals, then it will be harder to eradicate and could periodically infect people again.
Hong Kong University said in a statement that its faculty of medicine, working with the Centers for Disease Control and Prevention of Guangdong, Shenzhen and Guangzhou, had determined that "human SARS-like coronavirus are found to exist in many wild animals after an extensive sampling done on wild animals on sale in the wild animal markets" of nearby mainland Chinese cities.
The virus was especially common in civet cats, a species related to the mongoose, as suggested by previous research. The virus found in the Guangzhou man is genetically similar to virus samples taken from the civet cats, the statement said. |
