Re: China Influenza surveillance reports
As of September 19, 2010, CNIC has sequenced 576 pandemic influenza H1N1 2009 viruses. All the viruses have high homology (>98%) with the A/California/07/2009 (H1N1) and the A/Sichuan/SWL1/2009 reference virus in mainland China. Only 1 virus possesses mutation at the NA gene at amino acid position 274 and is resistant to the neuraminidase inhibitors.
CNIC has antigenically characterized 2411 pandemic influenza H1N1 2009 viruses. 2 viruses demonstrate reduced titers (≥8 fold lower in HI titer) with anti-sera produced against A/California/7/2009, which were isolated from Hunan and Zhejiang in December 9, 2009 and December 15, 2009 respectively.
During January 1- September 19, 2010, CNIC has antigenically characterized 90 influenza A (H3N2) viruses. 7 (7.8%) are related to A/Brisbane/10/2007(H3N2)-like; 83 (92.2%) demonstrate reduced titers (≥8 fold lower in HI titer) with anti-sera produced against A/Brisbane/10/2007(H3N2). 64 (64/87, 73.6%) are related to A/Perth/16/2009 (H3N2)-like; 23 (23/87, 26.4%) demonstrates reduced titers (≥8 fold lower in HI titer) with anti-sera produced against A/Perth/16/2009 (H3N2).
CNIC has tested 576 pandemic influenza H1N1 2009 viruses for antiviral resistance by sequence analysis. All viruses are resistant to adamantine; only 1 virus is resistant to the neuraminidase inhibitors, others are still sensitive to the neuraminidase inhibitors.
(also discusses B viruses)