|Home||Founder||What's New||In The News||Contact Us|
|Paradigm Shift Intervention Monitoring||Commentary
Fujian H5N1 Bird Flu Spreads Throughout China
April 5, 2006
A report from the Ministry of Health from the People's Republic of China contains some additional genetic information on H5N1 isolates in China. Recently China released the HA sequences from three H5N1 patients in China. All three were closely related to a Fujian duck isolate, A/DK/Fujian/1734/05(H5N1) and had the same HA cleavage site, RERRRKR, which was missing a lysine. The recent report describes three additional human isolates, A/Jiangxi/1/2005(H5N1), A/Hunan/1/2005(H5N1), and A/Sichuan/1/2006(H5N1). These isolates would appear to be from the index cases for each of those provinces. All three cases were fatal (age, gender, date of death 35M, Dec4; 41F, Dec 21, 35F, Jan 11, respectively).
Amino acid homology was available for the two most recent 2005 cases and like the first three cases, all were greater than 99% homologous to A/DK/Fujian/1734/05(H5N1) and all three had the same HA cleavage site (RERRRKR). These data indicate all six reported human cases in China are closely related to the Fujian strain as are the recent isolates from Malaysia and Laos. In China, there were human cases in five provinces (Anhui, Guangxi, Jiangxi, Fujian, Sichuan) indicating the Fujian strain is widespread.
The report also showed that all of the human cases as well as two chicken sequences (A/CK/Hunan/21/05 and A/CK/Lianoning/23/05) had sequences indicating they would be sensitive to M2 ion channel blockers (Amantadine and Rimantidine) and neuraminidase inhibitors (Tamiflu and Relenza). However, the sequence homology for the Liaoning isolate was markedly lower (96.9% with the Fujian duck). The H5N1 outbreak in Liaoning was difficult to control and several vaccines were used, which was probably related to the lack of sequence homology. Sequence data fro the human Liaoning case was not included.
The report also showed that the two most recent H5N1 human cases also had PB2 E627K, which is associated with a poor prognosis and is in all Qinghai strains. The report also had data on the isolate from the index case in Turkey, A/Turkey/12/06(H5N1). The report listed the HA S227N, but also indicated that the cleavage site was RERRRKKR, which if true would be unusual, because the cleavage site for the Qinghai strain was usually GERRRKKR (the report however may have been in error because the cleavage site for a bar headed goose isolate was listed as RERRRKKR, but the deposited sequence is GERRRKKR.