Identification of the Progenitors of Indonesian and Vietnamese Avian Influenza A (H5N1) Viruses from Southern China

[Sally Furniss]

Identification of the Progenitors of Indonesian and Vietnamese Avian Influenza A (H5N1) Viruses from Southern China

J. Wang,¹^,2 D. Vijaykrishna,¹^,2 L. Duan,¹^,2 J. Bahl,¹^,2 J. X. Zhang,¹^,2 R. G. Webster,³ J. S. M. Peiris,² H. Chen,¹^,2 Gavin J. D. Smith,¹^,2^* and Y. Guan¹^,2^* International Institute of Infection and Immunity, Shantou University, Shantou, Guangdong 515031, China,¹ State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, The University of Hong Kong, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China,² Virology Division, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38015<sup>3

</sup> Received 16 November 2007/ Accepted 16 January 2008

<!-- ABS --> The transmission of highly pathogenic avian influenza H5N1 virusto Southeast Asian countries triggered the first major outbreakand transmission wave in late 2003, accelerating the pandemicthreat to the world. Due to the lack of influenza surveillanceprior to these outbreaks, the genetic diversity and the transmissionpathways of H5N1 viruses from this period remain undefined.To determine the possible source of the wave 1 H5N1 viruses,we recently conducted further sequencing and analysis of samplescollected in live-poultry markets from Guangdong, Hunan, andYunnan in southern China from 2001 to 2004. Phylogenetic analysisof the hemagglutinin and neuraminidase genes of 73 H5N1 isolatesfrom this period revealed a greater genetic diversity in southernChina than previously reported. Moreover, results show thateight viruses isolated from Yunnan in 2002 and 2003 were mostclosely related to the clade 1 virus sublineage from Vietnam,Thailand, and Malaysia, while two viruses from Hunan in 2002and 2003 were most closely related to viruses from Indonesia(clade 2.1). Further phylogenetic analyses of the six internalgenes showed that all 10 of those viruses maintained similarphylogenetic relationships as the surface genes. The 10 progenitorviruses were genotype Z and shared high similarity (99&#37 withtheir corresponding descendant viruses in most gene segments.These results suggest a direct transmission link for H5N1 virusesbetween Yunnan and Vietnam and also between Hunan and Indonesiaduring 2002 and 2003. Poultry trade may be responsible for virusintroduction to Vietnam, while the transmission route from Hunanto Indonesia remains unclear.

http://jvi.asm.org/cgi/content/abstract/82/7/3405

[gsgs]

Re: Identification of the Progenitors of Indonesian and Vietnamese Avian Influenza A (H5N1) Viruses from Southern China

also:

http://www.flutrackers.com/forum/showthread.php?t=53536

http://www.flutrackers.com/forum/showthread.php?t=52610

why do they conclude poultry trade for China-->Vietnam
rather than wild birds ?
Just because there _is_ much poultry trade in that region ?