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. 2008 Apr;14(4):632-6.
doi: 10.3201/eid1404.071343.

Multiple sublineages of influenza A virus (H5N1), Vietnam, 2005-2007

Tien Dung Nguyen  1 , The Vinh Nguyen, Dhanasekaran Vijaykrishna, Robert G Webster, Yi Guan, J S Malik Peiris, Gavin J D Smith
Affiliations

Multiple sublineages of influenza A virus (H5N1), Vietnam, 2005-2007

Tien Dung Nguyen et al. Emerg Infect Dis. 2008 Apr.

Abstract

Phylogenetic analysis of influenza subtype H5N1 viruses isolated from Vietnam during 2005-2007 shows that multiple sublineages are present in Vietnam. Clade 2.3.4 viruses have replaced clade 1 viruses in northern Vietnam, and clade 1 viruses have been detected in southern Vietnam. Reassortment between these 2 sublineages has also occurred.

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Figures

Figure 1
Figure 1
A) Map of Vietnam showing the location of influenza A virus (H5N1) isolation from 2006 to 2007. B) Phylogenetic relationship of the hemagglutinin (HA) gene of influenza A viruses isolated in Vietnam during 2005–2007. Numbers above and below branches indicate neighbor-joining and Bayesian posterior probabilities, respectively. Analyses were based on nt 1–963 of the HA gene. The HA tree was rooted to swan/Hokkaido/51/96. Numbers to the right of the figure refer to World Health Organization influenza (H5N1) clade designations (Table). Virus names described in this study are shown in colored text; previously described Vietnam isolates are shown in bold italic text. *Denotes viruses with the Ser-123-Pro substitution in the HA. #Denotes a clade 2.3.4 and clade 1 reassortant virus. Scale bar, 0.01 substitutions per site. BHG, bar-headed goose; Ck, chicken; Dk, duck; FJ, Fujian; Gs, goose; GX, Guangxi; GY, Guiyang; HK, Hong Kong Special Administrative Region, People’s Republic of China; HN, Hunan; JX, Jiangxi; IDN, Indonesia; KHM, Cambodia; MusDk, muscovy duck; MYS, Malaysia; NGA, Nigeria; Qa, Quail; ST, Shantou; THA, Thailand; VNM, Vietnam; WDk, wild duck; YN, Yunnan.
Figure 2
Figure 2
Phylogenetic relationship of the polymerase basic 2 (PB2) gene of influenza A viruses isolated in Vietnam from 2006 to 2007. Numbers above and below branches indicate neighbor-joining and Bayesian posterior probabilities, respectively. Analyses were based on nt 986–2,288 of the PB2 gene. The tree was rooted to equine/Prague/1/56. Viruses names described in this study are shown in colored text; previously described Vietnam isolates are shown in bold italic text. #Denotes a clade 2.3.4 and clade 1 reassortant virus. Scale bar, 0.01 substitutions per site. BHG, bar-headed goose; Ck, chicken; Dk, duck; FJ, Fujian; Gs, goose; GX, Guangxi; GY, Guiyang; HK, Hong Kong Special Administrative Region, People’s Republic of China; HN, Hunan; JX, Jiangxi; IDN, Indonesia; KHM, Cambodia; MusDk, muscovy duck; MYS, Malaysia; NGA, Nigeria; Qa, Quail; ST, Shantou; THA, Thailand; VNM, Vietnam; WDk, wild duck; YN, Yunnan.
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References

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