Novel reassortant Avian influenza A(H5N6) viruses in humans, Guangdong, China, 2015

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From: Emerging Infectious Diseases(Vol. 22, Issue 8)
Publisher: U.S. National Center for Infectious Diseases
Document Type: Letter to the editor
Length: 1,333 words
Lexile Measure: 1450L

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To the Editor: Avian influenza A(H5N6) influenza viruses have circulated among poultry in southern (Jiangxi, Guangdong) and western (Sichuan) provinces of China since 2013 (1,2). In 2014, outbreaks of H5N6 virus infection occurred among poultry in China, Laos, and Vietnam (1). In April 2014, the first case of highly pathogenic H5N6 infection among humans was detected in Sichuan Province (3); the second case was detected on December 3, 2014, in Guangdong Province (4). In December 2015, 4 humans in Guangdong Province were infected with H5N6 influenza (5,6).

To study the genetic basis of continuing human infections with this avian influenza subtype, we sequenced the complete genomes of 2 of the 4 human H5N6 isolates obtained in December 2015 in Guangdong Province. We compared these sequences with those of 1 H6N6 and 8 H5N6 influenza viruses isolated from birds in live poultry markets in this region during 2013-2015 (online Technical Appendix, http://wwwnc.cdc.gov/ EID/article/22/8/16-0146-TechApp1.pdf) and other published genomes of H5, H6N6, and H9N2 avian influenza viruses (online Technical Appendix Table). Phylogenetic analyses of the hemagglutinin (HA) genes showed that all human H5N6 isolates belonged to clade 2.3.4.4 (online Technical Appendix Figure 1, panel A). HA and neuraminidase (NA) genes of some H5N6 viruses isolated in Guangdong Province during 2013-2014 were in the Sichuan-like lineage, but all of those from 2015 were in the Jiangxi-like lineage (online Technical Appendix Figure 1, panels A, B).

Despite the similarities of the HA and NA genes, the 6 internal genes from the 2 human isolates from 2015, A/Guangdong/ZQ874/2015 (H5N6) and A/Guangdong/ SZ872/2015 (H5N6) were different from 2 human H5N6 isolates from 2014, A/Sichuan/26221/2014 (H5N6) and A/Guangzhou/39715/2014 (H5N6). The polymerase basic (PB) 2 gene from isolate A/Guangdong/ZQ874/2015 (H5N6) appears to have derived from an H6N6 virus isolated from a duck; all other genes in this isolate were derived from H5N6 viruses that have been circulating among poultry since 2013 (online Technical Appendix Figure 1, panel C; online Technical Appendix Figure 2). This isolate showed high nucleotide identity to 6 of...

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Gale Document Number: GALE|A461529957