Characterization of the H5N1 highly pathogenic avian influenza virus derived from wild pikas in China.
The highly pathogenic H5N1 avian influenza virus emerged from China in 1996 and has spread across Eurasia and Africa, with a continuous stream of new cases of human infection appearing since the first large-scale outbreak among migratory birds at Qinghai Lake. The role of wild birds, which are the natural reservoirs for the virus, in the epidemiology of the H5N1 virus has raised great public health concern, but their role in the spread of the virus within the natural ecosystem of free-ranging terrestrial wild mammals remains unclear. In this study, we investigated H5N1 virus infection in wild pikas in an attempt to trace the circulation of the virus. Seroepidemiological surveys confirmed a natural H5N1 virus infection of wild pikas in their native environment. The hemagglutination gene of the H5N1 virus isolated from pikas reveals two distinct evolutionary clades, a mixed/Vietnam H5N1 virus sublineage (MV-like pika virus) and a wild bird Qinghai (QH)-like H5N1 virus sublineage (QH-like pika virus). The amino acid residue (glutamic acid) at position 627 encoded by the PB2 gene of the MV-like pika virus was different from that of the QH-like pika virus; the residue of the MV-like pika virus was the same as that of the goose H5N1 virus (A/GS/Guangdong [GD]/1/96). Further, we discovered that in contrast to the MV-like pika virus, which is nonpathogenic to mice, the QH-like pika virus is highly pathogenic. To mimic the virus infection of pikas, we intranasally inoculated rabbits, a species closely related to pikas, with the H5N1 virus of pika origin. Our findings first demonstrate that wild pikas are mammalian hosts exposed to H5N1 subtype avian influenza viruses in the natural ecosystem and also imply a potential transmission of highly pathogenic avian influenza virus from wild mammals into domestic mammalian hosts and humans.
Zhou
Jiyong
J
Key Laboratory of Animal Epidemic Etiology and Immunological Prevention of Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou 310029, People's Republic of China. jyzhou@zju.edu.cn
Sun
Wenbo
W
Wang
Junhua
J
Guo
Junqing
J
Yin
Wei
W
Wu
Nanping
N
Li
Lanjuan
L
Yan
Yan
Y
Liao
Ming
M
Huang
Yu
Y
Luo
Kaijian
K
Jiang
Xuetao
X
Chen
Hualan
H
D000818:Animals; D002681:China; D016000:Cluster Analysis; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification* / Q000472:pathogenicity; D007793:Lagomorpha / Q000821:virology*; D051379:Mice; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D012324:RNA-Dependent RNA Polymerase / Q000235:genetics; D011817:Rabbits; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D016036:Seroepidemiologic Studies; D014764:Viral Proteins / Q000235:genetics
D019267:Hemagglutinin Glycoproteins, Influenza Virus; C057027:PB2 protein, Influenzavirus A; D014764:Viral Proteins; C109963:hemagglutinin, avian influenza A virus; D012324:RNA-Dependent RNA Polymerase