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Letter
H5N1 Influenza Virus, Domestic Birds, Western Siberia,
Russia
Alexander M. Shestopalov,* Alexander G. Durimanov,* Vasily
A. Evseenko,* Vladimir A. Ternovoi,* Yury. N. Rassadkin,* Yulya V. Razumova,*
Anna V. Zaykovskaya,* Sergey I. Zolotykh,* and Sergey V. Netesov*
*State Research Center Virology and Biotechnology Vector,
Koltsovo, Novosibirsk, Russia
Suggested citation for this article
To the Editor: Highly pathogenic H5N1 avian influenza
virus caused disease outbreaks in poultry and wild birds in several Asian,
European, and African countries from 2003 to 2006. This virus caused >90
human deaths in Vietnam, Thailand, People's Republic of China, Indonesia,
Turkey, Iraq, and Cambodia (1–3). Hemagglutinin (HA) and neuraminidase
(NA) genes of this virus were derived from the Gs/Gd/1/96-like lineage, and 6
genes that encode internal viral proteins were derived from other lineages (1).
Highly pathogenic H5N1 virus genetically related to the
A/Chicken/Shantou/4231/03 (People's Republic of China) isolate caused disease
outbreaks in poultry in Japan from the end of December 2003 to March 2004 (4).
In May and June 2005, highly pathogenic H5N1 virus was isolated from migratory
birds during disease outbreaks near Lake Qinghai in western People's Republic
of China. HA, NA, and nucleoprotein genes of the Qinghai virus were closely
related to H5N1 virus A/Chicken/Shantou/4231/03 isolated in People's Republic
of China in 2003. Five other viral genes (matrix, PA, PB1, PB2, and
nonstructural protein) were closely related to an H5N1 Hong Kong Special
Administrative Region, People's Republic of China 2004 isolate (A/Peregrin
falcon/HK/D0028/04) and H5N1 virus A/Chicken/Shantou/810/05 isolated in
People's Republic of China in 2005 (5,6).
In July 2005, domestic poultry began to die in the village
of Suzdalka in western Siberia, Russia (Dovolnoe County, Novosibirsk region).
Autopsies showed serious alterations in all internal organs tested.
Approximately 95%–100% of the lungs were affected, and all serous membranes
showed petechial and confluent hemorrhages. The highest concentration of
hemorrhages was in the pericardium.
Organs from 3 birds (1 turkey and 2 chickens) that had died
during this outbreak were further analyzed. Homogenates of lungs, kidneys, and
spleens were tested by hemagglutination inhibition (HI) assay. The highest
titers, 32 and 16, were observed in the spleen of the turkey and kidneys of the
chickens, respectively. H5 influenza A virus was identified in a homogenate of
turkey spleen by conventional HI assay (7) with a panel of reference
antisera.
For the identification of NA subtype, RNA was isolated from
turkey spleen homogenate and synthesis of viral cDNA was performed as
previously described (7). Amplification by polymerase chain reaction
(PCR) and sequencing of an NA gene fragment were performed with in-house
primers (sequences of primers are available on request). The nucleotide sequence
obtained (547 bp, GenBank accession no. DQ231243) showed 100% identity with the
NA gene of H5N1 viruses isolated in People's Republic of China in 2005 (e.g.,
A/Great black-headed gull/Qinghai/1/05) (5,6).
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enlarged image
Figure. Phylogenetic tree of H5 hemagglutinin genes of
influenza A viruses. The 3 H5 western Siberian 2005 viruses isolated in this
study are shaded... |
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Homogenates of bird organs (turkey spleen and chicken
kidneys) were injected into the allantoic cavity of 10-day-old embryonated
chicken eggs. Three hemagglutinating agents were isolated (titers 1,024–2,048)
and identified as H5 influenza A virus (A/Turkey/Suzdalka/Nov-1/05,
A/Chicken/Suzdalka/Nov-11/05, and A/Chicken/Suzdalka/Nov-12/05) by reverse
transcription–PCR and sequencing (isolation of RNA from allantoic fluid and
synthesis of virus cDNA were performed as previously described [7]). PCR
amplification and sequencing of a fragment of the HA gene were performed with
an in-house primer set for the H5 gene (available on request). Phylogenetic
analysis of nucleotide sequences obtained (GenBank accession nos. DQ231242,
DQ231241, and DQ231240) indicated that western Siberian 2005 isolates belong to
the Gs/Gd/1/96-like lineage and form a cluster with H5N1 viruses isolated from
migratory birds in the People's Republic of China in 2005 (5), from
poultry in Japan in 2004 (4), and from poultry and humans in Asian
countries in 2003 and 2004 (1) (Figure). Deduced amino acid HA cleavage
site sequences of all isolates (PQGERRRKKR/GL) corresponded to highly
pathogenic Asian H5N1 influenza virus variants (5,6).
To test virulence, 10 six-week-old chickens were
intravenously infected with isolate A/Turkey/Suzdalka/Nov-1/05 as previously
described (7). All viruses isolated were highly pathogenic (all chickens
died within a day of infection).
We isolated H5N1 influenza virus from the spleen of a turkey
that died during an outbreak in poultry in western Siberia in July 2005. HA and
NA genes of this virus were closely related to those of H5N1 avian influenza
viruses that caused outbreaks in birds in Asian countries from 2003 to 2005 and
in Japan in 2003 and 2004. The corresponding isolate,
A/Turkey/Suzdalka/Nov-1/05, from turkey spleen was highly pathogenic for
chickens in the laboratory intravenous pathogenicity index test. The origin of
this H5N1 virus in western Siberia is not known. Migratory birds could have
introduced this virus because western Siberia is located on a flyway of wild
birds that migrate in the spring from southeastern Asia. Highly pathogenic
Asian H5N1 influenza virus in western Siberia demonstrates spread of these
Asian viruses into new areas and suggests a larger geographic distribution.
Acknowledgments
We thank G.G. Onishchenko, L.S. Sandakhchiev, R. Webster,
and M. Callahan for valuable advice.
This study was supported by grant BII/CRDF RUX2-20411-NO-04
from the US Department of State (US Civilian Research and Development
Foundation) and the Novosibirsk region governor reserve fund.
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Suggested citation
for this article:
Shestopalov AM,
Durimanov AG, Evseenko VA, Ternovoi VA, Rassadkin YN, Razumova YV, et al. H5N1
influenza virus, domestic birds, western Siberia, Russia [letter]. Emerg Infect
Dis [serial on the Internet]. 2006 Jul [date cited]. Available from
http://www.cdc.gov/ncidod/EID/vol12no07/05-1338.htm
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