Characterization of a non-pathogenic H5N1 influenza virus isolated from a migratory duck flying from Siberia in Hokkaido, Japan, in October 2009

<p>Abstract</p> <p>Background</p> <p>Infection with H5N1 highly pathogenic avian influenza viruses (HPAIVs) of domestic poultry and wild birds has spread to more than 60 countries in Eurasia and Africa. It is concerned that HPAIVs may be perpetuated in the lakes in Siberia where migratory water birds nest in summer. To monitor whether HPAIVs circulate in migratory water birds, intensive surveillance of avian influenza has been performed in Mongolia and Japan in autumn each year. Until 2008, there had not been any H5N1 viruses isolated from migratory water birds that flew from their nesting lakes in Siberia. In autumn 2009, A/mallard/Hokkaido/24/09 (H5N1) (Mal/Hok/24/09) was isolated from a fecal sample of a mallard (<it>Anas platyrhynchos</it>) that flew from Siberia to Hokkaido, Japan. The isolate was assessed for pathogenicity in chickens, domestic ducks, and quails and analyzed antigenically and phylogenetically.</p> <p>Results</p> <p>No clinical signs were observed in chickens inoculated intravenously with Mal/Hok/24/09 (H5N1). There was no viral replication in chickens inoculated intranasally with the isolate. None of the domestic ducks and quails inoculated intranasally with the isolate showed any clinical signs. There were no multiple basic amino acid residues at the cleavage site of the hemagglutinin (HA) of the isolate. Each gene of Mal/Hok/24/09 (H5N1) is phylogenetically closely related to that of influenza viruses isolated from migratory water birds that flew from their nesting lakes in autumn. Additionally, the antigenicity of the HA of the isolate was similar to that of the viruses isolated from migratory water birds in Hokkaido that flew from their northern territory in autumn and different from those of HPAIVs isolated from birds found dead in China, Mongolia, and Japan on the way back to their northern territory in spring.</p> <p>Conclusion</p> <p>Mal/Hok/24/09 (H5N1) is a non-pathogenic avian influenza virus for chickens, domestic ducks, and quails, and is antigenically and genetically distinct from the H5N1 HPAIVs prevailing in birds in Eurasia and Africa. H5 viruses with the HA gene of HPAIV had not been isolated from migratory water birds in the surveillance until 2009, indicating that H5N1 HPAIVs had not become dominant in their nesting lakes in Siberia until 2009.</p

Secondary EML4?ALK-positive Lung Adenocarcinoma in a Patient Previously Treated for Acute Lymphoblastic Leukemia in Childhood: A Case Reportated for Acute Lymphoblastic Leukemia in Childhood: A Case Report

It is widely recognized that the risk of secondary neoplasms increases as childhood cancer survivors progress through adulthood. These are mainly hematological malignancies, and recurrent chromosome translocations are commonly detected in such cases. On the other hand, while secondary epithelial malignancies have sometimes been reported, chromosome translocations in these epithelial malignancies have not. A 33-year-old man who had been diagnosed with acute lymphoblastic leukemia and treated with chemotherapy almost 20 years earlier was diagnosed with lung adenocarcinoma. After chromosomal rearrangement of echinoderm microtubule- associated protein-like 4 gene and the anaplastic lymphoma kinase gene was detected in this adenocarcinoma, he responded to treatment with crizotinib. It was therefore concluded that this echinoderm microtubule-associated protein-like 4 gene-anaplastic lymphoma kinase gene-positive lung adenocarcinoma was a secondary epithelial malignancy

Characterization of H5N1 highly pathogenic avian influenza virus strains isolated from migratory waterfowl in Mongolia on the way back from the southern Asia to their northern territory

AbstractH5N1 highly pathogenic avian influenza (HPAI) viruses were isolated from dead wild waterfowl at Khunt, Erkhel, Doityn Tsagaan, Doroo, and Ganga Lakes in Mongolia in July 2005, May 2006, May 2009, July 2009, and May 2010, respectively. The isolates in 2005 and 2006 were classified into genetic clade 2.2, and those in 2009 and 2010 into clade 2.3.2. A/whooper swan/Mongolia/6/2009 (H5N1) experimentally infected ducks and replicated systemically with higher mortality than that of the isolates in 2005 and 2006. Intensive surveillance of avian influenza in migratory waterfowl flying from their nesting lakes in Siberia to Mongolia in every autumn indicate that HPAI viruses have not perpetuated at their nesting lakes until 2009. The present results demonstrate that wild waterfowl were sporadically infected with H5N1 HPAI viruses prevailing in domestic poultry in the southern Asia and died in Mongolia on the way back to their northern territory in spring

Characterization of Highly Pathogenic Avian Influenza Virus A(H5N6), Japan, November 2016

Highly pathogenic avian influenza viruses (HPAIVs) A(H5N6) were concurrently introduced into several distant regions of Japan in November 2016. These viruses were classified into the genetic clade 2.3.4.4c and were genetically closely related to H5N6 HPAIVs recently isolated in South Korea and China. In addition, these HPAIVs showed further antigenic drift

Memory Immune Responses against Pandemic (H1N1) 2009 Influenza Virus Induced by a Whole Particle Vaccine in Cynomolgus Monkeys Carrying Mafa-A1*052∶02

We made an H1N1 vaccine candidate from a virus library consisting of 144 ( = 16 HA×9 NA) non-pathogenic influenza A viruses and examined its protective effects against a pandemic (2009) H1N1 strain using immunologically naïve cynomolgus macaques to exclude preexisting immunity and to employ a preclinical study since preexisting immunity in humans previously vaccinated or infected with influenza virus might make comparison of vaccine efficacy difficult. Furthermore, macaques carrying a major histocompatibility complex class I molecule, Mafa-A1*052∶02, were used to analyze peptide-specific CD8+ T cell responses. Sera of macaques immunized with an inactivated whole particle formulation without addition of an adjuvant showed higher neutralization titers against the vaccine strain A/Hokkaido/2/1981 (H1N1) than did sera of macaques immunized with a split formulation. Neutralization activities against the pandemic strain A/Narita/1/2009 (H1N1) in sera of macaques immunized twice with the split vaccine reached levels similar to those in sera of macaques immunized once with the whole particle vaccine. After inoculation with the pandemic virus, the virus was detected in nasal samples of unvaccinated macaques for 6 days after infection and for 2.67 days and 5.33 days on average in macaques vaccinated with the whole particle vaccine and the split vaccine, respectively. After the challenge infection, recall neutralizing antibody responses against the pandemic virus and CD8+ T cell responses specific for nucleoprotein peptide NP262-270 bound to Mafa-A1*052∶02 in macaques vaccinated with the whole particle vaccine were observed more promptly or more vigorously than those in macaques vaccinated with the split vaccine. These findings demonstrated that the vaccine derived from our virus library was effective for pandemic virus infection in macaques and that the whole particle vaccine conferred more effective memory and broader cross-reactive immune responses to macaques against pandemic influenza virus infection than did the split vaccine

鳥インフルエンザウイルスのワクチン開発および病原性の分子基盤に関する研究

1997年以来、H5またはH7ウイルスの感染に因る高病原性鳥インフルエンザ(HPAI)の発生が続いている。筆者はインフルエンザAウイルスの自然宿主である野生水禽に維持されているH5またはH7ウイルスとHPAIウイルス間でヘマグルチニン(HA)の抗原性が類似していることを示した。本結果に基づき、野生水禽から分離された非病原性鳥インフルエンザウイルスを元に、A/duck/Hokkaido/Vac-1/2004 (H5N1) [Vac-1/04 (H5N1)]、A/duck/Hokkaido/Vac-3/2007 (H5N1)、およびA/duck/Hokkaido/Vac-2/2004 (H7N7)[Vac-2/04 (H7N7)]をワクチン候補株として作出した。ホルマリン不活化したVac-1/04 (H5N1) を100μg皮下接種したマウスは、HPAIウイルスVietnam/1194/2004 (H5N1)の致死量の攻撃に耐過した。Vac-1/04 (H5N1)およびVac-2/04 (H7N7)によって試製したワクチンを接種したニワトリおよびサルは、HPAIウイルスの攻撃に耐過した。以上の結果は野生水禽から分離した非病原性ウイルスがHPAIウイルスに因る感染症に対するワクチン株として有用であることを示している。一方で、ワクチンの濫用はHPAIウイルスの見えない流行拡大を助長する恐れがある。ワクチン接種に依存しHPAI対策の基本である摘発淘汰が疎かとなっている地域では、抗原変異ウイルスの出現を招くと共に、人の感染例が増加している。本研究で確立したワクチン株と流行株間の交差反応性を調べると共に、世界各国が摘発淘汰を基本とした対策を行い、鳥インフルエンザを封じ込める必要がある。H5またはH7ウイルスに因るHPAIに加え、近年低病原性H9N2ウイルスによる鳥インフルエンザの発生がアジア・中近東で続いており、家禽に甚大な被害を及ぼしている。従ってH9ウイルスがH5およびH7ウイルスのように家禽に対する高い病原性を獲得し得るかどうかを確認しておくことは防疫上重要である。本研究において、H9ウイルスのHA開裂部位にHPAIウイルスに見られる塩基性アミノ酸の連続配列を人工的に導入し、さらにヒヨコの気嚢内で10代継代したウイルス、rgY55sub-P10 (H9N2)はニワトリに対して静脈内接種病原性を示した。HA 開裂部位に導入した塩基性アミノ酸、および継代によって起こったアミノ酸の置換がニワトリに対する高い病原性に関与するものと考えられる。rgY55sub-P10 (H9N2)はMDCK細胞における増殖に外来性のトリプシン(ニワトリの呼吸器・腸管に局在)を必要としなかったが、本株を鼻腔内に接種したニワトリはH5ウイルスを接種した場合と異なり全く症状を示さなかった。本結果はニワトリ体内のユビキタスなプロテアーゼによるHAの開裂活性化はウイルスの全身感染に必要であるが、十分条件ではないことを示している。H5ウイルスはH9ウイルスに比べニワトリの血管内皮細胞で効率的に増殖してウイルス血症を引き起こし、さらに脳に侵入して高い病原性を発揮するものと考える。本研究では、H9N2ウイルスが静脈内接種病原性を獲得し得ることを示した。H9ウイルスはニワトリに細菌と共感染すると、鼻腔内接種病原性が増強することが報告されている。HA開裂部位に塩基性アミノ酸の置換変異を有するウイルスが実際に野外のニワトリから分離されており、このようなウイルスが鶏群内で感染を繰り返すことによって、静脈内接種病原性に加え鼻腔内接種病原性を獲得する恐れがあるので、監視を続ける必要がある。本研究で得られた成績は野生水禽および家禽におけるインフルエンザサーベイランスが、1) 環境中のウイルスの抗原性を把握する、2) HPAIに対するワクチン株を得る、3) 新たなHPAIウイルスの出現予測、のために重要であることを示している

Factors responsible for pathogenicity in chickens of a low-pathogenic H7N7 avian influenza virus isolated from a feral duck

Highly pathogenic avian influenza viruses have poly-basic amino acid sequences at the cleavage site in their hemagglutinin (HA). Although this poly-basic region is a prerequisite factor for pathogenicity in chickens, not much is known about additional factors responsible for the acquisition of pathogenicity of the duck influenza virus in chickens. Here, we introduced multiple basic amino acid residues into the HA cleavage site of the A/duck/Hokkaido/Vac-2/2004 (H7N7) strain of avian influenza virus, which has low pathogenicity in chickens; the resultant Vac2sub-P0 strain was not intravenously pathogenic in chickens. In contrast, the Vac2sub-P3 strain, which was recovered from three consecutive passages of Vac2sub-P0 in chicks, was intravenously pathogenic in chickens. Six amino acid substitutions were identified by comparison of the Vac2sub-P3 and Vac2sub-P0 genomic sequences: Lys123Glu in PB2, Asn16Asp in PB1, Glu227Gly and Ile388Thr in HA, Gly228Arg in M1, and Leu46Pro in M2. The results of intravenous inoculations of chickens with recombinant virus indicated that all six amino acid substitutions were required to varying degrees for Vac2sub-P3 pathogenicity, with Glu227Gly and Ile388Thr in HA being particularly essential. These results reveal the roles of additional viral factors in the acquisition of pathogenicity in addition to the previously characterized role of the poly-basic amino acid sequences at the HA cleavage site

The PB2, PA, HA, NP, and NS genes of a highly pathogenic avian influenza virus A/whooper swan/Mongolia/3/2005 (H5N1) are responsible for pathogenicity in ducks

Background: Wild ducks are the natural hosts of influenza A viruses. Duck influenza, therefore, has been believed inapparent infection with influenza A viruses, including highly pathogenic avian influenza viruses (HPAIVs) in chickens. In fact, ducks experimentally infected with an HPAIV strain, A/Hong Kong/483/1997 (H5N1) (HK483), did not show any clinical signs. Another HPAIV strain, A/whooper swan/Mongolia/3/2005 (H5N1) (MON3) isolated from a dead swan, however, caused neurological dysfunction and death in ducks. Method: To understand the mechanism whereby MON3 shows high pathogenicity in ducks, HK483, MON3, and twenty-four reassortants generated between these two H5N1 viruses were compared for their pathogenicity in domestic ducks. Results: None of the ducks infected with MON3-based single-gene reassortants bearing the PB2, NP, or NS gene segment of HK483 died, and HK483-based single-gene reassortants bearing PB2, NP, or NS genes of MON3 were not pathogenic in ducks, suggesting that multiple gene segments contribute to the pathogenicity of MON3 in ducks. All the ducks infected with the reassortant bearing PB2, PA, HA, NP, and NS gene segments of MON3 died within five days post-inoculation, as did those infected with MON3. Each of the viruses was assessed for replication in ducks three days post-inoculation. MON3 and multi-gene reassortants pathogenic in ducks were recovered from all of the tissues examined and replicated with high titers in the brains and lungs. Conclusion: The present results indicate that multigenic factors are responsible for efficient replication of MON3 in ducks. In particular, virus growth in the brain might correlate with neurological dysfunction and the disease severity