Identification and phylogenetic analysis of five highly pathogenic avian influenza (H5N8) viruses isolated in Urumqi in 2016 / 中华微生物学和免疫学杂志

Objective:To analyze the genetic evolution and molecular characteristics of H5N8 avian influenza viruses (AIVs) isolated from the poultry in a live poultry market (LPM) in Urumqi, Xinjiang.Methods:Oropharyngeal and cloacal swabs of poultry were collected from a LPM in Urumqi in 2016. AIVs were isolated by inoculating swab samples into chicken embryos. Hemagglutination test and RT-PCR were used to identify the AIVs. The genes of isolated AIVs were amplified with the universal primers of AIV and whole-genome sequencing was also performed. Pairwise sequence alignment and analysis of phylogenetic and molecular characteristics were performed using BLAST, Clustal W, MEGA-X and DNAStar software.Results:Five H5N8 AIVs were isolated from poultry. These strains shared a nucleotide identity of 99.70%-100.00%, which indicated that they were from the same source, and were named XJ-H5N8/2016. Phylogenetic analysis based on hemagglutinin( HA), NS and PB2 genes showed that these isolates were clustered together with H5N8 AIVs isolated from the migratory swans in Hubei, Shanxi and Sanmenxia, and the ducks in India during 2016 to 2017. Moreover, they were also clustered together with H5N6 AIVs isolated from minks in China and the first case of human infection in Fujian. The phylogenetic tree of neuraminidase( NA) gene indicated the five isolates clustered together with H5N8 AIVs isolated from ducks in India in 2016, and the phylogenetic trees of PB1, MP, PA and NP genes showed that they were clustered together with H5N8 AIVs isolated from wild birds and poultry in Egypt, Cameroon, Uganda, Congo and other African countries in 2017. The HA cleavage sites of XJ-H5N8/2016 contained five consecutive basic amino acids, indicating high pathogenicity. Multiple mutations in the genes of XJ-H5N8/2016 could enhance its virulence and pathogenicity to mammals. Conclusions:The five strains of H5N8 AIVs isolated from the LPM were highly pathogenic and closely related to the H5N8 AIVs isolated from migratory birds and poultry in Hubei, Shanxi, Sanmenxia area, Africa and India during 2016 to 2017. Meanwhile, some of the viral genes were also closely related to the H5N6 AIVs isolated from the minks and human in China. Multiple mutations could increase the virulence and pathogenicity of AIVs to mammals, which could pose a potential threat to public health.

Novel reassortant 2.3.4.4B H5N6 highly pathogenic avian influenza viruses circulating among wild, domestic birds in Xinjiang, Northwest China

Background@#The H5 avian influenza viruses (AIVs) of clade 2.3.4.4 circulate in wild and domestic birds worldwide. In 2017, nine strains of H5N6 AIVs were isolated from aquatic poultry in Xinjiang, Northwest China. @*Objectives@#This study aimed to analyze the origin, reassortment, and mutations of the AIV isolates. @*Methods@#AIVs were isolated from oropharyngeal and cloacal swabs of poultry. Identification was accomplished by inoculating isolates into embryonated chicken eggs and performing hemagglutination tests and reverse transcription polymerase chain reaction (RT-PCR). The viral genomes were amplified with RT-PCR and then sequenced. The sequence alignment, phylogenetic, and molecular characteristic analyses were performed by using bioinformatic software. @*Results@#Nine isolates originated from the same ancestor. The viral HA gene belonged to clade 2.3.4.4B, while the NA gene had a close phylogenetic relationship with the 2.3.4.4C H5N6 highly pathogenic avian influenza viruses (HPAIVs) isolated from shoveler ducks in Ningxia in 2015. The NP gene was grouped into an independent subcluster within the 2.3.4.4B H5N8 AIVs, and the remaining six genes all had close phylogenetic relationships with the 2.3.4.4B H5N8 HPAIVs isolated from the wild birds in China, Egypt, Uganda, Cameroon, and India in 2016–2017, Multiple basic amino acid residues associated with HPAIVs were located adjacent to the cleavage site of the HA protein. The nine isolates comprised reassortant 2.3.4.4B HPAIVs originating from 2.3.4.4B H5N8 and 2.3.4.4C H5N6 viruses in wild birds. @*Conclusions@#These results suggest that the Northern Tianshan Mountain wetlands in Xinjiang may have a key role in AIVs disseminating from Central China to the Eurasian continent and East African.

Novel reassortant 2.3.4.4B H5N6 highly pathogenic avian influenza viruses circulating among wild, domestic birds in Xinjiang, Northwest China

Background@#The H5 avian influenza viruses (AIVs) of clade 2.3.4.4 circulate in wild and domestic birds worldwide. In 2017, nine strains of H5N6 AIVs were isolated from aquatic poultry in Xinjiang, Northwest China. @*Objectives@#This study aimed to analyze the origin, reassortment, and mutations of the AIV isolates. @*Methods@#AIVs were isolated from oropharyngeal and cloacal swabs of poultry. Identification was accomplished by inoculating isolates into embryonated chicken eggs and performing hemagglutination tests and reverse transcription polymerase chain reaction (RT-PCR). The viral genomes were amplified with RT-PCR and then sequenced. The sequence alignment, phylogenetic, and molecular characteristic analyses were performed by using bioinformatic software. @*Results@#Nine isolates originated from the same ancestor. The viral HA gene belonged to clade 2.3.4.4B, while the NA gene had a close phylogenetic relationship with the 2.3.4.4C H5N6 highly pathogenic avian influenza viruses (HPAIVs) isolated from shoveler ducks in Ningxia in 2015. The NP gene was grouped into an independent subcluster within the 2.3.4.4B H5N8 AIVs, and the remaining six genes all had close phylogenetic relationships with the 2.3.4.4B H5N8 HPAIVs isolated from the wild birds in China, Egypt, Uganda, Cameroon, and India in 2016–2017, Multiple basic amino acid residues associated with HPAIVs were located adjacent to the cleavage site of the HA protein. The nine isolates comprised reassortant 2.3.4.4B HPAIVs originating from 2.3.4.4B H5N8 and 2.3.4.4C H5N6 viruses in wild birds. @*Conclusions@#These results suggest that the Northern Tianshan Mountain wetlands in Xinjiang may have a key role in AIVs disseminating from Central China to the Eurasian continent and East African.

Avian influenza A (H7N9) virus: from low pathogenic to highly pathogenic / 医学前沿

The avian influenza A (H7N9) virus is a zoonotic virus that is closely associated with live poultry markets. It has caused infections in humans in China since 2013. Five waves of the H7N9 influenza epidemic occurred in China between March 2013 and September 2017. H7N9 with low-pathogenicity dominated in the first four waves, whereas highly pathogenic H7N9 influenza emerged in poultry and spread to humans during the fifth wave, causing wide concern. Specialists and officials from China and other countries responded quickly, controlled the epidemic well thus far, and characterized the virus by using new technologies and surveillance tools that were made possible by their preparedness efforts. Here, we review the characteristics of the H7N9 viruses that were identified while controlling the spread of the disease. It was summarized and discussed from the perspectives of molecular epidemiology, clinical features, virulence and pathogenesis, receptor binding, T-cell responses, monoclonal antibody development, vaccine development, and disease burden. These data provide tools for minimizing the future threat of H7N9 and other emerging and re-emerging viruses, such as SARS-CoV-2.

Isolation, identification and phylogenetic analysis of six strains of H5N6 highly pathogenic avian influenza virus / 中华微生物学和免疫学杂志

Objective:To analyze phylogenetic structure and molecular characteristics of H5N6 avian influenza virus (AIVs) isolated from live poultry market (LPM).Methods:Oropharyngeal and cloacal swabs from poultry, and environmental samples were collected from LPM in Urumqi in December 2018, AIVs were isolated and identified by inoculation of chicken embryo, hemagglutination test and RT-PCR, the viral whole genome was amplified with the universal primers of influenza A virus, and then sequenced, pairwise sequence alignments, phylogenetic and molecular characteristics analysis were performed by BLAST, Clustal W, MEGA-X and DNAStar software.Results:Six strains of H5N6 AIVs were isolated from poultry samples, the identity between the viral genes was high (99.4%-100.0%), so the isolates were the same source. BLAST analysis revealed that the viral NP sequence had the highest identity (99.7%) with H5N6 AIVs isolated from poultry in Suzhou, while the sequence of the remaining 7 viral genes had the highest identity (99.0%-100.0%) with H5N6 AIVs isolated from environment in Guangdong during 2017 to 2018. Phylogenetic analysis showed that the viral HA belonged to Clade 2.3.4.4C, and the viral HA, NA, PB1, PA, NP, and MP were all clustered together with H5N6 AIVs isolated from mink in Eastern China in 2018, while the PB2 and NS were clustered together with H5N6 AIVs isolated from environment in Guangdong from 2017 to 2018. The HA cleavage site contained multiple basic amino acid residues, which was highly pathogenic AIVs (HPAIVs). S137A and T160A mutations of HA could increase binding to human-type receptor SAα2, 6-Gal. Additionally, the viral multiple mutations, including 59-69 deletion in NA, the L89V, G309D, R477G, I495V, I504V, D391E, and A661E in PB2, as well as the P42S, D92E, and 80-84 deletion in NS1, could enhance the viral virulence and pathogenicity to mammals. Conclusions:The 6 strains of H5N6 HPAIVs isolated from LPM have relatively close genetic relationship with H5N6 AIVs isolated from mink in Eastern China and environment in Guangdong during 2017 to 2018, the viral multiple mutations could increase its pathogenicity to mammals, which could pose a potential risk to public health.

Isolation, identification and phylogenetic analysis of a wild bird-derived H1N1 avian influenza virus in the northern Tianshan Mountain / 中华微生物学和免疫学杂志

Objective:To analyze the complete genome sequence and phylogenetic structure of a wild bird-derived H1N1 avian influenza virus (AIV) in the northern Tianshan Mountain.Methods:In November 2018, 320 samples of fresh wild bird feces were collected from several reservoirs in the middle part of northern Tianshan Mountain. Chicken embryo inoculation test, hemagglutination inhibition test and RT-PCR with PB1 universal primer were used to isolate and identify AIVs. Eight fragments of the viral genome were amplified with the universal primers of influenza A virus and the whole viral genome was sequenced. Pairwise sequence alignments and analysis of phylogenetic and molecular characteristics were performed by BLAST, Clustal W, MEGA7.0 and MegAlign software. Results:Influenza viruses were isolated and identified from six samples of wild bird feces with a positive rate of 1.88%. One of them was H1N1 AIV, named A/wild bird/Xinjiang/010/2018 (H1N1) (XJ-H1N1). The eight gene segments of XJ-H1N1 were all derived from AIVs isolated from wild ducks of Anseriformes. The surface genes of HA and NA were Eurasian lineages and derived from H1N1 isolated from Mongolian Anas platyrhynchos and H3N1 isolated from Bangladesh wild duck, respectively. The six internal genes were derived from H6N8 isolated from Anas strepera in Siberia, H7N3 isolated from Anas clypeata and teal in Egypt, and H7N5 isolated from wild birds such as Anas platyrhynchos in the Netherlands. The HA cleavage site of XJ-H1N1 contained only one basic amino acid, suggesting that it was a low pathogenic AIV. Amino acids at positions 190 and 225 of HA receptor binding sites were E and G (H3 count), which could bind both α2, 3 galactoside sialic acid (SAα2, 3Gal) and SAα2, 6Gal receptors. T200A and E227A mutations in HA amino acid sequences and P42S mutation in NS1 amino acid sequences could all enhance the replication ability and pathogenicity of the virus in mammalian cells. Conclusions:A low pathogenic H1N1 AIV, XJ-H1N1, was isolated from wild birds in the northern Tianshan Mountain, resulting from multiple reassortments of AIVs carried by migrating wild ducks. The replication capacity and pathogenicity of XJ-H1N1 in mammalian cells might be enhanced. Moreover, the virus could bind both SA 2-3gal and SA 2-6gal receptors.

A novel carbon nanoparticle probe-based ultrasensitive lateral flow assay for rapid detection of Ebola virus / 生物工程学报

Ebola virus (EBOV) is an extremely contagious pathogen first discovered in Africa associated with severe hemorrhagic disease in humans and nonhuman primates, which has resulted in at least 28 500 suspected cases and 11 300 confirmed deaths in 2014-2016 Ebola epidemic in West Africa. Rapid and sensitive detection of EBOV is the key to increasing the probability of survival and reducing infection rates in pandemic regions. Here, we report an ultrasensitive and instrument-free EBOV detection assay based on colloidal carbon immunochromatography. Carbon nanoparticle-labeled rabbit anti-EBOV-VP40 IgG were concentrated in the conjugate pad, monoclonal antibody (McAb, 4B7F9) against EBOV-VP40 and goat anti-rabbit IgG were immobilized on the nitrocellulose membrane with 2 μL/cm at a concentration of 1 mg/mL as test and control lines, respectively. Then the sample application pad, conjugate release pad, nitrocellulose membrane and absorbent pad were assembled into a lateral flow test strip. The test strip shows strong specificity against related viruses that share similar clinical symptoms and geographic range with EBOV, including marburg virus, influenza virus, yellow fever virus and dengue virus. In addition, 1 500 negative serums were tested with false-positive rate of 1.3‰ which significantly lower than that of ReEBOV™ colloidal gold test kit recommended by World Health Organization (WHO). The sensitivity of this strip was analyzed using inactivated EBOV with detection limit of 100 ng/mL (10⁶ copies/mL) which clearly higher than that of ReEBOV™ dipstick (10⁸ copies/mL). Furthermore, the strip showed excellent thermal stability characteristics in room temperature and could be as a point-of-care (POC), ultra-sensitive and specific promising candidate for EBOV serological screening in rural Africa or entry/exit ports.

Genetic evolution of HA and NA genes of H9N2 influenza viruses isolated in regions of Hunan Province, China, in 2015 / 生物工程学报

The high prevalence of influenza A virus is identified in Hunan Province because of the high density of poultry farms. To survey the variations of H9N2 subtype avian influenza virus in Hunan province, we analyzed HA and NA genes of 10 virus strains isolated from different areas of Hunan Province. All these strains belong to the Eurasian lineage, Y280-like sub-lineage. The cleavage sites in their HA genes were all RSSR↓GLT, corresponding to the feature of low pathogenic AIV. All strains had an L (Leu) at the site 234 in the HA genes, indicating the ability of binding with the SAα-2,6 receptor. NA gene stalk deletions at aa 63-65 were also detected from all the isolates, indicating a possibility of increased virus replication in mammals. Our findings suggest that more attention should be paid to the surveillance of H9N2 influenza virus and its direction of reassortment.

Overview on duck virus hepatitis A / 生物工程学报

This article describes the nomenclature, history and genetic evolution of duck hepatitis A virus, and updates the epidemiology, clinical symptom and surveillances of duck virus hepatitis A. It also summarizes the present status and progress of duck virus hepatitis A and illustrated the necessity and urgency of its research, which provides rationale for the control of duck hepatitis A virus disease in China.