Complete genome sequence of a novel natural recombinant H5N5 influenza virus from ducks in central China.

We reported the complete genome sequence of an H5N5 avian influenza virus (AIV) that was first isolated from duck in central China in 2010. Genomic sequence and phylogenetic analyses showed that this virus was a recombinant between H5N1 AIV circulated in southeastern Asia and an N5 subtype influenza virus. These data are beneficial for investigating the epidemiology and ecology of AIVs in central China.

Complete genome sequence of a novel H4N1 influenza virus isolated from a pig in central China.

Pigs are proposed to be "mixing vessel" hosts that can produce genetically novel reassortant viruses with pandemic potential. The appearance of any novel influenza viruses among pigs should pose concerns for human health. Here, we report the complete genome sequence of a novel H4N1 influenza virus [A/Swine/HuBei/06/2009(H4N1)] isolated from a pig in Central China in 2009. The genomic sequence analysis indicates that this virus is a wholly avian-original influenza virus. Each gene may come from different avian influenza viruses outside mainland China, suggesting the role of migratory birds in the dispersal of influenza virus.

Complete genome sequence of an H10N5 avian influenza virus isolated from pigs in central China.

An avian H10N5 influenza virus, A/swine/Hubei/10/2008/H10N5, was isolated from pigs in the Hubei Province of central China. Homology and phylogenetic analyses of all eight gene segments demonstrated that the strain was wholly of avian origin and closely homologous to the Eurasian lineage avian influenza virus. To our knowledge, this is the first report of interspecies transmission of an avian H10N5 influenza virus to domestic pigs under natural conditions.

Quantum-dots-based fluoroimmunoassay for the rapid and sensitive detection of avian influenza virus subtype H5N1.

The continuous spread of highly pathogenic avian influenza virus (AIV) subtype H5N1 is threatening the poultry industry and human health worldwide. Rapid and sensitive diagnostic methods are required for the H5N1 surveillance. In this study, the fluorescent (FL) probe of CdTe quantum dots (QDs) was designed using covalently linked rabbit anti-AIV H5N1 antibody. Based on these QD-antibody conjugates, a novel sandwich FL-linked immunosorbent assay (sFLISA) was developed for H5N1 viral antigen detection. The sFLISA allowed for H5N1 viral antigen determination in a linear range of 8.0 × 10(-3) to 5.1 × 10(-1) µg mL(-1) with the limit of detection (LOD) of 1.5 × 10(-4) µg mL(-1) . In comparison with virus isolation for 103 clinic samples, the sensitivity and specificity of sFLISA were found to be 93.6 and 91.1% respectively. The sFLISA supplied a novel approach to rapid and sensitive detection of AIV subtype H5N1 and showed great potential for biological applications in immunoassays.

Simultaneously Improved Thermal and Dielectric Performance of Epoxy Composites Containing Ti3C2Tx Platelet Fillers.

Polymer composites with enhanced thermal and dielectric properties can be widely used in electric and energy related applications. In this work, epoxy composites have been prepared with Ti3C2Tx, one of the most studied MXene materials that can be massively produced by direct etching using hydrofluoric acid. The addition of conductive two dimensional Ti3C2Tx platelet fillers leads to improved but anisotropic thermal conductivity of the composites. The through-plane thermal conductivity reaches 0.583 Wm-1K-1 and the in-plane thermal conductivity reaches 1.29 Wm-1K-1 when filler content is 40 wt% (21.3 vol%), achieving enhancements of 2.92 times and 10.65 times respectively, as compared with epoxy matrix. The dielectric permittivity of epoxy composite is enhanced by a factor of ~2.25 with 40 wt% fillers, and the dielectric losses are within a small value of 0.02. The results prove the effectiveness of Ti3C2Tx in simultaneously improving thermal and dielectric performance of epoxy composites, and it is deduced that further improvements may be obtained by using Ti3C2Tx nanoflake fillers.

Isolation and molecular characterization of equine H3N8 influenza viruses from pigs in China.

During 2004-2006 swine influenza virus surveillance, two strains of H3N8 influenza viruses were isolated from pigs in central China. Sequence and phylogenetic analyses of eight gene segments revealed that the two swine isolates were of equine origin and most closely related to European equine H3N8 influenza viruses from the early 1990s. Comparison of hemagglutinin (HA) amino acid sequences showed several important substitutions. One substitution caused the loss of a potential glycosylation site, and two substitutions, located at the cleavage site and adjacent to the receptor-binding pocket, respectively, had been reported previously in canine H3 HAs. This expansion of host range of equine H3N8 influenza viruses with mutations in the HA protein might raise the possibility of transmission of these viruses to humans.

An indirect sandwich ELISA for the detection of avian influenza H5 subtype viruses using anti-hemagglutinin protein monoclonal antibody.

A sandwich ELISA test using AIV H5 subtype specific monoclonal antibody (clone 2H4) to an epitope of hemagglutinin protein has been developed. The monoclonal antibody was used to capture the antigen from clinical samples (swabs and tissues). Captured antigens from clinical samples were detected using polyclonal sera, purified AIV H5N1 particles were titrated in the sandwich ELISA and the limit of detection was determined to be approximately 1.0 ng of influenza viral protein in virus preparations. Fifteen AIV strains of H1-H15 subtypes and some other pathogens were tested by this system, and the test is specific to H5 subtype viruses as it failed to detect other AIV subtype viruses and other pathogens. Varieties of clinical samples originating from laboratory experiments (n=382) and from fields (n=288) were employed to test the efficacy of DAS-ELISA test. The test compared very well with the traditional method for detection of influenza virus: virus isolation (VI) in embryonated chicken eggs. In comparison to virus isolation the sensitivity and specificity of sandwich ELISA were found to be 98.6% and 97.6% respectively. In addition, the DAS-ELISA was used to test samples of experimentally infected birds and clinical samples obtained from central China in 2005. The assay proved to be sensitive and specific for the rapid detection of AIV H5 subtype virus form the tissues and swabs in infected animals.

Development and evaluation of a DAS-ELISA for rapid detection of avian influenza viruses.

Rapid detection of avian influenza virus (AIV) infection is critical for control of avian influenza (AI) and for reducing the risk of pandemic human influenza. A double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) was developed for this purpose. The method employed a monoclonal antibody (MAb) as the capture antibody and rabbit polyclonal IgG labeled with horseradish peroxidase as the detector antibody, and both antibodies were against type-specific influenza A nucleoprotein (NP). The DAS-ELISA could detect minimally 2.5 ng of influenza viral protein in virus preparations treated with Triton X-100, which is equvilent to 2.5 x 10(2) EID50 virus particles. This DAS-ELISA could detect all 15n AIV subtypes (H1-H15) and did not cross react with other avian pathogens tested. The DAS-ELISA were directly compared with virus isolation (VI) in embryonated chicken eggs, the current standard of influenza virus detection, for 805 chicken samples. The DAS-ELISA results correlated with VI results for 98.6% of these samples, indicating a sensitivity of 97.4% and specificity of 100%. The method was further tested with H5N1 and H9N2 AIV experimentally infected chickens, ducks, and pigeons, as well as field samples obtained from central China in 2005. The DAS-ELISA method has demonstrated application potential as an AIV screening tool and as a supplement for virus isolation in Asia.

A fast and sensitive immunoassay of avian influenza virus based on label-free quantum dot probe and lateral flow test strip.

A novel fluorescence immunoassay method for fast and ultrasensitive detection of avian influenza virus (AIV) was developed. The immunoassay method which integrated lateral flow test strip technique with fluorescence immunoassay used the label-free and high luminescent quantum dots (QDs) as signal output. By the sandwich immunoreaction performed on lateral flow test strip, the gold nanoparticle (NP) labels were captured in the test zone and further dissolved to release a large number of gold ions as a signal transduction bridge that was detected by the QDs-based fluorescence quenching method. Under the optimal conditions, the relative fluorescence intensity of QDs was linear over the range of 0.27-12 ng mL(-1) AIV, and the limit of detection was estimated to be 0.09 ng mL(-1) which was 100-fold greater than enzyme-linked immunosorbent assay (ELISA). The sensitive and specific response was also coupled with high reproducibility in the proposed method. A series of six parallel measurements produced reproducible fluorescent signals with a relative standard deviation of 4.7%. The proposed method can be used to directly detect clinical sample without any pretreatment, and showed high efficiency (90.0%), sensitivity (100.0%) and specificity (88.2%) compared with virus isolation (gold method). The new method shows great promise for rapid, sensitive, and quantitative detection of AIV in-field or point-of-care diagnosis.