Quantitative assessment of the virucidal activities of three commercial disinfectants against human in-fected highly pathogenic avian influenza viruses subtype H5 / 中华微生物学和免疫学杂志

Objective To quantitatively assess the virucidal activities of three commercial disin-fectants against human infected highly pathogenic avian influenza viruses subtype H5. Methods The 50%tissue culture infective dose ( TCID50 ) of avian influenza viruses was calculated. Quantitative suspension test was performed to evaluate the efficacy of three disinfectants. In that test, 105 TCID50 of avian influenza viru-ses were exposed to different disinfectants at different concentrations for different times with or without the in-terference with fetal bovine serum ( FBS) simulating the contaminated condition. The residual infectivity was determined by endpoint titration in Madin-Darby canine kidney ( MDCK) cells. The detail steps were that the mixture of viruses and disinfectants was inoculated at 37℃ with 5% CO2 for 1 hour. Then, it was re-placed by virus dilution medium and further incubated for 18 to 20 hours. ELISA was performed for the cal-culation of TCID50 . The titers of residual viruses were calculated according to Reed and Muench method. The low pathogenic avian influenza virus H9N2 was chosen as the control in this study. Results The re-mained infectivities of three viruses after 1 minute exposure to 1% Virkon solution were below the limit of de-tection (1. 0 lgTCID50/100 μl). Exposing to 0. 5% Virkon solution decreased the viral titers of H5N1 and H9N2 viruses below the detection limit and reduced the titer of H5N6 virus to 1. 75 lgTCID50/100 μl. The virucidal efficacy of 0. 25% Virkon solution against some of the detected viruses was achieved by increasing the exposure time to 5 minutes. The 84 Disinfectant solutions at concentrations of 10%, 5% and 2. 5% low-ered the viral titers of three viruses below the detection limit of 1. 0 lgTCID50/100 μl, but the 1. 25% 84 Disinfectant solution only lowered the viral titers to 1. 25-2. 5 lgTCID50/100 μl. The similar results were ob-served in groups treated with SOLARSEPT solutions. 1% 84 Disinfectant solution didn′t show any virucidal activity against the three viruses after 1 minute of exposure even when the exposure time was extended to 5 minutes. Under the contaminated condition, 1% Virkon solution, 10% and 5% 84 Disinfectant solutions as well as 100% and 50% SOLARSEPT solutions lowered the viral titers below 1. 0 lgTCID50/100μl. Conclu-sion The three commercial disinfectants (1% Virkon solution, 10% 84 Disinfectant solution and SOLAR-SEPT solution) were efficient virucides for highly pathogenic avian influenza viruses subtype H5 even under the contaminated condition. Increasing the exposure time had no significant effects on the efficacy of three disinfectants after the virucidal activities were neutralized by enough viruses. No significant differences in vi-rucidal activities of three disinfectants against HPAI H5 viruses and LPAI H9 virus were observed.

Phylogenetic and Molecular Analysis of an H7N7 Avian Influenza Virus Isolated in East Dongting Lake in 2012 / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>In March 2012, an H7N7 subtype avian influenza virus (AIV) named A/wild goose/Dongting/PC0360/2012 (H7N7) (DT/PC0360) was recovered from a wild goose in East Dongting Lake. We performed whole-genome sequencing of the isolate, and analyzed the phylogenetic and molecular characterization.</p><p><b>METHODS</b>RNA was extracted from environment samples (including fecal samples from wild bird or domestic ducks, and water samples) for detecting the presence of Influenza A Virus targeting Matrix gene, using realtime RT-PCR assay. The positive samples were performed virus isolation with embryonated eggs. The subtype of the isolates were identified by RT-PCR assay with the H1-H16 and N1-N9 primer set. The whole-genome sequencing of isolates were performed. Phylogenetic and molecular characterizations of the eight genes of the isolates were analyzed.</p><p><b>RESULTS</b>Our results suggested that all the eight gene segments of DT/PC0360 belonged to the Eurasian gene pool, and the HA gene were belonged to distinct sublineage with H7N9 AIV which caused outbreaks in Mainland China in 2013. The hemagglutinin cleavage site of HA of DT/PC0360 showed characterization of low pathogenic avian influenza virus.</p><p><b>CONCLUSION</b>Strengthening the surveillance of AIVs of wild waterfowl and poultry in this region is vital for our knowledge of the ecology and mechanism of transmission to prevent an influenza pandemic.</p>

Pathogenesis of influenza A (H5N1) virus-induced viral pneumonia in the rhesus macaque / 中国人兽共患病学报

At present ,the mechanism of highly pathogenic avian influenza H5N1 virus causing human infection or death is still not fully clear .In order to better understand the pathogenesis of the disease ,the rhesus macaques were infected with H5N1 virus (AF148678/ACGoose/Guangdong/11961H5N1) .We analyzed the clinical symptoms ,characteristics of the virus invades body ,pathological changes ,and immune response to discuss the pathogenesis of viral pneumonia induced by H 5N1 virus infection from the early time to the recovery time .The rhesus macaques were infected with H5N1 virus through nasal .Clinical signs were assessed daily ,and major organs and blood were collected for detection of blood routine analysis ,viruses were isola-ted and titrated from organs ,and pathologic and immunohistochemical were also conducted .As a result ,the rhesus macaques in-fected with H5N1 virus experienced fever ,dyspnea ,and anorexia .The respiratory tract was the major target of the virus and the virus could not replicate in organs outside the respiratory tract .Positive staining cells by immunohistochemistry were bronchial epithelial cells and alveolar macrophages .Rhesus macaques experienced temporary severe pneumonia after 1-3 days ,mainly be-cause of neutrophils infiltration ;gradual recovery 6 days later ,mainly with macrophage infiltration ;lung tissue presented recov-ery state after 14 days ,mainly with T lymphocytes infiltration .Finally ,we concluded that the predilection of the H 5N1 virus to infect the lower airway suggests that it may be a limiting factor in human-to-human transmissibility of the H5N1 virus .The pathogenesis may include virus invasion ,replication and immune injury .

Molecular characteristics of the hemagglutinin genes of avian influenza virus subtype H5N1 in the boundary region of Yunnan province / 中国人兽共患病学报

To elucidate the molecular characteristics of the hemagglutinin (HA) genes of H5N1 subtype of avian influenza viruses in the boundary region of Yunnan province. Of 420 samples were collected from the foreign poultry in boundary region of Yunnan province during 2003 to 2008 and these samples were subjected to screening by H5/N1 subtype-specific and multiplex RT-PCR. testing. The HA genes of H5N1 viruses from positive samples were amplified by RT-PCR and cloned into vector pMD18 T for subsequent sequencing. The alignment with sequences of the known reference strains and phylogenetic analysis were then performed. The genes from 21 representative positive samples with 4 different sequences at the cleavage site were obtained and all of them possessed the molecular characteristic of highly pathogenic avian influenza virus. The mutation of key amino acids had been found among receptor-binding sites, potential glycosylation sites and neutralizing epitopes.-Phylogenetic analysis showed those positive samples could be divided into 5 distinct clades, including clade 1, 2.4. 2.3.2, 2.3.4 and 7. It is evident that H5N1 viruses from the foreign boundary region of Yunnan province in 2003 to 2008 show genetic divergence and clade 2,3,4 is the dominant clade in this region.

Epidemiological Monitoring of Influenza Viruses in Guangzhou Area from 1998 to 2003 / 实用儿科临床杂志

Objective To explore the epidemics of influenza viruses in Guangzhou area from 1998 to 2003. Methods The specimens for viral isolation were taken with swabs from children's throats and the material was inoculated into the MDCK cells and were incubated at 33 ℃ The supernatant of MDCK cells culture was tested with hemagglutination test. Results Influenza viruses were isolated from 264 of 3444 children; total positive rate of influenza virus isolation was 7.6%. The positive rate of influenza viruses was 16.8% in 1998; the prevailing strain of influenza viruses was H3N2. The influenza viruses isolation rate was 7.4% in 1999;the positive rate was 8.4% ; HIN1 occurred in 2000, the positive rate was 3.8%. H3N2 did not occur in 2001; the positive rate was 7.3% ; influenza B viruses was the prevailing strain in 2002; the positive rate was 1.7% in 2003. Influenza B viruses was Yamagata like strain from 1998 to 2001, Victoria like strain from 2002 to 2003. H9N2 avian influenza virus was isolated from a child. Conclusions Influenza was prevalent in Guangzhou in 1998, but not prevalent from 1999 to 2003. Most of influenza B viruses were Yamagata strain. There were cases avian influenza caused by H9N2 in 1999.