ABSTRACT
Nowadays, there is a global concern about outbreaks caused by the highly pathogenic avian influenza virus H5N8 clade 2.3.4.4 which caused devastating losses in the poultry industry sector. This clade was subdivided into two waves: clade 2.3.4.4A from 2014 to 2015 and clade 2.3.4.4b from 2016 until now. In this literature we aimed to evaluate the efficacy of recently used inactivated commercial avian influenza vaccines against two new Egyptian highly pathogenic avian influenza virus H5N8 isolates of clade 2.3.4.4b, A/chicken/Egypt/1526v/2020/H5N8 (H5N8-CH) and A/Duck/Egypt/Qalubia321/2021 (H5N8-D). Three-week-old specific pathogen free chickens were vaccinated with eight types of the most recently used inactivated avian influenza vaccines containing homologous and heterologous virus to the circulating H5N8 isolates. All specific pathogen free chicken groups were bled weekly post vaccination for antibody analysis using two H5N8 isolates of chicken and duck origin as antigen in hemagglutination inhibition test. Also, all vaccinated chicken groups were challenged 4 weeks post vaccination against the H5N8 duck isolate with a dose of 109 EID50/0.1 mL per chicken to measure the protection percentage of the commercial vaccines used. The results showed that vaccines with homologous and heterologous virus showed variable degrees of accepted protection percentage ranged from 90percent to 100percent, thus it was concluded that not only the genetic and antigenic match of the vaccine strains with the circulating highly pathogenic avian influenza viruses influences vaccine efficiency; other factors, such as manufacturing procedures, adjuvant, antigen content, vaccine dose and administration factors could affect vaccine efficacy, therefore, further vaccine development studies are needed to improve the percentage of protection and prevention of viral shedding against local highly pathogenic avian influenza H5 viruses in Egypt(AU)
En la actualidad, existe una preocupación mundial por los brotes causados por el virus de la gripe aviar altamente patógena H5N8 clado 2.3.4.4 que causó pérdidas devastadoras en el sector de la industria avícola. Este clado se subdividió en dos oleadas: clado 2.3.4.4A de 2014 a 2015 y clado 2.3.4.4b de 2016 hasta ahora. En el presente trabajo, dos aislamientos egipcios de la gripe aviar altamente patógena H5N8 del clado 2.3.4.4b, A/chicken/Egypt/1526v/2020/H5N8 (H5N8_CH) y A/Duck/Egypt/Qalubia321/2021 (H5N8_D), se utilizaron para evaluar la eficacia de vacunas comerciales inactivadas contra la gripe aviar de reciente utilización. Pollos libres de patógenos específicos de tres semanas de edad fueron vacunados con ocho vacunas inactivadas contra la influenza aviar, de uso reciente, que contenían virus homólogos y heterólogos a los aislamientos circulantes de H5N8. Todos los grupos de pollos libres de patógenos específicos fueron sangrados semanalmente tras la vacunación para el análisis de anticuerpos; dos virus H5N8 aislados de pollo y pato se utilizaron como antígeno en la prueba de inhibición de la hemaglutinación. Además, todos los grupos de pollos vacunados fueron retados 4 semanas después de la vacunación con el virus H5N8 aislado de pato, con una dosis de 109 EID50/0,1 mL por pollo, para medir el porcentaje de protección de las vacunas comerciales utilizadas. Los resultados mostraron que las vacunas con virus homólogos y heterólogos presentaron grados variables de aceptada protección, la que osciló entre el 90 por ciento y el 100 por ciento, por lo que se concluyó que no sólo la coincidencia genética y antigénica de las cepas vacunales con los virus circulantes de la influenza aviar altamente patógena influye en la eficacia de la vacuna; otros factores, como los procedimientos de fabricación, el adyuvante, el contenido en antígenos, la dosis de la vacuna y los factores de administración podrían afectar a la eficacia de la vacuna, por lo que es necesario seguir estudiando el desarrollo de vacunas para mejorar la protección y la prevención de la excreción viral contra los virus H5 de la influenza aviar altamente patógena locales en Egipto(AU)
Subject(s)
Animals , Influenza Vaccines , Chickens , Ducks , Influenza A Virus, H5N8 Subtype , Influenza in Birds/transmission , EgyptABSTRACT
Commercial inactivated avian influenza H5 vaccine is used as an essential control strategy for avian influenza disease in Egypt. Since the initial outbreaks of highly pathogenic avian influenza H5N8, the virus has diverged with new genotypes and variant viruses continuing to emerge which mainly stand behind vaccination failure. In the present work, four different commercial avian influenza vaccines were inoculated in specific pathogenic free chickens for assessing its efficacy against local highly pathogenic avian influenza H5N8 virus isolated in 2018 and 2020. Two hundred and forty specific pathogenic free chickens were clustered into four groups; each group was inoculated with the corresponding vaccine (60 specific pathogenic free chickens/vaccine). Sixty specific pathogenic free chicks were kept as control unvaccinated group. Sera collected from vaccinated chicken groups at 3rd and 4th week post vaccination were examined for calculating neutralizing antibodies using heterologous highly pathogenic avian influenza H5N8 2018 and 2020. At 4th week post vaccination, vaccinated chickens were challenged; moreover, oropharyngeal swabs were collected from challenged vaccinated chickens to calculate the viral shedding. Our findings revealed the groups vaccinated with vaccine code no 1 and 2 that contains two vaccine strains (H5N1 and H5N8) of local origin exhibited the highest hemagglutination inhibition titer, protection (percent) and reduction in viral shedding titer when examined by highly pathogenic avian influenza H5N8 2018 while, vaccine code no 3 induced lower antibody response, protection (percent) and reduction in viral shedding, but still within satisfactory level when compared to previous groups. When highly pathogenic avian influenza H5N8 2020 was used, it was found the seroconversion rate, protection (percent) and mean titer of reduction of viral shedding decreased in comparison to those recorded for highly pathogenic avian influenza H5N8 2018. Vaccine code no 4 was impotent to either highly pathogenic avian influenza 2018 or 2020. Accordingly, it was recommended to update vaccine strain according to epidemiological condition and used the predominant circulating strain isolate in challenge test(AU)
La vacuna comercial inactivada H5 se utiliza como estrategia esencial de control de la enfermedad de la gripe aviar en Egipto. Desde los brotes iniciales de la gripe aviar altamente patógena H5N8, el virus ha variado al aparecer continuamente nuevos genotipos y variantes virales, que son los principales responsables del fracaso de la vacunación. En el presente trabajo, cuatro vacunas comerciales diferentes contra la gripe aviar se inocularon en pollos libres de patógenos específicos para evaluar su eficacia contra cepas del virus local de la gripe aviar altamente patógeno H5N8 aisladas en 2018 y 2020. Se agruparon 240 pollos pollos libres de patógenos específicos en cuatro grupos, cada uno fue inoculado con la vacuna correspondiente (60 pollos pollos libres de patógenos específicos/vacuna). Sesenta pollos SPF se mantuvieron como grupo control sin vacunar. Los sueros de los pollos vacunados recogidos en la 3ª y 4ª semana después de la vacunación se examinaron para calcular los anticuerpos neutralizantes contra la gripe aviar heteróloga H5N8 2018 y 2020. En la cuarta semana después de la vacunación, los pollos vacunados fueron retados; además, se recogieron hisopados orofaríngeos de los pollos vacunados retados para calcular la diseminación viral. Nuestros resultados revelaron que los grupos vacunados con las vacunas con códigos nº 1 y 2, que contienen dos cepas vacunales (H5N1 y H5N8) de origen local, mostraron el mayor título de inhibición de la hemaglutinación, protección (por ciento) y reducción del título de excreción viral cuando se evaluaron contra la gripe aviar altamente patógena H5N8 2018, mientras que la vacuna con código nº 3 indujo menor respuesta de anticuerpos, protección (por ciento) y reducción de la excreción viral, pero todavía dentro de un nivel satisfactorio en comparación con los grupos anteriores. Al utilizar la vacuna contra la gripe aviar altamente patógena H5N8 2020, se observó que la tasa de seronconversión, la protección (por ciento) y el título medio de reducción de la excreción viral disminuyeron en comparación con los registrados para la gripe aviar altamente patógena H5N8 2018. La vacuna con código nº 4 no fue potente para la gripe aviar altamente patógena de 2018 o de 2020. Por consiguiente, se recomendó actualizar la cepa de la vacuna de acuerdo con las condiciones epidemiológicas y utilizar el aislamiento de la cepa circulante predominante en la prueba de reto(AU)
Subject(s)
Animals , Chick Embryo , Serologic Tests/methods , Influenza Vaccines/therapeutic use , Influenza in Birds/prevention & controlABSTRACT
ObjectiveTo determine the prevalence of avian influenza viruses in the external environment of poultry in Anqing City， Anhui Province， and provide scientific evidence for prevention and control of animal-derived influenza in humans. MethodsA total of 28 farmers’ markets/farms in 10 counties （cities， districts） of Anqing City， Anhui Province， were selected as surveillance sites by simple random sampling strategy. Poultry faeces and other related samples were collected for 6 consecutive weeks. Real-time fluorescence quantitative PCR was used to examine the nucleic acids of influenza A virus. Subtypes H5， H7， and H9 of avian influenza virus were further tested in the positive samples. ResultsA total of 426 specimens were collected， among which 113 tested positive with a positive rate of 26.53%. Among the positive specimens， 104 were determined to be subtype H9， accounting for 92.04%. It did not significantly differ in the positive rate between the main and non-main urban areas （χ2<0.01， P>0.05） or among the specimens collected in different weeks （χ2=7.57， P>0.05）. However， it significantly differed in the positive rate among the specimens collected in the third week and other weeks （χ2=6.89， P<0.05）. Furthermore， among the different sampling sites， farms had the highest positive rate of 46.67%. Among the specimens from different sources， the surface-coated specimens from poultry cages had the highest positive rate of 34.78%. ConclusionAvian influenza viruses are prevalent in the external environment of poultry in Anqing City. It warrants strengthening the surveillance and risk assessment to reduce the virus transmission in the external environment and risk of human infection with animal-derived influenza.
ABSTRACT
@#Abstract: Objective To investigate the molecular characteristics of the H9N2 avian influenza virus (AIV) causing human infection in Yunnan Province in 2019, and to provide the scientific basis for the prevention and control of avian influenza in Yunnan Province. Methods Influenza virus typing was performed by real-time RT-PCR in two influenza-like illness samples, and the Illumina Miseq high-throughput sequencer was used to determine the viral genome sequence. HA and NA gene sequence alignment and phylogenetic tree construction were performed using Mega7.0 software. Results Real-time RT-PCR results showed that two influenza-like illness samples were positive for H9N2 subtype. The full length of HA and NA were obtained by genomic sequencing. Sequence system evolution analysis showed that the HA and NA of the two AIVs in Yunnan Province were in the same evolutionary clade as A/Chicken/Zhejiang/HJ/2007 and belonged to the G57 type. The HA nucleotide and amino acid homology of the two AIVs were 93.92% and 95.00%, respectively, and the NA nucleotide and amino acid homology was 93.31% and 82.03%, respectively. The nucleotide (amino acid) homology of HA was 92.29%-96.94% (93.77%-98.43%) and 92.84%-94.92% (94.18%-96.23%), respectively, and NA nucleotide homology (amino acid) were 91.81%-97.60% (77.82%-94.83%), 94.38%-97.22% (85.47%-94.55%), respectively, compared with that of human infected H9N2 epidemic strains obtained in China from 2015 to 2020. Both AIVs HA protein cleavage site sequences were PSRSSR↓GLF, which was in line with the characteristics of low pathogenic influenza. The analysis of HA protein receptor binding site showed that amino acids at positions 109, 161, 163, 191, 202, 203 and 234 were consistent with the reference strains, while amino acids at position 198 were mutated to T. N166D and 168N mutations were also found in HA protein, and both AIVs had 7 potential glycosylation sites. Analysis of the erythrocyte binding site of NA gene found that there were amino acid mutations at positions 369, 402, 403, and 432, and amino acid deletion at positions 63-65 was found in the NA genes. There were 4 and 5 potential glycosylation sites in the two AIVs, respectively, and no drug resistance site mutations were found. Conclusions The receptor binding sites, erythrocyte binding sites and glycosylation sites of HA and NA genes of H9N2 AIV in Yunnan Province have different degrees of variation, and monitoring and prevention and control should be strengthened.
ABSTRACT
The conserved hemagglutinin (HA) stem region of avian influenza virus (AIV) is an important target for designing broad-spectrum vaccines, therapeutic antibodies and diagnostic reagents. Previously, we obtained a monoclonal antibody (mAb) (5D3-1B5) which was reactive with the HA stem epitope (aa 428-452) of H7N9 subtype AIV. To systematically characterize the mAb, we determined the antibody titers, including the HA-binding IgG, hemagglutination-inhibition (HI) and virus neutralizing (VN) titers. In addition, the antigenic epitope recognized by the antibody as well as the sequence and structure of the antibody variable region (VR) were also determined. Moreover, we evaluated the cross-reactivity of the antibody with influenza virus strains of different subtypes. The results showed that the 5D3-1B5 antibody had undetectable HI and VN activities against H7N9 virus, whereas it exhibited strong reactivity with the HA protein. Using the peptide-based enzyme-linked immunosorbent assay and biopanning with a phage-displayed random peptide library, a motif with the core sequence (431W-433Y-437L) in the C-helix domain in the HA stem was identified as the epitope recognized by 5D3-1B5. Moreover, the mAb failed to react with the mutant H7N9 virus which contains mutations in the epitope. The VR of the antibody was sequenced and the complementarity determining regions in the VR of the light and heavy chains were determined. Structural modeling and molecular docking analysis of the VR verified specific binding between the antibody and the C-helix domain of the HA stem. Notably, 5D3-1B5 showed a broad cross-reactivity with influenza virus strains of different subtypes belonging to groups 1 and 2. In conclusion, 5D3-1B5 antibody is a promising candidate in terms of the development of broad-spectrum virus diagnostic reagents and therapeutic antibodies. Our findings also provided new information for understanding the epitope characteristics of the HA protein of H7N9 subtype AIV.
Subject(s)
Animals , Antibodies, Monoclonal , Antibodies, Viral , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Hemagglutinins , Influenza A Virus, H7N9 Subtype , Influenza in Birds , Molecular Docking SimulationABSTRACT
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.
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Compound houttuynia mixture belongs to OTC class A medicine, which is made from Houttuynia cordata, Scutellaria baicalensis, Radix Isatidis, Forsythia, and Lonicera. As a kind of compound preparation of traditional Chinese medicine, houttuynia cordata mixture has extensive pharmacological effects, for example, clearing away heat and detoxifying, thus it is used for the sore throat, acute pharyngitis, and tonsillitis with wind-heat syndrome. In this study, the antiviral activity against influenza viruses and the primary mechanism of compound houttuynia mixture was evaluated. The antiviral effect of compound houttuynia mixture was determined by cytopathic effects (CPE), Western blot, quantitive reverse transcription PCR (qRT-PCR), and virus titer assays. The effect of houttuynia mixture on the replication cycle of influenza virus was evaluated by time-of-addition assay. In conclusion, the results showed that the compound houttuynia mixture had a broad-spectrum effect against influenza virus, including the international common influenza virus strains, the drug-resistant strains and the highly pathogenic avian influenza viruses H5N1 and H7N9. It mainly impairs the early stage of the viral replication.
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Abstract Vaccination is a good strategy for the prevention of avian influenza virus. In this research Gamma Irradiated Avian Influenza (Sub type H9N2) Vaccine (GAIV) was prepared by 30 kGy irradiation and used for vaccination of broiler chickens. The purpose was a comparison of immune responses in the two routes of administration for the GAIV vaccine; intranasal and subcutaneously, use of Montanide ISA70 and Trehalose accompanied with irradiated vaccine and compare with formalin vaccine. The Influenza Virus A/Chicken/IRN/Ghazvin/2001/H9N2 was irradiated and used for vaccine formulation, and formalin inactivated AIV was used as conventional vaccine. Chickens were vaccinated by GAIV with and without Trehalose, GAIV and formalin vaccines with ISA70, two routes of administration were intranasal and subcutaneously. All the vaccinated chickens showed a significant increase in antibody titration. The most significant increase of antibody titration was in irradiated vaccine plus Trehalose groups intranasal and subcutaneously. After the first and second intranasal vaccination, the amount of IFN-gamma increased in the irradiated vaccine plus Trehalose group compared to other groups. However, most of the vaccinated groups did not show any significant increase of IFN-α concentration. Histopathological examination revealed lymphocyte infiltration (++), foci dispersed of hemorrhage and edema in intranasal vaccination groups and in addition to these, thickening of alveolar septa was observed in the injection groups. GAIV vaccine can be a good candidate for vaccine preparation, and Trehalose as a stabilizer protects viral antigenic proteins, also makes more absorbance of antigen by the inhalation route. In vaccinated chickens the ulcers in injected vaccines were lower than intranasal vaccines.
Subject(s)
Animals , Viral Vaccines/administration & dosage , Viral Vaccines/immunology , Influenza A Virus, H9N2 Subtype/immunology , Influenza in Birds/pathology , Influenza in Birds/prevention & control , Chickens , Influenza in Birds/immunologyABSTRACT
Objective@#To recover broad-neutralizing monoclonal antibodies (BnAbs) from avian influenza A (H5N1) virus infection cases and investigate their genetic and functional features.@*Methods@#We screened the Abs repertoires of expanded B cells circulating in the peripheral blood of H5N1 patients. The genetic basis, biological functions, and epitopes of the obtained BnAbs were assessed and modeled.@*Results@#Two BnAbs, 2-12D5, and 3-37G7.1, were respectively obtained from two human H5N1 cases on days 12 and 21 after disease onset. Both Abs demonstrated cross-neutralizing and Ab-dependent cellular cytotoxicity (ADCC) activity. Albeit derived from distinct Ab lineages, , V 1-69-D2-15-J 4 (2-12D5) and V 1-2-D3-9-J 5 (3-32G7.1), the BnAbs were directed toward CR6261-like epitopes in the HA stem, and HA I45 in the hydrophobic pocket was the critical residue for their binding. Signature motifs for binding with the HA stem, namely, IFY in V 1-69-encoded Abs and LXYFXW in D3-9-encoded Abs, were also observed in 2-12D5 and 3-32G7.1, respectively.@*Conclusions@#Cross-reactive B cells of different germline origins could be activated and re-circulated by avian influenza virus. The HA stem epitopes targeted by the BnAbs, and the two Ab-encoding genes usage implied the VH1-69 and D3-9 are the ideal candidates triggered by influenza virus for vaccine development.
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Objective To analyze and estimate the possibility of early control in Shanghai if COVID-19 had begun in Shanghai. Methods Comparison was made in the processes of early control between H7N9 avian influenza in Shanghai in 2013 and COVID-19 in Wuhan in 2019.The early incidence data of Korean COVID-19 was simulated and analyzed to predict whether the medical resources needed in Shanghai were available. Results If it had occurred in Shanghai, it would have taken 22 days from the first case to the government′s emergency response.It was estimated that there would have been 602-763 patients with cumulative onset and onset after incubation period.At least 500 beds of infectious diseases could have been allocated in Shanghai in case of emergency.Through adding beds and resources reallocation in the whole city, patients could have been fully admitted and treated. Conclusion If COVID-19 epidemic had occurred in Shanghai, it′s early control would have been possible though there might have difficulties.
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@#Objective To analyze genetic characteristics of hemagglutinin( HA) gene of H9N2 avian influenza viruses( AIVs) circulating in Anhui Province from 2013 to 2018． Methods All H9N2 positive samples tested by real－time polymerase chain reaction( PCＲ) were inoculated into specific patho- gen free ( SPF) chicken eggs for isolation and purification． Viral ＲNA was reversely transcribed into cD- NA and then amplified with gene specific primers． PCＲ products were sequenced and the gene sequences were analyzed using molecular and bioinformatics software． The DATAMONKEY online server was conducted to analyze selection pressure，and protein structure homology modelling was computed by the SWISS－MODEL server． Ｒesults 33 H9N2 AIVs isolated from live poultry markets belonged to h9．4．2．5 in the phylogenetic tree． The receptor binding sites of HA gene at 183，226 and 227 position were mutated into N，L and M，respectively． Meanwhile 189 and 190 sites presented with genetic polymorphism． Since 2015，all H9N2 viruses in this study carried 6 potential N－linked glycosylation sites． It was found that po- sition 160 of HA gene was subjected greater positive selection pressure，presented 7 spatial conformations at least． Conclusions The H9N2 viruses isolated from live poultry markets in Anhui Province possess the molecular characteristics of infecting mammals and the ability of antigenic drift，so we need to pay more attention to the genetic characteristics of the viruses．
ABSTRACT
@#In the search for universal vaccine candidates for the prevention of avian influenza, the non-structural (NS)-1 protein of avian influenza virus (AIV) H5N1 has shown promising potential for its ability to effectively stimulate the host immunity. This study was aimed to produce a bacterial expression plasmid using pRSET B vector to harbour the NS1 gene of AIV H5N1 (A/Chicken/Malaysia/5858/2004 (H5N1)) for protein expression in Escherichia coli (E. coli). The NS1 gene (687 bp) was initially amplified by polymerase chain reaction (PCR) and then cloned into a pGEM-T Easy TA vector. The NS1 gene was released from pGEM-T-NS1 using EcoRI and XhoI restriction enzymes (RE). The pRSET B vector was also linearized using the same RE. The digested NS1 gene and linearized pRSET B were ligated using T4 DNA ligase to form the expression plasmid, pRSET B-NS1. The NS1 gene sequence in pRSET B-NS1 was confirmed by DNA sequencing. To prepare recombinant bacterial cells for protein expression in the future, pRSET B-NS1 was transformed into E. coli strain BL21 (DE3) by heat-shock. Colonies bearing the recombinant plasmid were screened using PCR. The DNA sequencing analysis revealed that the NS1 gene sequence was 97% homologous to that of AIV H5N1 A/Chicken/Malaysia/5858/2004 (H5N1). These results indicated that the NS1 gene of influenza A/Chicken/Malaysia/5858/2004 (H5N1) was successfully amplified and cloned into a pRSET B vector. Bacterial colonies carrying pRSET B-NS1 can be used for the synthesis of NS1-based influenza vaccine in the future and thereby aid in the prevention of avian influenza.
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[Objective] To analyze and judge the possibility of early control in Shanghai if COVID-19 begins in Shanghai. [Methods] Compare the process of early control of H7N9 avian influenza in Shanghai in 2013 and Wuhan COVID-19 in 2019. The early incidence data of Korean COVID-19 was simulated and analyzed to predict whether the medical resources needed in Shanghai were available. [Results] (1) It would take 22 days from the first case to the government's emergency response in terms of Shanghai. (2) It is estimated that there would be 602-763 patients with cumulative onset and onset after incubation period. (3) At least 500 beds of infectious diseases can be allocated in Shanghai in case of emergency. Through adding beds and resources reallocation in the whole city, patients can be fully admitted and treated. [Conclusion] If COVID-19 epidemic occurs in Shanghai, early control is possible.
ABSTRACT
Background & objectives: Avian influenza (AI) viruses have been a major cause of public health concern. Wild migratory birds and contaminated environmental sources such as waterbodies soiled with bird droppings play a significant role in the transmission of AI viruses. The objective of the present study was to develop a sensitive and user-friendly method for the concentration and detection of AI viruses from environmental water sources. Methods: Municipal potable water, surface water from reservoirs and sea were spiked with low pathogenic AI viruses. To concentrate the viruses by precipitation, a combination of potassium aluminium sulphate with milk powder was used. Real-time reverse transcription-polymerase chain reaction was performed for virus detection, and the results were compared with a virus concentration method using erythrocytes. Drinking water specimens from poultry markets were also tested for the presence of AI viruses. Results: A minimum of 101.0 EID50(50% egg infectious dose)/ml spiked H5N1 and 101.7 EID50/ml spiked H9N2 viruses were detected from spiked potable water; 101.0 and 102.0 EID50/ml spiked H5N1 virus was detected from surface water and seawater samples, respectively. The present method was more sensitive than the erythrocyte-binding method as approximately 10-fold higher infectious virus titres were obtained. AI H9N2 viruses were detected and isolated from water from local poultry markets, using this method. Interpretation & conclusions: Viability and recovery of the spiked viruses were not affected by precipitation. The present method may be suitable for the detection of AI viruses from different environmental water sources and can also be applied during outbreak investigations.
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Background & objectives: The susceptibility of influenza viruses to neuraminidase inhibitors (NAIs) is studied using enzyme-based assays, sequence analysis and in vitro and in vivo studies. Oseltamivir carboxylate (OC) is the active prodrug of the NAI oseltamivir. There is lack of information on the use of embryonated chicken eggs for studying susceptibility of highly pathogenic avian influenza (HPAI) H5N1 viruses to antiviral drugs. The aim of the present study was to assess the use of 10 day old embryonated chicken eggs for studying antiviral susceptibility of HPAI H5N1 viruses. Methods: Two HPAI H5N1 viruses isolated from India were used in the study. Fluorescence-based NAI assay was performed to determine antiviral susceptibility of these viruses. In ovo antiviral assays were carried out using 10 day old embryonated chicken eggs. The virus dilutions were incubated with 14 ?g/ml of OC and inoculated in the allantoic cavity. In the eggs, 50 per cent egg infectious dose (EID50) titres as well as mortality were quantitated. Results: The two viruses used were susceptible to OC in the NAI assay. It was found that there was a significant drop in EID50titres; however, no significant protection from mortality after OC treatment was observed. Interpretation & conclusions: By measuring viral titres, the egg model was suitable to study the susceptibility of HPAI viruses to antiviral drugs along with NAI assay. The present study highlights the use of eggs as a model to study susceptibility of HPAI viruses to OC.
ABSTRACT
Infectious diseases remain as the major causes of human and animal morbidity and mortality leading to significant healthcare expenditure in India. The country has experienced the outbreaks and epidemics of many infectious diseases. However, enormous successes have been obtained against the control of major epidemic diseases, such as malaria, plague, leprosy and cholera, in the past. The country's vast terrains of extreme geo-climatic differences and uneven population distribution present unique patterns of distribution of viral diseases. Dynamic interplays of biological, socio-cultural and ecological factors, together with novel aspects of human-animal interphase, pose additional challenges with respect to the emergence of infectious diseases. The important challenges faced in the control and prevention of emerging and re-emerging infectious diseases range from understanding the impact of factors that are necessary for the emergence, to development of strengthened surveillance systems that can mitigate human suffering and death. In this article, the major emerging and re-emerging viral infections of public health importance have been reviewed that have already been included in the Integrated Disease Surveillance Programme.
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Objective To analyze host adaptability and drug resistance variation of highly pathogenic avian influenza (HPAI) A(H5N6) viruses obtained from outbreaks in Suzhou City. Methods Real-time fluorescent quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay was used for influenza virus detection in pharynx or anus swabs of dead birds and suspected cases. Full genome of H5N6 positive samples were sequenced by using Sanger method. Hemagglutinin (HA) and neuramidinase (NA) phylogenetic trees were constructed by MEGA software. Results A child was laboratory confirmed to have A(H5N6) viruses infection in November 2018. A outbreak of avian flu in poultry in W district during the Spring Festival was laboratory confirmed as a A(H5N6) epidemic situation. Avian-origin H5N6 viruses possessed D198N and Q226H resistance mutations. The homology of HA and NA genes of Suzhou strains were 98.01%-100.0% and 98.16%-100.0%, respectively. These H5N6 strains belonged to 2.3.4.4 H5 clad. Multiple basic amino acid at the cleavage site of HA implied the highly pathogenic characteristics of Suzhou H5N6 strains. Conclusion H5N6 is a kind of malti-sourse reassortment virus, which is still evolving. Multiple loci of Suzhou H5N6 strains of this epidemic were identified to have drifted. The prevalence of drug-resistant mutations should be closely monitored in order to timely take effective measures to prevent serious damage to public health and poultry production industries.
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Objective The aim is to analyze the spatial epidemiological characteristics for human infection with avian influenza H7N9 in Fujian Province, so as to provide scientific evidence for developing and adjusting related control strategies. Methods The epidemiological data of human infection with H7N9 avian influenza in Fujian Province, from 2013 to 2017 was analyzed by SAS 9.2, ArcGIS 10.3 and SaTScan 9.4 software.Results There were a total of 108 cases and 28 deaths reported in Fujian Province, up to December 31, 2017. The case fatality rate was 25.93%.96.30% of cases were sporadic. There were more incidences in winters and springs, more incidences in rural areas. The global spatial autocorrelation and high/low clustering analysis indicated that clusters at the county level were in the shore areas (Z=3.74, P<0.001; Z=5.26, P<0.001). The cities of Changle, Fuqing, Jinjiang and Siming were the high-high clustered areas and local hot-points. There were two clusters, from December 2014 to March 2015, the most likely cluster regions was centered around Zhangpu County with a radius of 63.04 km (RR=4.72, LLR=11.41, P<0.001). The secondary cluster regions was centered around Fuqing City with a radius of 81.98 km (RR=4.07, LLR=7.96, P=0.037). Conclusions Human infection with avian influenza H7N9 in Fujian Province is spatially and temporally clustered. The measures of prevention and control should be focused on high incidence seasons and key regions, and the surveillance of etiology should be strengthened.
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Objective To explore the source of human infection H9N2 avian influenza virus (AIV). Methods Environmental AIV nucleic acid monitoring was conducted for live poultry markets in Changsha city from 2014 to 2015, and data of human infection H9N2 subtype AIV cases worldwide were collected. Phylogenetic trees of hemagglutinin(HA), neuraminidase(NA)and non-structural protein(NS)genes from human infection H9N2 subtype AIV, the live poultry markets environmental H9N2 subtype AIV and partial avian H9N2 subtype AIV were constructed using the MEGA 6.06 software, respectively. Results In 2014-2015, H9 subtype AIV had the highest nucleic acid positive rate (44.76%) in the live poultry markets environment of Changsha city, and the pollution was serious. A total of 27 cases of human infection with H9N2 subtype AIV had been reported worldwide, and most of these patients recovered after treatments.Epidemiological survey showed that 59.26% (16/27) of cases had a clear history of exposure to poultry or live poultry markets. The phylogenetic trees of HA, NA and NS genes showed that the human infection H9N2 subtype AIV isolates isolated from Hunan and Guangdong were closely related to the H9N2 subtype AIV isolated from the live poultry markets environment in Hunan and Guangdong provinces from 2013 to 2016. The nucleotide similarity was as high as 97%-99%. Conclusion Live poultry market is one of the sources of human infection with H9N2 influenza virus.
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Objective To analyze the epidemiological characteristics of human infection with H7N9 avian influenza in Guilin in recent years and to provide on-site data and data support for scientific pre-vention and control of the epidemic of H7N9 avian influenza infection. Methods A descriptive epidemio-logical method was used to collect the data about human infection with H7N9 avian influenza form three as-pects, which were human infection cases in 2017, environmental monitoring for H7N9 avian influenza virus and sentinel surveillance of influenza-like cases. The epidemiological characteristics of human infection with H7N9 avian influenza in Guilin in 2017 were analyzed. Chi-square test was used to compare the positive rates of H7N9 avian influenza virus in environmental specimens. Results A total of six cases of confirmed human H7N9 infection including three deaths were reported in Guilin city in 2017. These cases were from five counties and districts and all occurred in winter and spring. The patients were middle-aged and old men. Most of them were farmers and had a clear history of poultry exposure before the onset of infection. No human H7N9 infection was reported in close contacts or in influenza-like cases. Conclusions H7N9 avian influen-za infection in Guilin was characterized by high sporadicity, high incidence in winter and spring, and pre-dominantly middle-aged and elderly men. Avian exposure history was a high risk factor for human infection with H7N9 avian influenza virus. All of the studied cases were severe cases. No human-to-human transmis-sion was reported. Farmers, having a history of poultry slaughter, and underlying diseases were potential risks causing death. Live poultry markets were the main sources of infection, hence closing market could re-duce the detection rate of H7N9 avian influenza virus. Strengthen the management of live poultry market and poultry environmental monitoring, closing live poultry markets when viral detection was positive, and suspen-ding live poultry trading were effective measures to control the epidemic of H7N9 avian influenza infection and prevent transmission.