A sandwich ELISA for detecting the hemagglutinin of avian influenza A (H10N8) virus.

Novel influenza A virus (H10N8) infected human with fatality in China during 2013-2014. It is important to detect such nonprevalent subtype influenza A virus in clinic and regular surveillance in the early stage for effective control and prevention from the potential pandemic. Unavailability of convenient rapid diagnosis for this subtype virus in resources-limited setting is an obstacle for timely recognizing human case. In the present study, a panel of mouse H10 specific monoclonal antibodies (mAbs) was generated, two of which were used to develop a sandwich enzyme-linked immunosorbent assay (ELISA) for detecting the hemagglutinin of avian influenza A (H10N8) virus. ELISA results showed high sensitivity with the lowest detection limit of 0.5HAU/50 µL for live virus, which laid a foundation for clinic use as a promising diagnostic methodology.

Rapid Detection of Subtype H10N8 Influenza Virus by One-Step Reverse Transcription-Loop-Mediated Isothermal Amplification Methods.

We developed hemagglutinin- and neuraminidase-specific one-step reverse transcription-loop-mediated isothermal amplification assays for detecting the H10N8 virus. The detection limit of the assays was 10 copies of H10N8 virus, and the assays did not amplify nonspecific RNA. The assays can detect H10N8 virus from chicken samples with high sensitivity and specificity, and they can serve as an effective tool for detecting and monitoring H10N8 virus in live poultry markets.

Cause of death in hospitalized patients with laboratory-confirmed influenza / Causa de muerte en pacientes hospitalizados con gripe confirmada por laboratorio

Background: We analyzed the underlying cause of death recorded in hospitalized patients with laboratory-confirmed influenza. Methods: The present study included all patients with a laboratory-confirmed diagnosis of influenza during the influenza seasons 2009-2010 to 2013-2014 who were attended to in hospital and died. Their underlying cause of death according to the International Classification of Diseases 10th Revision was obtained from the Navarre Mortality Registry. Results: Among 49 patients studied, the underlying causes of death were 35% influenza, 4% pneumonia, 14% other respiratory diseases, 10% circulatory disease and 37% other causes. Conclusions: Non-cardiorespiratory causes accounted for a third of deaths in patients with confirmed influenza, thus all-cause mortality should be considered in estimating the full burden of influenza mortality (AU)

Fundamento: La mortalidad por gripe no se conoce bien porque la mayoría de las personas que mueren por gripe no se confirman por laboratorio. Analizamos la causa básica de muerte registrada en los pacientes hospitalizados con gripe confirmada por laboratorio. Métodos: Se incluyeron todos los pacientes con diagnóstico de gripe por laboratorio que habían sido atendidos en el hospital y murieron durante las temporadas 2009-2010 a 2013-2014 en Navarra. La causa básica demuerte se obtuvo del Registro de Mortalidad. Resultados: Entre los 49 pacientes estudiados, la causa básica de muerte fue en el 35% gripe, en el 4% neumonía, en el 14% otras enfermedades respiratorias, en el 10% enfermedades cardiovasculares y en el 37% otras causas. Conclusiones: Un tercio de las muertes en pacientes con gripe confirmada se asignaron a causas no cardiorrespiratorias. Deberían tenerse en cuenta todas las causas para estimar la carga total de la mortalidad por gripe (AU)

Human infection with an avian influenza A (H9N2) virus in the middle region of China.

During the epidemic period of the novel H7N9 viruses, an influenza A (H9N2) virus was isolated from a 7-year-old boy with influenza-like illness in Yongzhou city of Hunan province in November 2013. To identify the possible source of infection, environmental specimens collected from local live poultry markets epidemiologically linked to the human case in Yongzhou city were tested for influenza type A and its subtypes H5, H7, and H9 using real-time RT-PCR methods as well as virus isolation, and four other H9N2 viruses were isolated. The real-time RT-PCR results showed that the environment was highly contaminated with avian influenza H9 subtype viruses (18.0%). Sequencing analyses revealed that the virus isolated from the patient, which was highly similar (98.5-99.8%) to one of isolates from environment in complete genome sequences, was of avian origin. Based on phylogenetic and antigenic analyses, it belonged to genotype S and Y280 lineage. In addition, the virus exhibited high homology (95.7-99.5%) of all six internal gene lineages with the novel H7N9 and H10N8 viruses which caused epidemic and endemic in China. Meanwhile, it carried several mammalian adapted molecular residues including Q226L in HA protein, L13P in PB1 protein, K356R, S409N in PA protein, V15I in M1 protein, I28V, L55F in M2 protein, and E227K in NS protein. These findings reinforce the significance of continuous surveillance of H9N2 influenza viruses.

Knowledge, Attitudes, and Practices (KAP) Relating to Avian Influenza (H10N8) among Farmers' Markets Workers in Nanchang, China.

Three cases of avian influenza virus H10N8 were reported in Nanchang, China, as of April 2014. To identify the knowledge, attitudes, and practices (KAP) related to H10N8 among farmers' market workers, a cross-sectional survey was conducted in 63 farmers' markets in Nanchang. Using the resulting data, characteristics of poultry and non-poultry workers' knowledge, attitudes, and practice were described. Results suggest that interventions targeting high-risk workers should be developed and implemented by public health agencies to prevent the spread of H10N8. Additionally policies that encourage farmers' market workers to receive influenza vaccine should be developed, adopted, and enforced.

Genetics, Receptor Binding, and Virulence in Mice of H10N8 Influenza Viruses Isolated from Ducks and Chickens in Live Poultry Markets in China.

We analyzed eight H10N8 viruses isolated from ducks and chickens in live poultry markets from 2009 to 2013 in China. These viruses showed distinct genetic diversity and formed five genotypes: the four duck isolates formed four different genotypes, whereas the four chicken viruses belong to a single genotype. The viruses bound to both human- and avian-type receptors, and four of the viruses caused 12.7% to 22.5% body weight loss in mice.

Emerging respiratory tract viral infections.

PURPOSE OF REVIEW: This article reviews the clinical and treatment aspects of avian influenza viruses and the Middle East Respiratory Syndrome coronavirus (MERS-CoV). RECENT FINDINGS: Avian influenza A(H5N1) and A(H7N9) viruses have continued to circulate widely in some poultry populations and infect humans sporadically. Sporadic human cases of avian A(H5N6), A(H10N8) and A(H6N1) have also emerged. Closure of live poultry markets in China has reduced the risk of A(H7N9) infection. Observational studies have shown that oseltamivir treatment for adults hospitalized with severe influenza is associated with lower mortality and better clinical outcomes, even as late as 4-5 days after symptom onset. Whether higher than standard doses of neuraminidase inhibitor would provide greater antiviral effects in such patients requires further investigation. High-dose systemic corticosteroids were associated with worse outcomes in patients with A(H1N1)pdm09 or A(H5N1). MERS-CoV has continued to spread since its first discovery in 2012. The mortality rates are high in those with comorbid diseases. There is no specific antiviral treatment or vaccine available. The exact mode of transmission from animals to humans remains unknown. SUMMARY: There is an urgent need for developing more effective antiviral therapies to reduce morbidity and mortality of these emerging viral respiratory tract infections.

A human-infecting H10N8 influenza virus retains a strong preference for avian-type receptors.

Recent avian-origin H10N8 influenza A viruses that have infected humans pose a potential pandemic threat. Alterations in the viral surface glycoprotein, hemagglutinin (HA), typically are required for influenza A viruses to cross the species barrier for adaptation to a new host, but whether H10N8 contains adaptations supporting human infection remains incompletely understood. We investigated whether H10N8 HA can bind human receptors. Sialoside glycan microarray analysis showed that the H10 HA retains a strong preference for avian receptor analogs and negligible binding to human receptor analogs. Crystal structures of H10 HA with avian and human receptor analogs revealed the basis for preferential recognition of avian-like receptors. Furthermore, introduction of mutations into the H10 receptor-binding site (RBS) known to convert other HA subtypes from avian to human receptor specificity failed to switch preference to human receptors. Collectively, these findings suggest that the current H10N8 human isolates are poorly adapted for efficient human-to-human transmission.

Identification of the source of A (H10N8) virus causing human infection.

A novel H10N8 influenza A virus has been detected in three humans in China since December 2013. Although this virus was hypothesized to be a novel reassortant among influenza viruses from wild birds and domestic poultry, its evolutionary path leading to human infection is unknown. Sporadic surveillance at the live poultry market (LPM) suspected to be the source of infection for the first H10N8 patient has shown a gradual increase in influenza virus prevalence culminating with a predominance of H10N8 viruses. Influenza viruses detected in the LPM up to 8 months prior to human infection contributed genetic components to the zoonotic virus. These H10N8 viruses have continued to evolve within this LPM subsequent to the human infection, and continuous assessments of these H10N8 viruses will be necessary. Serological surveillance showed that the virus appears to have been present throughout the LPM system in Nanchang, China. Reduction of the influenza virus burden in LPMs is essential in preventing future emergence of novel influenza viruses with zoonotic and pandemic potential.

Genetic diversity of avian influenza A (H10N8) virus in live poultry markets and its association with human infections in China.

Following the first human infection with the influenza A (H10N8) virus in Nanchang, China in December 2013, we identified two additional patients on January 19 and February 9, 2014. The epidemiologic, clinical, and virological data from the patients and the environmental specimen collected from 23 local live poultry markets (LPMs) were analyzed. The three H10N8 cases had a history of poultry exposure and presented with high fever (>38°C), rapidly progressive pneumonia and lymphopenia. Substantial high levels of cytokines and chemokines were observed. The sequences from an isolate (A/Environment/Jiangxi/03489/2013 [H10N8]) in an epidemiologically linked LPM showed highly identity with human H10N8 virus, evidencing LPM as the source of human infection. The HA and NA of human and environmental H10N8 isolates showed high identity (99.1-99.9%) while six genotypes with internal genes derived from H9N2, H7N3 and H7N9 subtype viruses were detected in environmental H10N8 isolates. The genotype of the virus causing human infection, Jiangxi/346, possessed a whole internal gene set of the A/Environment/Jiangxi/10618/2014(H9N2)-like virus. Thus, our findings support the notion that LPMs can act as both a gene pool for the generation of novel reassortants and a source for human infection, and intensive surveillance and management should therefore be conducted.

Investigation of avian influenza virus in poultry and wild birds due to novel avian-origin influenza A(H10N8) in Nanchang City, China.

Multiple reassortment events within poultry and wild birds had resulted in the establishment of another novel avian influenza A(H10N8) virus, and finally resulted in human death in Nanchang, China. However, there was a paucity of information on the prevalence of avian influenza virus in poultry and wild birds in Nanchang area. We investigated avian influenza virus in poultry and wild birds from live poultry markets, poultry countyards, delivery vehicles, and wild-bird habitats in Nanchang. We analyzed 1036 samples from wild birds and domestic poultry collected from December 2013 to February 2014. Original biological samples were tested for the presence of avian influenza virus using specific primer and probe sets of H5, H7, H9, H10 and N8 subtypes by real-time RT-PCR. In our analysis, the majority (97.98%) of positive samples were from live poultry markets. Among the poultry samples from chickens and ducks, AIV prevalence was 26.05 and 30.81%, respectively. Mixed infection of different HA subtypes was very common. Additionally, H10 subtypes coexistence with N8 was the most prevalent agent during the emergence of H10N8. This event illustrated a long-term surveillance was so helpful for pandemic preparedness and response.

Mutations of novel influenza A(H10N8) virus in chicken eggs and MDCK cells.

The recent emergence of human infection with influenza A(H10N8) virus is an urgent public health concern. Genomic analysis showed that the virus was conserved in chicken eggs but presented substantial adaptive mutations in MDCK cells. Our results provide additional evidence for the avian origin of this influenza virus.

[Retrospective analysis of human avian influenza A (H10N8) virus infection in Jiangxi province].

OBJECTIVE: To analyze and discuss the source and epidemic disposition of human infection with avian influenza A (H10N8) virus. METHODS: Epidemiological surveys were used to collect related data and RT-PCR was applied to detect the specimens collected from cases, close contacts related exposure to live poultry markets. Data were analyzed descriptively. RESULTS: Three cases were discovered by surveillance on patients with severe pneumonia, two of the three died, but one in the hospital with the course over 6 months. All the three cases had histories of exposure to live poultry or related markets. Lower respiratory tract gargle aspirate samples of 3 patients were detected by Nanchang Municipal Center for Disease Control and Prevention (CDC) and Jiangxi Provincial CDC, and the results showed the influenza 2009pdmH1, H3, H5, H7, H9 subtypes negative. Specimen of patient 1 and 2 was positive for influenza A universal primers. Specimen of patient 3 was positive for H10N8 detected by Chinese National Influenza Center. All 33 close contacts of the patients were negative for H10N8 virus. Positive rate of the total poultry environmental specimens collected from the cases exposure markets was 5.19%. No new cases were found, after the prevention and control messages were implemented. CONCLUSION: Three cases of H10N8 avian influenza virus infection province might be associated with exposure to live poultry market in Jiangxi.