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.
Animals ; COVID-19 ; China/epidemiology* ; Humans ; Influenza A Virus, H7N9 Subtype ; Influenza in Birds/epidemiology* ; Influenza, Human/prevention & control* ; Poultry ; SARS-CoV-2

China experienced a very high and severe influenza seasonal epidemics during the past winter and spring of 2017-2018 season. This year of 2018 is the 100(th) anniversary of the 1918 "Spanish influenza" pandemic, a series of papers under the topic "One Hundred Years of Influenza Pandemics" are produced to demonstrate the impact, characteristics and responses of the past influenza pandemics in global and China, to review the progress and experiences of influenza surveillance, prevention and control strategies, vaccination and antivirus in China, and to discuss the gap and challenges of the prevention, control and response to the seasonal influenza, human avian influenza infection and influenza pandemics. We hope this series could help to raise the awareness of the seasonal and pandemic influenza in publics, and to improve the pandemic preparedness in China.
Animals ; Awareness ; Birds ; China/epidemiology* ; Humans ; Influenza Vaccines ; Influenza in Birds/prevention & control* ; Influenza, Human/prevention & control* ; Pandemics/prevention & control* ; Seasons ; Vaccination

Fears of a potential pandemic due to A(H5N1) viruses have focussed new attention on our current vaccines, their shortcomings, and concerns regarding global vaccine supply in a pandemic. The bulk of current vaccines are inactivated split virus vaccines produced from egg-grown virus and have only modest improvements compared with those first introduced over 60 years ago. Splitting, which was introduced some years ago to reduce reactogenicity, also reduces the immunogenicity of vaccines in immunologically naïve recipients. The A(H5N1) viruses have been found poorly immunogenic and present other challenges for vaccine producers which further exacerbate an already limited global production capacity. There have been some recent improvements in vaccine production methods and improvements to immunogenicity by the development of new adjuvants, however, these still fall short of providing timely supplies of vaccine for all in the face of a pandemic. New approaches to influenza vaccines which might fulfil the demands of a pandemic situation are under evaluation, however, these remain some distance from clinical reality and face significant regulatory hurdles.
Animals ; Birds ; Disease Outbreaks ; prevention & control ; statistics & numerical data ; Global Health ; History, 20th Century ; History, 21st Century ; Humans ; Influenza A Virus, H5N1 Subtype ; isolation & purification ; Influenza Vaccines ; history ; Influenza in Birds ; epidemiology ; prevention & control ; Influenza, Human ; epidemiology ; prevention & control ; World Health Organization

The highly pathogenic avian influenza (HPAI) H5N1 virus was first detected in 1996 in Guangdong, China. Since 2003, H5N1 outbreaks have been reported in parts of Asia, Europe, the Middle East, and Africa. It is currently entrenched among poultry in parts of Asia and poses a major challenge to animal and human health. Singapore is free from HPAI. Given Singapore's need to import food, the Agri-Food and Veterinary Authority (AVA) has adopted a pro-active risk management system to prevent the introduction of HPAI. AVA's approach maybe described as a multi-layered control strategy for the prevention and control of HPAI. The strategy includes control measures at source, border control measures, local control measures and emergency preparedness.
Animals ; Birds ; Communicable Disease Control ; methods ; Disease Outbreaks ; prevention & control ; statistics & numerical data ; Global Health ; Health Planning ; Humans ; Influenza A Virus, H5N1 Subtype ; isolation & purification ; Influenza in Birds ; epidemiology ; prevention & control ; virology ; Poultry ; Singapore ; epidemiology

Avian influenza A H5N1 continues to be a major threat to global public health as it is a likely candidate for the next influenza pandemic. To protect public health and avert potential disruption to the economy, the Hong Kong Special Administrative Region Government has committed substantial effort in preparedness for avian and pandemic influenza. Public health infrastructures for emerging infectious diseases have been developed to enhance command, control and coordination of emergency response. Strategies against avian and pandemic influenza are formulated to reduce opportunities for human infection, detect pandemic influenza timely, and enhance emergency preparedness and response capacity. Key components of the pandemic response include strengthening disease surveillance systems, updating legislation on infectious disease prevention and control, enhancing traveller health measures, building surge capacity, maintaining adequate pharmaceutical stockpiles, and ensuring business continuity during crisis. Challenges from avian and pandemic influenza are not to be underestimated. Implementing quarantine and social distancing measures to contain or mitigate the spread of pandemic influenza is problematic in a highly urbanised city like Hong Kong as they involved complex operational and ethical issues. Sustaining effective risk communication campaigns during interpandemic times is another challenge. Being a member of the global village, Hong Kong is committed to contributing its share of efforts and collaborating with health authorities internationally in combating our common public health enemy.
Animals ; Birds ; Communicable Disease Control ; methods ; organization & administration ; Disease Outbreaks ; prevention & control ; statistics & numerical data ; Hong Kong ; epidemiology ; Humans ; Influenza A Virus, H5N1 Subtype ; isolation & purification ; Influenza in Birds ; epidemiology ; Population Surveillance ; Quarantine ; Risk Factors ; Time Factors ; World Health Organization

INTRODUCTIONAs the country hardest hit by avian influenza, both in poultry and in human, Indonesia's decision to withhold samples of avian influenza virus A (H5N1) has fired up a global controversy. The objective of this paper is to describe the position taken by Indonesia in the events leading to the decision and in those conducted to resolve the situation.

METHODSThe sources for this paper are the Indonesian human influenza A(H5N1) case reports and study results, summaries, minutes and reports of national and international meetings of virus sharing, and other related Indonesian and WHO documents.

RESULTSThe International Health Regulations 2005 have been applied in different ways based on different interpretations. While one party insists on the importance of free, non-conditional, virus sharing for risk assessment and risk response, Indonesia--as supported by most of the developing countries--stresses on the more basic principles such as sovereignty of a country over its biological materials, transparency of the global system, and equity between developed and developing nations.

CONCLUSIONSThis event demonstrates the unresolved imbalance between the affluent high-tech countries and the poor agriculture-based countries. Regional, global and in-country meetings must continue to be conducted to find solutions acceptable to all.

Animals ; Birds ; Communication ; Cooperative Behavior ; Global Health ; Humans ; Indonesia ; epidemiology ; Influenza A Virus, H5N1 Subtype ; isolation & purification ; Influenza in Birds ; epidemiology ; prevention & control ; transmission ; virology ; International Cooperation ; legislation & jurisprudence ; Risk Factors ; Trust

INTRODUCTIONDuring an avian influenza (AI) pandemic, primary-care physicians (PCPs) are expected to play key roles in the prevention and control of the disease. Different groups of PCPs could have different concerns and preparedness level. We assessed the concerns, perceived impact and preparedness for an outbreak among PCPs in Singapore.

MATERIALS AND METHODSA cross-sectional survey of PCPs working in private practice (n=200) and public clinics (n=205) from March to June 2006 with an anonymous self-administered questionnaire on concerns (12- items), perceived impact (10 items) and preparedness (10 items) for an outbreak.

RESULTSTwo hundred and eighty-five PCPs responded - 149 (response rate: 72.7%) public and 136 (response rate: 67.3%) private. The majority were concerned about risk to their health from their occupation (95.0%) and falling ill with AI (89.7%). Most (82.5%) accepted the risk and only 33 (11.8%) would consider stopping work. For perceived impact, most felt that people would avoid them (69.6%) and their families (54.1%). The majority (81.3%) expected an increased workload and feeling more stressed at work (86.9%). For preparedness, 78.7% felt personally prepared for an outbreak. Public PCPs were more likely to be involved in infection-control activities and felt that their workplaces were prepared.

CONCLUSIONSMost PCPs felt personally prepared for an outbreak but were concerned about their exposure to AI and falling ill. Other concerns included social ostracism for themselves and their families. Public PCPs appeared to have a higher level of preparation. Addressing concerns and improving level of preparedness are crucial to strengthen the primary-care response for any AI outbreak.

Adult ; Animals ; Birds ; Communicable Disease Control ; methods ; Cross-Sectional Studies ; Disease Outbreaks ; prevention & control ; statistics & numerical data ; Female ; Health Care Surveys ; Humans ; Influenza A Virus, H5N1 Subtype ; isolation & purification ; Influenza in Birds ; epidemiology ; Male ; Middle Aged ; Odds Ratio ; Physicians, Family ; statistics & numerical data ; Risk Factors ; Singapore ; epidemiology ; Surveys and Questionnaires

Animals ; Birds ; Communicable Disease Control ; methods ; Disease Outbreaks ; prevention & control ; statistics & numerical data ; Health Planning ; Humans ; Influenza A Virus, H5N1 Subtype ; Influenza in Birds ; epidemiology ; virology ; Risk Factors ; Singapore ; epidemiology

INTRODUCTIONWith the potential threat of an avian influenza (AI) pandemic, healthcare workers (HCWs) are expected to play important roles, and they encounter significant stress levels from an expected increase in workload. We compared the concerns, perceived impact and preparedness for an AI pandemic between HCWs working in public primary care clinics and a tertiary healthcare setting.

MATERIALS AND METHODSAn anonymous, self-administered questionnaire was given to 2459 HCWs working at 18 public polyclinics (PCs) and a tertiary hospital (TH) in Singapore from March to June 2006. The questionnaire assessed work-related and non-work-related concerns, perceived impact on personal life and work as well as workplace preparedness.

RESULTSWe obtained responses from 986 PC and 873 TH HCWs (response rate: 74.6% and 76.7%). The majority in both groups were concerned about the high AI risk from their occupation (82.7%) and falling ill with AI (75.9%). 71.9% accepted the risk but 25.5% felt that they should not be looking after AI patients with 15.0% consider resigning. HCWs also felt that people would avoid them (63.5%) and their families (54.1%) during a pandemic. The majority expected an increased workload and to feel more stressed at work. For preparedness, 74.2% felt personally prepared and 83.7% felt that their workplaces were prepared for an outbreak. TH HCWs were more likely to be involved in infection-control activities but the perception of infection-control preparedness in both groups was high (>80.0%).

CONCLUSIONSHCWs in both public primary and tertiary healthcare settings felt prepared, personally and in their workplaces, for a pandemic. Their main concerns were risks of falling ill from exposure and the possibility of social ostracism of themselves and their families. Preparedness levels appeared high in the majority of HCWs. However, concerns of HCWs could affect their overall effectiveness in a pandemic and should be addressed by incorporating strategies to manage them in pandemic planning.

Adolescent ; Adult ; Aged ; Animals ; Attitude of Health Personnel ; Birds ; Disaster Planning ; Disease Outbreaks ; Female ; Humans ; Infectious Disease Transmission, Patient-to-Professional ; prevention & control ; Influenza A Virus, H5N1 Subtype ; pathogenicity ; Influenza in Birds ; transmission ; Influenza, Human ; epidemiology ; prevention & control ; transmission ; virology ; Male ; Middle Aged ; Primary Health Care ; Singapore

The H9N2 subtype low pathogenic avian influenza is one of the most prevalent avian diseases worldwide, and was first documented in 1996 in Korea. This disease caused serious economic loss in Korea's poultry industry. In order to develop an oil-based inactivated vaccine, a virus that had been isolated in 2001 (A/chicken/Korea/01310/ 2001) was selected based on its pathogenic, antigenic, and genetic properties. However, in animal experiments, the efficacy of the vaccine was found to be very low without concentration of the antigen (2(7) to 2(10) hemagglutinin unit). In order to overcome the low productivity, we passaged the vaccine candidate virus to chicken eggs. After the 20th passage, the virus was approximately ten times more productive compared with the parent virus. For the most part, the passaged virus maintained the hemagglutinin cleavage site amino acid motif (PATSGR/GLF) and had only three amino acid changes (T133N, V216G, E439D, H3 numbering) in the hemagglutinin molecule, as well as 18 amino acid deletions (55-72) and one amino acid change (E54D) in the NA stalk region. The amino acid changes did not significantly affect the antigenicity of the vaccine virus when tested by hemagglutination inhibition assay. Though not complete, the vaccine produced after the 20th passage of the virus (01310 CE20) showed good protection against a homologous and recent Korean isolate (A/chicken/Korea/Q30/2004) in specific pathogen- free chickens. The vaccine developed in this study would be helpful for controlling the H9N2 LPAI in Korea.
Animals ; Chickens ; Gene Expression Regulation, Viral ; Hemagglutinins/genetics ; Influenza A Virus, H9N2 Subtype/*immunology/pathogenicity ; Influenza Vaccines/*immunology ; Influenza in Birds/epidemiology/*prevention & control/*virology ; Korea/epidemiology ; Neuraminidase/genetics ; Specific Pathogen-Free Organisms ; Time Factors ; Vaccines, Inactivated/*immunology