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Emerging Microbes & Infections Dec 2023Avian influenza viruses continue to present challenges to animal and human health. Viruses bearing the hemagglutinin (HA) gene of the H5 subtype and H7 subtype have... (Review)
Review
Avian influenza viruses continue to present challenges to animal and human health. Viruses bearing the hemagglutinin (HA) gene of the H5 subtype and H7 subtype have caused 2634 human cases around the world, including more than 1000 deaths. These viruses have caused numerous disease outbreaks in wild birds and domestic poultry, and are responsible for the loss of at least 422 million domestic birds since 2005. The H5 influenza viruses are spread by migratory wild birds and have caused three waves of influenza outbreaks across multiple continents, and the third wave that started in 2020 is ongoing. Many countries in Europe and North America control highly pathogenic avian influenza by culling alone, whereas some countries, including China, have adopted a "cull plus vaccination" strategy. As the largest poultry-producing country in the world, China lost relatively few poultry during the three waves of global H5 avian influenza outbreaks, and nearly eliminated the pervasive H7N9 viruses that emerged in 2013. In this review, we briefly summarize the damages the H5 and H7 influenza viruses have caused to the global poultry industry and public health, analyze the origin, evolution, and spread of the H5 viruses that caused the waves, and discuss how and why the vaccination strategy in China has been a success. Given that the H5N1 viruses are widely circulating in wild birds and causing problems in domestic poultry around the world, we recommend that any unnecessary obstacles to vaccination strategies should be removed immediately and forever.
Topics: Animals; Humans; Influenza in Birds; Influenza A Virus, H5N1 Subtype; Influenza A Virus, H7N9 Subtype; Poultry; Birds; Animals, Wild
PubMed: 36458831
DOI: 10.1080/22221751.2022.2155072 -
British Medical Bulletin Dec 2019Human infections with avian influenza viruses (AIV) represent a persistent public health threat. The principal risk factor governing human infection with AIV is from... (Review)
Review
BACKGROUND
Human infections with avian influenza viruses (AIV) represent a persistent public health threat. The principal risk factor governing human infection with AIV is from direct contact with infected poultry and is primarily observed in Asia and Egypt where live-bird markets are common.
AREAS OF AGREEMENT
Changing patterns of virus transmission and a lack of obvious disease manifestations in avian species hampers early detection and efficient control of potentially zoonotic AIV.
AREAS OF CONTROVERSY
Despite extensive studies on biological and environmental risk factors, the exact conditions required for cross-species transmission from avian species to humans remain largely unknown.
GROWING POINTS
The development of a universal ('across-subtype') influenza vaccine and effective antiviral therapeutics are a priority.
AREAS TIMELY FOR DEVELOPING RESEARCH
Sustained virus surveillance and collection of ecological and physiological parameters from birds in different environments is required to better understand influenza virus ecology and identify risk factors for human infection.
Topics: Animals; Antiviral Agents; Birds; Disease Outbreaks; Disease Susceptibility; Humans; Influenza A virus; Influenza Vaccines; Influenza in Birds; Influenza, Human; Risk Factors; Zoonoses
PubMed: 31848585
DOI: 10.1093/bmb/ldz036 -
Revue Scientifique Et Technique... Apr 2009Avian influenza (AI) viruses vary in their ability to produce infection, disease and death in different bird species. Based on the pathobiological effect in chickens, AI... (Review)
Review
Avian influenza (AI) viruses vary in their ability to produce infection, disease and death in different bird species. Based on the pathobiological effect in chickens, AI viruses (AIV) are categorised as low pathogenic (LPAIV) or highly pathogenic (HPAIV). Typically, LPAIV cause asymptomatic infections in wild aquatic birds, but when introduced into domesticated poultry, infections may be asymptomatic or produce clinical signs and lesions reflecting pathophysiological damage to the respiratory, digestive and reproductive systems. The HPAIV have primarily been seen in gallinaceous poultry, producing high morbidity and mortality, and systemic disease with necrosis and inflammation in multiple visceral organs, nervous and cardiovascular systems, and the integument. Although HPAIV have rarely infected domestic waterfowl or wild birds, the Eurasian-African H5N1 HPAIV have evolved over the past decade with the unique capacity to infect and cause disease in domestic ducks and wild birds, producing a range of syndromes including asymptomatic respiratory and digestive tract infections; systemic disease limited to two or three critical organs, usually the brain, heart and pancreas; and severe disseminated infection and death as seen in gallinaceous poultry. Although experimental studies using intranasal inoculation have produced infection in a variety of wild bird species, the inefficiency of contact transmission in some of them, for example, passerines and Columbiformes, suggests they are unlikely to be a reservoir for the viruses, while others such as some wild Anseriformes, can be severely affected and could serve as a dissemination host over intermediate distances.
Topics: Animals; Animals, Wild; Birds; Influenza A Virus, H5N1 Subtype; Influenza A virus; Influenza in Birds; Poultry; Species Specificity; Virulence
PubMed: 19618622
DOI: No ID Found -
Viruses Jan 2021Highly pathogenic avian influenza (HPAI) outbreaks in wild birds and poultry are no longer a rare phenomenon in Europe. In the past 15 years, HPAI outbreaks-in... (Review)
Review
Highly pathogenic avian influenza (HPAI) outbreaks in wild birds and poultry are no longer a rare phenomenon in Europe. In the past 15 years, HPAI outbreaks-in particular those caused by H5 viruses derived from the A/Goose/Guangdong/1/1996 lineage that emerged in southeast Asia in 1996-have been occuring with increasing frequency in Europe. Between 2005 and 2020, at least ten HPAI H5 incursions were identified in Europe resulting in mass mortalities among poultry and wild birds. Until 2009, the HPAI H5 virus outbreaks in Europe were caused by HPAI H5N1 clade 2.2 viruses, while from 2014 onwards HPAI H5 clade 2.3.4.4 viruses dominated outbreaks, with abundant genetic reassortments yielding subtypes H5N1, H5N2, H5N3, H5N4, H5N5, H5N6 and H5N8. The majority of HPAI H5 virus detections in wild and domestic birds within Europe coincide with southwest/westward fall migration and large local waterbird aggregations during wintering. In this review we provide an overview of HPAI H5 virus epidemiology, ecology and evolution at the interface between poultry and wild birds based on 15 years of avian influenza virus surveillance in Europe, and assess future directions for HPAI virus research and surveillance, including the integration of whole genome sequencing, host identification and avian ecology into risk-based surveillance and analyses.
Topics: Animal Migration; Animals; Animals, Wild; Birds; Europe; Influenza A virus; Influenza in Birds
PubMed: 33573231
DOI: 10.3390/v13020212 -
The Lancet. Microbe Aug 2022
Topics: Animals; Humans; Influenza A Virus, H5N1 Subtype; Influenza in Birds; Influenza, Human
PubMed: 35907426
DOI: 10.1016/S2666-5247(22)00202-6 -
Current Allergy and Asthma Reports Mar 2006The current epidemic of H5N1 highly pathogenic avian influenza in Southeast Asia raises serious concerns that genetic reassortment will result in the next influenza... (Review)
Review
The current epidemic of H5N1 highly pathogenic avian influenza in Southeast Asia raises serious concerns that genetic reassortment will result in the next influenza pandemic. There have been 164 confirmed cases of human infection with avian influenza since 1996. In 2004 alone, there were 45 cases of human H5N1 in Vietnam and Thailand, with a mortality rate over 70%. In addition to the potential public health hazard, the current zoonotic epidemic has caused severe economic losses. Efforts must be concentrated on early detection of bird outbreaks with aggressive culling, quarantines, and disinfection. To prepare for and prevent increased human cases, it is essential to improve detection methods and stockpile effective antivirals. Novel therapeutic modalities, including short, interfering RNAs and new vaccine strategies that use plasmid-based genetic systems offer promise, should a pandemic occur.
Topics: Animals; Asia, Southeastern; Disease Outbreaks; Humans; Influenza A Virus, H5N1 Subtype; Influenza in Birds; Influenza, Human; Poultry
PubMed: 16566867
DOI: 10.1007/s11882-006-0055-y -
Chang Gung Medical Journal Nov 2005Influenza is an old disease but remains vital nowadays. Three types of influenza viruses, namely A, B, C, have been identified; among them influenza A virus has pandemic... (Review)
Review
Influenza is an old disease but remains vital nowadays. Three types of influenza viruses, namely A, B, C, have been identified; among them influenza A virus has pandemic potential. The first outbreak of human illness due to avian influenza virus (H5N1) occurred in 1997 in Hong Kong with a mortality of 30%. The most recent outbreak of the avian influenza epidemic has been going on in Asian countries since 2003. As of March 2005, 44 incidental human infections and 32 deaths have been documented. Human influenza viruses differ with other avian influenza viruses on the choice of cellular receptors. Avian influenza viruses bind to cell-surface glycoproteins or glycolipids containing terminal sialyl-galactosyl residues linked by 2-3-linkage [Neu5Ac(alpha2-3)Gal], whereas human viruses, including the earliest available isolates from the 1957 and 1968 pandemics, bind to receptors that contain terminal 2-6-linked sialyl-galactosyl moieties [Neu5Ac(alpha2-6)Gal]. Recent evidence suggests that human bronchial ciliated epithelial cells contain Neu5Ac(alpha2-3)Gal and can be infected with avian influenza viruses. Nevertheless, avian influenza viruses can not infect non-ciliated bronchial epithelial cells. Hence, adaptation of the avian influenza virus to nonciliated cells is a prerequisite for a pandemic virus to emerge. Biological behaviors of influenza viruses indicate that once a pandemic virus emerges, isolation is not likely to contain this epidemic. A specific vaccine against the pandemic strain will not be available until 6 to 12 months after the inception of the pandemic. Judicious use of antiviral agents and stringent disease control measures are imperative to decrease the impact of a future pandemic.
Topics: Animals; Disease Outbreaks; Humans; Influenza A Virus, H5N1 Subtype; Influenza Vaccines; Influenza in Birds; Influenza, Human; Poultry
PubMed: 16422180
DOI: No ID Found -
ELife Apr 2023The H3N2 canine influenza virus - which originally came from birds - is evolving to become more transmissible between dogs.
The H3N2 canine influenza virus - which originally came from birds - is evolving to become more transmissible between dogs.
Topics: Animals; Dogs; Birds; Dog Diseases; Influenza A virus; Influenza A Virus, H3N2 Subtype; Influenza in Birds; Mammals; Orthomyxoviridae Infections
PubMed: 37039775
DOI: 10.7554/eLife.86051 -
Seminars in Respiratory and Critical... Aug 2016Although efficient human-to-human transmission of avian influenza virus has yet to be seen, in the past two decades avian-to-human transmission of influenza A viruses... (Review)
Review
Although efficient human-to-human transmission of avian influenza virus has yet to be seen, in the past two decades avian-to-human transmission of influenza A viruses has been reported. Influenza A/H5N1, in particular, has repeatedly caused human infections associated with high mortality, and since 1998 the virus has evolved into many clades of variants with significant antigenic diversity. In 2013, three (A/H7N9, A/H6N1, and A/H10N8) novel avian influenza viruses (AIVs) breached the animal-human host species barrier in Asia. In humans, roughly 35% of A/H7N9-infected patients succumbed to the zoonotic infection, and two of three A/H10N8 human infections were also lethal; however, neither of these viruses cause influenza-like symptoms in poultry. While most of these cases were associated with direct contact with infected poultry, some involved sustained human-to-human transmission. Thus, these events elicited concern regarding potential AIV pandemics. This article reviews the human incursions associated with AIV variants and the potential role of pigs as an intermediate host that may hasten AIV evolution. In addition, we discuss the known influenza A virus virulence and transmission factors and their evaluation in animal models. With the growing number of human AIV infections, constant vigilance for the emergence of novel viruses is of utmost importance. In addition, careful characterization and pathobiological assessment of these novel variants will help to identify strains of particular concern for future pandemics.
Topics: Animals; Birds; Disease Reservoirs; Humans; Influenza A Virus, H5N1 Subtype; Influenza A Virus, H7N9 Subtype; Influenza in Birds; Influenza, Human; Poultry; Swine; Zoonoses
PubMed: 27486732
DOI: 10.1055/s-0036-1584953 -
Influenza and Other Respiratory Viruses Apr 2023Avian influenza viruses have had a significant burden of disease on animal and public health in countries of the Eastern Mediterranean Region. In this review, we aimed... (Review)
Review
Avian influenza viruses have had a significant burden of disease on animal and public health in countries of the Eastern Mediterranean Region. In this review, we aimed at describing the state of avian influenza in the region from 2011 to 2021. We gathered information available through the peer-reviewed scientific literature, public gene sequence depositories, OIE World Animal Health Information System platform, World Health Organization FluNet, Joint External Evaluation reports, and governmental, Food and Agriculture Organization of the United Nations, and World Organization for Animal Health websites. We used an interdisciplinary perspective consistent with the One Health approach to perform a qualitative synthesis and making recommendations. Analysis showed that although avian influenza research in the Eastern Mediterranean Region has gained more attention during the last decade, it was limited to only few countries and to basic science research. Data highlighted the weakness in surveillance systems and reporting platforms causing underestimation of the actual burden of disease among humans and animals. Inter-sectoral communication and collaboration for avian influenza prevention, detection, and response remain weak. Influenza surveillance at the human-animal interface and the application of the One Health paradigm are lacking. Countries' animal health and public health sectors rarely publish their surveillance data and findings. This review suggested that surveillance at the human-animal interface, research, and reporting capacities should be enhanced to improve understanding and control of avian influenza in the region. Implementing a rapid and comprehensive One Health approach for zoonotic influenza in the Eastern Mediterranean Region is recommended.
Topics: Animals; Humans; Influenza in Birds; Influenza, Human; Public Health; World Health Organization; Global Health; Mediterranean Region
PubMed: 37102060
DOI: 10.1111/irv.13137