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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 -
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 -
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 -
Saudi Medical Journal May 2006A rapidly spreading, highly pathogenic avian influenza virus A H5N1 in the domestic poultry population has crossed the species barrier to humans and other mammalian... (Review)
Review
A rapidly spreading, highly pathogenic avian influenza virus A H5N1 in the domestic poultry population has crossed the species barrier to humans and other mammalian species, thus, posing an increasing pandemic threat. The World Health Organization, other agencies, and countries worldwide are closely monitoring the prevalent influenza viruses and their related illnesses to detect any increased virulence or transmissibility that might signal the beginnings of any future pandemic. So far, the H5N1 virus has infected birds in more than 30 countries in Asia, Europe and Africa, while further geographical spread remains likely. Human infections are still rare and the virus does not spread easily from birds to humans or readily from person to person. Although antiviral drugs and vaccination are among the most important measures to be used in case of an influenza pandemic, a timely supply of sufficient quantities will not be possible. This review describes various aspects of avian influenza in birds and in humans; epidemiology, transmission, diagnosis and clinical manifestations. Also presented are the global preparedness, the anti-influenza drugs and vaccines.
Topics: Africa; Animals; Antiviral Agents; Asia; Disease Outbreaks; Disease Transmission, Infectious; Europe; Global Health; Humans; Influenza A Virus, H5N1 Subtype; Influenza in Birds; Influenza, Human; Poultry; Vaccination
PubMed: 16680243
DOI: No ID Found -
The Veterinary Record Aug 2022
Topics: Animals; Humans; Influenza A Virus, H5N1 Subtype; Influenza A virus; Influenza in Birds; Influenza, Human
PubMed: 35984267
DOI: 10.1002/vetr.2135 -
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 -
Australian Veterinary Journal Dec 1989
Review
Topics: Animals; Australia; Birds; Disease Outbreaks; Influenza A virus; Influenza in Birds
PubMed: 2695043
DOI: 10.1111/j.1751-0813.1989.tb13568.x -
The Veterinary Record Jul 2022
Topics: Animals; Disease Outbreaks; Humans; Influenza A virus; Influenza in Birds; Influenza, Human
PubMed: 35802102
DOI: 10.1002/vetr.1988 -
The Veterinary Record Apr 2023
Topics: Animals; Humans; Influenza in Birds; Disease Outbreaks; Influenza A virus; Influenza, Human
PubMed: 37084226
DOI: 10.1002/vetr.2978 -
Revue Scientifique Et Technique... Apr 2009Reports of sporadic avian influenza outbreaks involving domestic poultry date back to the 1960s. With the exception of A/turkey/Ontario/7732/1966 (H5N9), which was... (Review)
Review
Reports of sporadic avian influenza outbreaks involving domestic poultry date back to the 1960s. With the exception of A/turkey/Ontario/7732/1966 (H5N9), which was isolated from a turkey breeding establishment, all viruses characterised prior to 2004 fit the criteria of low pathogenic avian influenza (LPAI). Only in retrospect was A/turkey/Ontario/7732/1966 shown to meet the criteria of a highly pathogenic avian influenza (HPAI). In 2004, Canada reported its first case of HPAI to the World Organisation for Animal Health (OIE). The outbreak, which began in a broiler breeder farm in the Fraser Valley of British Columbia, involved an H7N3 LPAI virus which underwent a sudden virulence shift to HPAI. More than 17 million birds were culled and CAN$380 million in gross economic costs incurred before the outbreak was eventually brought under control. In its aftermath a number of changes were implemented to mitigate the impact of any future HPAI outbreaks. These changes involved various aspects of avian influenza detection and control, including self-quarantine, biosecurity, surveillance, and laboratory testing. In 2005, a national surveillance programme for influenza A viruses in wild birds was initiated. Results of this survey provided evidence for wild birds as the likely source of an H5N2 LPAI outbreak that occurred in domestic ducks in the Fraser Valley in the autumn of 2005. Wild birds were once again implicated in an H7N3 HPAI outbreak involving a broiler breeder operation in Saskatchewan in 2007. Fortunately, both of these outbreaks were limited in extent, a consequence of some of the changes implemented in response to the 2004 British Columbia outbreak.
Topics: Animals; Birds; Canada; Disease Outbreaks; Influenza A Virus, H5N2 Subtype; Influenza A virus; Influenza in Birds; Poultry; Sentinel Surveillance
PubMed: 19618638
DOI: 10.20506/rst.28.1.1875