Avian influenza is a viral disease of poultry and is distributed worldwide. Highly pathogenic avian influenza hpai ah5n1 viruses have been circulating since 2003 in indonesia, with major impacts on poultry health, severe economic losses, and 168 fatal laboratoryconfirmed human cases. A highly pathogenic avian influenza a h5n1 virus has crossed the species barrier to cause deaths in humans in asia and poses an increasing threat of a pandemic. Avian influenza a h5n1 virus causes human influenzalike illness with a high rate of complications in adults admitted to hospital.
Health, general avian influenza prevention risk factors disease transmission methods influenza health aspects soil pollution. Asian h5n1 was first detected in humans in 1997 during a poultry outbreak in hong kong and has since been detected in poultry and wild birds in more than 50 countries. Public health concerns of highly pathogenic avian influenza h5n1. Highly pathogenic avian influenza virus hpaiv h5n1 was first officially reported in africa in 2006. The results of this study confirm that avian influenza h5n1 is readily inactivated by chlorination.
A powerpoint presentation on influenza virus h5n1 delivered by dr. Although the viral inoculum exerted a considerable initial chlorine demand, the maintenance of a free chlorine residual 0. Department of agriculture usda is working with its partners on the international and domestic fronts to help control the spread of highpathogenicity h5n1 avian influenza. Ecology and biochemical properties of avian influenza viruses history of the h5n1 avian influenza virus surveillance strategies for avian influenza references and information sources. Cumulative number of confirmed human cases for avian influenza a h5n1 reported to who, 20032017 source. The country joins three others, vietnam, china, and indonesia, in which the disease has resurfaced in recent weeks following the widespread outbreaks across asia earlier in the year. The highly pathogenic avian influenza virus subtype h5n1 is already. Chlorine inactivation of highly pathogenic avian influenza.
Since december 2003, an asian hpai h5n1 virus has resulted in high mortality in poultry and wild birds in asia, the middle east, europe, and africa. Highly pathogenic avian influenza a h5n1 virus has caused approximately equal to 1,000 human infections since the first case was reported in 1997 overall casefatality rate 54% 1. Influenza a viruses cause recurrent epidemics with substantial human morbidity and mortality, and are also associated with pandemics. It continues to cross species barriers to infect humans and other mammals, often with fatal outcomes. Cumulative number of confirmed human cases for avian. A pandemic can occur if this new influenza virus subtype, which has already been shown to cause serious illness in humans, is able to either exchange genes with human flu viruses or mutate sufficiently over time to allow. Influenza a viruses are classified into subtypes based on two surface proteins, hemagglutinin ha and neuraminidase na. Highly pathogenic avian influenza hpai a virus subtype h5n8 was detected in wild birds found dead at uvsnuur lake at the border between russia and mongolia in may 2016. The highly pathogenic avian influenza virus subtype h5n1 is already panzootic. Currently, highly pathogenic h5n1, a specific strain of avian. Summary pandemic influenza virus has its origins in avian influenza viruses. Optimising the detectability of h5n1 and h5n6 highly. Asian highly pathogenic avian influenza hpai ah5n1 virus occurs mainly in birds and is highly contagious among them.
Thus, infected freerange ducks may serve as trojan horses, introducing virus. Jan 31, 2019 similarly, we are 95% confident that the specificity, i. Free ranged flocks have been identified to be more likely exposed to wild. Experimental infection of swans and geese with highly. Asian h5n1 was first detected in humans in 1997 during a poultry outbreak in hong kong and has since been detected in poultry and wild birds in more than 50 countries in. Human disease from influenza a h5n1, thailand, 2004 this transmission electron micrograph tem, taken at a magnification of 108,000x, revealed the ultrastructural details of two avian influenza a h5n1 virions, a type of bird flu virus, which is a subtype of avian influenza a. Avian influenza a h5n1 viruses are entrenched among poultry in parts of asia and africa and continue to cause disease with high mortality in humans. Influenza a viruses can cause three distinct diseases in humans. Avian influenza refers to the disease caused by infection with avian bird influenza flu type a viruses. Highly pathogenic avian influenza hpai is a devastating disease in poultry. Highly pathogenic asian avian influenza ah5n1 virus avian. Update on highly pathogenic avian influenza in animals type h5 and h7 external. Letters, letter to the editor by emerging infectious diseases.
The pattern of highly pathogenic avian influenza h5n1. However, this vaccine, which is used for h5n1 treatment, has not been made available to the general public and has been stockpiled, in case of an outage this vaccine can be used. Avian influenza a viruses can infect the respiratory and gastrointestinal tract of birds and have been isolated from more than 100 different species of wild birds around the world. Human infections with avian influenza h5n1 are reported in hong kong. Antigenic and genetic characteristics of influenza a h5n1 and influenza ah9n2 viruses and candidate vaccine vi. Containment of highly pathogenic avian influenza ah5n1. Highly pathogenic avian influenza virus an overview. Avian influenza a h5n1 viruses cause severe disease in humans, but the basis for their virulence remains unclear. In 1999, h9n2 avian influenza infected two children in hong kong and there were other cases in mainland china. The role of wild birds in the epidemiology of the asian lineage highly pathogenic avian influenza hpai virus subtype h5n1 epizootic and their contribution to the spread of the responsible viruses in eurasia and africa are unclear. The presence of free grazing ducks fgd has consistently been shown to be associated with highly pathogenic avian influenza virus hpaiv h5n1. The circulating h5n1 highly pathogenic avian influenza in chicken has created devastating problems in indonesia since 2003.
Close monitoring is required of hpai of the subtypes ah5n1 and. The underlying infection should be treated with antivirals as soon as possible, and supportive care provided as indicated. Avian influenza current situation summary avian influenza flu. In order to ensure transparency in the global animal disease situation, to safeguard international trade on animals and animal products and to be consistent with chapters 1. Highly pathogenic avian influenza ah5n1 virus can cause morbidity and mortality in humans but thus far has not acquired the ability to be transmitted by aerosol or respiratory droplet airborne transmission between humans. H5n1, for example, a highly pathogenic ai virus, was initially diagnosed in humans in hong kong in 1997. Malaysia joins resurgence of h5n1 avian flu cidrap. Zoonotic influenza viruses circulating in poultry and swine pose an ever present threat to human health. Survivability of highly pathogenic avian influenza h5n1 virus. A virus is defined as hpai or lpai by its ability to cause severe disease in intravenously inoculated young chickens in the laboratory, or by its. Cidrap news h5n1 avian influenza has today been confirmed in a privately owned flock of chickens in northern malaysia near the thai border. Aug 4, 2006 cidrap news a swan tested positive for h5n1 avian influenza at a german zoo yesterday, signaling the viruss reemergence in the country after a 3month lull. Avian influenza h5n1 virus ppt influenza a virus subtype. Information on avian influenza avian influenza flu.
Highly pathogenic asian avian influenza ah5n1 virus. Tropism of avian influenza a h5n1 in the upper and lower respiratory tract. A h5n1 and ah9n2 avian influenza viruses are enzootic in egyptian poultry, and most a h5n1 human cases since 2009 have occurred in egypt. Whogip, data in hq as of 25 july 2017 total number of cases includes number of deaths.
No cases of the highly pathogenic h5n1 influenza have been reported in humans or birds in the united states. In vitro and animal studies indicate that high and disseminated viral. Download a pdf of perspectives on research with h5n1 avian influenza by the institute of medicine and national research council for free. For each of these three pathways we estimated risk as the number of h5n1 infectious bird days for an introduction by multiplying the number of birds entering or passing through a country by an estimate of the prevalence of h5n1 and by an estimate of the number of days that each bird would shed virus. Contaminated soil and transmission of influenza virus h5n1. Influenza a virus subtype h5n1 a h5n1 is a subtype of the influenza a virus which can cause illness in humans and many other animal species. Use of highly pathogenic avian influenza a h5n1 gainof. Feb 2003 two human cases of avian influenza h5n1 infection one fatal are confirmed in a hong kong family with a recent travel history to fujian province, china. We generated the full genome of a highly pathogenic h5n1 avian influenza virus that caused an outbreak on a chicken farm in lebnaon in april 2016. Phylogenetic analysis of h5n1 virus 20032011 revealed the introduction of a single ancestral of 2. An updated loopmediated isothermal amplification method. Avian influenza ai is an infectious disease of birds caused by type a. Highly pathogenic avian influenza hpai h5n1 has caused severe illnesses in poultry.
Up to cases among farmers and poultry workers occurred. The temperatures in the western india reach as high as 45 c during the summer season and is also very dry. Organization international des epizooties oie and insure the free of status for avian. For each of these three pathways we estimated risk as the number of h5n1infectious bird days for an introduction by multiplying the number of birds entering or passing through a country by an estimate of the prevalence of h5n1 and by an estimate of the number of days that each bird would shed virus. Probable persontoperson transmission of avian influenza a h5n1 external. Feb 2003 2 human cases of avian influenza h5n1 infection 1 fatal are confirmed in a china hong kong sar family with a recent travel history to fujian province, china. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Highly pathogenic avian influenza h5n1, thailand, 2004. Avian influenza ai, caused by the influenza virus typea, can affect several species of. Although human cases of avian influenza could be exceptionally reduced, however, it remains unsettled in poultry. To better understand the potential role of swans and geese in the epidemiology of this virus, we infected 4 species of swans and 2 species of geese with an hpai. Multiple reassorted viruses as cause of highly pathogenic.
Highly pathogenic asian avian influenza a h5n1 in people. Highly pathogenic avian influenza hpai ah5n1 virus occurs mainly in birds, is highly contagious among birds, and can be deadly, especially in domestic poultry. Avian influenza viruses are classified as either low pathogenic also called low pathogenicity avian influenza viruses or highly pathogenic high pathogenicity avian influenza viruses. A black australian swan at the dresden zoo in eastern germany was found dead on aug 1, but zoo officials werent too concerned at first because deaths in the breed are. Asian highly pathogenic avian influenza hpai a h5n1 virus occurs mainly in birds and is highly contagious among them. The avian influenza h5n1 outbreaks in asia are concerning because of the risk of a possible pandemic, or worldwide outbreak. Haemagglutinin mutations responsible for the binding of h5n1 influenza a viruses to humantype receptors. The number of affected countries increased during 20032008, and infections spread from east and southeast asia to west asia and several regions of africa 2. Avian influenza a h5n1 virus infection etiology bmj. There is an avian influenza vaccine available which is known to treat a certain strain of asian avian influenza a h5n1 viruses. Mar 04, 2008 for those looking for a single, exhaustive reference to help educate or train individuals in dealing with avian influenza, this will be money well spent.
The objective is to describe what is happening currently, explain what we are seeing, and consider what might happen next. Wild birds and avian influenza an introduction to applied. Altogether, 18 cases 6 fatal are reported in the first known instance of human infection with this virus. Highly pathogenic avian influenza ah5n1 in birds and. Hpai outbreaks were relatively rare until 1990 but occurred in many countries in the last decade. Thus a name like h5n1 is a very incomplete description of the virus. A birdadapted strain of h5n1, called hpai a h5n1 for highly pathogenic avian influenza virus of type a of subtype h5n1, is the highly pathogenic causative agent of h5n1 flu, commonly known as avian influenza bird flu. Wild birds and increased transmission of highly pathogenic avian influenza h5n1 among poultry.
Freegrazing ducks and highly pathogenic avian influenza, thailand. United states prepares for highly pathogenic h5n1 avian influenza in wild birds introduction avian influenza aithe bird fluis a disease caused by a virus that infects domestic poultry, wild birds geese and ducks and shorebirds. Therefore, h5n1 virus has rightly received attention as a potential pandemic threat. Influenza a viruses are the only type reported to cause natural infections of birds and are further divided into subtypes according to antigenic characteristics of the surface glycoproteins hemagglutinin h and neuraminidase n. Human infection with an avian influenza a virus subtype h5n1 was reported recently in hong kong. Frequently updated information on h5n1 avian influenza cases and pandemic flu. However, sporadic human infections with avian flu viruses. It is often referred to simply as bird flu or avian influenza, even though it is only one of many subtypes.
Oie situation report for avian influenza 19 september 2017 1 oie situation report for avian influenza latest update. Avian influenza h5n1 virus ppt influenza a virus subtype h5. Program pnsa manual for the contingency of avian influenza and. An avian influenza h5n1 virus that binds to a humantype receptor.
Epidemiology, evolution, and recent outbreaks of avian influenza. Its possible to have an h5n1 strain with six other genes from an avian flu virus, or an h5n1 with six other genes from a humanadapted or pigadapted flu virus. Avian influenza refers to disease caused by infection with avian bird influenza flu type a viruses. Sep 01, 2006 influenza viruses are segmented, negativestrand rna viruses that are placed in the family orthomyxoviridae in 3 genera. The h5n1 only describes two of the eight genes, so there are six other genes, halvorson said. Number of poultry destroyed since the last report 07082017. Avian influenza a h5n1 virus causes human influenza like illness with a high rate of complications in adults admitted to hospital. Wild birds and increased transmission of highly pathogenic avian. Nearly 600 cases of human h5n1 have been reported, worldwide, since 2003. Rapid h5subtypespecific laboratory diagnosis can be made by rt. Host range of the asian lineage h5n1 avian influenza viruses and reassortants. Virulence determinants of avian h5n1 influenza a virus in mammalian and avian hosts.
Avian influenzakent informally as avian flu or bird flu is a variety o influenza caused bi viruses adaptit tae birds. Highly pathogenic avian influenza ah5n1 virus has caused approximately equal to 1,000 human infections since the first case was reported in 1997 overall casefatality rate 54% 1. To address the concern that the virus could acquire this ability under natural conditions, we genetically modified ah5n1 virus by sitedirected mutagenesis. Avian influenza samplingcleaning containers at anchorage lab.
Recommendations and laboratory procedures for detection of avian influenza a h5n1 virus in specimens from suspected human cases. Highly pathogenic avian influenza hpai is a highly infectious viral disease that affects a wide range of bird species. The virus was first detected in 1996 in geese in china. We describe the clinical presentation of the first 12 patients and options for rapid viral diagnosis. Clinical signs of the disease depend on the strain and subtype of virus and. Occasionally mammals, including humans, may contract avian influenza. Perspectives on research with h5n1 avian influenza. A fatal human case of avian influenza h5n1 infection occurs in china in a. Avian influenza a h5n1 virus infection complications.
Encephalitis is an uncommon complication of highly pathogenic avian influenza hpai h5n1 virus infection, but cases of cns infection and detection of virus in csf have been described. The teep wi the greatest risk is heichly pathogenic avian influenza hpai. Avian influenza h5n1 virus ppt free download as powerpoint presentation. Avian influenza and the h5n1 virus pdf, 720 kb 11 pp. Two human cases of avian influenza h5n1 infection one fatal are confirmed in a. Asian h5n1 was first detected in humans in 1997 during a poultry outbreak in hong kong and has since been detected in. Each year, there is a bird flu season just as there is. Countries affected by the h5n1 avian influenza virus in domestic poultry, free ranging. Predicting the global spread of h5n1 avian influenza. Jun 22, 2012 highly pathogenic avian influenza ah5n1 virus can cause morbidity and mortality in humans but thus far has not acquired the ability to be transmitted by aerosol or respiratory droplet airborne transmission between humans.
We performed phylogenetic analysis on 39 fullgenome h5n1 virus samples collected during outbreaks among poultry in 20152016 in west java and compared them with recently published. The highly pathogenic avian influenza virus subtype h5n1 is already panzootic in poultry, with attendant economic consequences. Pdf pandemic influenza virus has its origins in avian influenza viruses. Hpai viruses may be transmitted from birds to humans 3,4, and they are a potential source of future human influenza pandemics. Update on avian influenza a h5n1 virus infection in humans. This discovery was considered an early warning for the potential spread of the virus by autumn migration of wild birds. Fifteen low pathogenic avian influenza lpai outbreaks were reported in three. Mar, 2020 occasionally mammals, including humans, may contract avian influenza. Complete genome sequence of the first h5n1 avian influenza. The highly pathogenic influenza a virus subtype h5n1 is an emerging avian influenza virus that is causing global concern as a potential pandemic threat. Unfortunately there is now much confusion about the different human diseases caused by influenza viruses. Countries affected by the h5n1 avian influenza virus in domestic poultry, freeranging. Journal of the american veterinary medical association, march 2009 david swaynes book avian influenza is both timely and important. In 2003, h5n1 and h9n2 infections were confirmed in hong kong, while in the netherlands, a large avian influenza outbreak involved an h7n7 virus.
May 15, 20 analysis of outbreaks of h5n1 avian influenza in eastern india indicated that favorable climatic conditions could have ensured the persistence of the virus and could be one of the major reasons for repeated outbreaks. Engineering h5n1 avian influenza viruses to study human. Analysis revealed that the virus belonged to clade 2. Highly pathogenic avian influenza virus hpaiv h5n1 was first officially. Cases of hpai ah5n6 infection in freeliving wild birds, ordered. Avian influenza and the h5n1 virus food and agriculture. Transmission of highly pathogenic avian influenza in the. What is the global incidence of avian influenza h5n1. In particular, the rapid geographical expansion of highly pathogenic avian influenza hpai a h5n1 throughout asia and then into europe, the middle east, and africa during the 2000s galvanized the global community in an attempt to control this rapidly growing threat. Avian influenza ai or bird flu is a highly contagious viral infection which can affect all species of birds and can manifest itself in different ways depending mainly on the ability of the virus to cause disease pathogenicity and on the species affected. Although there are several types of bird flu, h5n1 was the first avian influenza virus to infect humans. Highly pathogenic avian influenza hpai h5n1 virus binds to receptors with sialic acids bound to galactose by alpha2,3 linkages, which are primarily, but not entirely, distributed in the human lower respiratory tract. In addition, although most avian influenza viruses do not infect humans, some, such as avian influenza h5n1 and h7n9, are well known to the public because of their implication in serious and sometimes fatal infections in people.
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