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Bird Flu rears its head again (FAO, August 29 2011, edited)

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  • Bird Flu rears its head again (FAO, August 29 2011, edited)

    [Source: FAO, full text: (LINK). Edited.]
    Bird Flu rears its head again



    29-08-2011
    Increased preparedness and surveillance urged against variant strain


    Major resurgence H5N1 possible


    29 August 2011, Rome - FAO today urged heightened readiness and surveillance against a possible major resurgence of the H5N1 Highly Pathogenic Avian Influenza amid signs that a mutant strain of the deadly Bird Flu virus is spreading in Asia and beyond, with unpredictable risks to human health.

    The H5N1 virus has infected 565 people since it first appeared in 2003, killing 331 of them, according to WHO figures. The latest death occurred earlier this month in Cambodia, which has registered eight cases of human infection this year -- all of them fatal.

    Since 2003 H5N1 has killed or forced the culling of more than 400 million domestic poultry and caused an estimated $20 billion of economic damage across the globe before it was eliminated from most of the 63 countries infected at its peak in 2006.

    However, the virus remained endemic in six nations, although the number of outbreaks in domestic poultry and wild bird populations shrank steadily from an annual peak of 4000 to just 302 in mid 2008. But outbreaks have risen progressively since, with almost 800 cases recorded in 2010-2011.


    Virus spread in both poultry and wild birds

    At the same time, 2008 marked the beginning of renewed geographic expansion of the H5N1 virus both in poultry and wild birds.

    The advance appears to be associated with migratory bird movements, according to FAO Chief Veterinary Officer Juan Lubroth. He said migrations help the virus travel over long distances, so that H5N1 has in the past 24 months shown up in poultry or wild birds in countries that had been virus-free for several years.

    "Wild birds may introduce the virus, but peoples' actions in poultry production and marketing spread it," Lubroth noted.
    Recently affected areas are to be found in Israel and the Palestinian Territories, Bulgaria, Romania, Nepal and Mongolia.

    A further cause for concern, Lubroth said, is the appearance in China and Viet Nam of a variant virus apparently able to sidestep the defences provided by existing vaccines.

    In Viet Nam, which suspended its springtime poultry vaccination campaign this year, most of the northern and central parts of the country -- where H5N1 is endemic -- have been invaded by the new virus strain, known as H5N1 - 2.3.2.1.


    High alert

    Viet Nam's veterinary services are on high alert and reportedly considering a novel, targeted vaccination campaign this fall.

    Virus circulation in Viet Nam poses a direct threat to Cambodia, Thailand and Malaysia as well as endangering the Korean peninsula and Japan further afield. Wild bird migration can also spread the virus to other continents.

    "The general departure from the progressive decline observed in 2004-2008 could mean that there will be a flareup of H5N1 this fall and winter, with people unexpectedly finding the virus in their backyard," Lubroth said.

    The countries where H5N1 is still firmly entrenched ? Bangladesh, China, Egypt, India, Indonesia and Vietnam ? are likely to face the biggest problems but no country can consider itself safe, he said.

    "Preparedness and surveillance remain essential," Lubroth underlined. "This is no time for complacency. No one can let their guard down with H5N1."

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  • #2
    Re: Bird Flu rears its head again (FAO, August 29 2011, edited)

    Bird-swine flu hybrid could be a killer combo

    Bird flu is back on the radar, with the United Nations Food and Agriculture Organization (FAO) warning of a new mutant strain that is spreading amongst bird populations in Asia and beyond.

    According to the FAO, this could lead to a resurgence of the H5N1 Highly Pathogenic Avian Influenza, which has already infected 565 people since 2003, and killed 331.

    However, should such a strain of influenza happen to cross with the recent H1N1 ‘swine flu’ strain, it could morph into a serious threat, said Professor Peter Doherty, Laureate Professor at the University of Melbourne.

    “The recent H1N1 ‘swine ‘flu’ pandemic was caused by the reassortment of genes from two pig viruses. That virus was incredibly infectious and went around the world in six months though, fortunately, it was not especially virulent as it took about six months before we started getting vaccine into peoples’ arms.

    “If, however, a pig became infected simultaneously with an HP H5N1 virus and the 2009 pandemic strain, it is possible that an extremely virulent variant that spreads readily between humans could emerge,” he said.

    Professor Doherty has spent a lifetime studying the immune system, and in 1996 he and Professor Rolf Zinkernagel received the Nobel Prize in Physiology or Medicine for their work uncovering the role of the Major Histocompatibility Complex in immunity.

    ..

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    • #3
      Re: Bird Flu rears its head again (FAO, August 29 2011, edited)

      [Source: World Health Organization, full PDF document: (LINK). Edited.]


      Influenza at the human-animal interface - Summary and assessment as of 3 Aug 2011



      Human infections with avian influenza H5N1 virus and associated animal health events

      As of 2 August, 563 confirmed human cases of infection with avian influenza H5N1 virus from 15 countries were reported to WHO (see figure).
      Of these, 330 died (CFR: 58.6%).

      Epidemiologic investigations have identified only limited human to human transmission of this virus since its emergence in 2003, and no community-level spread.

      In the past month, only one human case of H5N1 infection was reported, from Cambodia.

      No other countries reported human cases since the last summary (4 July).
      The case, who died, was a 4 year old girl from Banteay Meanchey Province, Cambodia, with onset date on 11.07.2011. She was reported to have had exposure to dead poultry. Poultry outbreaks have recently been reported to the OIE from two villages in this province, as well as one outbreak in wild birds kept in a zoo in Takeo province. Birds in the two villages were culled.

      This is the seventh H5N1 human case reported from Cambodia in 2011, all of which were in people under 19 years of age and all of which were fatal.
      This is the highest number of human H5N1 cases reported in one year from Cambodia.

      The bases for the increased incidence and the high case fatality rate remain unclear.

      In Cambodia, sporadic reintroduction of avian influenza H5N1 virus into poultry populations is thought to occur. Available information suggests that H5N1 viruses belonging to clade 1 are responsible for 2011 human cases and outbreaks in poultry. Currently, clade 1 viruses are being reported only from Viet Nam and Cambodia.

      (...)

      It is anticipated that people in Cambodia (as well as in the endemic counties) will continue to be exposed to the virus through contact with infected poultry or contaminated environments, and therefore sporadic human cases will occur as long as the virus continues to circulate in poultry.

      Egypt and Indonesia have officially declared the H5N1 virus endemic in poultry(1), and information from FAO suggests the H5N1 virus is also circulating endemically in poultry in China, India, Viet Nam, and Bangladesh(2).

      A decline in the overall number of poultry outbreaks reported through the FAO EMPRESi was seen in July.

      The number of infected villages in Indonesia, as detected by surveillance, has also decreased slightly in recent months.

      New outbreaks of HPAI H5N1 in poultry have been reported from Vietnam during July to the OIE. No other countries reported HPAI H5N1 in poultry or wild birds since the last summary.

      The downward trend in H5N1 events was predicted based on the seasonal pattern of outbreaks seen in previous years and the onset of warmer weather in the northern hemisphere. However, human cases are possible whenever the virus is circulating in birds, especially in household poultry.

      More information on animal influenza is available from OIE (LINK), FAO (LINK), and OFFLU (LINK).



      Relevant Links:
      • WHO Table: Cumulative Number of Confirmed Human Cases of Avian Influenza A/(H5N1) Reported to WHO (LINK)
      • WHO Table: H5N1 avian influenza: timeline of major events (LINK)
      • WHO Archive: Avian Influenza situation updates (LINK)
      • World Organisation of Animal Health (OIE) webpage: Web portal on Avian Influenza (LINK)
      • Food and Agriculture Organization of the UN (FAO) webpage: Avian Influenza (LINK)
      • Government of Egypt website: "Strengthening Avian Influenza Detection and Response" (SAIDR) website: (LINK)
      (1) OIE WAHID interface. HPAI Summary of Immediate notifications and Follow-ups - 2010. Available online: (LINK)

      (2) Approaches to Controlling, Preventing and Eliminating H5N1 Highly Pathogenic Avian Influenza in Endemic Countries. Rome, United Nations Food and Agriculture Organization, 2011

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      Comment


      • #4
        Re: Bird Flu rears its head again (FAO, August 29 2011, edited)

        [Source: US Centers for Disease Control and Prevention, full page: (LINK). Edited.]
        "Have You Heard?"



        Recent media coverage stemming from a Food and Agriculture Organization (FAO) press release has contained misleading information about highly pathogenic avian influenza A (H5N1) viruses (?H5N1?) in Asia.

        Some of that media coverage has implied that there is a new, mutant variant H5N1 virus that is spreading in Asia, and that the risk to human health posed by this H5N1 virus has somehow been recently and dramatically raised. This is not true.

        Highly pathogenic (deadly) avian influenza A (H5N1) virus infections in poultry and wild birds, resulting in high mortality, have been detected in Asia, the Middle East, Europe, and Africa since December of 2003.

        Currently, H5N1 viruses are widespread in poultry and wild birds in many countries in Asia, but rarely infect humans.
        When humans become ill with H5N1 virus infection, severe illness and death may occur.

        Sporadic human cases mainly occur after contact with infected poultry that were sick or dead, and have been reported in 15 countries.

        Like all influenza viruses, H5N1 viruses continue to evolve.
        The Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), World Organization for Animal Health (OIE), and Food and Agriculture Organization of the United Nations (FAO) conduct routine surveillance to monitor influenza viruses, including H5N1 viruses, for changes that may have implications for animal and public health.

        CDC and WHO surveillance efforts are geared toward human health. FAO and OIE are concerned with issues affecting food and agriculture.

        Over time, H5N1 viruses have evolved into different groups, called ?clades.? Since 2007, 12 different clades of H5N1 viruses have been identified. The FAO report and subsequent media stories focused on an H5N1 virus that has been given a nomenclature (name) of ?clade 2.3.2.1?.

        However, this virus is not new. It was first detected in poultry during 2009 in Vietnam and evolved from viruses that had previously been circulating in Vietnam since 2005.

        CDC has been watching the evolution of all H5N1 viruses closely. Changes in viruses that WHO and CDC look for specifically are those that could increase the threat to human health.

        There is nothing to indicate that clade 2.3.2.1 viruses pose any greater threat to human health than any of the other H5N1 viruses.

        The clade 2.3.2.1 viruses are very active viruses and are spreading more widely in poultry and wild birds. While this increases the possibility of human exposures to infected birds or poultry, it does not increase their ability to infect and transmit between people.

        However, as part of the U.S. government?s pandemic preparedness activities, a 2.3.2.1 vaccine virus candidate to protect humans against this virus already has been created so that vaccine production could begin rapidly if this virus were to change to infect humans and spread easily from person to person. The vaccine virus candidate is an exact match to currently circulating 2.3.2.1 viruses.

        CDC does not believe the risk from H5N1 to humans has increased; however, the evolution of H5N1 viruses has implications for the poultry industry in parts of the world where H5N1 viruses are widespread among poultry.

        In many of these countries, poultry is routinely vaccinated to protect against infection with H5N1 viruses, which is frequently deadly to them. Vaccination of poultry against avian influenza viruses is a tool used to protect a food asset.

        The FAO report was drawing attention to the fact that the H5N1 poultry vaccines currently being used in Vietnam do not protect poultry against the new H5N1 clades. This is because the viruses have evolved since the H5N1 poultry vaccine viruses were chosen in 1996.

        While this development highlights the importance of updating the antigen composition of all influenza vaccines, it does not have any bearing on the issue of protecting humans from this virus.

        In summary, H5N1 influenza viruses have been circulating among birds for many years, some are highly pathogenic, and infections in humans are uncommon.

        There have been no recent changes that pose any additional risk to humans.

        More information on avian influenza can be found on the WHO website at http://www.who.int/csr/disease/avian_influenza/en/index.html



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