The United Nations Food and Agriculture Organisation (FAO) has warned of a potential new threat from avian influenza.
The FAO – the United Nations organisation responsible for food security – says that wild bird migrations have introduced AI to previously virus free countries. It has also warned that a mutant strain of H5N1 is spreading in Asia and beyond. From its headquarters in Rome, the FAO has issued an international alert for countries to heighten readiness and surveillance against a possible resurgence of the virus.
"Preparedness and surveillance remain essential," said Juan Lubroth, chief veterinary officer of the Food and Agriculture Organisation. "This is no time for complacency. No one can let their guard down with H5N1."
Since it first appeared in 2003 the H5N1 virus has infected 565 people, killing 331 of them, according to World Health Organisation figures. It also 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.
Although the virus remained endemic in six nations - Bangladesh, China, Egypt, India, Indonesia and Vietnam - 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, and the FAO says that the resurgence in cases seems to be associated with the migratory movements of wild birds.
Juan Lubroth said that migrations helped the virus to travel over long distances, so that H5N1 had in the past 24 months shown up in poultry or wild birds in countries that had been virus-free for several years. However, he said that people also had to accept some responsibility for the spread of the virus.
"Wild birds may introduce the virus, but peoples’ actions in poultry production and marketing spread it," he said.
Recently affected areas include Israel and the Palestinian Territories, Bulgaria, Romania, Nepal and Mongolia. The World Health Organisation reported that a six-year-old Cambodian girl had died from bird flu - the eighth person to die from H5N1 avian influenza this year in Cambodia. The death occurred in Taing Thleung Village, Mepring Commune, Cheung Prey District, Kampong Cham Province. The child was initially treated by local practitioners with no effect and was later admitted to Kantha Bopha Children Hospital in Phnom Penh five days later. She died two days after admission to hospital. The World Health Organisation said that national and local rapid response teams (RRT) were conducting outbreak investigation and response following the national protocol. Health education messages were ongoing in the community.
Juan Lubroth said that the FAO was also concerned by the appearance in China and Vietnam of a variant virus that was 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, which is known as H5N1 - 2.3.2.1.
Viet Nam’s veterinary services are on high alert and reportedly considering a novel, targeted vaccination campaign this autumn. Juan Lubroth says that virus circulation in Viet Nam poses a direct threat to Cambodia, Thailand and Malaysia, as well as endangering the Korean peninsula and Japan.
He said that wild bird migration could 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 flare up of H5N1 this fall and winter, with people unexpectedly finding the virus in their backyard."
He said that Bangladesh, China, Egypt, India, Indonesia and Vietnam –
the countries where H5N1 is still firmly entrenched – were likely to face the biggest problems, but no country could consider itself safe.
AI is not an airborne disease. It is spread either directly or through contaminated objects, clothes or vehicles. The highly pathogenic H5N1 strain of the virus first came to light in South East Asia, although a series of H5N1 outbreaks in domestic and wild birds have occurred across Europe, including Great Britain. However, they were eradicated quickly as a result of early detection and effective control.
In November 2008 the United Kingdom became officially free from avian influenza according to the rules laid down by the World Organisation for Animal Health.
