Experts in human and animal health are downplaying the alarm raised by the United Nations Food and Agriculture Organization (FAO) over the emergence of another strain of H5N1 highly pathogenic avian influenza (HPAI), saying variations are expected and that a vaccine is being developed to deal with the latest one. FAO warned this week that the new strain could touch off another round of disease in birds that could lead to the much-feared human pandemic.
In Australia, the country’s chief medical officer, Dr. Chris Baggoley, said the FAO statement rang the alarm bell more loudly than warranted by the facts.
“We’ve been keeping an eye on this for quite some time, and we know that from time to time strains change and events arise that need to be responded to,” Baggoley said. “Clearly they were looking for vigilance on behalf of the whole world in relation to bird flu, but they were using language that I certainly wouldn’t have used.”
The World Health Organization (WHO) agreed that the risk level hasn’t moved up.
“They (viruses) keep changing, and when you say mutation, this is a phenomenon we usually see in influenza virus,” said Dr. Takeshi Kasai of WHO. “The risk of H5 influenza virus among poultry to become a pandemic influenza strain remains the same.”
In a news release entitled “Bird flu rears its head again,” FAO pointed to a “clade,” or variant, of H5N1 HPAI known as Fujian 2.3.2. The agency said the sub-clade 2.3.2.1 has “invaded” Vietnam after developing in China. Previous reports indicated that 2.3.2.1 had been isolated from a chicken in Vietnam. FAO said the sub-clade is “apparently able to sidestep the defenses provided by existing vaccines.”
The FAO release said the countries in which H5N1 HPAI is still entrenched, including Bangladesh, China, Egypt, India, Indonesia, and Vietnam, are likely to have the biggest problem but that no country can consider itself safe.
“Preparedness and surveillance remain essential,” said FAO chief veterinary officer Juan Lubroth. “This is not time for complacency. No one can let their guard down with H5N1.”
After the FAO statement made headlines around the world, the World Organization for Animal Health (OIE from its initials in French) said it knew about 2.3.2.1 and is working on a vaccine.
“The OIE Reference Laboratory in Harbin, China, has developed a new vaccine seed strain that experimentally protects poultry from the identified H5N1 virus clade 2.3.2.1,” OIE said in its own news release. “This vaccine, once available for field use, will be used in countries where H5N1 virus clade 2.3.2.1 has been identified. Registration and manufacturing of a poultry vaccine with the new seed strain is in progress.”
Like WHO, OIE pointed out that “small genetic changes are known to routinely occur in influenza A viruses,” and 2.3.2.1 is one of these.
“This is not immediate cause for alert, but, as with the emergency of any new strain, reinforces the need for sustained monitoring of viruses in animal populations,” OIE said.
