ANALYSIS – At a recent WHO meeting, experts agreed to extend a moratorium on research into modified H5N1 flu strains, whilst expressing their support of work on naturally occurring strains. Senior editor, Jackie Linden, reports that the decision follows recent controversy in the scientific world over the potential risks of publishing information that could be misused by bioterrorists. Since the start of February, thousands of poultry have died or been culled as the result of H5N1 flu in Viet Nam, and outbreaks have also occurred this year in India, Bangladesh, Nepal and Bhutan and in ostriches in South Africa.
Controversy over scientific publication
A small group of global public health and influenza experts at a WHO-convened meeting in Geneva, Switzerland, last week reached consensus on two urgent issues related to the newly created H5N1 influenza viruses: extending the temporary moratorium on research with new laboratory-modified H5N1 viruses and recognition that research on naturally-occurring H5N1 influenza virus must continue in order to protect public health.
Dr Keiji Fukuda, Assistant Director-General of Health Security and Environment for the World Health Organization (WHO) said: “Given the high death rate associated with this virus – 60 per cent of all humans who have been infected have died – all participants at the meeting emphasised the high level of concern with this flu virus in the scientific community and the need to understand it better with additional research. The results of this new research have made it clear that H5N1 viruses have the potential to transmit more easily between people, underscoring the critical importance for continued surveillance and research with this virus.”
WHO convened the meeting as a first step to facilitate the discussion of differing opinions that have arisen in recent months after two research groups – one in the Netherlands and the other based in the United States – have created versions of the H5N1 influenza virus, which are more transmissible in mammals than the H5N1 virus that occurs naturally.
The group also came to a consensus that delayed publication of the entire manuscripts would have more public health benefit than urgently partially publishing.
Two critical issues at the WHO meeting were to increase public awareness and understanding of this research through communications and the review of biosafety and biosecurity aspects raised by the new laboratory-modified H5N1 influenza virus. WHO will continue discussion with relevant experts to move this forward.
WHO convened the meeting after leading influenza researchers from around the world, faced with a relentless controversy over experiments dealing with potentially dangerous H5N1 viruses, announced a 60-day pause in such research in late January to allow time to discuss its risks, benefits and oversight.
La Nina linked to bird flu pandemics
La Nina events may make flu pandemics more likely, research suggests. US-based scientists found that the last four pandemics all occurred after La Nina events, which bring cool waters to the surface of the eastern Pacific.
Following the publication of research in Proceedings of the National Academy of Sciences, it is reported that flu-carrying birds may change migratory patterns during La Nina conditions.
However, many other La Nina events have not seen novel flu strains spread around the world, they caution. So while the climatic phenomenon may make a pandemic more likely, they say, it is not sufficient on its own – and may not be necessary either.
Recent H5N1 outbreaks impacting the poultry industry
Since early February, a series of outbreaks of H5N1 flu has hit many poultry flocks in Viet Nam; the total for the month to date is 21 outbreaks, involving the culling of thousands of birds, mostly in village flocks.
H5N1 outbreaks in poultry have been reported since January in the Indian states of Orissa, Meghalaya, Jharkhand and Tripura. Having built up a considerable export market for eggs over years, India has found its trading partners reduced by the outbreaks.
At the end of January, three outbreaks of H5N1 bird flu were reported in Dhaka and Khulna in Bangladesh. The authorities there say they had destroyed nearly 140,000 birds and eggs up to the end of January.
In Bhutan, veterinary authorities reported outbreaks of highly pathogenic bird flu in the districts of Thimphu and Chhukha.
Thousands of chickens were culled following the discovery of the H5N1 strain of bird flu in eastern and southeastern Nepal.
Several wild birds have been found dead in Hong Kong and subsequently found to have been infected with the H5N1 flu virus.
In the Western Cape province of South Africa, more than 12,000 commercial ostriches were culled in mid-December after about 1,000 of them were found to be seropositive for H7N1 during routine surveillance for HPAI. More than 2,000 ostriches in the same province were found to be positive for highly pathogenic H5 in mid-January.
The low pathogenic H5N2 subtype of bird flu was reported in wild birds and poultry in Taiwan in early January 2012.
Another low-pathogenic sub-type of the virus – H5N3 – caused 24,500 ducks in the Australian state of Victoria to be culled in late January.
Indonesia is expected to be able to begin mass production of bird flu vaccine next year, according to the country’s Health Minister.
Nine human H5N1 cases so far this year
So far this year, the World Health Organization (WHO) reports there have been nine cases of H5N1 influenza, of whom, six have died. There have been three cases but no deaths in Egypt, while Indonesia and Viet Nam have each reported two deaths and there has been one death in Cambodia and one in China.
In Indonesia in the last week, five people from Sulawesi were reported to have been admitted to hospital and a fourth victim of H5N1 has died this week, according to local news reports.
According to WHO, there were 62 cases of H5N1 flu in humans in 2011, 34 of whom died. Most of the victims were in Egypt (39 cases; 15 deaths) but there were also 12 cases in Indonesia, eight in Cambodia and two in Bangladesh. These figures are slightly higher than for 2010, when 48 cases were reported worldwide, of whom 24 died but they are well below the peak in 2006.
Since the emergence of H5N1 influenza in 2003, 587 humans are reported to have become infected, 346 of whom have died.