Avian influenza (AI) is currently the best known but least understood viral infectious disease on the planet, as a result of a barrage of media-led misinformation and pseudo-science, not to mention vested interest in the funds that flow in such a crisis for good or bad reasons. If nothing else this short news item will attempt to lay down some facts and suggest where the science should be going to mitigate the risks to humans and other animals of this complex virus that can cause disease particularly in relation to wild and game birds.

Avian influenza is a term given for infection with a virus, which like all families has many and varied strains, or phylogenetic types in scientific jargon, and equally diverse clinical syndromes. H5N1 is like Arsenal in the football world (a hard hitter) and is characterised by specific identifiers or antigens (the code refers to these) on the surface of the virus, which laboratories and their sophisticated testing procedures can detect. The majority of the AI viruses circulating in birds on the planet cause little or no harm, unlike H5N1, which is the cause of highly pathogenic avian influenza (HPAI) or Fowl Plague. This is a pathogen which is legally monitored as being notifiable in all countries which are members of the Office Internationale des Epizooties (OIE) – equivalent to World Health Organisation (WHO) – requiring official veterinary service notification of each case. The reason is that it can cause and has been causing severe disease and high mortality (>90%) in poultry, mainly in the Far East for several years, with a few epidemics occurring elsewhere in Central Asia, Europe, the Near and Middle East and West/North Africa more recently. It was essentially a poultry issue with occasional spill over locally into wild bird populations until 2005.

What has been different in the last year or so is that a true wild bird epizootic has been occurring, spreading (independently of poultry disease) from the South East Asia focus into Asia and Europe with a lot of dramatic news events. Few if any of the poultry epidemics occurring over this period in these areas are directly linked to migrant or wild birds in general, although probably a few cases are a result of a spill over from wild birds (mallard ducks most likely) to poultry in extensive systems. However, this event is not necessarily the harbinger of the deadly disease we all fear, human influenza derived from avian flu viruses combining with human and/or pig viruses. This is a different issue altogether and could happen anywhere, anytime. This is not to say the H5N1 cannot affect man it can, but very rarely as it does cats dogs and so forth. Some 100 or so people have died so far during this pandemic - roughly as many as die on the road from motorcar accidents around the world every minute.

News has been fairly quiet this last month – isn’t spring wonderful! This does not mean that the virus is not active as the recent outbreak in Norfolk, England, showed. Funnily enough this was not H5 but H7, so we should remain vigilant but no more or no less than we will have to be next year and probably the year after. Wildlife epidemics can last 3 or so years and how far this one will go is not certain, but it will result in a few dramatic pictures and some panic but most probably very little real harm. Meanwhile the poultry industry will suffer from more significant disease events in the epicentre of Asia and from spread through legal and illegal movements of poultry and perhaps even the wild bird trade. This is a much more important issue and should be on the agenda of the game farming fraternity and others rather than migratory birds which are something of a scapegoat albeit an interesting one and worthy of research. This should be done independently of research into poultry movements and controls, illegal trade in birds and all the rest. Hunters and others concerned with the sustainable use of wild birds meanwhile should lobby for a sensible and scientifically based approach on whether bans should or should not be in place and what measures should be taken to reduce risk of spread and exposure to game birds and humans of the highly pathogenic strains of AI. (N.B. The European Union has again extended its suspension of wild bird imports, this time until the end of July. Ed.) After the novelty of this re-emerging virus has died down some serious work can be done and hopefully action taken to reduce the risk that inappropriate poultry husbandry systems, which act as HPAI factories, present to the global human and animal community both in terms of health, biodiversity conservation and livelihoods.

These reflections have been penned following a Scientific Seminar on Avian Influenza, the Environment and Migratory Birds held by CMS (the Convention on Migratory Species) in Nairobi, 10-11 April 2006 and attended by the author.

April 2006. Richard Kock is Co-Chair of the IUCN Species Survival Commission and Programme Manager Deserts and Rangelands Conservation Programmes Zoological Society of London at the Zoological Society of London: Richard.Kockzsl.org

Sustainable, June 2006, contents page