The discovery of avian flu-infected birds in UK and Dutch poultry farms has authorities scrambling to contain the disease.
This week, separate detections of avian influenza in Yorkshire, UK and Hekendorp in the Netherlands have lead to large culls of all poultry within set protection zones around the farms affected. The strain detected in the Netherlands, H5N8, is very pathogenic to chickens and can potentially be transmitted to humans.
UPDATE: The strain detected in Yorkshire has now been confirmed as H5N8.
Our colleagues at the UK SMC collected the following expert commentary. Feel free to use these quotes in your reporting. If you would like to contact a New Zealand expert, please contact the SMC (04 499 5476; firstname.lastname@example.org).
UPDATED COMMENT: Prof Andrew Easton, Professor of Virology, University of Warwick, said:
“The identification of this strain as H5N8 increases the likelihood that it is linked with the outbreaks in Germany and the Netherlands. This will be the subject of further investigations to try to confirm the link by genetic analysis of the virus. The finding that it is H5N8, which has not been associated with infection of humans or other species, means that the threat to humans remains very low.”
Mr John Blackwell, President of the British Veterinary Association (BVA), said:
“Defra has confirmed a case of avian flu on a duck breeding farm in Yorkshire.
“British Veterinary Association (BVA) and British Veterinary Poultry Association (BVPA) understand immediate and robust action has been taken, including a cull of all poultry on the farm and a 10km restriction zone. The restriction zone bans movements of all poultry, products and waste within the area. Poultry must be housed or isolated in the zone. Bird gatherings (fairs, shows, exhibitions) are banned and game birds cannot be released. A detailed investigation is ongoing.
“BVA and BVPA emphasise Defra’s statement that the risk to public health is very low and there is no risk to the food chain. We would also point out that the strain of flu has been identified as H5 avian flu and NOT the more serious H5N1, which has caused disease in some people.
“The quick identification and containment of this disease illustrates the ongoing importance of a robust veterinary surveillance system working in sync with government departments such as Defra.
“BVA and BVPA will continue to work with Defra as the department keeps the situation under review.”
Dr Linda Klavinskis, Reader in Immunobiology, King’s College London, said:
“The current poultry outbreak in Holland concerns the H5N8 influenza virus, a virus that is very pathogenic to chickens, but not necessarily to other species. There have been outbreaks of H5N8 in South Korea earlier this year and also in China. The virus was reported in Europe (N-E Germany) earlier this month, again in a poultry outbreak. To date the virus has been isolated only from birds. Migratory birds can carry these viruses. Chickens are very vulnerable to this virus.
“To my knowledge there are no reported cases of human infection with H5N8. In South Korea, some dogs that live on farms where the virus broke out seroconverted (developed an immune response to the virus) suggesting that they were infected but likely without obvious symptoms.
“The risk for humans is always a possibility because of the massive shedding of these viruses by infected chicken flocks, however in my opinion the chances are very low. The measures that are being taken by the Dutch authorities (and now in Yorkshire in response to infection in ducks) have been effective in the past to contain outbreaks of highly pathogenic avian influenza. At the moment we need to wait and see what happens.”
Professor Ian Jones, Virologist, University of Reading, said:
“The outbreak of bird flu in Yorkshire is one of the occasional infections that get into poultry houses. It is likely to be the same virus that has caused outbreaks in the Netherlands and Germany and may have arrived with migrating birds. The risk to human health is minimal and a slaughter policy will eradicate the virus from the location concerned. Duck meat and eggs do not constitute any risk if cooked properly.”
Dr James Rudge, Lecturer in Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, said:
“That this bird flu case in Yorkshire has been identified as an H5 virus, and coincides with the H5N8 outbreak in the Netherlands, does point to a link between the events, but we won’t know for certain if or how they are connected until more data on the virus are available. There’s probably very little, if any, risk to human health. The main concern is the impact it could have on the poultry industry if it spreads further.”
Dr Colin Butter, Head of Avian Viral Immunology, The Pirbright Institute, said:
“Defra have confirmed that a strain of avian influenza highly pathogenic to birds has been found on a duck farm in East Yorkshire. The strain of virus is identified as H5, though the N type has not yet been confirmed. The disease control measures agreed at EU level, including protection and restriction zones, are now in place.
“It is of note that an outbreak of highly pathogenic (to birds) H5N8 was confirmed in the Netherlands at the weekend, having first been identified in Germany at the beginning of the month. Further investigations should confirm shortly if the Yorkshire virus is identical and is the result of transmission from wild birds or a common human factor.
“Whilst it may be possible that this strain of virus could infect people as the result of direct contact with infected birds, this is likely to be a rare event and there is no suggestion that the virus could transfer from person to person. The danger to public health is therefore very low and the public should not be concerned that this represents a significant threat.”
Prof Andrew Easton, Professor of Virology, University of Warwick, said:
“We do not yet know what strain of avian flu has been detected, though H5N1 that carries risks to humans seems to have been ruled out. Aquatic birds such as ducks can harbour over 100 (in fact 144) different types of influenza. In these birds the viruses do not usually cause disease but when certain types spread to domestic poultry such as chickens serious disease can be seen.
“Human infections with flu strains that infect birds are not common and have been restricted to only a very small number, so the risk to humans from this incident is likely to be very small or non-existent. However, the risk to the poultry industry is high and the current measures require that infected birds are killed as quickly as possible to stop spread to other flocks.
“There is always concern that some strains of flu may be spread by wild birds and surveillance measures are also likely to be introduced in surrounding areas to check for the possibility of spread.”
Prof Wendy Barclay, Chair in Influenza Virology, Imperial College London, said:
“Avian influenza viruses can be devastating for the poultry industry. Two of the subtypes of avian influenza, H5 and H7, are particularly feared because they can carry unusual sequence motifs that make them highly pathogenic in the birds, killing almost every infected bird in a matter of days. However, it is important to realize that not all H5 viruses have this motif, so we need to wait for detailed sequence information to be released before we know if the virus in Yorkshire is of this type, and whether it is directly related to viruses reported in the Netherlands and also in Germany.
“Sometimes avian influenza viruses can infect people, so it will be important for those dealing with infected bird carcasses to wear appropriate protective equipment. However, only a small subset of avian influenza viruses infect humans, and these viruses can be of low or high pathogenicity in the birds. Even low pathogenicity bird viruses can cause severe disease in humans like the H7N9 recently identified in China. In previous outbreaks of H5 viruses in the UK, no humans have been infected. Without undergoing further mutations these infections do not pass from person to person. We just don’t know what type of virus this one is until we get more sequence information and also more biological information about it, that will come from experimental testing in high containment laboratories.
“Because influenza viruses can mutate readily, it will be important over the coming weeks to maintain vigilant surveillance and monitor any new viruses found for changes.
“Overall this new twist underscores the extant threat that avian influenza viruses pose to our agriculture and to humans.”