January 10, 2008

scientists react to news of bird flu in Dorset

The H5N1 strain of bird flu was found in three dead swans at a swannery near Weymouth.

Dr Paul Yeo, Lecturer in Microbiology and Infectious Diseases at Durham University, said:

“The source of the bird flu in this case could be migratory birds over-wintering in the UK. The virus is now being increasingly detected in birds all over Europe so unfortunately it was not unexpected that it would, once again, appear in the UK.

“The risk of someone being infected directly from birds is low, but we must be vigilant as humans have been infected, and some have died, in other countries. Those most at risk are those who work, or are in regular contact, with poultry but even then bird-to-human transmission is still very rare.

“The main risk is to commercial stocks of birds and a repeat of last November’s outbreak. It reinforces the need for monitoring wild bird deaths for the presence of the virus. Hopefully the actions of DEFRA in imposing a control area will limit any spread of the virus. We now have to consider that the virus may be endemic in the wild bird population in the UK.”

Dr Colin Butter, Avian Viral Immunology Group, Institute for Animal Health, said:

“The finding of H5N1 in Swans in Dorset is consistent with the results of investigations following the November outbreak in turkeys. These suggested that farmed birds were infected from migratory wildfowl. Whilst the Dorset swans are essentially non-migratory they will have been in close contact with migratory species.

“The finding that H5N1 has spread within wildfowl populations has implications for the control of disease in domesticated poultry. Whilst stamping out of disease by culling is the most appropriate method of control when the infection rate is low, this situation may change if the risk of poultry being infected by contact with wild birds is substantially increased. If further infections are confirmed it may be appropriate to reconsider whether at-risk populations of domestic poultry, such as free-range laying hens, should be the subject of routine vaccination, as in the Netherlands.”

Professor Ian Jones, a virologist at Reading University, said:

“Further H5 outbreaks are to be expected but the small numbers of birds found so far holds out the hope that they arrived here infected and have not passed it on to any great extent. The important thing is to keep it out of farmed flocks so Biosecurity in the vicinity is clearly a top priority in the next few days and weeks.”

Dr John McCauley, Division Of Virology, MRC National Institute For Medical Research, said:

“The outbreak of H5N1 virus in turkeys in farms on the Norfolk, Suffolk borders in November was thought to have been spread to turkeys from wild fowl that may have migrated from Europe. Sampling of domestic poultry and domestic fowl in the regions around the farm did not pick up any evidence of H5N1 infection. Before Christmas Bird-Flu restrictions in the area were lifted.

“The new detection of H5N1 infected swans in Dorset is not particularly surprising in light of the outbreak in November. The H5N1 virus seems to have made its way not only to East Anglia but now also on the South Coast.

“There is ongoing extensive surveillance of wild birds throughout Europe. A report published last summer concluded that H5N1 virus was present in wild bird populations but detection of the H5N1 virus was not common. It also concluded that the most sensitive way to pick up H5N1 viruses was in surveillance of dead birds, especially swans.

“The report for 2006 is available http://ec.europa.eu/food/animal/diseases/controlmeasures/avian/annrepres_surv_wb_02-12-2006_en.pdf

“Sampling dead or diseased at risk species (ducks, swans and geese in particular) was the most effective way to determine if H5N1 virus was present in wild birds. In the study of 2006 the proportion of swans infected with H5N1 was much higher than other species. This may mean that they are particularly susceptible to H5N1 infection or alternatively it may mean that they are more likely to be sampled than smaller species.

“The swans infected in Dorset are not of a species that undegoes significant migration but it is likely that the mute swans mix with waterfowl from regions in which H5N1 infection is more common.

“The consequences for the poultry industry is that a heightened awareness will need to be maintained and disease security measures in farms enhanced. To reduce the risk of virus spreading from the area should poultry become infected, DEFRA have restricted poultry movement in the area.””

Paul Hunter, Professor of Health Protection, University of East Anglia and European Editor – Journal of Water and Health, said:

“Although the risk of infection spreading from these birds to humans is very low, it can occur through close physical contact. People should not touch dead swans that they find but report them to the appropriate authority. If people have to touch any wild bird they should wear rubber gloves and then wash their hands thoroughly afterwards.”

Nigel Horrox, Poultry Veterinarian, Senior Vice President of British Veterinary Poultry Association, said:

“Considering the situation in Europe this is not a totally unexpected occurrence. I look forward to Defra’s expertise and experience clarifying the situation in the near future.

“As far as poultry producers are concerned the situation is as it has been for sometime. It is important to regularly check outdoor flocks and especially those in areas with large wild waterfowl populations for signs of illness. If any are found you should consult your veterinarian.”

Nick Blayney, President, The British Veterinary Association (BVA), said:

“While we must never be complacent about the risk of human disease, avian Influenza is a disease of birds and given the number of outbreaks throughout the world in recent years it is important that we remain vigilant. In this case vigilance would seem to have enabled the arrival of the disease to have been promptly identified. Domestic flock owners, not only in the vicinity but countrywide, are reminded of the need to protect their birds by following biosecurity guidelines, for instance those produced by the Poultry Club of Great Britain, and to continually monitor their birds’ health. Members of the public too can help the surveillance effort by remaining vigilant and reporting any dramatic local incident such as a large number of dead, dying or sick birds to the Defra Helpline on 08459 335577.”

Dr Jim Robertson, Principal Scientist In Virology, National Institute for Biological Standards and Control, said:

“At this time of year, there has been an upsurge of cases in poultry worldwide, although not many in the EU. The limited experience that we have in the UK and in the EU is that with appropriate actions and precautions, the infection can be contained effectively and so the public should not be overly concerned with this situation. It is, as ever, unfortunate for those in the poultry industry and all bird keepers because of the restrictions that get imposed, the concern for their stock and the economic burden that results. Information on the source of the infection should derive from a detailed examination of the virus at the genetic level.”

NFU RESPONSE: “The NFU is monitoring the situation very closely. At this stage it appears to be confined to three wild birds. We are in contact with Defra and have already had discussions with key Defra officials both at a national and regional level. Investigations are ongoing into the source of the infection and no one yet knows its cause. “It is important to remember Avian Influenza is a disease of birds. There is no reason for public concern. While it has been known under extreme circumstances to pass to humans this has only happened where people have had extremely close contact with infected birds and in particular their faeces. “We fully support the measures put in place by Defra at this stage and will be working to ensure that poultry producers understand the implications of the restrictions.”