Update on the Outbreak of Avian Influenza in UK
An outbreak of H5N1 avian influenza, which occurred on 1 February 2007, has been confirmed on a large closed poultry farm in Suffolk, east England, according to the United Kingdom ministry of agriculture (DEFRA, http://www.defra.gov.uk/). The UK State Veterinary Service was contacted by a private veterinarian who suspected an avian notifiable disease. Laboratory testing of poultry found dead on the farm was undertaken at the European Community laboratory in Weybridge, UK. The samples were shown to contain the highly pathogenic Asian strain of the H5N1 avian influenza virus. The same strain was responsible for a recent outbreak in Hungary.
In 2007, the UK is the 2nd EU Member State, along with Hungary, to report a case of highly pathogenic avian influenza H5N1 in poultry.
As required by European Union legislation, control measures were put in place around the affected premises on the evening of 1 February, and a cull of all poultry on the farm began on 3 February. The operation was completed on 5 February. Among the total of 159,000 turkeys on the farm, 2,500 were reported to have died due to avian influenza and the rest were culled.
A three-kilometre protection zone and a 10-kilometre outer surveillance zone have been imposed around the farm to prevent further spread to neighbouring flocks and farms. Within the protection and surveillance zones, poultry movement restrictions are in place, and farmed birds must be isolated from wild birds. A wider zone of 2,000 square kilometres has also been established around the protection and surveillance zones, and poultry in this zone must also be isolated from wild birds and can only be moved under license. All organised bird gatherings, including shows, markets and fairs, and pigeon races, have been banned throughout Britain until further notice.
Risk to Humans
Despite this incident, the current level of risk to humans from H5N1 has been assessed as extremely low. Nonetheless, any possibility of exposure is taken very seriously, and measures to protect the considerable number of people involved in the culling and disposal operations that may have been exposed to the virus have been put in place. Specifically, this involves the wearing of personal protective equipment and antiviral drugs and seasonal influenza vaccine being offered to those who have been in close contact with the infected poultry. Potentially exposed people have been advised to monitor their own health and report any symptoms.
The Health Protection Agency (HPA) in the UK has now carried out testing on three workers who have been involved in the avian flu outbreak. All three had symptoms that could indicate the possibility of avian influenza and which required further investigation according to HPA protocols. All three have tested negative for avian flu and are now being treated under normal clinical care, or have been discharged from hospital where appropriate .
H5N1 avian influenza remains predominantly a disease of birds. All evidence to date indicates that close contact with dead or sick birds is the principal source of human infection with the H5N1 virus. Especially risky behaviours identified include the slaughtering, de-feathering, butchering and preparation for consumption of infected birds. In a few cases, exposure to chicken faeces when children played in an area frequented by free-ranging poultry is thought to have been the source of infection. In all human cases to date there has been no evidence of efficient human-to-human transmission and human infections remain a rare event. As of the 12th February 2007, 272 confirmed human cases and 166 (61%) deaths from avian influenza A (H5N1) have been reported to the WHO from Azerbaijan, Cambodia, China, Djibouti, Egypt, Indonesia, Iraq, Nigeria, Thailand, Turkey and Vietnam.
The advice from the Department of Agriculture and Food in Ireland is not to handle dead wild birds unless necessary. For further information please consult the Department of Agriculture and Food website. For queries relating to dead birds please contact the Department of Agriculture and Food on the Avian Influenza Hotline: 1890 252 283.
At present, recommendations on travel, personal protection and food safety remain unchanged. Current travel advice is available here. The WHO level of pandemic alert remains unchanged at phase 3. This is defined as a virus new to humans that is causing infections, but does not spread easily from one person to another. The latest updates from the WHO are available on the WHO website.
Further information on avian influenza is also available on the HPSC website.