#15,516
Yesterday, in Netherlands: HPAI H5N8 In Two Dead Mute Swans, we looked at the latest in a series of recent reports of HPAI H5 viruses affecting both wild birds and poultry - first in Russia (see Russia's Worsening HPAI H5 Outbreak (in Poultry), then in Northern Kazakhstan, followed by Israel, and now in Northern Europe.
Although avian flu activity has been on the decline in Europe the past 3 years, these reports are reminiscent of the run-up to Europe's record setting 2016-2017 epizootic (see OIE: Russia - HPAI H5 In Wild & Migratory Birds), which saw a highly virulent reassorted HPAI H5N8 virus arrive in Germany in October, and spread rapidly across the continent.
Ten days ago DEFRA Warned On the Avian Flu Threat to the UK, and a week earlier, in FLI: Risk Assessment Of HPAI H5 Affecting Germany This Fall & Winter, we saw an assessment by Germany's Friedrich-Loeffler-Institut that warned of a high risk of HPAI's entry from wild birds during their autumn bird migration.
Today DEFRA is back with a preliminary outbreak assessment on the detection of HPAI H5 in the Netherlands, and raises their risk of seeing an incursion into the UK this fall and winter to moderate.
Preliminary Outbreak Assessment
Highly pathogenic avian influenza (HPAI) in The Netherlands
22 October 2020
Ref: VITT/1200 HPAI in Europe
Disease Report
The Netherlands has reported two cases of HPAI H5N8, in the west of the country, in mute swans (Cygnus olor). According to the disease report, at least one mute swan was found dead on the 20 th October and tested positive for the virus at their national reference laboratory. This follows outbreaks of HPAI H5N8 in Russia, in poultry on the Black Sea coast in late September; plus outbreaks in poultry and cases in wild waterbirds in southern central Russia, and along the border into Kazakhstan, across August and September.
(https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_
data/file/915180/poa-avian-influenza-H5N8-russia-Sep20.pdf).
Situation Assessment
We consider the detection of H5N8 in wild birds in this region is significant, particularly at this time of year; and it is likely to indicate wider infection in the local wild bird population. Although mute swans do not generally migrate over long distances, there will be some short distance local movements. As such, mute swans, are primarily resident, which raises the possibility they have acted as local sentinels; exposed to virus brought to local locations by other species, such as migratory waterfowl. The virus has yet to be reported in any migratory wild birds in Western Europe; however it is possible some of the Anseriforme species, such as the dabbling ducks, may be infected but show such low case fatality rates that they are less likely to be picked up during passive surveillance. Further, there is uncertainty of the actual levels of passive surveillance being conducted in wild birds at present across Europe.
The migration season for wild waterfowl to overwinter in the UK has started, and will reach a peak usually around December to January, but this is weather-dependent. Generally the Netherlands has a far higher number of migratory birds during this period than the UK, but cold weather on the Continent can encourage birds to move across to the British Isles.
We await specific results of sequencing and genotyping but if this is the same virus as currently reported in Russia and also in Kazakhstan this year, we would expect to see typical patterns of high mortality in chickens and turkeys, as well as some mortality in ducks and geese.
On the 30 th September the European Centre for Disease Prevention and Control (ECDC) issued an alert for the EU about the likely detection of avian influenza as a result of spread from Russia and Kazakhstan (and the likelihood of undisclosed disease in the wider region); particularly to Eastern and Northern Europe (ECDC, 2020). Therefore this finding is not entirely surprising. ECDC also confirms the risk of transmission to the general public is very low with this particular strain.
Conclusion
As a consequence of this wild bird case in the northwest of the Netherlands, and the likely migration routes to the UK, the risk of HPAI incursion in wild birds has been raised to MEDIUM. The overall risk of infection of poultry in the UK remains LOW; but the risk of introduction to individual premises depends upon the level of biosecurity implemented on farm, to prevent direct or indirect contact with wild birds. We recommend biosecurity measures should be maintained or strengthened, as required.
Immunity of UK wild birds to H5 HPAI may be low at present. We strongly recommend that all poultry keepers (including backyard keepers) review their biosecurity measures and business continuity plans, as the risk has now increased. Keepers should familiarise themselves with government guidance on good biosecurity and how to report suspicion of disease appropriately.
The OIE/FAO International Reference Laboratory/UK national laboratory at Weybridge has the necessary ongoing diagnostic capability for these strains of virus, whether low or high pathogenicity AI, and continually monitors changes in the virus. We will continue to report on any updates to the situation in Europe and, in particular, any changes in disease distribution or wild bird movements which may increase the risk to the UK.
Further information is available here: https://www.gov.uk/guidance/avian-influenza-bird-flu
including updated biosecurity advice for poultry keepers for England;
https://gov.wales/avian-influenza for Wales and; http://gov.scot/avianinfluenza for
Scotland.
We ask that the public use the Defra helpline (Tel: 03459 33 55 77) to report findings of dead wild birds. In particular, any wild ducks, wild geese, swans, gulls or birds of prey and where more than five birds of any other species are found dead in the same location.
Authors
Charlotte Coxon
Anthony Pacey
Dr Helen Roberts
Professor Ian Brown
Joe Bowen
Dr Clare Wild
