Reinforce surveillance to reduce avian influenza spillover: UN-backed scientific task force

In India, several instances of bird flu were reported in 2021. Representational photo: istock

The circulating avian influenza outbreaks, including in India, do not seem to pose the 'high' risk but surveillance and biosecurity measures are necessary to reduce spillover risk between poultry and wild birds, a UN-backed scientific task force said.

Throughout the past autumn and current winter in the northern hemisphere, multiple avian influenza outbreaks, caused predominantly by the H5N1 HPAI virus, plus other subtypes, including H5N8, have occurred in India, the UK, the Netherlands and Israel with the ever recorded mortality of the Svalbard barnacle geese in Solway Coast.

The Scientific Task Force on Avian Influenza and Wild Birds, co-convened by the Convention on the Conservation of Migratory Species of Wild Animals (CMS) and the UN's Food and Agriculture Organization (FAO), on Monday recommended that surveillance and biosecurity measures are reinforced to reduce spillover risk between poultry and wild birds.

The Task Force has convened and produced recommendations and guidance for authorities and managers of countries affected or at risk.

Wild birds, including globally threatened species, are victims of HPAI viruses causing avian influenza. Affected sites also include areas of international relevance for conservation such as protected wetlands.

It is essential that authorities with responsibility for animal health apply the One Health approach for communicating and addressing avian influenza. That means recognising the health of humans, domestic and wild animals, plants, and the wider environment and acting with a coordinated and unified approach.

The Task Force reminds authorities of their international obligations to ensure their response to the pathogenic virus does not include the culling of wild birds, nor actions that would cause damage to natural ecosystems, especially wetlands.

Ruth Cromie, who coordinated the work of the Task Force and the production of the statement, said: "Avian influenza represents a One Health issue threatening health across the board. The highly pathogenic viruses are still relatively new in wild birds and this winter's high levels of mortality remind us of their vulnerability and that working to promote healthy wildlife benefits us all."

H5N1 is currently the avian influenza lineage most found in Africa and Eurasia in both poultry and wild birds.

The wide range of wild birds affected include wildfowl, waders, gulls, cranes, grebes, herons, pelicans, gamebirds, corvids and raptors (diurnal and nocturnal), in addition to sporadic cases in mammals such as red fox (Vulpes vulpes), Eurasian otter (Lutra lutra) and harbour Phoca vitulina and grey seal Halichoerus grypus.

In terms of human health, the currently circulating H5N1 HPAI viruses do not seem to pose the same zoonotic risk as the 'original' Asian lineage H5N1 (clade 2.2 and their derivatives plus clade 2.3.4.4b H5N6 viruses currently in China).

In general, the risk can be considered low, recognising that some agencies now consider occupational exposure, e.g. those working on poultry culling operations, as low or moderate.

In India, several instances of bird flu were reported in 2021. More than 2,400 migratory water birds, and almost half of them being endangered bar-headed goose, died in the Pong wetlands in Himachal Pradesh last year and that avian influenza (H5N1) was the cause.

Besides the bar-headed goose, the other species that died were the shoveler, the river tern, the pochard and the common teal.

An 11-year-old boy died at All India Institute of Medical Sciences in Delhi last year due to avian influenza, country's first fatality. India reported the first outbreak of avian influenza in 2006.

RSPB Scotland is calling for an emergency local moratorium restricting shooting on the Solway for the rest of the wildfowling season.

It calls for urgent action to reduce the devastating impacts of avian influenza. New statistics from the most recent counts show that the UK is this winter experiencing the worst outbreak of this deadly disease on record, with migratory geese which 'over winter' on the Solway being the hardest hit.

According to RSPB Scotland, the latest population counts of the Svalbard barnacle goose show a drop in numbers from 43,703 in November last year to 27,133 in this month's count. This represents a decline of 38 per cent in the Svalbard breeding population of this species from winter 2020-21.

CMS Executive Secretary Amy Fraenkel said: "Through late 2021 and early 2022 there have been numerous outbreaks of highly pathogenic avian influenza H5N1, with severe impacts on migratory birds.

"The CMS Secretariat responded by convening the Scientific Task Force on Avian Influenza and Wild Birds together with the FAO. We are pleased to share its advice and key recommendations for countries affected or at risk, and look forward to continuing our collaborative work to minimise risks to humans, poultry and wild populations of migratory birds."