13 Feb 2023
A conservation group that alerted officials to the cases says one of the affected mammals is likely to have died from the virus, as concerns grow about its potential to spread to other species.
Allister Webb
Job Title
The number of avian influenza cases discovered in non-bird species in Great Britain has increased to 13 after 4 more were confirmed in seals found off the Scottish coast.
Although the incidents are said to have occurred during 2021-22, details have only now been confirmed by the APHA.
A senior official has also warned of a “step change” in the spread of the virus, amid calls for increased global preparations for a potential outbreak among humans.
The seals infected with the H5N1 strain of the virus were found in Aberdeenshire, Fife and the Highlands, as well as off the Orkney Islands, and were referred to the APHA by the Scottish Marine Animal Stranding Scheme (SMASS).
Three of the cases involved harbour seals, while the other was in a grey seal. Samples from two other carcases were also sent to the APHA for testing.
In a post on its Facebook page, SMASS said the discovery raised questions both about the ecology of the virus and potential conservation implications for harbour seals.
The post continued: “In one case – an adult harbour seal – gross and histopathology revealed a viral meningoencephalitis, meaning influenza was the likely cause of death. We’re hoping to send more cases for screening to better understand what this means in terms of disease ecology and epidemiology.
“We also want to check our more recent cetacean cases for evidence of spillover.”
However, the group also stressed that the risk to the public remains “very low”, and recommendations for its volunteers to wear gloves and a mask when handling or moving carcases is still thought to be sufficient.
Elsewhere, three new cases of the virus have also been confirmed at premises in Cumbria, Powys and Fife since the beginning of this month.
The latest was discovered at a site near Newtown, yesterday (12 February). They take the total number of outbreaks across the UK to 170 since the start of last October. In England, 280 separate outbreaks have now been confirmed since the start of the crisis in the autumn of 2021.
Concerns about the potential risk to other species, including humans, have been heightened by international cases of the virus being transmitted between mammal populations, including the deaths of more than 50,000 mink at a Spanish farm and several hundred sea lions within colonies in Peru.
The World Health Organization has also called for increased monitoring of infections among mammals, warning it could not be assumed that the disease will not spread to humans.
Speaking alongside German and Spanish experts at a media briefing on 10 February, Ian Brown, the APHA’s director of strategic services, said it would be “foolhardy” to make a vaccine for use in humans now; although, preparatory steps could be made.
He said: “In terms of the preparedness, I think the WHO was signalling it’s really important that globally we work together; we do the tracking; we do the monitoring.
“So, I think that’s really the signalling that we’re seeing a change – a bit of a step change in the spread of this infection.”
In its latest assessment, published prior to Prof Brown’s comments, the UK Health Security Agency said its view was in line with the international picture with “evidence of mammalian spillover, but very few detected human infections”.
It added: “At present, there are no indicators of increasing risk to human health; however, this is a low confidence assessment.
“The risk assessment is dynamic and requires regular review during this period of unusually high levels of transmission in birds with mammalian spillover.”
