Prepared by the Antarctic Wildlife Health Network (AWHN) and Joint Expert Group for Human Biology and Medicine (JEGHBM)
First published 22nd December 2023, upated on Monday 15th January 2024
Update from the Antarctic Wildlife Health Network
On the 23 October 2023, the British Antarctic Survey (BAS) confirmed the first case of highly pathogenic avian influenza (HPAI) clade 2.3.4.4b H5N1 in Brown Skuas (Stercorarius antarcticus) at Bird Island, South Georgia. In early October, birds were observed displaying signs of HPAI and died a few days later. Samples were collected and sent to the United Kingdom Animal and Plant Health Agency (APHA) for testing. Since this confirmation, there have been further confirmed cases in Kelp Gulls and Brown Skuas on South Georgia.
A high level of mortality has been detected in Southern Elephant seal (Mirounga leonina) and fur seal pups at some sites at South Georgia. Samples collected show positive results for HPAI H5N1 in elephant seals and fur seals as well as brown skuas, kelp gulls and Antarctic terns. Investigations are continuing.
In addition to South Georgia, there have been two (2) confirmed cases of HPAI in Southern Fulmars (Fulmarus glacialoides), one individual found deceased in Stanley and one individual on Pebble Island, in the Falkland Islands (Islas Malvinas), as well as one (1) Black-Browed Albatross (Thalassarche melanophris) at Saunders Island. A mass mortality event of 20−30 Black-browed Albatrosses were observed at Steeple Jason with one individual testing positive1. Samples have been sent to APHA for further testing and full genome sequencing for report to the World Organization for Animal Health (WOAH).
Following rapid sequencing and analysis, viral genome sequences from the Skuas on South Georgia and one Fulmar on the Falkland Islands (Islas Malvinas) were generated and have been deposited in GISAID [Global Initiative on Sharing All Influenza Data] sequence database (EPI_ISL_18439562-64). An analysis of these genomes demonstrate that the viruses found in these regions are most closely related to those found in South America. Critically, the analysis shows that the genomes from South Georgia and the Falkland Islands (Islas Malvinas) are not closely related to each other, indicating two independent introductions of HPAI into this region (Bennison et al. 2023. bioRxiv).
We would like to recognise the rapidity with which these results were generated, and importantly that genome sequences have been freely shared with the scientific community prior to publication of the results in peer-reviewed journals. Public sharing of sequencing data is important for furthering our knowledge of the outbreak and its potential movement into the Antarctic region.
It is important to note, there is limited information available on clinical signs of HPAI for many sub-Antarctic and Antarctic species, especially during early stages of infection. For some species the first sign of HPAI is a mass mortality event. It is also worth noting that many signs of HPAI can also be associated with other infectious diseases, toxins, or head and neck trauma, and therefore we cannot assume HPAI infection based on behavioural signs alone, therefore confirmation of the virus in the region is critical. It is advisable to report any unusual behaviour and mortality and closely monitor the site.
As of the 11th of December, the South Shetland Islands, South Orkneys, and the Antarctic Peninsula remain free of signs of HPAI. However, the risk to these regions has significantly increased, with all three areas considered by the AWHN to be at “very high risk” given their proximity to the latest outbreaks in South Georgia and movement and mixing of species between these regions.
Suspected and confirmed cases of HPAI are being added to the Antarctic Wildlife Health Network Database and information about recent cases are available on our webpage. However please note that only cases suspected as being HPAI (i.e., unusual mortality events or behaviours) will be reported publicly on the website: https://scar.org/library-data/avian-flu.
Updates from JEGHBM
- Potential human contact with HPAI within the Sub-Antarctic and Antarctic regions is increasing and may include contact with mammalian populations as well as avian populations.
- The possibility of transmission of HPAI within a mammalian population raises concern about the potential of increased risk of spread to, and between, human vectors. The importance of prevention of human infection through limitation of potential contact with Avian Influenza is highlighted.
- Globally, there have been no reports or evidence of sustained human to human transmission.
- The risk of exposure via contact with both dead and live animals infected with HPAI should be considered at all times.
- This risk should inform justification for potential animal contact and processes to mitigate risk as much as reasonable, based on the assessed level of risk.
- Robust infection control measures and correct use of Personal Protective Equipment (PPE) during contact with all animals as per National Antarctic Program (NAP) guidance continues to be strongly recommended.
- Each NAP should have infection control processes and plans in place, recognising that it is often not possible to distinguish between viral infections on clinical grounds, especially in the early phases of infection and at remote locations.
- The basics of good personal hygiene practices including hand washing, face masks and social distancing in any person with symptoms of any viral infection remains key to limitation of most viral spread in communities. It is recognised that remote small groups of people living in close quarters remain at risk of viral spread across the group, despite best able practices.