SCAR HPAI Update Bulletin


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.

New Recommendations from AWHN and the SCAR/COMNAP Joint Expert Group on Human Biology & Medicine  (JEGHBM)

Based on the evolving situation over the past few weeks since HPAI was confirmed in the Sub-Antarctic region, the AWHN guidance/recommendations2 and the JEGHBM guidance/recommendations3. have been revised with updated information below.

Biosecurity

Pre-landing/Activity Survey

  • Tourism Activities
    • In addition to pre-landing surveys via Zodiacs, a land-based survey of the landing site should be undertaken by a scientist or appropriately qualified person or person with appropriate qualifications and experience working with Antarctic/sub-Antarctic wildlife (e.g. expedition leader) with expert advice to ensure that the area is clear of signs indicating HPAI or mass mortality prior to visitors disembarking the ship. Visitation should be cancelled if there is evidence of unusual animal mortality or behaviours consistent with current viral infection.
  • Scientific Activities
    • Prior to beginning scientific activities, conduct a visual survey of the area/colony to look for signs indicating HPAI (Dewar et al 2023) or mass mortality before starting activities.
    • In the event of confirmed HPAI, it is strongly recommended that essential contact occurs only after expert wildlife health advice has been sought and approval given.

Site Departure/Post-visit

  • Boot Cleaning
    • All Sites visited by vessel.
      • Clean boots at water’s edge to remove soiled material before getting back on Zodiac or vessel.
    • Sites with Infection
      • If possible, remove contaminated boots, and put clean boots/shoes on before leaving the site/boarding zodiac. Bag contaminated boots or place in a container and clean back on the boat/base with soap and water and then disinfect with biocide.
    • Animal Excrement from Boat/Bases
      • Scavenging seabirds such as Snowy Sheathbills have been observed scavenging on carcasses and then defecating on vessels and around land-based infrastructure (including stations). Given HPAI can remain viable on surfaces in cold temperatures for long periods of time, it is recommended that in areas of high use, bird faeces should be removed (whilst wearing appropriate PPE) from regularly touched vessel surfaces such as handrails, tables, etc and on infrastructure on stations such as door handles, (if HPAI is suspected in the region). This should be coupled with regular reminders about the importance of good hand hygiene.
    • Clinical testing of HPAI in Marine Mammals (specifically pinnipeds).
      • Chile, Argentina, and South Georgia have all reported false negatives and inconclusive results in pinnipeds from traditional nasal and anal swabs. This is believed to be due to the neurotropism of the virus in pinnipeds. Invasive sampling (brain tissue) may be required to confirm or exclude HPAI infection in pinnipeds. The WOAH is currently preparing guidelines for collection of samples from marine mammals for diagnostic testing.

Additional Information on Scientific Priorities

Testing and Full Genome Sequencing of Outbreaks

  • Testing suspected cases is very important for confirming the arrival of HPAI in any region.
  • Genomic sequencing of outbreaks assists with:
    • Understanding movement of the virus and tracing introductory source; and
    • Identification of any mutations or changes to the genomic structure which could make the virus more virulent or more transmissible to mammals including humans.

Environmental Testing

  • There is limited information available on how long the virus will remain viable in the environment after an outbreak. Current research highlights that at 4 degrees Celsius the virus can last for up to 200 days in soils, animal faeces and water sources, however, little is known about how long it can survive in the sub-Antarctic and various Antarctic environments and how environmental conditions (e.g., 24 hr sunlight and UV radiation) will affect the survival of the virus and its potential to cause infections in subsequent seasons. This information is critical in understanding the likelihood of HPAI surviving in the environment over the Antarctic winter and the likelihood that wildlife could be reinfected from environmental sources in addition to migratory animals. This information can also provide information on if and when sites can be reopened to tourism and scientific activities.
  1. Banyard et al 2023. Continued expansion of high pathogenicity avian influenza H5 in wildlife in South America and incursion into the Antarctic region. OFFLU
  2. Dewar et al 2023. Biological Risk Assessment of Highly Pathogenic Avian Influenza in the Southern Ocean. https://scar.org/~documents/route%3A/download/5976
  3. JEGHBM (2023). Avian Influenza: A summary of “The Risk of Avian Influenza in the Southern Ocean: A practical guide for operators interacting with wildlife”

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