Avian Influenza Continues to Impact Wild Migratory Birds: The Case of Prespa National Park

On March 11 2022, an outbreak of avian influenza was reported at the Prespa National Park, in Greece, resulting in mass mortality events that have severely impacted the Dalmatian pelican (Pelecanus crispus) nesting population found in the Lesser Prespa Lake.

The Dalmatian pelican is classified as Near Threatened according to the IUCN and is protected under the Convention on Migratory Species (CMS) – listed on both appendix I and II – and the African-Eurasian Migratory Waterbird Agreement (AEWA). These migratory waterbirds are known to nest in colonies running along south-east Europe to central-eastern Asia.

The Greek National Reference Laboratory for Avian Influenza has confirmed the presence of H5N1 HPAI virus in the samples taken from the Lesser Prespa Lake population. The transmission of the highly pathogenic avian influenza can be influenced by a variety of environmental and biological factors. Colonial breeding in Dalmatian pelicans can facilitate the disease transmission due to the proximity and density of its breeding populations. 

The Society for the Protection of Prespa (SPP) has reported that the authorities have collected most carcasses to date, amounting to 1143 individuals. Dalmatian pelican mass mortality has also been observed in adjacent wetland regions. The sad news coming from Greece confirm several reports of similar outbreaks happening over the past few months in different countries such as the UK, the Netherlands, Israel, Canada or Senegal.

However, following recommendations given by the co-convened CMS-FAO Scientific Task Force on Avian Influenza (see below) the Prespa authorities have been fast in taking action and successfully removing most dead wild birds. This is an encouraging development as a fresh batch of migratory waterbirds such as Great White Pelicans are expected to be arriving to the Park in the coming weeks, highlighting the importance of effective measures in containing the outbreak.

Avian influenza continues to remain a threat to wildlife species, and as the Prespa National Park case shows, conservation gains could be wiped out by a disease outbreak within a short period of time. The Park authorities have for instance counted only 32 active Dalmatian pelican nests following the mass mortality event, while there were reportedly 1370 nests in the same period, last year. The need for proper guidance in dealing with outbreaks is therefore of high importance.

As a response to the recent outbreaks, the Scientific Task Force on Avian Influenza and Wild Birds has released a statement and a set of recommendations aimed at countries at risk :

  • The Task Force continues to emphasize the One Health approach, which entails taking into account the interconnectedness of humans, animals, and the environment in an effort to balance the health of all three. 
  • Authorities have been reminded to recognize and maintain appropriate surveillance and biosecurity measures in preventing the spread of avian influenza especially in areas that are high risk. 
  • Responsible bodies are reminded to pay heed to the United Nations Food and Agricultural Organization (FAO) and the World Organisation for Animal Health (OIE) advice, international obligations under the Convention on Migratory Species (CMS), the Ramsar Convention and the African-Eurasian Migratory Waterbird Agreement (AEWA), in order to ensure attempts to control the spread of the virus via culling of wild birds or habitat destruction do not take place. 
  • When responding to HPAI occurrence in poultry, OIE international standards and guidelines must be adhered to. Measures to prevent the spread of the virus from infected poultry to wild birds are advised, as well as a reorganization of poultry production systems highly susceptible to avian influenza exposure. 
  • Pre-emptive culling of captive birds has been deemed unjustified. 

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