Abstract Title
Mass Mortality i Terns and Gulls Associated with Highly Pathogenic Avian Influenza Viruses (HPAIV) in Caspian Sea, Kazakhstan
Abstract
In June 2022, a mass mortality event was reported among Caspian terns (Hydroprogne caspia), Pallas’s gulls (Ichthyaetus ichthyaetus), and Caspian gulls (Larus cachinnans) nesting on artificial islands in the Kashagan offshore field and Zuid-West Island in the northern part of the Caspian Sea. Over 2,200 dead adults, fledglings, downy chicks of Caspian terns were counted, along with 550 adults and feathered chicks of Caspian gulls on the artificial isles. Hundreds of weak and sick individuals were also observed among adult and juvenile Caspian terns on these islands. More than 5,000 gulls and terns died due to this outbreak.
An investigation was conducted in the field, during which representative samples were collected and analyzed using pathological, virological, and molecular techniques. The highly pathogenic avian influenza A (H5N1) virus was detected and isolated from samples taken from the deceased birds. Genetic and phylogenetic analyses showed that the hemagglutinin (HA) genes belonged to the clade 2.3.4.4.b of the H5Nx HPAI viruses, B2 sub-lineage, and were closely related to highly pathogenic influenza viruses responsible for previous outbreaks in wild birds with high mortality rates in the western part of the Caspian Sea.
It is recommended that intensive monitoring of wild bird populations, especially Caspian gulls and terns on the Northern Caspian Sea Islands, continue. This ongoing surveillance will help evaluate the long-term effects of HPAIVs on these populations and assess the likelihood of HPAIV becoming endemic in the area.
An investigation was conducted in the field, during which representative samples were collected and analyzed using pathological, virological, and molecular techniques. The highly pathogenic avian influenza A (H5N1) virus was detected and isolated from samples taken from the deceased birds. Genetic and phylogenetic analyses showed that the hemagglutinin (HA) genes belonged to the clade 2.3.4.4.b of the H5Nx HPAI viruses, B2 sub-lineage, and were closely related to highly pathogenic influenza viruses responsible for previous outbreaks in wild birds with high mortality rates in the western part of the Caspian Sea.
It is recommended that intensive monitoring of wild bird populations, especially Caspian gulls and terns on the Northern Caspian Sea Islands, continue. This ongoing surveillance will help evaluate the long-term effects of HPAIVs on these populations and assess the likelihood of HPAIV becoming endemic in the area.
Co-Author(s)
Aidyn Kydyrmanov 1,* , Kobey Karamendin 1 , Yermukhammet Kassymbekov 1 , Klara Daulbayeva 1,
Temirlan Sabyrzhan 1 , Yelizaveta Khan 1, Sardor Nuralibekov 1 , Barshagul Baikara 1 and Sasan Fereidouni
1 Research and Production Center for Microbiology and Virology, Almaty A26T6C0, Kazakhstan
2 Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, 1160 Vienna, Austria
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds