Transatlantic spread of highly pathogenic avian influenza H5N1 by wild birds from Europe to North America in 2021

Highly pathogenic avian influenza (HPAI) viruses of the A/Goose/Guangdong/1/1996 lineage (GsGd), which threaten the health of poultry, wildlife and humans, are spreading across Asia, Europe and Africa, but are currently absent from Oceania and the Americas. In December 2021, H5N1 HPAI viruses were detected in poultry and a free-living gull in St. John, Newfoundland and Labrador, Canada. Phylogenetic analysis showed that these viruses were most closely related to HPAI GsGd viruses circulating in northwestern Europe in spring 2021. Analysis of wild bird migration suggested that these viruses may have been carried across the Atlantic via Iceland, Greenland/Arctic or pelagic routes. The here documented incursion of HPAI GsGd viruses into North America raises concern for further virus spread across the Americas by wild bird migration.

Avian influenza surveillance in wild birds using sentinel ducks

We conducted active surveillance for avian influenza virus using sentinel ducks in central region of Mongolia (Khunt lake Saikhan soum, Bulgan province) that major wild bird habitat and outbreak site of H5N1 HPAI in wild birds in Mongolia from 2005 to 2011. Total of 39/104 (37,5%) samples were positive by insulated isothermal PCR (iiPCR) and 42/104 (40,38%) swab samples were positive by real time PCR (qPCR). In addition, AIV antibody detected in 35/104 (33,65%) serum samples tested by AIV NP ELISA kit. These results indicated that sentinel surveillance using domestic birds could be an effective method for avian pathogens including influenza in Mongolia. Enhanced sentinel surveillance in wild bird populations in Mongolia is therefore crucial for the understanding of global AIV transmission and epidemiology. Шувууны томуугийн тандах судалгаанд туршуул шувуу (Sentinel bird) байршуулах арга ашигласан дүнгээс Бид шувууны томуугийн тандах судалгаанд туршуул шувуу байршуулах арга зүйг ашиглах боломжийг судлах зорилгоор урьдчилсан туршилтыг 2019 оны 7-10 сард Булган аймгийн Сайхан сумын Хунт нууранд хийж гүйцэтгэв. Хунт нуур нь олон тооны нүүдлийн усны шувууд зусах болон дайрч өнгөрдөг ач холбогдолтой цэг бөгөөд 2005-2011 онд өндөр хоруу чанартай шувууны томуугийн (HPAI) A/H5N1 дэд хэвшлийн вирус илэрч байсан. Шувуунаас авсан арчдасны зарим дээжийг insulated isothermal PCR (iiPCR)-р шинжлэхэд 39/104 (37,5%), дээж эерэг, бүх дээжийг PCR (qPCR)-р шинжлэхэд 42/104 (40,38%) нь дээж эерэг дүн үзүүлсэн. Харин ийлдсэнд шувууны томуугийн эсрэг бием илрүүлэх ELISA-ийн шинжилгээгээр 35/104 (33,65%) дээжинд эсрэг бием илэрсэн. Иймд энэ арга зүйг Монгол орны нөхцөлд тохируулан сайжруулж шувууны томуугийн үүсгэгчийг илрүүлэхэд ашиглах нь уг өвчний эпидемиологийн байдлыг танин мэдэхэд чухал ач холбогдолтой юм. Түлхүүр үг: нугас, вирус, дархлаа, эпидемиологи, тархалт, ПГУ (Полимеразан гинжин урвал)

The pathogenecity of H5N1 highly pathogenic Avian Influenza (HPAI) virus clade 2.3.2. in Indonesian indigenous chicken by contact tranmission with infected duck

An experimental transmission study was conducted using nine healthy Indonesian indigenous chickens placed together with two 30 days old ducks which were experimentally infected with H5N1 HPAI clade 2.3.2 virus in the Biosafety Laboratory Level 3 (BSL-3) facilities. The aim of the study was to find out the pathogenicity of H5N1 HPAI virus clade 2.3.2 in Indonesian indigenous chickens. The study showed that within twenty four hours rearing, the chickens were exhibited mild clinical signs and by 48 hours, all of the chickens died, whereas the ducks survived but with severe clinical signs. The H5N1 HPAI virus has been successfully isolated from chickens and ducks swabs, confirming that those animals were infected by the virus. Histologically, the infected chicken encountered with severe inflammation reaction namely non suppuratives encephalitis, tracheitis, myocarditis, interstitial pneumonia, hepatitis, proventriculitis, enteritis, pancreatitis, nephritis and bursitis. Necrotizing spleen and pancreas were also prominent. Viral antigen was detected by immunohistochemistry staining in various affected visceral organs. This suggests that Indonesian indigenous chickens were susceptible to H5N1 HPAI virus clade 2.3.2 and it can be transmitted easily to Indonesian indigenous chickens by contact transmission with infected ducks.

Highly Pathogenic Avian Influenza (H5N1) Virus in Feathers

H5N1 highly pathogenic avian influenza (HPAI) virus causes high mortality of infected birds, with infection in multiple organs, including in feathers. Feathers have been proposed as samples for diagnosis of HPAI infection in birds, and this study is part of a broader investigation validating the use of feathers for diagnostic purposes. To understand and characterize the morphological basis for feather infection, sections from 7 different skin tracts of ducks and chickens infected with 3 different clades of H5N1 HPAI virus from Indonesia and Vietnam were examined histologically. Results showed that in ducks, lesions and viral antigen were mainly detected in the epidermis of feathers and follicles, whereas in chickens, they were mostly found in the dermis of these structures. Abundant viral antigen was found in nearly all the feathers examined from chickens, and there was no apparent difference between virus isolates or skin tracts in the proportion of feathers that were antigen positive. By immunohistochemistry, the majority of feathers from most skin tracts from ducks infected with a Vietnamese H5N1 HPAI virus contained abundant levels of viral antigen, while few feathers were antigen positive from ducks infected with 2 Indonesian viruses. These results support and inform the use of feathers for diagnostic detection of H5N1 HPAI virus in birds.