First Reported Incursion of Highly Pathogenic Notifiable Avian Influenza A H5N1 Viruses from Clade 2.3.2 into European Poultry

• Published in: Transboundary and emerging diseases Vol. 58; no. 1; pp. 76 - 78
• Main Authors: Reid, S.M, Shell, W.M, Barboi, G, Onita, I, Turcitu, M, Cioranu, R, Marinova-Petkova, A, Goujgoulova, G, Webby, R.J, Webster, R.G, Russell, C, Slomka, M.J, Hanna, A, Banks, J, Alton, B, Barrass, L, Irvine, R.M, Brown, I.H
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-02-2011; Hindawi Limited
• Subjects: Animals; Animals, Wild - virology; Aves; Avian flu; avian influenza; avian influenza surveillance; Birds - virology; Bulgaria - epidemiology; Coasts; Communicable Diseases, Emerging - epidemiology; Communicable Diseases, Emerging - transmission; Communicable Diseases, Emerging - veterinary; Disease Outbreaks - veterinary; disease surveillance; Dispersal; European poultry; Fowl plague; geographical distribution; H5N1 clade 2.3.2 virus; Hemagglutinins; highly pathogenic notifiable avian influenza A H5N1; highly pathogenic notifiable avian influenza A H5N1 virus; Infection; influenza; Influenza A virus; Influenza A Virus, H5N1 Subtype - classification; Influenza A Virus, H5N1 Subtype - isolation & purification; Influenza A Virus, H5N1 Subtype - pathogenicity; Influenza in Birds - epidemiology; Influenza in Birds - transmission; Influenza in Birds - virology; Maintenance; new geographic records; notifiable avian disease; nucleotide sequencing; outbreaks; Pathogenicity; Polymerase chain reaction; Poultry; Poultry - virology; Reverse Transcriptase Polymerase Chain Reaction; Reverse transcription; Romania - epidemiology; strains; Vigilance; Virology; Viruses; waterfowl; Bulgaria; Romania; Europe; MED, Black Sea; MED, Romania; INW, Russia; Mongolia; MED, Bulgaria; ANE, Europe
• DOI: 10.1111/j.1865-1682.2010.01175.x
• EISSN: 1865-1682
• ISSN: 1865-1674

This study reports the first incursion into European poultry of H5N1 highly pathogenic notifiable avian influenza A (HPNAI) viruses from clade 2.3.2 that affected domestic poultry and wild birds in Romania and Bulgaria, respectively. Previous occurrences in Europe of HPNAI H5N1 in these avian populations have involved exclusively viruses from clade 2.2. This represents the most westerly spread of clade 2.3.2 viruses, which have shown an apparently expanding range of geographical dispersal since mid-2009 following confirmation of infections in wild waterfowl species in Mongolia and Eastern Russia. During March 2010, AI infection was suspected at post-mortem examination of two hens from two backyard flocks in Tulcea Country, Romania. HPNAI of H5N1 subtype was confirmed by reverse transcription polymerase chain reaction (RT-PCR). A second outbreak was confirmed 2 weeks later by RT-PCR, affecting all hens from another flock located 55 km east of the first cluster. On the same day, an H5N1 HPNAI virus was detected from a pooled tissue sample collected from a dead Common Buzzard found on the Black Sea coast in Bulgaria. Detailed genetic characterization of the haemagglutinin gene revealed the cleavage site of the isolates to be consistent with viruses of high pathogenicity belonging to clade 2.3.2 of the contemporary Eurasian H5N1 lineage. Viruses from a clade other than 2.2 have apparently spread to wild birds, with potential maintenance and spread through such populations. Whilst the scale of threat posed by the apparent westward spread of the clade 2.3.2 viruses remains uncertain, ongoing vigilance for clinical signs of disease as part of existing passive surveillance frameworks for AI, and the prompt reporting of suspect cases in poultry is advised.