title: Isolation and characterization of influenza A virus (subtype H5N1) that caused the first highly pathogenic avian influenza outbreak in chicken in Bhutan.
abstract: We characterized Influenza A/H5N1 virus that caused the first outbreak of highly pathogenic avian influenza (HPAI) in chickens in Bhutan in 2010. The virus was highly virulent to chicken, killing them within two days of the experimental inoculation with an intravenous pathogenicity index (IVPI) of 2.88. For genetic and phylogenetic analyses, complete genome sequencing of 4 viral isolates was carried out. The isolates revealed multiple basic amino acids at their hemagglutinin (HA) cleavage site, similar to other "Qinghai-like" H5N1 isolates. The receptor-binding site of HA molecule contained avian-like amino acids ((222)Q and (224)G). The isolates also contained amino acid residue K at position 627 of the PB2 protein, and other markers in NS 1 and PB1 proteins, highlighting the risk to mammals. However, the isolates were sensitive to influenza drugs presently available in the market. The sequence analysis indicated that the Bhutan viruses shared 99.1-100% nucleotide homology in all the eight genes among themselves and 2010 chicken isolate from Bangladesh (A/chicken/Bangladesh/1151-11/2010) indicating common progenitor virus. The phylogenetic analysis indicated that the Bhutan isolates belonged to sub-clade 2.2.3 (EMA 3) and shared common progenitor virus with the 2010 Bangladesh virus. Based on the evidence of phylogeny and molecular markers, it could be concluded that the outbreaks in Bhutan and Bangladesh in 2010 were due to independent introductions of the virus probably through migratory birds.
authors: High Security Animal Disease Laboratory, Indian Veterinary Research Institute, ICAR, Anand Nagar, Bhopal 462021, Madhya Pradesh, India.
authors: S C
authors: SC
authors: Dubey
authors: N
authors: N
authors: Dahal
authors: S
authors: S
authors: Nagarajan
authors: C
authors: C
authors: Tosh
authors: H V
authors: HV
authors: Murugkar
authors: K
authors: K
authors: Rinzin
authors: B
authors: B
authors: Sharma
authors: R
authors: R
authors: Jain
authors: M
authors: M
authors: Katare
authors: S
authors: S
authors: Patil
authors: R
authors: R
authors: Khandia
authors: Z
authors: Z
authors: Syed
authors: S
authors: S
authors: Tripathi
authors: P
authors: P
authors: Behera
authors: M
authors: M
authors: Kumar
authors: D D
authors: DD
authors: Kulkarni
authors: Lal
authors: L
authors: Krishna
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D001459:Bangladesh / Q000453:epidemiology; D001483:Base Sequence; D001631:Bhutan / Q000453:epidemiology; D002645:Chickens / Q000821:virology; D004196:Disease Outbreaks / Q000662:veterinary*; D053124:Influenza A Virus, H5N1 Subtype / Q000145:classification* / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity; D005585:Influenza in Birds / Q000453:epidemiology* / Q000401:mortality / Q000821:virology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D000998:Antiviral Agents