Avian Influenza (H5N1) Virus of Clade 2.3.2 in Domestic Poultry in India

Jang

et al. 2017

J Virol

Whole-genome sequences of representative highly pathogenic avian influenza A(H5) viruses from Vietnam were generated, comprising samples from poultry outbreaks and active market surveillance collected from January 2012 to August 2015. Six hemagglutinin gene clades were characterized. Clade 1.1.2 was predominant in southern Mekong provinces throughout 2012 and 2013 but gradually disappeared and was not detected after April 2014. Clade 2.3.2.1c viruses spread rapidly during 2012 and were detected in the south and center of the country. A number of clade 1.1.2 and 2.3.2.1c interclade reassortant viruses were detected with different combinations of internal genes derived from 2.3.2.1a and 2.3.2.1b viruses, indicating extensive cocirculation. Although reassortment generated genetic diversity at the genotype level, there was relatively little genetic drift within the individual gene segments, suggesting genetic stasis over recent years. Antigenically, clade 1.1.2, 2.3.2.1a, 2.3.2.1b, and 2.3.2.1c viruses remained related to earlier viruses and WHO-recommended prepandemic vaccine strains representing these clades. Clade 7.2 viruses, although detected in only low numbers, were the exception, as indicated by introduction of a genetically and antigenically diverse strain in 2013. Clade 2.3.4.4 viruses (H5N1 and H5N6) were likely introduced in April 2014 and appeared to gain dominance across northern and central regions. Antigenic analyses of clade 2.3.4.4 viruses compared to existing clade 2.3.4 candidate vaccine viruses (CVV) indicated the need for an updated vaccine virus. A/Sichuan/26221/2014 (H5N6) virus was developed, and ferret antisera generated against this virus were demonstrated to inhibit some but not all clade 2.3.4.4 viruses, suggesting consideration of alternative clade 2.3.4.4 CVVs. IMPORTANCE Highly pathogenic avian influenza (HPAI) A(H5) viruses have circulated continuously in Vietnam since 2003, resulting in hundreds of poultry outbreaks and sporadic human infections. Despite a significant reduction in the number of human infections in recent years, poultry outbreaks continue to occur and the virus continues to diversify. Vaccination of poultry has been used as a means to control the spread and impact of the virus, but due to the diversity and changing distribution of antigenically distinct viruses, the utility of vaccines in the face of mismatched circulating strains remains questionable. This study assessed the putative amino acid changes in viruses leading to antigenic variability, underscoring the complexity of vaccine selection for both veterinary and public health purposes. Given the overlapping geographic distributions of multiple, antigenically distinct clades of HPAI A(H5) viruses in Vietnam, the vaccine efficacy of bivalent poultry vaccine formulations should be tested in the future.

Section: Discussionmentioning

confidence: 99%

Shifting Clade Distribution, Reassortment, and Emergence of New Subtypes of Highly Pathogenic Avian Influenza A(H5) Viruses Collected from Vietnamese Poultry from 2012 to 2015

Jang

et al. 2017

J Virol

“…2), represented by the human isolates Hubei/1/10 and Guangxi/1/09. Clade 2.3.2 viruses were originally identified from wild birds (42,43) but have also been reported in domestic poultry, such as chickens and ducks (44)(45)(46). This clade contains recent H5N1 isolates and is located at the extremity of the phylogenetic tree, indicating active virus evolution.…”

Section: Methodsmentioning

confidence: 98%

Complex Reassortment of Multiple Subtypes of Avian Influenza Viruses in Domestic Ducks at the Dongting Lake Region of China

Deng

Dai

Shi

et al. 2013

J Virol

bTo gain insight into the ecology of avian influenza viruses (AIV), we conducted active influenza virus surveillance in domestic ducks on farms located on the flyway of migratory birds in the Dongting Lake region of Hunan Province, China, from winter 2011 until spring 2012. Specimens comprising 3,030 duck swab samples and 1,010 environmental samples were collected from 101 duck farms. We isolated AIV of various HA subtypes, including H3, H4, H5, H6, H9, H10, H11, and H12. We sequenced the entire coding sequences of the genomes of 28 representative isolates constituting 13 specific subtypes. When the phylogenetic relationships among these isolates were examined, we observed that extensive reassortment events had occurred. Among the 28 Dongting Lake viruses, 21 genotypes involving the six internal genes were identified. Furthermore, we identified viruses or viral genes introduced from other countries, viral gene segments of unknown origin, and a novel HA/NA combination. Our findings emphasize the importance of farmed domestic ducks in the Dongting Lake region to the genesis and evolution of AIV and highlight the need for continued surveillance of domestic ducks in this region.

“…Our result is differ with the previous report in Indonesia that cleavage site motive of AIV isolated from duck was -PQRERRRKR/GLF-, (Wibawa et al, 2012). The CS feature is also differ to AIV belong to clade 2.3.2 which were reported for the fi rst time in China 2009 (Li et al, 2011), in India (Nagarajan et al, 2012), in Bulgaria and Rumania (Reid et al, 2011).…”

Section: Analysis Of Cleavage Site Areamentioning

confidence: 87%

The Development of Pathogenicity of Avian Influenza Virus Isolated from Indonesia

Wibowo¹,

Srihanto²,

Putri³

et al. 2015

IJBiotech

Highly pathogenic avian infl uenza outbreak in Indonesia has been reported in various poultry due to H5N1 subtype. The presence of multiple basic amino acids within the cleavage site of HA glycoprotein has been identifi ed to be associated with the pathogenicity of avian infl uenza virus. The study was retrospective study which was designed to characterize the cleavage site and fusion site region of haemagglutinin gene of AIV isolated from various poultry in 2003 to 2013. Isolation, Identifi cation and propagation were carried out to collect viral stock. For virus detection, reverse transcriptase PCR (RT-PCR) method on H5 and N1 gene fragment was performed. All of RT-PCR HA gene positive products were sequenced for further nucleotide analysis and to determine the nucleotide composition at the targeted fragment. The results are all AIV isolates were identifi ed as H5N1 subtype. The sequence analyses revealed some motives of basic amino acid motive that were classifi ed as highly pathogenic avian infl uenza virus. Further analyses on fusion domain of all AIV isolated during the period 2003 to 2013 showed conserved amino acid.