Phylogenetic Analysis Of Neuraminidase Genes Research Articles

PHYLOGENETIC ANALYSIS OF NEURAMINIDASE GENE OF INFLUENZA A(H3N2) VIRUSES ISOLATED IN UKRAINE IN 2013–2014 SEASON

Influenza remains a serious problem for the world. The accumulation of genetic changes (mutations) in influenza viruses leads to changes in their antigenic properties, the emergence of strains resistant to antiviral drugs and the emergence of new epidemics. The aim of recent study was to perform the phylogenetic analysis of neuraminidase gene of influenza A(H3N2) viruses isolated in Ukraine in 2013–2014 season. Methods. Molecular genetics, phylogenetic and statistical methods were used for this study. Results. High (94%) genetic similarity of Ukrainian isolates and isolates from other countries of 2013–2014 epidemic seasons demonstrates the stability of viral populations in Ukraine. The allocation of Ukrainian viruses to three different clusters points to different ways of their spread to Ukraine. The analysis of NA sequences revealed novel amino acid substitutions Y155F, D251V, S315G to the majority of Ukrainian isolates. None of virus isolates of season 2013–2014 in Ukraine contained an E119D mutation in NA sequence which is associated with oseltamivir resistance. Conclusions. The results of our work showed that influenza viruses isolated in 2013–2014 epidemic season had not specific mutations, associated with resistance to antiviral drugs such as oseltamivir.

Molecular characterization and phylogenetic analysis of neuraminidase gene of avian Influenza H9N2 viruses isolated from commercial broiler chicken in Iran during a period of 1998-2007

Avian influenza (AI) outbreaks due to H9N2 subtype of avian influenza virus (AIV) occurred in poultry industry in Iran, throughout the past decade and caused serious economic losses as a result of decreased egg production, increased mortality and the cost of vaccination in Iranian poultry industry. Our aim was to find the phylogenic and genetic relationships among avian influenza viruses recently isolated from poultry in Iran with other Asian H9N2 lineages (1998-2007). The complete nucleotide sequences of the neuraminidase (NA) genes of ten H9N2 influenza virus strain isolated from diseased chickens in different farms in Iran during 1998-2007, were amplified and sequenced and phylogenetic relationships between these and previously reported N2 genes were investigated. The viruses surface glycoprotein genes was >90% similar to those of A/Quail/Hongkong/G1/97 (H9N2) lineage. The NA stalks regions in these viruses had no deletion or insertion or shortening as compared to that A/DK/HK/Y280/97 lineage (CK/Bei-like viruses) and the 2 human isolates A/HK/1073/99, A/HK/1074/99. The hemadsorbing site of NA had up to 3 amino acid substitution and is different from those of earlier Iranian viruses and ten Iranian isolates possessed seven potential glycosylation sites like the most H9N2 isolates. Phylogenetic analysis of NA gene showed that they belonged to the same A/Quail/Hong Kong/G1/97 like virus sub lineage. Key words: Avian influenza virus, H9N2, neuraminidase gene, phylogenetic analysis, Iran.

Sequence and phylogenetic analysis of neuraminidase genes of H9N2 avian influenza viruses isolated from commercial broiler chicken in Iran (2008 and 2009)

A total of 512 tissue samples collected from 30 farms located in various states of Iran during 2008-2009 as part of a program to monitor avian influenza viruses (AIVs) infection in Iran's poultry population. To determine the genetic relationship of Iranian viruses, neuraminidase (NA) genes from ten isolates of H9N2 viruses isolated from commercial chickens in Iran during 2008-2009 were amplified and sequenced. The viruses' neuraminidase gene was >90% similar to those of A/Quail/Hong Kong/G1/97 (H9N2) sublineage. The neuraminidase stalk regions in these Viruses had no deletion as compared to that of chicken/Beijing/1/94 sublineage (Beijing-like viruses) and the two human isolates A/HK/1073/99, A/HK/1074/99. Phylogenetic analysis of neuraminidase (NA) gene showed that it shares a common ancestor A/Quail/Hong Kong/G1/97 isolate which had contributed the internal genes of the H5N1 virus. The results of this study indicated that No (Beijing-like) virus and (Korean-like) virus were found in chickens in Iran, and the NA genes of H9N2 influenza viruses circulating in Iran during the past years were well conserved and the earlier Iranian isolates may be considered to represent such a progenitor.

Phylogenetic analysis of neuraminidase gene of H9N2 influenza viruses prevalent in chickens in China during 1995-2002.

The neuraminidase (NA) genes of 12 H9N2 influenza virus strains isolated from diseased chickens in different farms in mainland China during 1995-2002 were amplified and sequenced. Amino acids at hemadsorbing (HB) site of these isolates are different from those of A/quail/Hong Kong/G1/97-like viruses and A/chicken/Korea/96-like viruses. Neuraminidases of the 12 strains had a deletion of 3 amino acid residues at positions 63-65 as compared to that of A/turkey/Wisconsin/189/66, while those of Korea and Pakistan H9N2 isolates had no deletion. Phylogenetic analyses showed NA gene of these isolates belonged to that of A/duck/Hong Kong/Y280/97-like virus lineage. NA gene of the H9N2 viruses isolated in Korea and Pakistan belonged to lineage different from those of the 12 isolates. The present results indicate that the NA of H9N2 strains isolated in mainland China during the past 8 years were well preserved and the geographical distribution play a significant role in the evolution of the H9N2 influenza viruses.