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Reassortant avian influenza virus (H5N1) in poultry, Nigeria, 2007.

Monne I, Joannis TM, Fusaro A, De Benedictis P, Lombin LH, Ularamu H, Egbuji A, Solomon P, Obi TU, Cattoli G, Capua I - Emerging Infect. Dis. (2008)

Bottom Line: Genetic characterization of a selection of influenza virus (H5N1) samples, circulating in 8 Nigerian states over a 39-day period in early 2007, indicates that a new reassortant strain is present in 7 of the 8 states.Our study reports an entirely different influenza virus (H5N1) reassortant becoming predominant and widespread in poultry.

View Article: PubMed Central - PubMed

Affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Padova, Italy [corrected]

ABSTRACT
Genetic characterization of a selection of influenza virus (H5N1) samples, circulating in 8 Nigerian states over a 39-day period in early 2007, indicates that a new reassortant strain is present in 7 of the 8 states. Our study reports an entirely different influenza virus (H5N1) reassortant becoming predominant and widespread in poultry.

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Related in: MedlinePlus

Phylogenetic tree for the hemagglutinin gene of influenza viruses constructed by neighbor-joining method. Sequences obtained in this study were labeled with a circle (EMA1/EMA2-2:6-R07 group) and triangle (EMA2 group). The remaining sequences can be found in GenBank. The numbers at each branch point represent bootstrap values, and they were determined by bootstrap analysis by using 1,000 replications. Scale bar = 0.01 nucleotide substitutions/site.
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Figure 1: Phylogenetic tree for the hemagglutinin gene of influenza viruses constructed by neighbor-joining method. Sequences obtained in this study were labeled with a circle (EMA1/EMA2-2:6-R07 group) and triangle (EMA2 group). The remaining sequences can be found in GenBank. The numbers at each branch point represent bootstrap values, and they were determined by bootstrap analysis by using 1,000 replications. Scale bar = 0.01 nucleotide substitutions/site.

Mentions: Phylogenetic analysis of all 8 gene segments of the recent Nigerian strains showed that 10 of these strains, labeled EMA1/EMA2-2:6 reassortant 2007 (EMA1/EMA2-2:6-R07) (Table 1), have the same genotype. In particular, the genetic comparison of the hemagglutinin (HA) and nonstructural (NS) genes of EMA1/EMA2-2:6-R07 shows that they are derived from viruses of the EMA1 sublineage (1) and have the highest similarity with the first Nigerian strain isolated, A/chicken/Nigeria/641/2006 (homology ranged between 99.3% and 99.7%). We observed different topology for the remaining gene segments (neuraminidase, nucleoprotein [NP], matrix, heterotrimeric polymerase complex [PA, PB1, and PB2]). Phylogenetic analysis showed that the nucleotide sequences of these genes fall into EMA2 sublineage; the highest homology was observed with respective gene segments of the Nigerian strains isolated in 2006, which belong to EMA2 (homology ranged between 99.4% and 99.7%). The separation of the gene segments into 2 clusters (Figures 1, 2) is evidence of reassortment (7). The genetic pattern of EMA1/EMA2-2:6-R07 virus is distinct from that of A/chicken/Nigeria/1047-62/2006 virus isolated in June, 2006 in Taraba State and recognized previously as an EMA1/EMA2-4:4 reassortant virus (1) (Table 2). The remaining 2 viruses were not reassortants. They were detected in Sokoto State and belong to sublineage EMA2.


Reassortant avian influenza virus (H5N1) in poultry, Nigeria, 2007.

Monne I, Joannis TM, Fusaro A, De Benedictis P, Lombin LH, Ularamu H, Egbuji A, Solomon P, Obi TU, Cattoli G, Capua I - Emerging Infect. Dis. (2008)

Phylogenetic tree for the hemagglutinin gene of influenza viruses constructed by neighbor-joining method. Sequences obtained in this study were labeled with a circle (EMA1/EMA2-2:6-R07 group) and triangle (EMA2 group). The remaining sequences can be found in GenBank. The numbers at each branch point represent bootstrap values, and they were determined by bootstrap analysis by using 1,000 replications. Scale bar = 0.01 nucleotide substitutions/site.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2570913&req=5

Figure 1: Phylogenetic tree for the hemagglutinin gene of influenza viruses constructed by neighbor-joining method. Sequences obtained in this study were labeled with a circle (EMA1/EMA2-2:6-R07 group) and triangle (EMA2 group). The remaining sequences can be found in GenBank. The numbers at each branch point represent bootstrap values, and they were determined by bootstrap analysis by using 1,000 replications. Scale bar = 0.01 nucleotide substitutions/site.
Mentions: Phylogenetic analysis of all 8 gene segments of the recent Nigerian strains showed that 10 of these strains, labeled EMA1/EMA2-2:6 reassortant 2007 (EMA1/EMA2-2:6-R07) (Table 1), have the same genotype. In particular, the genetic comparison of the hemagglutinin (HA) and nonstructural (NS) genes of EMA1/EMA2-2:6-R07 shows that they are derived from viruses of the EMA1 sublineage (1) and have the highest similarity with the first Nigerian strain isolated, A/chicken/Nigeria/641/2006 (homology ranged between 99.3% and 99.7%). We observed different topology for the remaining gene segments (neuraminidase, nucleoprotein [NP], matrix, heterotrimeric polymerase complex [PA, PB1, and PB2]). Phylogenetic analysis showed that the nucleotide sequences of these genes fall into EMA2 sublineage; the highest homology was observed with respective gene segments of the Nigerian strains isolated in 2006, which belong to EMA2 (homology ranged between 99.4% and 99.7%). The separation of the gene segments into 2 clusters (Figures 1, 2) is evidence of reassortment (7). The genetic pattern of EMA1/EMA2-2:6-R07 virus is distinct from that of A/chicken/Nigeria/1047-62/2006 virus isolated in June, 2006 in Taraba State and recognized previously as an EMA1/EMA2-4:4 reassortant virus (1) (Table 2). The remaining 2 viruses were not reassortants. They were detected in Sokoto State and belong to sublineage EMA2.

Bottom Line: Genetic characterization of a selection of influenza virus (H5N1) samples, circulating in 8 Nigerian states over a 39-day period in early 2007, indicates that a new reassortant strain is present in 7 of the 8 states.Our study reports an entirely different influenza virus (H5N1) reassortant becoming predominant and widespread in poultry.

View Article: PubMed Central - PubMed

Affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Padova, Italy [corrected]

ABSTRACT
Genetic characterization of a selection of influenza virus (H5N1) samples, circulating in 8 Nigerian states over a 39-day period in early 2007, indicates that a new reassortant strain is present in 7 of the 8 states. Our study reports an entirely different influenza virus (H5N1) reassortant becoming predominant and widespread in poultry.

Show MeSH
Related in: MedlinePlus