Replacement of sublineages of avian influenza (H5N1) by reassortments, sub-Saharan Africa.
Eight new full-length sequences from highly pathogenic avian influenza viruses (H5N1) from 4 states in southwest Nigeria were analyzed. All gene sequences were more closely related to the first strains found in Nigeria in 2006 than to any strain found outside the country. Six viruses had evolved by at least 3 reassortment events (AC HA/NS, AC NS) from previously identified sublineages A (EMA 2) and C (EMA 1). Our results suggest that highly pathogenic avian influenza viruses (H5N1) initially imported into Nigeria in 2006 have been gradually replaced by various reassortments. In all reassortants, nonstructural genes were derived from sublineage C with 2 characteristic amino acids (compared with sublineage A). If the high prevalence of reassortants was typical for West Africa in 2007, the absence of such reassortants anywhere else suggests that reintroductions of influenza A (H5N1) from Africa into Eurasia must be rare.
Owoade
Ademola A
AA
University of Ibadan, Ibadan, Nigeria.
Gerloff
Nancy A
NA
Ducatez
Mariette F
MF
Taiwo
Jolaoso O
JO
Kremer
Jacques R
JR
Muller
Claude P
CP
D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens / Q000821:virology*; D005814:Genes, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics; D053124:Influenza A Virus, H5N1 Subtype / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D005585:Influenza in Birds / Q000453:epidemiology* / Q000821:virology*; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000235:genetics; D009549:Nigeria / Q000453:epidemiology; D010802:Phylogeny; D016865:Reassortant Viruses / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D014764:Viral Proteins / Q000235:genetics
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D014764:Viral Proteins; C109963:hemagglutinin, avian influenza A virus; D009439:Neuraminidase