Giuseppe
Emeritus
[Source: US National Library of Medicine, full text: (LINK). Abstract, edited.]
J Gen Virol. 2012 Jul 12. [Epub ahead of print]
Antigenic Analysis of Highly Pathogenic Avian Influenza Virus H5N1 Sublineages Co-Circulating in Egypt.
Watanabe Y, Ibrahim MS, Ellakany HF, Kawashita N, Daidoji T, Takagi T, Yasunaga T, Nakaya T, Ikuta K.
Source: Research Institute for Microbial Diseases, Osaka University, Japan;
Abstract
Highly pathogenic avian influenza virus H5N1 has spread across Eurasia and Africa, and outbreaks are now endemic in several countries, including Indonesia, Viet Nam and Egypt. Continuous circulation of H5N1 virus in Egypt, from a single infected source, has led to significant genetic diversification with phylogenetically separable sublineages, providing an opportunity to study the impact of genetic evolution on viral phenotypic variation. In this study, we analyzed the phylogeny of H5 hemagglutinin genes in influenza viruses isolated in Egypt from 2006-2011 and investigated the effect of conserved amino acid mutations in the hemagglutinin genes in each of the sublineages on their antigenicity. The analysis showed that viruses in at least four sublineages still persisted in poultry in Egypt as of 2011. Using reverse genetics to generate HA reassortment viruses with specific hemagglutinin mutations, we found antigenic drift in the hemagglutinin in two influenza virus sublineages, compared to the other currently co-circulating influenza virus sublineages in Egypt. Moreover, the two sublineages with significant antigenic drift were antigenically distinguishable. Our findings suggested that phylogenetically divergent H5N1 viruses, that were not antigenically cross-reactive, were co-circulating in Egypt, indicating that there was a problem in using a single influenza virus strain as seed-virus to produce influenza virus vaccine in Egypt and providing data for designing more efficacious control strategies in H5N1 endemic areas.
PMID: 22791605 [PubMed - as supplied by publisher]
- ------Watanabe Y, Ibrahim MS, Ellakany HF, Kawashita N, Daidoji T, Takagi T, Yasunaga T, Nakaya T, Ikuta K.
Source: Research Institute for Microbial Diseases, Osaka University, Japan;
Abstract
Highly pathogenic avian influenza virus H5N1 has spread across Eurasia and Africa, and outbreaks are now endemic in several countries, including Indonesia, Viet Nam and Egypt. Continuous circulation of H5N1 virus in Egypt, from a single infected source, has led to significant genetic diversification with phylogenetically separable sublineages, providing an opportunity to study the impact of genetic evolution on viral phenotypic variation. In this study, we analyzed the phylogeny of H5 hemagglutinin genes in influenza viruses isolated in Egypt from 2006-2011 and investigated the effect of conserved amino acid mutations in the hemagglutinin genes in each of the sublineages on their antigenicity. The analysis showed that viruses in at least four sublineages still persisted in poultry in Egypt as of 2011. Using reverse genetics to generate HA reassortment viruses with specific hemagglutinin mutations, we found antigenic drift in the hemagglutinin in two influenza virus sublineages, compared to the other currently co-circulating influenza virus sublineages in Egypt. Moreover, the two sublineages with significant antigenic drift were antigenically distinguishable. Our findings suggested that phylogenetically divergent H5N1 viruses, that were not antigenically cross-reactive, were co-circulating in Egypt, indicating that there was a problem in using a single influenza virus strain as seed-virus to produce influenza virus vaccine in Egypt and providing data for designing more efficacious control strategies in H5N1 endemic areas.
PMID: 22791605 [PubMed - as supplied by publisher]