Filogenetik dan Struktur Antigenik Virus Avian Influenza Subtipe H5N1 Isolat Unggas Air

Abstract

A study was carried (1) to analyze the phylogenetic relationship of fragment hemaglutinin (HA) gene of avian influenza viruses (AIV) subtype H5N1 isolated from apparently healthy backyard waterfowls in West Java with representative of animal and human isolates from Indonesia and some countries in Asia; (2) to find out cross-reactivity of those viruses with a standard Indonesian strain. Nucleotide sequences of HA gene of AIV H5N1 from backyard waterfowls along with other H5N1 isolates of Indonesian and Asian origin were aligned using with ClustalW of MEGA 3.1 program. Estimation of genetic distance and the construction phylogenetic tree were conducted by Neighbor Joining method and calculation of distance matrix using Kimura 2-parameter. Antigenic analysis was conducted using hemagglutination inhibition (HI) test. Result of phylogenetic analysis indicated that all viruses from backyard waterfowls form three distinct sublineages. One lineage was located in Indonesia cluster and two lineages in Asia cluster. In the phylogenetic analysis, it was concluded that multiple introductions of AIV H5N1 to Indonesia have occurred. Six A1 H5N1 viruses from backyard waterfowls (IPB1-RS to IPB6-RS) appeared to be different ancestors those isolated previously in Indonesia. Cross-antigenic analysis showed that nine viruses isolates used in this study were antigenically different to Legok 2003 chicken strain of AIV H5N1. The HI titer of anti- Legok 2003 antibnd.7 with all newly isolated viruses is up to 6 log lower then the HI titer using homolog strain.