1Bioinformatics Group, National Institute of Virology, Pune-411 001.
2Avian Influenza Group, Microbial Containment Complex, Pune-411 001.
Abstracts of the papers presented at the XVIII National Conference of Indian Virological Society at Post Graduate Institute of Medical Education and Research, Chandigarh, India, December 11–13, 2008.
The avian influenza A H5N1 genotype Z has emerged as the dominant circulating strain in both aquatic and terrestrial poultry since 2002, and has been responsible for outbreaks in several countries in Asia, Middle East, Europe and Africa. The genotype has evolved into two major clades, viz. Clade 1 and clade 2 with the latter distinguishing into six sub-clades (2.1 to 2.6). Outbreaks of highly pathogenic avian influenza A (H5N1) virus in poultry has been reported in different states of India since 2006, the first one being in Nandurbar and Jalgaon districts of Maharashtra and Burhanpur in Madhya Pradesh in January 2006. The full genome sequences of the sestrains showed that all the genes belong to clade 2.2 of the Z genotype and was close to the isolates from Iran, Afghanistan, Mongolia, Italy and Krasnodar. Molecular characterization of the genes has been done considering the amino acid residues responsible for pathogenesis, glycosylation and receptor binding. Molecular markers suggested that the isolates are sensitive to drugs Oseltamivir and Amantadine. Further, the molecular evolution in the Z genotype viruses belonging to clade 2.2 has been investigated based on the analysis of non-synonymous and synonymous substitution rates and selection pressure acting on the genes. The positive selection sites could be mapped on to validated immunogenic epitopes indicating that the diversification enables evasion of the host immune response. The study would be useful in understanding the evolutionary patterns within the clades of the Z genotype.
