Amino acid diversity of antigenic sites of Iranian type O foot-and-mouth disease virus

Foot-and-mouth disease (FMD) is a major cause of endemic outbreaks in livestock in Iran. In this study, clinical field samples of foot-and-mouth disease virus were collected from an outbreak in Khorasan Razavi Province during April and August of 2010, and subjected to indirect sandwich ELISA and RT-PCR. The viral serotype circulating during the period was confirmed to be type O. The virus was then genetically characterized for its complete P1 genomic sequences to compare with nine corresponding nucleotide sequences of representative foot-and-mouth disease viruses (FMDVs) registered in the GenBank. The P1-coding region was 2208 nucleotides in length with 736 encoded amino acid residues. Phylogenetic analysis revealed two major lineages of A (with three additional clusters) and B. Iranian field isolate was grouped within cluster I, most closely related to Pakistani strains PAK/39/2008 and PAK/29/2008 sharing 98.37 and 98.1% amino acid identity, respectively, demonstrating the close epidemiological links between countries in the region. In contrast, our isolate showed low amino acid identity with Italian isolate O-2-Brescia (93.48%) and Argentinean isolate O1 Caseros (93.75%). Based on multiple sequence alignments, comparison of sequences showed that the characteristic amino acid mutations were found in the VP1, VP2 and VP3 proteins of isolated virus. This article is the first to report on the complete P1 genomic characterization of type O FMDV circulating in Iran