Genetic and antigenic evaluation of Foot and Mouth Disease virus type A in outbreak area of Iran, 2014 and 2015

Document Type: Original Articles

Authors

1 Foot and Mouth Disease Reference Laboratory, Razi Vaccine & Serum Research Institute. Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran Agricultural Research, Education and Extention Organization (AREEO), Karaj, Iran

2 Quality Control Department, Razi Vaccine & Serum Research Institute. Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran

Abstract

The foot-and-mouth disease virus (FMDV) is one of the infectious agents that seriously threatens the animal health and welfare. FMDV has a very variable genome and complicated biology. Therefore, ongoing evaluation of genetic changes of the circulating viruses in field is essential to introduce the suitable strains for vaccine production.
During 2014 and 2015, 126 clinical specimens consisting of epithelial tissue and vesicular fluid from tongue, dental pad, and hoofs suspected of FMD virus were submitted to the Reference laboratory for FMD in Razi vaccine and serum research institute and 86 of them were identified as FMD virus type A by sandwich ELISA. Viruses were isolated from 42 samples from sixteen provinces by cell culture. At first by PCR the coding region that produces the main part of viral capsid was amplified. This part of genome by 800 bp length was related to the 1D gene that synthesizes the VP1 protein.
The phylogenetic evaluation was performed by analysis of the VP1 coding region. The result determined two distinct genotypes with more than 15% nucleotide differences. The first cluster was categorized with closely related viruses registered in GeneBank of neighboring countries, e.g. Afghanistan, Pakistan, and Turkey. All samples in Cluster1 were determined as relative viruses with genotype Iran-05. In-vitro serological examination indicated an antigenic relationship between Cluster 1 viruses and routine vaccine strain (A-IRN-2013). The second cluster with only two members genetically far from earlier one and could be considered as a separate genotype. In this study were found that the cluster 2 has not been previously reported in Iran. Genetic tracing indicates that these viruses might have been originated from circulating viruses from India. Antigenic evaluation exhibited that this group could not be cross-protected by the routine vaccinal strain (A-IRN-2013) that used during the studying period.

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