Genetic Characterization of the H Gene of Mev Strains (H1, B3, and D4) Recently Circulated in Iran for Improving the Molecular Measles Surveillance in the National Measles Lab



Zarehkhoshchehreh R^{1, 2} ; Salimi V^{1, 3} ; Nasab GSF^{1, 3} ; Naseri M¹ ; Fard FAN^{1, 3} ; Azad TM^{1, 3} Show Affiliations
Source: Iranian Journal of Public Health Published:2023

Abstract

Background: Despite decreasing the global burden of measles disease after the introduction of vaccination, measles remains one of the most devastating childhood diseases. Since genotype B3 is reported as a predomi-nant Measles Virus (MeV) genotype recently, the current study aimed to better understand MeV genetic varia-tion by analyzing the complete sequence of Hemagglutinin (H) gene associated with outbreaks of circulated genotypes in Iran. Methods: Nine positive measles specimens were selected from three circulated different genotypes H1, B3, and D4. Two different regions of MeV RNA were detected by RT-PCR assay. Sequence data and phylogenetic trees were analyzed and constructed by MEGA X software program. Moreover, missense and silent mutations in critical positions of the MeV-H protein were investigated. Results: The result of phylogenetic analysis from the C-terminus of the Nucleoprotein gene (NP-450) and the complete H gene revealed that the mean sequence diversity was 0.06%-0.08% and 0.04%, respectively. Geno-type H1 had the highest mutation in this study; however, the substitutions in genotype B3 fundamentally oc-curred in critical epitopes. Moreover, genotype D4 was more stable than genotypes B3 and H1. Conclusion: Mutations were investigated in the whole sequence of H protein. Moreover, the mutations that occur in the critical sites of the protein have an important effect on the pathogenicity of the virus. In this way, we were able to illustrate why genotype B3 is more transmissible than other measles genotypes and is the most important circulating genotype around the world. © 2023 Zareh-Khoshchehreh et al. Published by Tehran University of Medical Sciences.