Genetic Characterization of Wild-Type Measles Viruses Isolated in Peshawar Pakistan

Abstract

Background: Measles is a highly contagious disease, caused by the Measles Virus (MV). Knowledge of genotypes prevalent in any region is important in effective measles surveillance; by mapping distribution of prevalent MV genotypes at different points of time, in a region, gives an idea about the success of measles control through vaccination programs, by documenting the interruption of transmission of the endemic viral genotype. Objectives: To detect genotypes of wild type measles virus isolated from the samples collected of measles patients in Peshawar valley of Khyber Pakhtunkhwa (KPK) province, Pakistan.Material and Methods: This was a cross-sectional descriptive study. Nasopharyngeal and/or throat swab samples were collected during a measles outbreak, from February to March 2014, from clinically diagnosed measles patients (cases who met the clinical case definition of WHO). Collection and processing were done according to the standard protocols. RNA (Ribo-Nucleic Acid) was extracted directly from samples; cDNA (Complimentary Deoxy-Ribonucleic Acid) was synthesized, amplification and sequencing of 528bp of carboxy-terminal of N gene was carried out. Sequences were analyzed and data were compared with the standard reference strains of measles virus.Results: A total of nine sequences obtained were of good quality and enough in length to meet WHO criteria for genotype assignment. It was found that all the nine strains of measles virus belonged to clade B, genotype B3 and cluster B3.1. The rest of the 13 sequences which were shorter in length for genotype assignment also showed close resemblance to Genotype B3.Conclusion: Wild type measles virus strains, isolated from the samples of measles patients, in Peshawar valley of Khyber Pakhtunkhwa province of Pakistan were found to be genotype B3. It shows that genotype B3 may be the predominate genotype prevalent in Peshawar region at the time of this study.Keywords: B3 genotype, Genotyping of measles, Measles Virus, Molecular epidemiology.