Complete genome sequencing and phylogenetic analysis of dengue type 1 virus isolated from Jeddah, Saudi Arabia.

Esam I Azhar,Said Abol-Ela,Norah A Othman,Tariq A Madani,Suha A Farraj,Ghazi Jamjoom,Ahmed Ashshi,Sayed Sartaj Sohrab,Anwar M Hashem,Sherif A El-Kafrawy,Adly Mm Abd-Alla,Huda G Ben-Helaby

doi:10.1186/s12985-014-0235-7

Esam I Azhar, Said Abol-Ela + Show 10 more

Open Access

https://doi.org/10.1186/s12985-014-0235-7

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Abstract

BackgroundDengue viruses (DENVs) are mosquito-borne viruses which can cause disease ranging from mild fever to severe dengue infection. These viruses are endemic in several tropical and subtropical regions. Multiple outbreaks of DENV serotypes 1, 2 and 3 (DENV-1, DENV-2 and DENV-3) have been reported from the western region in Saudi Arabia since 1994. Strains from at least two genotypes of DENV-1 (Asia and America/Africa genotypes) have been circulating in western Saudi Arabia until 2006. However, all previous studies reported from Saudi Arabia were based on partial sequencing data of the envelope (E) gene without any reports of full genome sequences for any DENV serotypes circulating in Saudi Arabia.FindingsHere, we report the isolation and the first complete genome sequence of a DENV-1 strain (DENV-1-Jeddah-1-2011) isolated from a patient from Jeddah, Saudi Arabia in 2011. Whole genome sequence alignment and phylogenetic analysis showed high similarity between DENV-1-Jeddah-1-2011 strain and D1/H/IMTSSA/98/606 isolate (Asian genotype) reported from Djibouti in 1998. Further analysis of the full envelope gene revealed a close relationship between DENV-1-Jeddah-1-2011 strain and isolates reported between 2004–2006 from Jeddah as well as recent isolates from Somalia, suggesting the widespread of the Asian genotype in this region.ConclusionsThese data suggest that strains belonging to the Asian genotype might have been introduced into Saudi Arabia long before 2004 most probably by African pilgrims and continued to circulate in western Saudi Arabia at least until 2011. Most importantly, these results indicate that pilgrims from dengue endemic regions can play an important role in the spread of new DENVs in Saudi Arabia and the rest of the world. Therefore, availability of complete genome sequences would serve as a reference for future epidemiological studies of DENV-1 viruses.

Highlights

Introduction of newDengue viruses (DENVs) viruses can lead to the emergence of recombinant strains which might have a great impact on the epidemiological and clinical outcomes
These data suggest that strains belonging to the Asian genotype might have been introduced into Saudi Arabia long before 2004 most probably by African pilgrims and continued to circulate in western Saudi Arabia at least until 2011. These results indicate that pilgrims from dengue endemic regions can play an important role in the spread of new DENVs in Saudi Arabia and the rest of the world
Availability of complete genome sequences would serve as a reference for future epidemiological studies of DENV-1 viruses

Summary

Introduction

Introduction of newDENV viruses can lead to the emergence of recombinant strains which might have a great impact on the epidemiological and clinical outcomes. Tolou and colleagues reported that DENV-1 Singapore S275/90 strain is a product of a recombination event between viruses from two distinct lineages in which one lineage includes an African strain isolated in Abidjan in Ivory Coast and the other includes isolates from Djibouti (AF298808-Djibouti-1998) and the closely related isolate from Cambodia [21]. Identification of such events depends on the availability of full genome sequences of DENV strains from various regions which is missing in Saudi Arabia. While the four DENV serotypes share 65–70% sequence homology, they are further clustered into different genotypes due to the high mutation rates [6,7]

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