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Volume 43, Number 1, February 2010

Continued Persistence of a Single Genotype of Dengue Virus Type-3 (DENV-3) in Delhi, India Since its Re-emergence Over the Last Decade



Division of Biochemistry and Biotechnology, National Institute of Communicable Diseases, 22-Shamnath Marg, Delhi-110054, India.

Received: November 18, 2008    Revised: January 3, 2009    Accepted: April 7, 2009   

 

Corresponding author:

Division of Biochemistry and Biotechnology, National Institute of Communicable Diseases, 22-Shamnath Marg, Delhi-110054, India.
E-mail: drarvindrai32@yahoo.com



 

Background and purpose: 

The re-emergence of an epidemic strain of dengue virus type-3 (DENV-3) in Delhi in 2003 and its persistence in subsequent years marked a changing trend in dengue virus circulation in this part of India. Its evolving phylogeny over the past decade has not been studied in detail as yet.



 

Methods:

Reverse transcription polymerase chain reaction and sequencing of the CprM gene junction of DENV-3 from different outbreaks since 2003 was carried out. Thirty CprM DENV-3 sequences from this study were compared with 46 other previously reported CprM DENV-3 sequences from India and other countries. Multiple sequence alignment and phylogenetic trees were constructed to determine the extent of genetic heterogeneity and trace the phylogeny of DENV-3.



 

Results:

Thirty CprM DENV-3 sequences (Accession numbers AY706096–99, DQ645945–52, EU181201–14, and EU846234–36) were submitted to GenBank. The CprM junction was found to be AT rich (approximately 53%). Nucleotide sequence alignment revealed only nucleotide substitutions. Phylogenetic analysis indicated sustained evolution of a distinct Indian lineage of DENV-3 genotype III in Delhi.



 

Conclusion:

Active circulation of DENV-3 genotype III over the last decade in Delhi was evident and worrying. This genotype has been implicated in several outbreaks in South-East Asia and other parts of the world.



 

Key words:

dengue virus, genotype, India, lineage, phylogeny