Reemergence of dengue virus type-3 (subtype-III) in India: implications for increased incidence of DHF & DSS.
BACKGROUND
Dengue virus infection has recently taken endemic proportion in India implicating all the four known dengue serotypes. There was a major dengue outbreak in northern India including Delhi in October- December, 2003 and again in 2004. We have carried out a detailed investigation of the 2004 outbreak by Serosurveillance, RT-PCR, nested PCR, virus isolation and genotyping. We also report the molecular epidemiological investigation of these outbreaks.


RESULTS
The serological investigation of 162 suspected serum samples using an in-house dengue dipstick ELISA revealed 11%-IgM, 51%-IgG and 38%-both IgM and IgG antibody positivity. The RT-PCR analysis revealed presence of dengue RNA in 17 samples. Further subtyping and genotyping by nested PCR and nucleotide sequencing of C-prM gene junction revealed the association of subtype III of dengue virus type 3 in the outbreak.


CONCLUSIONS
The sudden shifting and dominance of the dengue virus serotype-3 (subtype III) replacing the earlier circulating serotype-2 (subtype IV) is a point of major concern and may be attributed to increased incidence of DHF and DSS in India.
Dash
Paban Kumar
PK
Division of Virology, Defence R&D Establishment, Jhansi Road, Gwalior- 474002, MP, India. pabandash@rediffmail.com
Parida
Man Mohan
MM
Saxena
Parag
P
Abhyankar
Ajay
A
Singh
C P
CP
Tewari
K N
KN
Jana
Asha Mukul
AM
Sekhar
K
K
Rao
P V Lakshmana
PV
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D003716:Dengue Virus / Q000145:classification* / Q000235:genetics / Q000276:immunology; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007194:India / Q000453:epidemiology; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D019595:Severe Dengue / Q000097:blood / Q000453:epidemiology* / Q000276:immunology / Q000821:virology*
D007074:Immunoglobulin G; D007075:Immunoglobulin M