Circulation of Dengue virus-1 (DENV-1) serotype in Delhi, during 2010-11 after Dengue virus-3 (DENV-3) predominance: a single centre hospital-based study.
BACKGROUND
Delhi, a city in north India, has so far witnessed several reported outbreaks of dengue. Dengue in Delhi from being epidemic is slowly changing towards being endemic and hyper-endemic. Circulating type of the virus is also changing over the years. In the absence of an effective vaccine, dengue prevention to a major extent relies on virological surveillance, and development of effective, locally adapted control programmes. In the present study, we tried to identify the between-year non-epidemic serotype of dengue virus circulating in Delhi, during 2010-11.


METHODS
Acute-phase samples were collected from the patients attending the Institute of Liver & Biliary Sciences, New Delhi, India. Dengue diagnosis was done using WHO case definitions. All the samples were subjected to Dengue NS1 Ag ELISA and modified nested RT-PCR.


RESULTS
A total of 75 acute-phase samples were received, of which 19 (25.3%) were positive for dengue NS1 antigen. Dengue RT-PCR was positive in 14.6% (11/75) samples. All the RT-PCR isolates were of DENV-1 serotype. No case of concomitant infection with more than one serotype was observed. Median age of involvement was 23 yr (range10-86). Maximum number of cases were seen in the age group of 21-30 yr. Male to female ratio was 1.2 : 1. Maximum number of suspected dengue cases (n=79) was seen during September and October.


CONCLUSIONS
DENV-1 was circulating in Delhi in the year 2010-11 in non-epidemic period following reported predominance of DENV-3 and co-circulation of all dengue serotypes in the epidemic years 2003, 2006 and 2007.
Department of Virology; New Delhi, India. ektagaurisha@gmail.com
Ekta
E
Gupta
Sweta
S
Mohan
Meenu
M
Bajpai
Aashish
A
Choudhary
Gaurav
G
Singh
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000956:Antigens, Viral / Q000097:blood; D002648:Child; D003715:Dengue / Q000453:epidemiology* / Q000821:virology*; D003716:Dengue Virus / Q000145:classification* / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005838:Genotype; D006761:Hospitals; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012703:Serotyping; D055815:Young Adult
D000956:Antigens, Viral; D012367:RNA, Viral