Seroprevalence and Trend of Dengue Cases Admitted to a Government Hospital, Delhi – 5-Year Study (2006-2010): A Look into the Age Shift

Background: diagnosis of dengue infection is easily and bestaccomplished by demonstration of specific igm antibodies inblood. we analyzed retrospectively the dengue igm seropositivityavailable for samples obtained over a period of 5 years (2006–2010) from patients with suspected dengue fever (df)-like illnessto investigate whether there was an overall increase in the dengueigm prevalence over this period.methods: blood samples were collected from patients with dflikefebrile illnesses attending the pediatric, medicine, and feverclinics of a government hospital, delhi. a total of 8138 individuals(suspected dengue cases) obtained over 5 years were tested fordengue specific igm antibodies. year wise, month wise, and agewise data on geographic distribution and clinical manifestationswere analyzed.results: of the 8138 samples, 1600 (19.66%) were positive fordengue specific igm. the year 2006 had the highest number ofreported cases, 761 (46.23%). in our study, the age group mostcommonly affected of all 5 years was 11–20 years. out of the total1600 cases admitted to the hospital between 2006 and 2010, 279(58.9%) had df, 178 (37.6%) had dengue hemorrhagic fever, and16 (3.38%) had dengue shock syndrome. we found a high burdenof dengue in young children and late adolescents in both ruraland urban communities at a magnitude greater than previouslydescribed.interpretation and conclusion: we observed an increase in thedengue positive cases every alternate year, thereby indicating apossible role of herd immunity in northern india. we did not finda steady increase in the number of cases over 5 years. we foundan increase in the number of positive cases in children and youngadolescents.