Serodiagnosis of dengue during an outbreak at a tertiary care hospital in Delhi.

Dengue, an important human arboviral infection, is endemic in many parts of India. Outbreaks are now reported quite frequently from different parts of the country. We report here findings of serological investigation of serum samples received during a recent outbreak of dengue infection in Delhi from September to November 2003. Acute phase serum samples from suspected cases of dengue infection (including dengue fever, dengue haemorrhagic fever and dengue shock syndrome) of duration 5 days, were tested for dengue specific IgM antibodies by enzyme linked immuno sorbant assay (ELISA). Of the 874 serum samples tested, 456 (52.3% ) were positive for dengue specific IgM antibodies. The maximum number of positive cases was reported in October, peaking in second and third week. Patients in the age group of 21-30 yr accounted for 34.2 per cent of positive cases. This outbreak was less severe as compared to the previous 1996 outbreak and showed a shift towards an older age group.