Concurrent outbreak of leptospirosis and dengue in Mumbai, India, 2002

This prospective study was undertaken to investigate the possibility of a concurrent outbreak of leptospirosis and dengue and to describe the clinical illnesses. From 20 June to 14 November 2002, children who presented to our hospital with a suspected diagnosis of leptospirosis or dengue were admitted. In every child with suspected leptospirosis, a screening latex agglutination test was carried out to detect anti-Leptospira antibodies. The diagnosis of leptospirosis was confirmed by a positive enzyme-linked immunosorbent assay (ELISA) test or microagglutination test. The diagnosis of dengue was confirmed by a positive IgM antibody capture ELISA test. Clinical features in the leptospirosis and leptospirosis-negative groups, and dengue and dengue-negative groups were analysed. Of 90 children screened, 15 (16.7 per cent) had leptospirosis. Two children with Weil's disease died and the remaining 13 responded well to intravenous penicillin. Five clinical features were significantly associated with leptospirosis, namely conjunctival suffusion (p=0.007), haemorrhage (p=0.020), abdominal pain (p=0.011), hepatosplenomegaly (p=0.044), and oedema (p=0.007). As the number of these five features concomitantly present increased, the chances of the child having leptospirosis also increased significantly (p<0.0001). Of 90 children screened, 16 (17.8 per cent) had dengue. All responded well to the treatment and went home. Two clinical features were significantly associated with dengue, namely arthralgia (p=0.020) and thrombocytopenia (p=0.001). If both these features were present, the chances of the child having dengue increased significantly (p=0.001). Our study shows that a concurrent outbreak of leptospirosis and dengue had occurred in the slums of Mumbai city.