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.