Epidemiological aspects of leptospirosis in a slum area in the city of Rio de Janeiro, Brazil. Search for leptospires and specific antibodies in rodents.

101 Rattus norvegicus and 3 Mus musculus were captured in an urban slum of Rio de Janeiro city and examined for leptospiral infection. Direct examination of urine, serology (microagglutination) and culture together gave a positivity rate of 39%. Separately direct examination and serology gave positivity rates of 13% and 36% respectively. Serogroup Icterohaemorrhagiae predominated in the serological tests. Leptospires were isolated from 24 of the 104 rodents (23%), but 4 cultures died. The remaining 20 were identified as members of the Icterohaemorrhagiae serogroup, and 5 were further identified as serovar copenhageni. Human leptospiral infection, mainly caused by Icterohaemorrhagiae, is endemic in Rio de Janeiro city, and rodents are a major source of the disease.