Field rats form a major infection source of leptospirosis in and around Madurai, India.

AIMS: To determine the seroprevalence of leptospires and to isolate Leptospira spp. from field rats and bandicoots in and around Madurai. MATERIALS AND METHODS: Thirteen rats and five bandicoots were trapped alive from fields in and around Madurai. Blood samples were tested for anti-leptospiral antibodies by microscopic agglutination test while the urine and kidney samples were used for isolation of leptospires. The isolated leptospires were tested for pathogenic status (13 degrees C test and PCR) followed by serological and genetic characterization. RESULTS: Serology revealed the presence of anti-leptospiral antibodies in 58% (7/12) of field rats and leptospires were isolated from two urine and six kidney samples. The bandicoots were negative in both serology and culture. Analysis of the isolates from field rats revealed that all the isolates were pathogenic except for one, which was further confirmed by serological and genetic characterization. Six of the seven pathogenic isolates were identified as L. interrogans serogroup Autumnalis serovar Akiyami A and one as L. borgpetersenii serogroup Javanica serovar Veldrat Batavia 46. CONCLUSIONS: Serology and isolation reveals that field rats are major natural carriers and shedders of leptospires in and around Madurai.

Lai-like leptospira from the Andaman Islands.

BACKGROUND & OBJECTIVES: Leptospirosis has been an important public health problem in the Andaman Islands since 1988. As information about the exact etiological agent is not available, the present study was undertaken to isolate and identify Leptospira from human patients. METHODS: An isolate coded AF61 was recovered from the blood of a patient clinically suspected to have leptospirosis, with fever, headache and body aches as the main symptoms. The isolation was done using Ellinghausen-McCullough-Johnson-Harris (EMJH) medium following standard procedure. The isolate was identified using microscopic agglutination test (MAT) with 'groupsera', cross agglutination absorption test (CAAT) and monoclonal antibodies. RESULTS: Agglutination tests with rabbit antisera revealed that the isolate belonged to the serogroup icterohaemorrhagiae. The CAAT results showed that it was closely related to the serovar lai. Analysis of AF61 with monoclonal antibodies confirms our observation with CAAT that it is closely related to the reference strain Lai serovar lai. INTERPRETATION & CONCLUSIONS: Serovar lai, has been associated with pulmonary haemorrhage in China and Korea. However, the strain AF61 was not isolated from a patient with pulmonary symptoms. Further studies are needed to understand the possible relationship between serovars and clinical patterns and the distribution of serovar lai and lai-like strains in Asia.