[Hospital-based active surveillance of human leptospirosis in Cambodia]

Leptospirosis has been so far poorly described in Cambodia and is probably underdiagnosed in the current local medical practices, although conditions to its active circulation exist in this country. Between June 2006 and July 2007, 612 patients admitted to Takeo hospital and Calmette hospital in Phnom Penh presenting clinical symptoms compatible with leptospirosis, were recruited for biological investigation of leptospirosis markers: PCR detection of bacterial DNA and serology using an Elisa-IgM test and the micro-agglutination reference test (MAT). One hundred eighty-three patients (29.9%) were found to be carrying at least one biological marker of leptospirosis, 88 (14.4%) showed an acute infection profile, evidenced by a positive PCR. The proportion of patients with an immune phase profile (15.5%) suggests former contacts with Leptospira and possible infections with little or no symptoms. Thirteen serogroups of Leptospira have been identified, with predominance of Panama, Pyrogenes and Australia, illustrating a probable wide range of animal reservoir hosts. Serogroup Icterohaemorrhagiae was found in only 4% of cases, contrasting with usual features of human leptospirosis. No significant link between infection and sex, age or occupation could be established, suggesting a permanent exposure of the population in its daily life rather than the existence of risk groups. This study, the largest conducted to date on leptospirosis in Cambodia, confirms the importance of this zoonotic disease, that must be considered a real public health issue in this country.