During an arbovirus outbreak, screening for leptospirosis following exposure to a risk factor is a priority.

Indeed, the symptoms can be confused with those of other infectious diseases, such as dengue fever. Any delay in diagnosis and treatment can be dangerous. In 2006, a transient increase in leptospirosis mortality (six times higher than usual) was reported during the chikungunya epidemic. This is possibly linked to confusion in the initial diagnosis (similar clinical presentation), a delay in initiating antibiotic therapy, and possibly greater pathogenicity or leptospirosis/chikungunya co-infection.

To provide guidance for diagnosing leptospirosis in this context, tools identifying the clinical, biological, and epidemiological characteristics of leptospirosis, chikungunya, and dengue—developed in Réunion in collaboration with infectious disease specialists and hospital laboratory scientists, the CVAGS, the URMLOI, the Health Insurance Fund, and Santé publique France, are available:

• A guidance document summarizing the most essential information

• Guidelines on "Biological Confirmation of Leptospirosis, Dengue, and Chikungunya and Case Reporting"