Dificultades en el diagnóstico diferenciado del dengue y la leptospirosis en Guayaquil

Leptospirosis and dengue fever are infectious diseases that co-occur during rainy seasons and both produce similar clinical signs. The purpose of this study was to assess the relative frequency of leptospirosis and dengue fever during a rainy season and the clinical difficulty to distinguish them. Blood samples from febrile patients in Guayaquil were obtained during the rainy season of 2008 and were analyzed by IgM ELISA for both diseases. Additionally, retrospective data (2003-2007) from febrile patients who attended one of largest public hospitals in Guayaquil were obtained. From 135 febrile patients samples, 15 (11.1%) were positive to leptospirosis; 36 (26,7%) to dengue fever; 3 (2.2%) to both pathogens and 81 (60%) were negative for both. Based on clinical diagnosis, cases were classified 68.1% as dengue fever; 20.7% as leptospirosis; 9.6% as malaria and 1.5% as other. However, 60% of patients clinically diagnosed as dengue had only antibodies against Leptospira and 25% patients diagnosed as leptospirosis had antibodies to dengue virus. The hospital archives indicated that 72.8% of patients clinically diagnosed as dengue fever had antibodies to Leptospira and not to dengue virus. The results suggest the two diseases are often misidentified which is a serious problem because both diseases require different medical treatment.