Leptospirosis: a silent epidemic disease.

This special issue of International Journal of Environmental Research and Public Health is dedicated to leptospirosis, an endemic zoonotic disease that is a cause of many acute undifferentiated fevers, especially in tropical countries. While it can be debated whether leptospirosis is an emerging disease, it is evident that it is becoming an emerging public health problem. It is recognized as a disease of epidemic potential that has a significant health impact in many parts of the world.