These people are in a medium that is contaminated with Leptospira interrogans bacteria; because of their activities, they cannot wear protective devices like water goggles or neoprene suits; and the same activity favors skin lesions that can facilitate infection. If the question is who performs an activity that entails the risk of becoming infected by leptospirosis, the answer is: those who practise water sports like rowing, sailing, open water swimming, yachting and thriatlon.