Leptospirosis ( also known as Weil 's disease , canicola fever , canefield fever , nanukayami fever or seven day fever ) is a bacterial disease . It is caused by spirochaetes of the genus Leptospira . Leptospirosis ( also known as Weil 's disease , Weil 's syndrome , canicola fever , canefield fever , nanukayami fever , 7-day fever , Rat Catcher 's Yellows , Fort Bragg fever , and Pretibial fever ) is a bacterial zoonotic disease caused by spirochaetes of the genus Leptospira that affects humans and a wide range of animals , including mammals , birds , amphibians , and reptiles .