Leptospira

Leptospira (from Ancient Greek λεπτός (leptós) 'fine, thin, narrow, etc.' and Latin spira 'coil') is a genus of spirochaete bacteria, including a small number of pathogenic and saprophytic species. Leptospira was first observed in 1907 in kidney tissue slices of a leptospirosis victim who was described as having died of "yellow fever". In 1917, Hideyo Noguchi named the genus Leptospira after witnessing it in the kidneys of American rats seemingly producing the same disease in Guinea pigs as in European rats.