Leptospira interrogans

Leptospira interrogans is a Gram negative, obligate aerobe spirochete, with periplasmic flagella. When viewed through a dark-field microscope, it often resembles a question mark, and this gives the species its name. It is a member of the genus Leptospira. Some important pathogenic serovars from this species are Canicola, Icterohaemorrhagiae and Australis. L. interrogans is difficult to culture, requiring special media and extended incubation periods. L. interrogans infects wild and domestic animals, including pet dogs. Humans are accidental hosts. It can survive in neutral or slightly alkaline water for 3 months or longer. L. interrogans is usually transmitted to humans through contact with infected animal urine, either directly or in water. It invades directly through broken skin and can replicate in the liver and kidneys. Risk factors for infection include working in sewers, farming, and recreational water activities. Infection is known as leptospirosis, which can be asymptomatic, a mild non-specific illness, or result in death from liver damage and renal failure (Weil's syndrome).