What is Leptospirosis?

Leptospirosis is a zoonotic disease caused by pathogenic Leptospira species. Leptospira are  spirochetes (helically-wound bacteria) that cause infection in animals, and are carried asymptomatically by rodents, especially rats. When humans are infected, clinical presentation ranges from asymptomatic or mildly febrile illness (90% of cases) to severe leptospirosis or life-threatening (10% of cases). Complicated leptospirosis is also known as Weil’s syndrome.

Leptospirosis is a biphasic disease, with the first phase presenting as a flu-like illness, followed by brief respite and then aseptic meningitis/encephalitis, liver damage (causing jaundice), and renal failure. Infection takes many different clinical forms usually with sudden onset of fever, severe headache, myalgia, chills, vomiting, diarrhoea, abdominal pain, conjunctival suffusion and skin rash. The disease may progress to meningitis, haemolytic anaemia, jaundice, haemorrhagic fever and other complications, including hepato-renal failure (Weil’s disease). Initial presentation may resemble pneumonia. The symptoms in humans appear after a 2–26 (mode=10) day incubation period.