around 10 million people are infected worldwide each year and around 60,000 die
disease was brought to America by the first Europeans and is thought to have killed over half the Native American population whose practices were high risk for catching the disease
most common in the tropics where there is year round high rainfall, but occurs elsewhere, usually seasonally, while outbreaks can occur in slums infested with rodents or following floods
relatively rare in Australia, but it is more common in warm and moist regions such as northeastern NSW and Queensland
it was common during trench warfare in World War I
highest risk age groups: children over 5 yrs to young adults
some infected host animals have lifelong excretion of leptospires in the urine, but most probably only for up to a year
primary hosts
secondary hosts
human infection
humans become infected through contact with water, food, or soil that contains urine from these infected animals, either by ingesting or through open wound, eye or nose contact
hence river sailors, surfers, white water paddlers, sewer workers, campers, hikers, gardeners, farmers, vets, abattoir workers and those who work on derelict buildings are a particular risk
person-to-person transmission is rare
habitats
seasonal nature