A coiled, thin, long gram negative rod of which there are > 214 serotypes. L. interrogans is the most common pathogen, but includes. L borgpetersenii, L. inadai, L. kirschneri, L. noguchii, L. sanatarosi, L. weilii.
It is worldwide in distribution; wherever there is water, espcially flood waters, and animals (PubMed). Contact with water or soil that animals (cows, dogs, rodents) have peed in. It is found in virtually all animals, and outbreaks often occur after flooding, with the infected pee washing into common water. Swimmers, kayakers, iron man competitors, triathaletes, racing in the tropical forest of Martinique, endurance-length swamp racers (PubMed), etc are at risk. In other words, anyone fool enough to play in animal pee containing water. It is common in Hawaii. When you are in the warm waterfall, you are in cow piss. The good news? In Hawaii the strains have changed from L. icterohemorrhagiae to L. australis and recreational exposures have plateaued, while occupational exposures have increased. So avoid work in Hawaii, braugh (PubMed).
In Europe, where they can't do the real deal, they river surf, basically surf on a standing wave. Looks lame. But a risk (PubMed).
Urban slum acquisition is common, in Brazil it is 3% per year and reinfection is common (PubMed).
Men are more likely to get severe disease, at least in Germany (PubMed). And, of all things, strawberry pickers. And there is the rare urban case. Animal pee is everywhere.
Varies from mild illness to multi organ system failure with death. Hints: water or animal exposure. On exam look for conjunctival suffusion, calf and lumbar muscle tenderness, bilirubin out of proportion to the rest of the LFT's; hepato-renal failure (Weils), aseptic meningitis, low magnesium (PubMed). I had one patient with a very low calcium, which is reported as a manifestation in dogs.
It may be a common cause of aseptic meningitis. Can grow it on Fletchers media, what ever the hell that is. Found, I think, on the Bounty.
Penicillin, amoxicillin, doxycycline oral if mild, iv penicillin >= ceftriaxone if severe. Can get a Jarisch-Herxheimer reaction with therapy. Cefazolin is effective in vitro, in people not known (PubMed).
I know you are just itching to give steroids. The data? "Four studies demonstrated a benefit of corticosteroids in treating severe disease with pulmonary involvement when administered early in the course of the disease, but these studies had several methodological constraints as highlighted in the text. Only the randomized controlled trial study showed that corticosteroids are ineffective and may increase the risk of nosocomial infections. There is no robust evidence to suggest that high dose corticosteroids are effective in severe leptospirosis (PubMed)."
About 2% will die untreated but the more organs that fail, the higher the mortality (PubMed).
200 mg po q week of doxycycline may prevent illness. Or maybe not. The Cochrane reviews says the studies for prophylaxis are of such poor quality they canna make a recommendation for efficacy (PubMed).