Read condition-specific symptoms and clinical context for Leptospira interrogans. A hook-ended spirochete spread through animal urine in water and soil, causing everything from a flu-like week to organ failure.
Bilung and colleagues describe Leptospira as finely coiled, filamentous spirochetes, extremely thin and helically coiled, typically measuring 6 to 20 micrometres in length and approximately 0.1 micrometre in diameter, with question-mark hook-shaped ends that distinguish them from other spirochetes, a double-membrane envelope and periplasmic endoflagella anchored at both cell poles. They stain poorly with conventional dyes including Gram stain and are too thin to be seen by ordinary light microscopy, so dark-field or phase-contrast microscopy is used. PHAC records at least 218 serovars in 23 serogroups. CDC states that about 1 million cases occur globally each year with nearly 60,000 deaths, and that the bacteria are spread through the urine of infected animals and can survive in contaminated water or soil for weeks to months.
PHAC describes a biphasic illness lasting 3 days to a few weeks, with an incubation period usually of 10 days and a range of 4 to 19 days. CDC gives 2 to 30 days.
Possible symptoms: Fever; Headache; Chills; Severe malaise; Vomiting; Muscle pain; Red eyes; Diarrhea; Rash.
CDC describes an initial phase that may be followed by temporary improvement before a severe second phase. PHAC gives a low case fatality rate that increases with age. Diagnosis and treatment are clinical decisions.
PHAC describes Weil’s disease manifestations, and CDC describes a severe second phase that may develop after apparent improvement.
Possible symptoms: Jaundice; Kidney failure; Liver failure; Anaemia; Bleeding; Meningitis.
CDC describes this as a possible second phase rather than the usual course. PHAC notes case fatality increases with age. Severe illness needs hospital care.
Contact with contaminated water or soil does not always produce recognised illness.
CDC states that some infected individuals show no signs at all, and that many symptoms resemble other illnesses. There is no symptom list for this state and none is invented here. PHAC describes transmission through contact of the skin or mucous membranes with contaminated water, soil or vegetation, and names occupational groups including rice and sugar cane field workers, farmers, veterinarians and miners. That is an exposure category, not a diagnosis, and this profile assigns no human carriage state: the reservoir is animals, whose urine contaminates the environment.
Occupational and recreational exposure questions, and any preventive measures, belong with local health services. This app gives no exposure advice.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.