Microbiology and Epidemiology: -

Leptospires are spirochetal organisms that cause an important zoonosis with a broad spectrum of clinical manifestations.

  • The organisms are small enough to pass through filters used to sterilize culture medium.
  • The most important sources of transmission to humans are rats, dogs, cattle, and pigs. Transmission can occur during contact with urine and other excreta (e.g., placenta, products of parturition) from infected animals or during exposure to contaminated environments.
  • Only ~50–100 cases in the U.S. are passively reported annually to the CDC, but these numbers are likely to represent significant underestimates given that leptospirosis is not a notifiable disease.


After an average incubation period of 5–14 days, infection by Leptospira results in a subclinical infection, an undifferentiated febrile illness, or Weil’s disease (the most severe form).

  • Leptospirosis is a biphasic illness. The initial leptospiremic phase lasts 3–10 days and is characterized by fever. After another 3–10 days (the immune phase), some pts experience a return of fever, headache, and other systemic

symptoms in association with the clearance of leptospires from the blood.

– Only the initial phase is responsive to antibiotic therapy.

– Nonspecific physical findings may include conjunctival suffusion, nonexudative pharyngeal erythema, muscle tenderness, rales on lung auscultation, jaundice, meningismus, and hypo- or areflexia (particularly in the legs).

  • Weil’s disease is characterized by variable combinations of jaundice, acute

renal injury, hypotension, and hemorrhage—most commonly involving the lungs. Cardiac involvement (e.g., myocarditis), severe myalgias (occasionally mimicking acute abdomen), rash, and neurologic findings (e.g., aseptic meningitis) are common.


A high index of suspicion prompting elicitation of a detailed exposure history is critical and guides confirmatory testing.

  • Serologic assays are the diagnostic mainstay in leptospirosis. The microscopic agglutination test is the gold standard and typically is performed only in reference laboratories, such as the CDC. Most other serologic tests use a saprophytic leptospire as the antigen and provide nonspecific results.
  • Definitive diagnosis rests on demonstration of the organism by culture isolation (which takes weeks), detection of nucleic acids or antigen in body fluids (a method typically limited to research settings), or immunohistochemical visualization in tissue.

– Leptospires can be cultured from blood and CSF during the first 7–10 days of illness.

– Urine cultures are positive in the second week of illness and can remain positive for months or years despite antibiotic therapy.


The medicines that can be thought of use are:-

  • Aconite
  • Arsenicum album
  • Merc cor
  • Crotalus horridus
  • Phosphorus
  • Lycopodium