Leptospira

A 35-year-old male agricultural worker from Kerala presents with a 3-day history of fever, severe headache, and myalgia. He has conjunctival suffusion without exudate and normal renal function (creatinine 0.9 mg/dL). Blood culture is positive for a thin, aerobic spirochete. The patient recovers spontaneously within 10 days without jaundice or renal involvement. Which stage of leptospirosis was this patient in when blood culture was performed?

A 28-year-old construction worker from Kerala presents with high fever, jaundice, oliguria, and pulmonary hemorrhage on day 10 of illness. Blood and CSF cultures are positive for Leptospira interrogans. What is the drug of choice for severe leptospirosis (Weil's disease) with renal and CNS involvement?

A 28-year-old farmer from Tamil Nadu presents with fever, myalgia, and jaundice on day 8 of illness. He had waded through flooded rice fields 10 days ago. Serum bilirubin is elevated with normal transaminases. What is the most appropriate investigation to confirm leptospirosis at this stage of illness?

A 32-year-old farmer from Tamil Nadu presents with fever, myalgia, and jaundice on day 7 of illness. Blood culture and urine culture are sent. Which Leptospira serovar is the most common cause of severe leptospirosis (Weil's disease) in India?

Which is the most common site of leptospiral shedding in the urine during the immune phase of leptospirosis?