Leptospirosis and Scrub Typhus

A 32-year-old male farmer from Tamil Nadu presents with a 7-day history of high-grade fever, severe headache, and myalgia. On examination, he has a temperature of 39.5°C, generalized lymphadenopathy, and a painless eschar on his left thigh with surrounding erythema and regional lymphadenopathy. His WBC count is 11,200/μL with left shift, and platelet count is 85,000/μL. Liver function tests show ALT 240 IU/L and AST 320 IU/L. What is the most likely diagnosis?

A 28-year-old male agricultural worker from Odisha presents with a 5-day history of fever, chills, and severe headache. On day 4, he developed a maculopapular rash on his trunk and limbs. Physical examination reveals temperature 39.2°C, generalized lymphadenopathy, hepatosplenomegaly, and no eschar. Laboratory investigations show WBC 9,800/μL, platelets 92,000/μL, bilirubin 1.8 mg/dL, AST 380 IU/L, ALT 210 IU/L, and creatinine 1.4 mg/dL. Weil–Felix test is positive. What is the most appropriate next step in management?

In leptospirosis, which phase of the biphasic illness is characterized by the appearance of IgM antibodies and immune complex deposition?

A 32-year-old male farmer from Tamil Nadu presents with a 7-day history of high-grade fever, severe headache, and myalgia. He reports wading through flooded rice fields 10 days ago. On examination, he has conjunctival suffusion without exudate, a petechial rash on the trunk, and mild jaundice. His blood pressure is 100/65 mmHg. Laboratory investigations show: WBC 12,500/μL with left shift, platelets 85,000/μL, serum creatinine 2.1 mg/dL, total bilirubin 3.2 mg/dL (predominantly direct), and ALT 320 U/L. Urine dipstick shows 2+ proteinuria. What is the most likely diagnosis?

A 28-year-old male trekker from Himachal Pradesh presents with a 10-day history of fever, headache, and generalized myalgia. He recalls being bitten by mites while camping in scrub forest 12 days ago. On examination, he has a maculopapular rash on the trunk and extremities (sparing palms and soles), a 1 cm × 1 cm black necrotic ulcer with surrounding erythema on the left thigh, and generalized lymphadenopathy. His temperature is 39.5°C, heart rate 110/min, and respiratory rate 28/min. Laboratory findings: WBC 8,500/μL, platelets 120,000/μL, ALT 280 U/L, creatinine 1.4 mg/dL. Chest X-ray shows bilateral interstitial infiltrates. What is the most appropriate initial antibiotic therapy?