rural rodent-borne febrile illnesses compared
Hantavirus vs leptospirosis
| Feature | Hantavirus | Leptospirosis |
|---|---|---|
| Pathogen class | RNA virus (Hantaviridae) | Spirochete (Leptospira interrogans complex) |
| Reservoirs | Specific rodent per species | Many mammals; Rattus and dogs especially |
| Transmission | Inhaled aerosols of dried excreta | Skin/mucous-membrane contact with water contaminated by urine |
| Hallmark | Lung capillary leak (HPS) or renal (HFRS) | Conjunctival suffusion, jaundice, AKI |
| Antibiotic responsive? | No (supportive only; ribavirin marginal in HFRS) | Yes (doxycycline, penicillin) |
| Geography | Hemisphere-specific | Worldwide, especially tropics with flooding |
Hantavirus and leptospirosis are the two great rodent-borne febrile illnesses of rural and post-flood medicine. Both can begin indistinguishably — abrupt fever, severe muscle aches, headache, and a history of rodent exposure or work in damp rural environments. Distinguishing them quickly matters because the treatment is different.
Hantavirus. An RNA virus inhaled from aerosolised rodent excreta. The disease unfolds as either pulmonary capillary leak (HPS, the Americas) or renal failure with bleeding (HFRS, Eurasia). Antibiotics are useless. Supportive care is the only intervention; ribavirin offers marginal benefit in early-treated HTNV-HFRS but does nothing for HPS.
Leptospirosis. A spirochaete acquired through broken skin or mucous membranes from water contaminated with the urine of infected animals — Rattus, dogs, livestock, and wildlife. Hallmark clinical features include conjunctival suffusion (red eyes without discharge), calf-muscle tenderness, jaundice (Weil's syndrome), and AKI. Critically, leptospirosis responds to early antibiotic therapy — doxycycline for milder disease, IV penicillin or ceftriaxone for severe.
Clinical clues that point one way or the other. Conjunctival suffusion strongly favours leptospirosis. Pulmonary leak with thrombocytopaenia and immunoblasts on the smear strongly favours HPS. Acute kidney injury without jaundice can be either; the bleeding diathesis of severe HFRS is distinctive but not specific. Recent flooding or mud exposure favours leptospirosis; recent rural cabin clean-up favours hantavirus.
Practical approach. In a returning traveller or rural patient with undifferentiated fever, empirical doxycycline is cheap, well-tolerated, and treats leptospirosis if present. Hantavirus confirmation requires serology and PCR; supportive ICU care begins as soon as it is suspected. Many emergency departments empirically cover both.