Man’s Camping Trip Results in 40-Day ICU Battle with Hantavirus

By Beth Mole – May 28, 2025

Case Presentation

An otherwise healthy 52-year-old office worker from Buenos Aires presented to a local emergency department with a persistent high-grade fever (39.5 °C) of one-week duration. Initial vital signs were notable only for fever and mild tachycardia; oxygen saturation was 97% on room air. A rapid molecular PCR test for SARS-CoV-2 was negative. He was discharged with antipyretics and supportive care.

Within five days he developed diffuse abdominal pain, nausea, diarrhea, and progressive dyspnea. On re-presentation he was tachypneic (respiratory rate 28 breaths/min) with an SpO₂ of 89% on room air. A chest X-ray revealed bilateral, diffuse ground-glass opacities. He was started on 4 L/min oxygen via nasal cannula, then escalated to a non-rebreather mask when his PaO₂/FiO₂ ratio fell below 200 mmHg.

ICU Admission and Clinical Deterioration

• Day 2: Admitted to ICU; intubated for acute hypoxemic respiratory failure consistent with ARDS.
• Day 4: Developed distributive shock requiring norepinephrine infusion at 0.1 µg/kg/min.
• Day 5: Acute kidney injury (AKI) Stage 3 with oliguria; continuous renal replacement therapy (CRRT) initiated.
• Day 7: Sedation regimen of fentanyl (2 µg/kg/h) and midazolam (0.1 mg/kg/h); prone positioning two sessions daily.

Diagnostic Workup

Laboratory studies identified:

• Hematology: Hemoconcentration (Hct 52%), leukocytosis (WBC 19 ×10⁹/L), thrombocytopenia (platelets 75 ×10⁹/L).
• Biochemistry: Elevated AST/ALT (2× ULN), lactate 4.5 mmol/L, creatinine 3.2 mg/dL.
• Microbiology: Negative PCR/serology for SARS-CoV-2, influenza A/B, HIV, dengue, leptospira, CMV, and Legionella.

High-resolution CT imaging showed confluent ground-glass opacities, dependent consolidation, interlobular septal thickening, and a subtle “halo sign” in the right upper lobe, raising suspicion for an invasive process.

Diagnostic Challenge

Differential diagnoses included community-acquired pneumonia, pulmonary–renal syndromes, hematologic malignancies, and invasive fungal infection. Absence of productive cough, negative blood cultures, normal peripheral smear, and lack of lymphadenopathy or splenomegaly on ultrasound argued against these.

“The combination of hemoconcentration, thrombocytopenia, rapid onset pulmonary edema, and shock pointed us toward a viral etiology, specifically hantavirus cardiopulmonary syndrome (HCPS),” said Dr. María Ruiz, Infectious Diseases Consultant at Hospital Alemán, Buenos Aires.

Final Diagnosis: Hantavirus Cardiopulmonary Syndrome

Serologic assay by ELISA detected high titers of hantavirus-specific IgM. Reverse-transcription PCR on a whole-blood sample confirmed New World hantavirus RNA (likely Andes virus, endemic to southern Buenos Aires province). No antiviral therapies are FDA-approved for HCPS; supportive care remains the mainstay.

Virology and Pathophysiology

Hantaviruses are enveloped, tri-segmented, negative-sense RNA viruses of the Hantaviridae family. Rodent reservoirs (e.g., Oligoryzomys spp.) shed virus in excreta. Inhalation of aerosolized particles leads to capillary leak mediated by dysregulated host immune responses—particularly cytotoxic T-cell activation and cytokine storm, resulting in pulmonary edema and myocardial depression.

Ventilator Management and Critical Care Advances

• Ventilation Strategy: Lung-protective ventilation (tidal volume 6 mL/kg PBW, PEEP titrated to maintain alveolar recruitment; driving pressure <15 cm H₂O).
• Adjuncts: Prone positioning improved oxygenation (PaO₂/FiO₂ rose from 85 to 150 mmHg).
• ECMO Consideration: Venovenous ECMO reserved for refractory hypoxemia; not required in this case.

Recovery and Rehabilitation

After 28 days of mechanical ventilation, the patient was weaned successfully. CRRT discontinued on day 20 as renal function recovered. He was transferred to a specialized physical therapy unit for neuromuscular reconditioning and respiratory physiotherapy, regaining full functional status by day 40.

Public Health and Prevention

HCPS remains rare but highly lethal (35% fatality in the U.S.; up to 50% in Argentina). Between 1993 and 2024, the CDC logged >800 U.S. cases, predominantly west of the Mississippi River. Recent high-profile cases—pianist Betsy Arakawa in New Mexico—underscore persistent rodent control challenges.

Recent Research and Future Directions

Current studies are evaluating:

1. Monoclonal antibodies targeting the Gn/Gc glycoprotein complex to neutralize viral entry.
2. Host-directed therapies to modulate vascular permeability (e.g., bradykinin receptor antagonists).
3. AI-driven surveillance systems integrating remote sensing and rodent population data to predict outbreak hotspots.

Expert Commentary

“Advances in next-generation sequencing and point-of-care PCR can shorten diagnostic delays, a key factor in reducing HCPS mortality,” notes Dr. Alan Peterson, virologist at the National Institute of Infectious Diseases, Buenos Aires.

Given the absence of a human vaccine, prevention hinges on environmental control: sealing cabins, safe disposal of rodent droppings (using bleach solutions), and wearing N95 respirators in high-risk settings.