When should I seek emergency care for possible hantavirus infection?

Seek emergency care immediately — do not wait — if any of these three warning signs apply: (1) Severe muscle aches (thighs, hips, lower back) with high fever above 38°C (100.4°F), AND a history of rodent contact or rural travel in South America (especially Argentina, Chile, Uruguay) within the past 8 weeks. (2) Progressive shortness of breath or difficulty breathing appearing 4–10 days after a fever begins — this signals the life-threatening cardiopulmonary phase of Hantavirus Pulmonary Syndrome (HPS), which can deteriorate to respiratory failure within hours. (3) Any influenza-like illness if you were a passenger or crew member aboard MV Hondius (2026 Andes virus cluster) within the past 6 weeks — tell the emergency team about your ship itinerary immediately. CDC clinical guidance emphasizes that outcomes improve significantly with early hospitalization, oxygen support, and ICU monitoring before respiratory failure develops. Hantavirus has a 30–40% case fatality rate in HPS — 'it might be the flu' is a dangerous assumption if the exposure risk factors above apply.