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... Diagnosis
There was one other possibility that seemed to tick all the boxes: fever, gastrointestinal symptoms, low oxygen saturation, pulmonary edema, and shock -- a hantavirus infection.
Hantaviruses are RNA viruses that infect rodents worldwide. They typically cause asymptomatic, chronic infections in the animals, which spread the virus widely into their environments through their urine, feces, and saliva. Humans get infected when virus particles from rodent-contaminated areas are stirred up into the air and inhaled or through direct contact with the virus via the eyes, nose, mouth, or cuts.
In humans, the viral infection is anything but asymptomatic. While the disease mechanism isn't entirely understood, the virus appears to be able to modulate immune responses in humans, causing blood vessels and capillaries in various places in the body to start leaking plasma. This leads to fluid building up in the lungs (the pulmonary edema) and systemic circulatory collapse.
A cardiopulmonary hantavirus infection typically has four stages: the incubation period, which can last up to 45 days after virus exposure; a prodromal phase of up to 12 days, which is marked by fever, fatigue, and pains; the cardiopulmonary phase, where breathing trouble, low oxygen saturation, and shock can develop; then, if you make it, the fourth stage, in which respiratory symptoms improve, but there's lingering fatigue and the kidneys make abnormally large amounts of urine.
Haunting risks
There is no specific treatment for hantavirus; medical care is mostly supportive. ...