A previously healthy 28 yo F presents to your ED with HA, myalgias, abdominal cramps, nausea, vomiting, and diarrhea. She reports recent trip 2 weeks ago to Yosemite National Park where she was camping with her boyfriend. Pt is coughing, sob, febrile and appears unwell in pain. She mentions that there was some warning while at Yosemite but not sure what it referred to. What is your diagnosis? (hint: there was a recent outbreak notice from CDC) How do you treat this patient?


The patient presents with Hantavirus/Hantavirus Pulmonary syndrome which carries a mortality rate of 38%. The virus is transmitted via rodents most commonly the deer mouse in North America. The virus is mainly in the urine, feces, and saliva of rodents that infects via airborne transmission.

Diagnosing HPS in an individual who has only been infected a few days is difficult, because early symptoms such as fever, muscle aches, and fatigue are easily confused with influenza. Symptoms present within 1-5 weeks from exposure.

The simultaneous appearance of thrombocytopenia, a left-shifted granulocytic series, and an immunoblast count that exceeds 10 percent of the total lymphoid series is referred to as the diagnostic triad. This triad is sufficiently diagnostic that it is used at centers with substantial experience with HCPS to triage patients for extracorporeal membrane oxygenation (ECMO) and other specialized tertiary care.

Treatment is primarily supportive and if survives, patients can expect full recovery to baseline. ECMO has shown some benefit. Although Ribavirin may have some benefit, trials were halted due to slow accrual and off protocol cannot be recommended for established HCPS (Grade 1C)