Version July 2025
| Stage of illness | Time post-symptom onset | Clinical | Laboratory |
| Early febrile | Days 1-3 | Fever, malaise, fatigue, body aches | Leukopenia, lymphopenia, thrombocytopenia, elevated AST and ALT |
| Gastrointestinal | Days 3-10 | Primary: Epigastric and abdominal pain, nausea, vomiting, diarrhea Associated: Persistent fever, asthenia, headache, conjunctival injection, chest pain, dysphagia, odynophagia, arthralgias, myalgias, hiccups, delirium, and rash | Persistently elevated AST/ALT and thrombocytopenia Elevated BUN and creatinine Hypokalemia, hypomagnesemia, hyponatremia, hypoalbuminemia Elevated PT/PTT/INR/fibrin-split products Leukocytosis (elevated neutrophils and band cells) |
| Shock | Days 7-12 | Diminished consciousness or coma, thready pulse, oliguria, anuria, tachypnea | In addition to findings during gastrointestinal stage: Elevated lactate, decreased bicarbonate |
| Other complications | Day 10 and after | Gastrointestinal hemorrhage, respiratory failure associated with aggressive fluid resuscitation or lung injury, secondary infections, neurocognitive abnormalities, seizures, syndrome consistent with meningoencephalitis | Findings may overlap with prior stages of illness Decreased hemoglobin and hematocrit observed with gastrointestinal bleeding Hypoxemia observed with respiratory failure |
| Recovery | Days 7-12 | Resolution of gastrointestinal symptoms, increased oral intake, increased energy | Resolution of laboratory abnormalities |
| Convalescence | Up to 12 months | Arthralgias, myalgias, abdominal pain, fatigue, persistent neurocognitive abnormalities, uveitis, meningitis, hearing loss |
