Hantaan river virus is the causative agent of Korean hemorrhagic fever in humans. Initial symptoms begin suddenly and include intense headaches, back and abdominal pain, fever, chills, nausea and blurred vision. Individuals may have flushing of the face, inflammation or redness of the eyes or a rash. Later symptoms can include low blood pressure, acute shock, vascular leakage and acute kidney failure, which can cause severe fluid overload.