Symptoms in early period of avian influenza are similar to those of human influenza, including headaches, myalgia, runny nose, coughs, sore throat, and conjunctivitis (according to the H7N7-infected patient in Netherlands). Moreover, the H5N1-infected cases in Vietnam also show the symptom of diarrhea. In the later period, the patients may suffer from high fever, pneumonia, multiple organ failure, and even die.