Symptoms occur approximately two to eight days after exposure, on average. Infected people experience typical flu-like symptoms that may includefever (above 38 C or 100.4 F),feeling unwell (malaise),cough (usually dry or nonproductive of sputum),sore throat,muscle aches and pain,nausea,vomiting,diarrhea,headache,joint pain,lethargy,nasal secretions (runny nose or sneezing),insomnia, andeye infections (conjunctivitis). Children get similar symptoms. This viral infection can progress to pneumonia and even respiratory failure. Bird flu causes a very aggressive form of pneumonia (acute respiratory distress syndrome or ARDS) that is often fatal.