What are symptoms of the avian influenza in human?
The incubation period for H5N1 avian influenza may be longer than that for normal seasonal influenza, which is around two to three days. Current data for H5N1 infection indicate an incubation period ranging from two to eight days and possibly as long as 17 days. Initial symptoms include a high fever, usually with a temperature higher than 38°C, and influenza-like symptoms. Diarrhoea, vomiting, abdominal pain, chest pain, and bleeding from the nose and gums have also been reported as early symptoms in some patients. The spectrum of clinical symptoms may, however, be broader, and not all confirmed patients have presented with respiratory symptoms; it may include neurological symptoms as well. Many patients have symptoms in the lower respiratory tract when they first seek treatment. On present evidence, difficulty in breathing develops around five days following the first symptoms. Almost all patients develop pneumonia, usually without microbiological evidence of bacterial supra-infection
