The clinical manifestations associated with H5N1 infection in humans range from 
asymptomatic infection to mild upper respiratory illness, severe pneumonia, and 
multiple organ failure. The ratio of symptomatic cases to asymptomatic cases is 
not known, because it is not possible to precisely define the number of 
asymptomatic cases. A total of 97 cases suffering from avian flu were suspected 
based on history taking, demographic data, clinical manifestations, laboratory 
and radiological investigations. The followings were done for all cases; 
complete blood picture (differential leucocytic count), coagulation profile, 
renal and liver function tests. H5N1 influenza virus was diagnosed thorough PCR 
technique. Changes in arterial blood gases and repeated chest X-rays were 
reported frequently. All patients were given specific antiviral therapy 
(oseltamivir). The study described the clinical picture and laboratory results 
of 81 confirmed avian influenza human cases in an Egyptian hospital (Abassia 
chest hospital), and reviewed the avian influenza current situation covering 
from March 2006 to June 2009 with very high pick in the first half of 2009. The 
significant apparent symptoms were fever as initial and main symptom (93.75%), 
followed by shortness of breathing (73%), cough (66.6%), muscle & joint pain 
(60%) and sore throat (40%).