We used reagents based on the types of flu virus that were currently circulating in the human population, known as H1, H2 and H3 strains because of the type of haemogglutinin - a protein on the surface of the virus which antibodies attack, and confirmed that the sample did not contain any of the strains of flu that affect humans. So we checked the sample against a wider range of reagents based on 15 haemogglutinins from strains of flu that affect birds. Neuraminidase is an enzyme that cuts the bond which holds new virus particles to the infected cell. It appeared that the young boy in Hong Kong had died from a flu viral infection that infects only birds. This was a significant and extremely worrisome finding.
Influenza is one of the oldest and most common diseases known to man.
It can also be one of the deadliest. Influenza is a serious infection of the breathing passages causing symptoms of fever, cough, sore throat, runny nose, headache, muscle aches and extreme fatigue. Most people recover completely within 1-2 weeks. However, compared with other viral respiratory infections like common colds, flu causes more severe complications such as pneumonia particularly in children, elderly people and other vulnerable groups. Flu epidemics kill hundreds of thousands of people a year and cause millions of cases of illness.