Avian influenza – KSLAT nr 10-2006

What similarities are there between today’s avian influenza and the Spanish influenza of 1918? The answer is that despite different strains of the influenza virus being involved, both are zoonoses, that is, they can infect humans with lethal effect. But the similarities end there. Spanish influenza was transmitted rapidly from person to person during the period 1918-19 in post-war Europe, while today ’s avian influenza has mainly circled the globe within bird populations since it first appeared in Hong Kong in 1997.

In contrast to Spanish influenza, the current H5N1 virus only infects humans after close and intensive contact with infected domestic fowl and further cross-infection between humans has not yet been demonstrated. Thus, the high risk for people to be infected is in the poor world where man and birds are living close together. However the real harm to people is the fact that millions of birds are killed and destructed to stop the virus and the result is shortage of protein rich food. Likely the number of weakened and even dead persons is many times higher than the direct H5N1 affected. Avian influenza is therefore more of a veterinary problem than a human medicine problem. The aggressive H5N1 virus has now been circulating for almost ten years among both domestic and wild fowl in Asia in particular, and is now continuously spreading west. This spread seems to be occurring through trade in domestic fowl and via migratory birds. This gives us an entirely new epidemiological perspective and an unpredictable global situation. This report gives the current knowledge of the background of the avian influenza virus and the spread of the virus and also discusses risk management and risk communication.