Imprimer cette page 4th-11-2005 10:41

Avian influenza: prevention, protection and information

The avian influenza virus must be approached in different manners, depending on whether transmission is occurring solely between animals (epizootic without human infection), from animals to humans (epizootic with human infection) or between humans (pandemic). With cases already recorded in the European Union, the Government has made provision for measures to be taken at a variety of levels.

“For the moment, we are talking about an epizootic in which the virus has been transmitted from birds to humans - but only in Asia,” stated the Prime Minister on Friday 14 October 2005. He added that the “virus is getting closer” and that “it is important to be on full alert”.

What is a pandemic of avian influenza?

Influenza is a contagious, acute respiratory infection cause by a virus. Influenza viruses, which vary in nature from one species to another, can infect humans, horses, pigs, marine mammals and birds. Those affecting birds are referred to as “avian influenza” viruses, one example being the A(H5N1) strain. These are different to the human influenza viruses which affect 5% to 15% of French people each winter and for which vaccines are available.

A pandemic is an outbreak of a disease which lasts for a considerable period of time and affects people across a large geographical zone, leading to a large number of serious cases and a high mortality rate.

A pandemic of avian influenza would therefore result from the transmission, from animals to humans, of a new type of influenza virus to which humans have no immunity - a hybrid influenza virus which would be:
-  “human inside”, i.e. dangerous to humans;
-  “avian outside”, i.e. not recognized by the human immune system, which could not therefore react efficiently.

A sudden mutation such as that which could render the avian influenza virus hybrid is referred to as a “break”. Unless such a “break” occurs, there can be no pandemic, since the virus can be transmitted only between animals or from animals to humans. This situation is known as an epizootic.

The most recent cases were observed in Turkey and Romania

Since 2003, a large number of birds have died in Asia, where the epizootic began. Furthermore, of the 117 humans known to have been infected with the A(H5N1) strain of the virus, 60 have died. In these cases, the virus was transmitted from animals to humans; no human-to-human transmission has been recorded.

Since the epizootic began in December 2003, cases have been observed in 14 countries: Cambodia, China, South Korea, Indonesia, Japan, Kazakhstan, Laos, Malaysia, Mongolia, Russia (Siberia), Romania, Thailand, Turkey and Vietnam.

The most recent outbreaks observed were in Turkey (Western Anatolia) and Romania.

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