Still a false alert tell the nasty language

For some, they are part of the first inhabitants of the planet born three billion years ago. They are therefore a way our very distant ancestors. For others, they are located to midway between the living and the inert. Until the development of electron microscopy in the 1940s, they have remained invisible to the observer. Since the emergence of SARS in 2003, the revelation of avian flu incorporated in 2005 and the arrival of the Mexican episode of influenza A, they became stars. Their progress is followed on the day the day by worldwide health authorities. It must be said that viruses are among these the strangest creatures on Earth.

A small sphere of a few tens of nanometers in diameter, one hundred times smaller than a human cell. Protected by an outer envelope hirsuta hundreds of disturbing protuberances, these parasites contain only a handful of genes. Their ambition is simple and daunting: enter a body living, deceive the officers of the immune system, take control of its cellular machinery and order him to make billions of identical viruses.

Record claims

These bugs accumulated record claims. Of HIV, is cold in the back in terms of "productivity": not far from 10 billion virus particles produced every day, from a single infected cell. On the side of effectiveness, it is the pathogen of influenza which is at the top of the rankings in recent history: between 30 and 50 million people during the pandemic of 1918-1919. But the greatest plagues viral of the history of humanity are today controlled by effective vaccines: smallpox which eliminated the Amerindian populations, the yellow fever which decimated the immigrants from Europe to the new world in the 19th century or polio returned to the surface in the 20th century after an inexplicable silence of a thousand years. Since the beginning of 20th century, viruses and virus hunters play cache cache. The latter have paid a heavy price in this quest for knowledge. To solve the mystery of the yellow fever, several American physicians have not hesitated to voluntarily stick by mosquitoes, to demonstrate the role of this vector in the spread of the disease. Some have left their lives.

Tropical forest

What is the responsibility of men in these eruptions that seem to strike without warning and then disappear snuck "Viruses are often nestled at the bottom of the tropical forests and, before that human Vienna find, nothing does prédestine them great travel", indicates the virologist Jean-François Saluzzo in his book "A conquest of viruses".

Influenza viruses are the most multifaceted and the most unpredictable of all these enemies of humankind. Last year, seasonal flu has affected in France about 2.5 million people resulting in the death of nearly 5,000 sick. Ironically, this severe infection is often seen as relatively benign and "treated with disdain" by a majority of French. Less than one-third of them is vaccinated and this figure is rather declining. "Respiratory disease and lung complications are the leading cause of mortality in the world," said biologist Didier Raoult of the University of the Mediterranean in Marseille.

For this specialist who pleads for his parish, should urgently launch a considerable research effort to understand the logic of these infectious diseases that remain generally misunderstood. Scientists who intervened in recent days on the antennae have also all appear uncomfortable to answer questions from listeners worried or goguenards. Why all the hype around the Mexican H1N1 Will the next winter flu be very harsh WHO was even embossed for his alarmism, whereas the Geneva institution did apply strictly the established rules. The recommendations of the kind "must wash their hands regularly" came to accentuate the gap between risk announced by health authorities and the threat perceived by the citizens.

In fact the flu virus is a curious amalgam combining genetic instructions for avian, swine and human origin. Southeast Asia is the election of this perpetual pot from which emerge more or less aggressive combinations: H5N1 in the South of China in 1997, then in Hong Kong in 2005, H7N3 in Pakistan in 2004... As soon as a new Member of the family appears, or the Paris Pasteur Institute U.S. CDC virus hunters are heating their genome sequencers for the genetic identification of the newcomer. Objectives: to measure its dangerousness and determine its contagiousness. Apparently the Mexican H1N1 is neither one nor the other. Still a false alert, tell the nasty language. But perhaps is it only a dress rehearsal. Pending the arrival of the "Big One" that all experts promise. In ten years or the next winter.