Abstract
SARS, or Severe Acute Respiratory Syndrome, has left its mark on people's minds. It was the first major pandemic of the 21st century. Its emergence was due to the crossing of the species barrier by a totally unknown coronavirus whose reservoir was the bat, and which infected humans via the masked palm civets consumed in restaurants in south-east China. Thanks to advances in molecular biology, it has been possible to trace the path of this new virus, which conquered the planet in the space of a few weeks. In particular, it has been shown that a doctor in Guangzhou infected ten people in a Hong Kong hotel at the end of February 2003, who then travelled to five different countries, triggering the pandemic. Although mortality was low (774 deaths in six months), the epidemic had a resounding media impact, due to the novelty of the virus, its rapid spread in industrialized countries (Hong Kong/China, Singapore and Canada) and its hospital tropism (infection of staff, hospital closures).
It took two months for the coronavirus to be identified by teams from the University of Hong Kong and the CDC in Atlanta. The presence of cooks among the first patients prompted virologists and epidemiologists to investigate markets in Guangzhou to identify the animal responsible for transmitting the virus to humans, which turned out to be a small carnivore consumed locally, the masked palm civet. Given the similarity of the ACE2 receptors in the oropharyngeal epithelium of civets and humans, only two mutations allowed a virus adapted to the civet receptor to be adapted to the human receptor, thus explaining how the civet was able to play the role of intermediate host in the transmission of the virus to man. The reservoir of the coronavirus, a bat of the species Rhinolophus, was finally identified, although it is not known how the virus passed from the bat to the masked palm civet. The epidemic was brought under control by strict measures to isolate cases, which became contagious only four to five days after the onset of symptoms, and to restrict travel. China's delay in reporting the first cases led to a change in the International Health Regulations in 2005, requiring countries to report abnormal outbreaks of suspected cases to the WHO. In the end, this pandemic was like a dress rehearsal for what awaits us in the event of the emergence of an unknown virus. Let's hope we've learned our lesson.
