SARS, belonging to the same family as the virus responsible for COVID-19, had already caused an epidemic in 2003. But what are the causes? Symptoms ? Are there any treatments?

Onset of SARS

Onset in 2002, SARS spread to four countries, mainly Asian, causing nearly 800 deaths. Thanks to the responsiveness of public authorities and hospital systems, the spread was contained in 2003. A look back at this virus, from the same family as COVID-19.

A virus from the coronavirus family

“SARS, or Severe Acute Respiratory Syndrome, is a virus from the coronavirus family, responsible for respiratory diseases” explains Bruno Canard, coronavirus specialist and research director at the CNRS (National Center for Scientific Research).

In this family, there are seven pathogenic viruses, three of which are dangerous for humans, namely MERS (Middle East Respiratory Syndrome Coronavirus), SARS and SARS 2 responsible for COVID-19. SARS has a 10% death rate but low contagiousness. “Whereas for SARS 2, the mortality rate is lower but the contagion rate is higher” recalls the researcher.

The SARS virus appeared in China, in Guangdong Province, in November 2002 where it was present in bats. Following adaptations mainly through mutations, and animal promiscuity observed in Chinese markets, he then transferred to the civet, an animal very appreciated in Chinese cuisine. The virus could thus be transmitted to humans in the same way. It was first detected in February 2003.

“The SARS epidemic started in Hong Kong and then spread to Vietnam, Canada and the United States” adds Bruno Canard. “The virus is not very infectious, there has not been a big spread like with SARS 2 today”.

SARS situation in France

And in France ? According to the Public Health France website, “a total of 437 possible cases of SARS were reported in France between March and July 2003. Seven probable cases were selected, including one patient who died, and 77 contacts were followed. No secondary transmission has been identified on French territory ”. In 2003 and 2004, the SARS virus affected 8 people, claiming 000 victims. The epidemic ended on its own in May 774 thanks to the mobilization of hospital services, the responsiveness of governments and a probable reduction in contagion in summer.

SARS is spread by droplets ejected through speech and breathing. The transmission is also manual, that is to say that the contraction of the disease can take place after having touched contaminated objects. The incubation period of the disease is between 2 and 11 days after infection.

But according to the World Health Organization (WHO) “it would seem that the contamination of the environment by the faecal excretion of the virus plays a role in the transmission of the disease since at the end of March 2004 , more than 300 residents of a building in Hong Kong where the sewage system was faulty were infected almost simultaneously. ”

SARS, or Severe Acute Respiratory Syndrome, is a respiratory disease. In the first days of contamination, a high fever appears, often above 38 ° C, and sometimes diarrhea. Significant respiratory symptoms follow: dry cough, shortness of breath, breathing difficulties.

Other symptoms can be seen like headache, muscle pain and general discomfort. They are very similar to those of COVID-19. According to the Institut Pasteur, “the incubation period does not generally exceed 10 days. WHO considers the overall case fatality rate to be 15% and may exceed 50% in people over 65 ”.

It is difficult to diagnose SARS because the symptoms can be very variable. But when in doubt, doctors do an x-ray and a virological test. The radio can detect the presence of alveolar opacities, typical of the disease.

The virological test, meanwhile, is based on the detection of the virus from nasal swabs, blood, stool or urine by a PCR method (Polymerase chain reaction). Shedding of the virus is quite low at the onset of the disease, and peaks around 10 days after the onset of clinical signs.

To date, there is no treatment for SARS. The only way to contain an epidemic remains isolation. The patients still receive drugs to treat the various symptoms: antipyretic against fever, analgesic against pain.

There is no preventive or curative treatment for SARS. However, it is possible to limit the risks by keeping a distance of more than one meter from other people to avoid droplets. It is also essential to wash your hands very regularly and avoid touching your face to limit manual transmission.

The disease is now under control and it is unlikely that an epidemic will re-emerge. But in case of doubt, you can always consult your doctor who will refer you to specialists.

“SARS has inadvertently returned two or three times because of labs working on it. But this has not given rise to epidemics. There are other viruses of this family in bats as in other animals and the risk of transfer to humans exists if precautions are not taken ”worries the researcher. But then, how to limit the risk of contamination?

“You have to know where these animals and viruses live to leave them alone. Man must avoid interfering with and destroying their habitats. The protection of nature and biodiversity is essential to maintain this precarious balance ”. 

As we can see today with SARS 2, from the same family as SARS, transfers of viruses from animals to humans are very real. But the SARS experience has provided a significant amount of data on coronaviruses. “The results of research on SARS have made it possible to very quickly determine the structure of the genomic components of SARS 2, how they work, how the virus fights the immune system and what are the best ways to approach the design of vaccines or treatments. ”Summarizes Bruno Canard.