Treatment of Severe acute respiratory syndrome (SARS):
Treatment of SARS-CoV infection is symptomatic. An antibiotic can be administered as bacterial causes of pneumonia have not been eliminated. An oxygen therapy should be considered in terms of desaturation. The corticosteroid therapy should be considered based on the risk of acute respiratory distress syndrome (ARDS). The prescription of ribavirin, an antiviral used during the 2003 epidemic, is in question because of the many side effects and their potential severity.
Isolation of patients and protection of nursing staff and patients' relatives are an integral part of treatment since it is a disease that can be transmitted by direct contact.
In 2006, the Atlanta CDC (USA) reviewed scientific studies dealing with experimental treatments for severe acute respiratory syndrome. Despite 54 clinical studies of 54 drugs tested on humans, no evidence of drug efficacy could be found. Eight revealed significant side effects. For ethical reasons, clinical trials were carried out in a hurry, without a reference group receiving a placebo, which makes it difficult to evaluate the drugs. (Source: Journal Public Library of Science - Medicine).
Epidemiology of Severe acute respiratory syndrome (SARS):
The human coronaviruses OC43 and 229E are responsible for winter epidemics occurring mainly in small communities (boarding schools, schools, families, etc.) and generally lasting a few weeks. Human contamination occurs through inhalation of infected saliva droplets or through direct contact with nasal secretions.
Severe Acute Respiratory Syndrome is a new infectious disease first identified in February 20032, but present in November 2002 in the province of Guangdong (China). The infection is spreading to Hong Kong, a region close to the initial focus, suggesting low contagiousness of the virus. The epidemics that followed remained limited to family groups residing in areas of high population density, hotels (Hong Kong) or hospitals ( Hanoi, Toronto). This limited extension is an argument in favour of the low transmissibility of the virus. Compared to influenza viruses capable of rapidly infecting millions of people around the world, the SARS virus does not appear to spread quickly. To date, only one outbreak has occurred in 2003, affecting at least 8,000 people, with a number of secondary cases likely not having been identified. The following year, in 2004, 9 cases were reported, only in China. That year, the index cases were systematically described in people working in laboratories studying the virus responsible for severe acute respiratory syndrome (virology student, contract researcher). These index cases were at the origin of the contamination of other affected people (parents, nurse, etc.).
Severe Acute Respiratory Syndrome virus appears to be mainly spread by direct contact with droplets of respiratory secretions from infected people. Transmission by faecal or airborne route seems possible but rare (in 2003, one of the foci of infection in a district of Hong Kong seems to have developed from contaminated sewage). Airborne spread of severe acute respiratory syndrome virus does not appear to be essential but should not be ruled out. Indeed, the contamination of nursing staff performing high-risk procedures (bronchoscopy, endotracheal intubation, etc.) is an argument in favour of airborne contamination from a contaminated environment.
End May 2003, the study of samples of wild animals sold for food in markets in Guangdong province (China) showed the presence of severe acute respiratory syndrome coronavirus in civets, suggesting that the respiratory syndrome virus severe acute has crossed the species barrier. In 2005, two studies found coronaviruses similar to severe acute respiratory syndrome coronavirus in bats in China. Phylogenetic analyses of these viruses have found a high probability that severe acute respiratory syndrome originated in bats and spread to humans, via cats and / or civets. The infected bats showed no visible signs of disease.
A 2013 study isolated a virus living in the feces of wild bats in China, a virus very close to severe acute respiratory syndrome (genetic similarity of the order of 95%) and which undoubtedly confirms that these animals are the natural reservoir at the origin of this infectious disease. This study also shows that the bat virus can pass directly to humans without an intermediary.
Epidemic of SARS between November 2002 to July 2003
The first patient with severe acute respiratory syndrome is a farmer from Shunde District, Foshan County, identified on November 16, 2002. On February 10, 2003, the Chinese authorities inform the World Health Organization (WHO) of the epidemic, and mention 305 contaminations including 105 among health personnel, and 5 deaths. Later, she indicates that the epidemic in Guangdong peaked in mid-February 2003 but it was far from it as 806 cases of infection and 34 deaths were subsequently reported.
Due to its transmission through the air, the disease spreads very quickly to large numbers of people in many countries. The Chinese authorities seem not to have taken very strict security measures early enough, such as the quarantine of probable cases and adequate information of the population. Chinese doctor Jiang Yanyong gives the first information on the disease in China. There are 7,761 cases of severe acute respiratory syndrome in China (including Hong Kong, Taiwan and Macao). The cities of Singapore and Toronto are also affected, with 206 cases and 252 cases respectively. Preventive behaviours have been instituted in Beijing, Hong Kong and Singapore, where the population systematically wears respiratory masks when traveling in public
The July 2, 20034, the epidemic appears to be contained. Taiwan is the last possible focus of a local chain of disease transmission. The epidemic is confined to Canada, Singapore and most of China, the three main affected countries.
According to Inserm statistics, there have been more than 8,000 cases of severe acute respiratory syndrome worldwide, and 774 deaths, bringing the case fatality rate to nearly 10%.
New sporadic cases appear in September 2003in Singapore. The disease is contained in May 2004. During this period, 9 people seem to have contracted the disease.
Immunity of SARS acquired from contact with the virus lasts only about 3 years.