The Severe Acute Respiratory Syndrome SARS is a contagious disease which is spread by contact with infected persons or with objects recently contaminated by respiratory secretion of persons affected by the disease or by faeces and urine from infected patients. Animals would not seem to be involved in the transmission, whereas the possibility of transmission by food contaminated with faeces or urine from SARS patients is still to be defined.
This new disease appeared first in November 2002 in the Chinese province of Guangdong where still today the highest number of cases is registered. Attributed at first to Chlamydia pneyumoniae, is was identified as a new pathology only in February this year, after it spread to Vietnam, Hong Kong and Singapore and was then carried by airline passengers to various countries including Canada.
The etiological agent is a new Coronavirus of the family of virus hitherto know to cause the common cold and minor intestinal pathologies.
The disease is spread, as we have said, through direct contact with a person infected who coughs minute droplets of secretion containing the virus. Symptoms are manifested after an incubation period normally between 2 and 7 days, rarely after 10 days and start with high temperature (over 38C) and a dry cough, sometimes accompanied by other influenza type of symptoms, such as headache and local muscle pain. In 80% to 90% of the cases symptoms regress without recourse to special treatment, but in 5-10% of the cases serious forms of respiratory insufficiency may occur which demand suitable means of reanimation. The lethality, on the basis of cases in Canada, China, Hong Kong Singapore and Vietnam, is estimated by the World Health Organisation WHO, to be around 15% average, swinging from 1% under 24 years of age, 6% between 25 and 44 years, 15% between 45 and 64 and 50% over 65. The mortality for SARS can be affected by factors connected with the person, existence of other pathologies, or environmental factors such as lack of access to suitable hospital care.
At present diagnosis is still based essentially on clinical and radiological criteria, as well as the fact of a recent journey to affected zones, with the exclusion of other pathologies which could explain the patient's symptoms. However it has been announced that a system of rapid laboratory diagnosis will soon be available.
So far some 7000 cases have been reported in 30 different places or countries. The greatest number of cases has been registered in China (Province of Guangdong and Hong Kong SAR), Taiwan, Singapore, Vietnam and Taiwan, and Canada. Present areas at risk are China, (Beijing, Guangdong, Hong Kong, Mongolia, Shanxi, Tianjin), Mongolia (Ulaanbaator), Singapore and Taiwan, and Canada (Toronto area). Vietnam was recently removed from the list of high-risk areas because after 20 days, double the maximum incubation period, no new cases of SARS were reported. In other countries, while isolated cases have been reported, there has been no local spreading of the virus: the patients all came from risk areas. In Italy up to 7 May, nine cases had been reported, isolated immediately and none of them mortal. Lethal cases registered so far have been only in South East Asia and Canada.
Information on the spreading and means of prevention has often been contradictory, on the part of both the media and official bodies. In fact until late April the Chinese authorities reported only 37 SARS cases in Beijing a number which rose to 741 when it was discovered that 704 earlier cases had not been reported. It was only then that Chinese authorities began to take drastic measures to prevent the disease from spreading. In fact in other places affected by SARS cases reported were only sporadic and local, whereas China is the only country in which the spread of the disease seems to have assumed the characteristic of an epidemic. It should also be taken into account for a correct evaluation, that information received concerns mainly large cities in South East Asia while little is known of the rural situation where many villages are isolated, not reached by systems of notification of infectious disease and can rely only on traditional medical treatment.
Recent information issued by WHO show a considerable reduction of the number of cases reported daily which proves the effectiveness of preventative measures undertaken by the Chinese government. Also scarce and contradictory media information with regard to contact and prevention of the disease. Often we were led to believe that a mere encounter with an infected person could cause the spread of the virus, but that, it was reported a few days ago, "people living with a SARS patient are not at risk". It should be pointed out that WHO guidelines speak of close contact and this means someone living with or caring for a SARS patient. All available information shows that medical and paramedical personnel are most at risk unless suitable preventive measures are taken. In a word those in direct contact with the bronchial secretion diffused by coughing on the part of the person with SARS. Other examples of close contact can be embracing, kissing, conversation at close range, medical visiting of the sick, caring for the patient by nursing personnel or any direct physical contact with a patient which includes also people living under the same roof. This means that close contact does not include sitting or walking in a doctor's waiting room for short period of time.
Lastly, a few days ago ample space was given to news with regard to the great resistance of the virus in the open air. The virus was said to be a super virus. But in the days that followed there was a correction to say that the supervirus is sensitive to all common disinfectants. Taking a good look at information issued by WHO it is clear that the Coronavirus shows more resistance to exterior agents than those of other components of the same virus family. It can resist under good conditions up to four days, less in other conditions. Entirely omitted is the observation, far more important from an epidemic point of view, of the observed secretion of virus on the part of cured patients who have left hospital.
As we said health workers are most at risk and it is not by chance that epidemic episodes reported in Canada originate all from people returning from affected areas, involved family members or medical personnel assigned to visiting and treating SARS patients.
Prevention is based on the adoption of suitable measures to avoid the inhalation of particles issued by the sick person through coughing speaking or sneezing. This means than when visiting or assisting a possible case of SARS, to be necessarily isolated, apart from following common normal hygiene norms such as washing frequently hands with soap and water, medical personnel must also wear protective gloves and clothing, masks and disposable overshoes. Furthermore it should be said that surgical masks, used widely judging from the images coming from the Far East, give only limited protection if worn by a healthy person. Worn by an infected person they will not help to diminish the diffusion of the droplets coming from the respiratory tract projected to the outside through coughing speaking or sneezing, which is perhaps the main means of the diffusion of the virus. (Fides Service 20/5/2003 EM Words: 1229,84)