SARS (atypical pneumonia) is a new infectious disease, first emerged in November 2002 in southern China and spread on the territory of 29 countries in Europe, Asia, North and South America, Africa and Australia. Officially it is reported on 8422 cases and more than 900 deaths from SARS.
On April 16, 2003 it was announced the confirmation of the role of the SARS-associating coronavirus (SARS-AKB) as the causative agent of SARS in accordance with Koch’s postulates. Coronavirus is RNA viruses having peripheral corona-like outgrowths. Coronaviruses cause rather serious diseases in animals, while in humans they have always been agents of mild upper respiratory tract diseases. Coronaviruses are combined into three groups: 1st and 2nd groups are viruses that cause diseases in mammals, the third group – in the birds. Coronavirus that cause disease in humans are included in the 1st and 2nd groups. The most popular theory of the origin of SARS-AKV is a spontaneous mutation of coronavirus, which is pathogenic to animals.
Features of SARS in children
Over the entire period of the epidemic SARS was revealed only in several dozen of children. In young children SARS is characterized by less aggressive current than in older children and adults. May be there are differences in the contagiousness of the virus in children and the established very high level of contagiousness in adults. There is no information about the deaths of children who were ill with SARS. The described clinical cases of SARS in children and adults confirm that the disease has no specific clinical signs. In this regard, experts of CDC and WHO published the criteria which allow to narrow the diagnostic search at the suspicion on SARS. Probable case of SARS is the severe respiratory syndrome of unknown etiology and epidemiological criteria (contact with persons with suspicion on SARS, stay in the epidemic region), laboratory criteria may be confirming, negative, uncertain.
The etiological diagnosis
Molecular tests – PCR with reverse transcriptase (highly specific, but less sensitive test). A negative result does not preclude SARS. Serological tests – immunosorbent assay (determination of IgM and IgG levels in blood plasma), indirect immunofluorescence reaction (determination of the IgM content). The results of the serological research can be definitively interpreted only when working with samples obtained after day 21 from the onset of the disease. The lack of specific antibodies after day 21 from the onset of the disease eliminates SARS. Viral shedding in cell culture – growth of virus can be obtained by introduction of biological samples (respiratory secretions, feces, blood) to the cell culture.
Treatment of SARS
Standards for treatment of adult patients with probable and confirmed diagnosis of SARS include antibiotics (levofloxacin, amoxicillin / clavulanate, clarithromycin), glucocorticoid (methylprednisolone, prednisolone) and antiviral (RBV) therapy. With an increase in the phenomena of respiratory failure patient is transferred to the IVL.
Control of the spread of SARS
Taking into account well-known transmission routes of SARS, CDC experts have developed lists of restrictive measures for the medical and social institutions. This implies adherence to certain restrictive measures in patients with suspicion on SARS or confirmed SARS:
1) Standard precautions (hand hygiene);
2) Precautions for direct contact (use of gowns, goggles, gloves);
3) Precautions to limit the spread of droplet infection (negative pressure in the rooms where the patients are held, the use of disposable respirators N 95).
The international community managed to achieve the first victory over the this epidemic. However, a number of issues remain unclear regarding the epidemiology and pathogenesis of SARS. The main conditions of the victory over the SARS are obvious – it is the creation of an effective vaccine, the development of highly specific and sensitive diagnostic tests and interruption of the chain of the infection transmission.