The new coronavirus (SARS-CoV, Urbani Coronavirus associated with SARS, coronavirus associated with SARS Urbani) was discovered in March 2003, when the first cases of severe acute respiratory syndrome (SARS) appeared. Phylogenetic analysis and comparison of the nucleotide sequence have shown that SARS-CoV is not closely linked to the type 1 and 2 coronaviruses described above.

In Hong Kong and Shenzhen (China), several coronaviruses genetically closely linked to the SARS pathogen have been isolated from animals (palm civet and raccoon dog). Another animal species (Chinese ferret badger) has shown antibodies against SARS-CoV. Sequencing of viruses isolated from animals has shown their identity with the human SARS pathogen, with the exception of a small additional sequence, however, the role of animals in the transmission of SARS is still unclear.

Between November 1, 2002 and June 23, 2003, WHO recorded 8,459 cases of SARS in 28 countries and 804 deaths. Mortality in SARS is 9%. Of the 363 cases of SARS diagnosed in 41 US states and Puerto Rico, 297 (82%) were considered suspect and 66 (18%) probable. Out of 66 patients with probable SARS, 43 people (65%) were hospitalized and 2 patients (3%) underwent mechanical ventilation. No lethal results were noted.

64 (97%) of the 66 patients with possible SARS no more than 10 days before the onset of the disease have visited countries at high risk for SARS infection. Of the 2 remaining patients (3%), one was a health worker who had direct contact with a patient with SARS, and the second case was associated with an intra-family infection.

Serological examination was performed in 111 patients with a suspected case of SARS, but no anti-coronavirus antibodies were detected. 32 patients with probable SARS also underwent serological testing. Positive results were obtained in 7 patients, 6 of which were previously described as laboratory confirmed cases. In the seventh patient, the SARS-CoV RNA in the sputum was detected by reverse transcriptase PCR. Subsequently, antibodies appeared in this patient.

In 4 of 7 patients, serological reactions were positive on day 12 and earlier since the onset of the disease. In three patients, serological reactions were negative on days 4, 6 and 14, respectively, and antibodies appeared in serum on days 28, 25 and 41, respectively.

To date, there have been no cases of infection of patients in the prodromal period, although transmission in the initial period of the disease is possible. The peak of contagiousness occurs during the second week of the disease, when the greatest number of viruses are released. It is also not known how long the patient has been infected since the onset of the disease.

The pathogen's RNA is detected by PCR with reverse transcriptase in sputum, urine and feces within a few weeks of the onset of disease symptoms, although it is not clear whether the presence of RNA indicates the presence of complete viruses that can cause the disease.

The contagiousness of the virus is different for different people. In most cases, close contact is necessary for infection, transmission taking place in large drops and through direct contact. In the external environment, the pathogen persists for 1 to 2 days, so the likelihood of infection by objects is high.

Upon admission to a patient suspected of SARS, the epidemiological service must be immediately informed and the patient must be immediately isolated. In addition to the usual precautions, medical personnel should wear safety glasses, gowns, gloves and respirators when in contact with the patient.

SARS begins with fever, chills, headache, malaise and myalgia. Respiratory symptoms are usually absent in the first 3-4 days of the disease. Among the respiratory symptoms, dry cough and shortness of breath are the most characteristic. Most patients then develop wheezing and hypoxia. A significant proportion of patients suffer from diarrhea.

The number of white blood cells remains normal or decreases slightly. Often there is lymphopenia, thrombocytopenia, increased CPK, AST and ALT can also be observed.

Changes in X-rays in the lungs, appearing on the 5-7th day of the onset of the disease, are represented by interstitial infiltration and focal cuts, gradually increasing and occupying several parts.

10 to 20% of patients develop respiratory failure and respiratory distress syndrome in adults. Mortality can reach 10 to 15%, but there is a dependence inversely proportional to the age of the sick - thus, in the elderly, mortality exceeds 40%.

At autopsy, the most significant changes are detected in the lungs and are represented by diffuse alveolar lesions.

Currently, methods for identifying pathogens are still under development, and the sensitivity and specificity of the methods applied have not been specified. It is also unclear which tests should be preferred at different periods of the disease. The following tests are used: serological tests to determine specific antibodies, including ELISA and indirect immunofluorescence reaction. Currently, according to CDC criteria, positive serological results obtained 21 days after the onset of the disease and later are evidence of a previous infection. Serological reactions can be negative within 21 days.

For diagnosis, PCR with reverse transcriptase can be used, which allows the detection of pathogenic RNA in various biological fluids.

Virus culture is also used in cell culture followed by the detection of replication of pathogens.

Currently, antibiotics, ribavirin, and glucocorticoids are used to treat SARS, but no controlled studies confirm the effectiveness of these treatment methods.