Progress on SARS Epidemiological Studies

2004-06-13 15:07

The Chinese National S& T .Panel on SARS Prevention and Treatment has recently announced its major accomplishments achieved so far in its SARS epidemiological studies. Those accomplishments follow:

* Chinese scientists have achieved an understanding of the external life process of SARS viruses. This provides scientific evidence for comprehensive SARS prevention. The research results have shown that SARS viruses are able to keep their vitality for an extended period of time in regular wastes discharged by the human body such as sputum, stools and urine, and blood. In temperatures of 24℃, SARS viruses are able to survive for about 5 days in sputum or stools, 10 days in urine, and 15 days in blood. Under normal indoor conditions, SARS viruses may survive for 3 days on the surfaces of filter paper, cotton cloth, wooden boards, soil, metal, plastics, and glass.

* Evaluations have been made on the major disinfectants currently applied against SARS in this nation. The testing results have shown that chlorine — based disinfectants and peroxyacetic acid in the concentrations recommended by the Chinese Ministry of Public Health can completely kill the SARS viruses in human stools and urine within several minutes. Ultraviolet rays may, within a range of 80—90 cm, and with intensity larger than 90 μw/cm2, kill external SARS viruses within 30 minutes. SARS viruses have been proven sensitive to temperature. They show a remarkable declining survival rate with an ascending temperature. Under a serum free culture condition, the viruses may survive for 4 days at 37℃ , but only for 90 minutes at 56℃ and 30 minutes at 75℃ .

* The research results also show that the recovered SARS patients have no further ability to infect, as they discharge no more toxins. It has been initially confirmed that people who have close contact with SARS patients are very low in hidden infections and SARS patients in the latent period also have very limited ability to infect.

China has established the national SARS control and warning geographic information system, through which concerned authorities may spatially and temporally classify, summarize, and conduct statistical analysis of confirmed patients, suspected SARS patients, and those who have close contact with these two types of patients according to the given indicators and space locations. The results are then marked on maps.

China has, by means of the SIR Model, established short and medium range SARS analysis and prediction models to predict the short and medium range SARS development tendencies in the nation. The priority is to make one — week predictions for the new SARS patients in Beijing with the help of the latest data and information on SARS development as published by the Ministry of Public Health.