Reporter : Wei Yuzheng
Publisher : Lianhe Zaobao
Translation, editing : Gan Yung Chyan
/ KUCINTA SETIA
Image : Confirmed reported cases of covid in Singapore in April 2020 in colour. Grey areas are places with no reported covid cases. Courtesy of Wikipedia
Local studies have shown that patients with covid, regardless of whether they have symptoms or not, will emit a large amount of SARS-CoV-2 in the first week of infection, and the virus will adhere to the surface of the objects around the patient and the air. After the first seven days, the number of viruses in the environment will drop sharply.
This study, jointly conducted by the National Center for Infectious Diseases, the Duke-National University of Singapore (NUS) Medical School, and the National Defense Science and Technology Research Institute, echoes the results of another study conducted by the Center for Infectious Diseases earlier. After 11 days, it will no longer be contagious.
In the new round of research, the team collected samples from surfaces often contacted by patients such as bed rails, chairs, and toilet seats in the negative pressure isolation ward where 30 patients with coronary disease were admitted for testing. They also tested air samples from three of the wards.
The results showed that the presence of the coronavirus SARS-CoV-2 on the surface and in the air, and the concentration of the virus were proportional to the number of days of infection and the amount of virus in the nasal cavity.
The amount of virus on the surface of the object is the highest in the first week of the patient's infection, and then as the disease lasts longer, the degree of surface contamination decreases gradually. Three of the 30 wards are intensive care units. The researchers did not find any surface contamination in the intensive care units. This may be because the patients in the intensive care unit have entered the second week of the infection period, so the amount of virus discharged is less .
The team also reached a similar conclusion in the air samples of the three wards. They detected the virus in the samples of two of the wards, and the other did not. The occupants of the first two wards were all patients on the fifth day of infection, and there were a lot of viruses in the nasal cavity. The patients in the third ward had been infected for nine days, and the nasal virus concentration had been reduced.
The research was published in the scientific journal Nature Communications on 29 May 2020.
At the same time, Kalisvar Marimuthu, a senior consultant doctor at the National Center for Infectious Diseases who led the research, pointed out that although tiny ribonucleic acid (RNA) particles of the coronavirus have been found, it shows that the virus may be scattered through an aerosol but this alone is not enough to prove this, and it must be confirmed whether the virus can survive in the air.
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