The MERS epidemic in South Korea shows signs of further spread. According to local officials, the virus can survive for up to two days, but according to experiments in the United States the year before last, the MERS virus can actually survive for more than 48 hours in a low temperature and low humidity environment.
"It is said that the survival time of MERS virus is 48 hours. If you sit where the patient has sat, is it possible to be infected? " (Reporter)
"According to limited research results, the viability of the virus will also change under different temperatures and humidity. In a dry environment, the virus dies quickly, and depending on whether it is iron, wood or plastic, its viability will also change. After a long distance (where the patient has been), you can think that there is no (virus). " (Jin Yuzhu, President of Korea Infectious Society)
This is a question-and-answer session held at the press conference of MERS Civil and Official Joint Countermeasures Room in Sejong City on the 2nd. In response to concerns about secondary and tertiary infections caused by MERS patients, the countermeasure room replied: "Although it will change according to different environments, the longest survival time of the virus is 48 hours." The specific basis has not been announced.
However, the experimental results of the American Institute of Allergy and Infectious Diseases (NIAID) under the National Institutes of Health (NIH) in 20 13 were different. The virus research team of the institute put MERS-CoV in different temperature and humidity environments to observe its survival time. The experimental results show that MERS virus can survive for 48 hours at 20℃ and 40% humidity, but only for 24 hours at 30℃ and 30% humidity, and only for 8 hours at 30℃ and 80% humidity. That is, low temperature and low humidity conditions are more conducive to the survival of MERS virus. The MERS virus was popped up by imitating the patient's cough, and the results were similar when it was collected again after 10 minutes. In the environment of 20℃ and 40% humidity, the virus amount decreased by 7%, while in the environment of the same temperature and 70% humidity, the virus amount decreased by 89%.
There is almost no difference in the material of the object attached with MERS virus. The research team attached the virus to plastic and iron, and compared the time (average half-life) when the virus number was reduced by half in different temperature and humidity environments. The results show that the plastic surface at 20℃ and 40% humidity takes about 57 minutes and 27 seconds, and the iron surface at the same temperature and humidity takes about 56 minutes and 40 seconds. Although there are some differences under other temperature and humidity conditions, the same time does not exceed 1 hour.
Jin Jizheng, a professor and virologist at the School of Pharmacy of Korea University, said: "This may be one of the reasons why MERS virus spreads faster than expected." He explained: "Although the weather in South Korea is very hot during the day recently, it is cooler at night or when entering the room, and the humidity is low enough to issue a dry warning, which is equivalent to providing the most suitable environment for the survival of MERS virus." Professor Jin said that the reason why MERS virus is easy to survive in low humidity environment is "one of the characteristics of enveloped virus". MERS virus has a thin film wrapped around virus particles, and it is easy to die when the envelope is broken. Professor Jin explained: "Some research results show that if the humidity increases, the number of water molecules will increase, and the virus envelope will be easily destroyed because the surface tension of water molecules is caught in the middle."
Korea Central Daily News Chinese website