%{tishi_zhanwei}%

What is coronavirus, Yuan Lei's little editor takes you to know it

Release time:

2024-01-29 09:38

 

What is coronavirus, Yuan Lei's little editor takes you to know it

 

Introduction of 1. Novel Coronavirus

 

Coronavirus belongs to the set virus, coronavirus family, coronavirus genus, is a class of RNA virus with a capsule membrane, the genome is a linear single strand. The 5 'end of the viral genome has a methylated cap structure, the 3' end has a poly(A) tail, and the genome is 27 ~ 32kb, which is the largest genome of the known RNA virus. Coronaviruses are widespread in nature and are named after many small projections (spines) on the surface of the virus, which resemble a corolla (Figure 1).

Coronavirus only infects vertebrates and is related to a variety of diseases of humans and animals. It can cause diseases of the respiratory system, digestive system and nervous system, and cardiovascular system of humans and animals.

 

According to the phylogenetic tree, coronaviruses can be divided into four genera: alpha, beta, gamma, delta, of which beta coronaviruses can be divided into four independent subgroups A, B, C, D group. Animal coronaviruses include mammalian coronaviruses and avian coronaviruses. Mammalian coronaviruses are mainly alpha and beta coronaviruses, which can infect a variety of animals including bats, pigs, dogs, cats, rats, cattle, horses, etc. Avian coronaviruses are mainly derived from gamma and delta coronaviruses, which can cause many kinds of birds such as chickens, turkeys, sparrows, ducks, geese, pigeons and so on.

 

Coronaviruses that can infect humans are referred to as human coronaviruses. So far, in addition to the new coronavirus (2019-nCoV) that caused the viral pneumonia outbreak in Wuhan, a total of six human-infecting coronaviruses (HCoV-229E, HCoV-OC43, SARS-CoV, HCoV-NL63, HCoV-HKU1 and MERS-CoV) have been identified. Among them, four coronaviruses cause common human infections, but have low pathogenicity, and generally only cause mild respiratory symptoms similar to the common cold; the other two coronaviruses-severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome coronavirus, also known as SARS coronavirus and MERS coronavirus, can cause serious respiratory diseases. According to the World Health Organization (WHO) and domestic experts confirmed that the virus infection source of the new pneumonia is the seventh member of the coronavirus family, temporarily known as the new coronavirus (2019-nCoV).

 

Human coronavirus is sensitive to heat. The virus is moderately stable in a suitable maintenance solution at 4 ℃ and can be stored at -60 ℃ for several years. However, as the temperature increases, the resistance of the virus decreases. For example, HCoV-229E can lose infectivity at 56 ℃ for 10 minutes or 37 ℃ for several hours. SARS-CoV can survive for 4 days at 37 ℃, and virus can be inactivated by heating at 56 ℃ for 90 minutes and 75 ℃ for 30 minutes. Human coronavirus is not acid-resistant and alkali-resistant, and is sensitive to organic solvents and disinfectants. 75% alcohol, ether, chloroform, formaldehyde, chlorine-containing disinfectant, peracetic acid and ultraviolet rays can inactivate the virus. In human coronavirus, SARS-CoV can survive for at least 10 days in urine at room temperature of 24 ℃, more than 5 days in sputum and feces of diarrhea patients, about 15 days in blood, and 2-3 days in plastic, glass, mosaic, metal, cloth, copy paper and other surfaces. At present, the survival time of the new coronavirus at room temperature is unknown, but it is very similar to the SARS virus, and it can be compared in many places.

The novel coronavirus is similar to the human coronavirus in nature and is sensitive to heat and can be inactivated in 30 minutes at 56°C, while 75% alcohol, peracetic acid, and chlorine-containing disinfectants (except chlorhexidine) can effectively kill the novel coronavirus.

 

2. epidemic situation at home and abroad

The new coronavirus pneumonia outbreak began in Wuhan and then spread rapidly. As of 24:00 on February 2, the National Health Commission had received a total of 17205 confirmed cases from 31 provinces (autonomous regions and municipalities directly under the Central Government) and the Xinjiang Production and Construction Corps (3 cases in Beijing and 1 case in Jiangxi Province). There were 2296 severe cases, 361 deaths, 475 cured and discharged cases, and 21558 suspected cases. At present, a total of 189583 close contacts have been traced, 10055 people were released from medical observation on the same day, and a total of 152700 people are under medical observation. A total of 33 confirmed cases have been reported in Hong Kong, Macao and Taiwan: 15 in the Hong Kong Special Administrative Region, 8 in the Macao Special Administrative Region, and 10 in Taiwan. As of February 2, 2020, a total of 27 countries and regions worldwide have announced confirmed cases of pneumonia with new coronavirus infection, with a total of 14569 confirmed cases, 305 deaths and 346 cures.

 

In accordance with the International Health Regulations (2005), WHO Director-General Dr Tedros Tedros reconvened the Novel Coronavirus (2019-nCoV) Emergency Committee on Thursday, 30 January 2020. In the early morning of January 31, Beijing time, he announced that the novel coronavirus pneumonia epidemic constituted a "public health emergency of international concern" (PHEIC) and put forward seven suggestions: ① travel and trade restrictions on China are not recommended, and any measures should be based on evidence; ② support and protect countries with relatively fragile medical systems; ③ accelerate scientific research and vaccine-related research; ④ jointly fight against rumors and false information; ⑤ Countries actively seek prevention, treatment and programs to stop further transmission; ⑥ Countries actively share information with WHO; ⑦ All countries work together to fight the virus. The World Health Organization explained that these procedures are not binding, but practical and political, and can cover travel, trade, quarantine, inspection and treatment. The World Health Organization can also develop global practice standards.

 

At present, Wuhan and parts of Hubei Province have formed obvious community transmission. In addition, the early symptoms of the disease are mild and there are mild and asymptomatic cases. It is difficult to be diagnosed and isolated in time, resulting in the accumulation of infection sources in the community and the control of disease transmission. The difficulty increases. In the future, the number of patients in a few Hubei areas such as Wuhan will continue to increase. Wuhan, Huanggang, Xiaogan and other places in Hubei Province have adopted measures such as suspending public transportation, stopping crowd gathering activities, strengthening community prevention and control, actively detecting and investigating fever patients, and strengthening patient treatment, and prevention and control efforts have been significantly strengthened. The implementation of these measures will have a positive impact on the effective control of the epidemic. The provinces (autonomous regions and municipalities directly under the central government) outside Hubei are still in the stage of mainly importing the epidemic from Wuhan, and there has been no obvious community transmission. At present, all provinces have launched high-level emergency response, taken strong prevention and control actions, adopted a variety of measures and technical means, strictly investigated and controlled, timely detected early isolated imported cases and close contacts, strengthened community disease publicity and elimination work, and resolutely curbed community transmission.

 

3. the dangers of the novel coronavirus

 

At present, the novel coronavirus is in an epidemic period, and people's information on the novel coronavirus is still in the stage of gradual discovery and continuous understanding. It is not possible to simply compare the mortality rate and interpersonal transmission capacity of the SARS virus based on the current clinical manifestations and epidemiological data of the novel coronavirus pneumonia. Moreover, China is at a critical juncture in the prevention and control of novel coronavirus pneumonia, and the statement that "the novel coronavirus is milder than the SARS virus" may be misleading and even weaken the public's emphasis on the protection of the novel coronavirus, and even cause some people's laxity and fluke mentality, which is not conducive to epidemic control.

 

The results of a study published by Chinese scholars in the Lancet show that from 41 cases of 2019-nCoV infection in Wuhan, 2019-nCoV infection has clinical symptoms of respiratory diseases similar to SARS, and the mortality rate should not be underestimated.. Therefore, great attention must be paid to the seriousness and active prevention and control of this epidemic disease.

 


 Chan, J., Yuan, S., KokK., et al. (2020). A familial cluster of pneumonia associated with the 2019 novel-coronavirus indicating person-to-person transmission: a study of a family cluster. The Lancet.

 

Transmission route of 4. novel coronavirus

 

Usually, there are several ways of virus transmission: first, droplet transmission, which causes infection by droplets produced by coughing, sneezing and talking entering the surface of susceptible mucosa; second, contact transmission, which causes virus transmission by touching one's mouth, nose or eyes after contacting something the infected person has touched; third, airborne transmission, in which pathogens can still be infectious after long-term and long-distance dissemination; and the latest case studies suggest that, pathogens may also be transmitted through the digestive tract. For the new coronavirus, these ways of isolation and protection measures should be done well.

On January 21, Academician Zhong Nanshan pointed out that there is human-to-human transmission of pneumonia caused by novel coronavirus infection, and relevant experts at home and abroad and the World Health Organization have also confirmed that human-to-human transmission of novel coronavirus pneumonia is taking place.

For the traceability of the novel coronavirus, some scholars have suggested that the novel coronavirus may have originated from bats. However, the virus in bats cannot directly infect humans under normal conditions, and may infect humans through "intermediate hosts. So who is the intermediate host? There are scientific research papers and popular social arguments that point the "suspect" to animals such as snakes and jackals, which need to be further verified.

In fact, the determination of the intermediate host requires a rigorous and recognized scientific process, including: isolating a virus that can reproduce and replicate in the intermediate host; The isolated virus can show pathogenicity and pathological characteristics in animal models; Confirm the position of the virus in the infection transmission chain (whether it infects humans through animals carrying the virus, or re-infects animals from people who have already contracted the virus?), etc. In short, the current study can not determine the intermediate host of the new coronavirus, which needs further scientific research.
 
 
 
 
 
 
 
 
 



Awareness, coronavirus, novel, virus, spread, case, infection, pneumonia, current, cause

Yuanlei Classroom | As a key material, how many applications does precipitated barium sulfate have?

2024-07-11


The appearance of precipitated barium sulfate is a white amorphous powder, with a relative density of 4.50 (15 ℃) and a melting point of 1580 ℃. Due to its high refractive index (1.63-1.65), it exhibits a relatively white color and a certain degree of covering power. It is almost insoluble in water, ethanol, and acid, soluble in hot sulfuric acid. It is easy to form mixed crystals with potassium permanganate, calcium carbonate, or metal nitrates, and can be reduced to barium sulfide with carbon at high temperatures.

Yuan Lei's Little Knowledge | Application of Wet Mica Powder in Other Fields

2024-07-03


Wet mica powder is a high-quality mineral filler made from high-quality mica raw materials, which are washed, impurity removed, soaked, crushed, low-temperature dried, and screened. Its unique production process maximizes the preservation of mica's sheet-like structure, large diameter to thickness ratio, high refractive index, high purity, high whiteness, high gloss, low sand and iron content, and other industrial characteristics that cannot be compared to dry process technology. The unique performance of wet mica powder has greatly improved its application in multiple industries such as plastics, paint, rubber, etc., and has a significant effect on improving product performance and reducing costs.

Yuan Lei's Little Knowledge | Application of Wet Mica Powder in Resin and Plastics

2024-06-27


Wet mica powder is a high-quality powder with good whiteness, large diameter to thickness ratio, smooth surface, and uniform particle size obtained by special processes of crushing, drying, and grading mica fragments after washing, impurity removal, and purification. It is widely used in rubber, plastics, coatings, paints, cosmetics, and other industries.