2021-06-11

Science: Two more coronaviruses that can infect humans have been discovered

By yqqlm yqqlm

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This is not a mutant strain of the new crown, it is Two new coronaviruses that can infect humans.

Science: Two more coronaviruses that can infect humans have been discovered

Report by Science , The electron microscope picture shows a new coronavirus isolated from a child in Malaysia

There are many types of coronaviruses in nature. In the past, the coronaviruses confirmed to infect humans, including SARS, MERS and COVID-19, are only 7 kinds.

Recently, two were discovered at once, which aroused considerable attention. The first type was found in children with pneumonia in Malaysia, and the second type was isolated from children with acute unexplained fever in Haiti.

Malaysia’s coronavirus is a 4-in-1 “monster”

Malaysia’s new coronavirus was discovered in Malaysian hospitalized children with pneumonia——

Science: Two more coronaviruses that can infect humans have been discovered(1)

8 patients were younger than 5 years old, 4 of them baby. I usually live in a long house in the Sarawak countryside in Malaysia. The researchers judged that the mixed living of humans and animals in the local countryside may have caused this coronavirus to infect humans from animals.

But the exact path of infection is not clear, because this coronavirus is a four-in-one chimera (Chimera), which combines three kinds of animal origin from dogs, cats and pigs. Viruses, and come from four different strains. This is also the concern of other virus researchers, because under normal circumstances, chimeras often lack the ability to infect humans due to their own structural problems, while this new chimera has the ability to infect humans.

Benjamin Neuman, a virologist at Texas A&M University, believes that this chimeric coronavirus is a “monster”, and pointed out that it was never formed overnight. The formation of such a “monster” is that the coronavirus is in our country. The invisible place is caused by repeated and long-term mutual combination, and we only discovered it “suddenly” when we observe it accidentally.

In fact, local hospitals for pneumonia do not specifically detect animal-derived coronaviruses. Therefore, these patients were not found to be infected with the new coronavirus until the researchers conducted scientific research. Explore. The author of the paper also pointed out that this ability to infect people is not produced in a short period of time. It is the long-term dynamic change of the coronavirus, which is constantly combined and mutated, and gradually evolved. Therefore, he hopes that the world can strengthen the dynamic monitoring of the coronavirus.

This virus was named CCoV-HuPn-2018 in the paper (the patient was admitted to the hospital in 2017-2018). No evidence of human-to-human transmission has been found, and the children with pneumonia eventually recovered. Science pointed out that the Alpha virus is not very virulent, so it is easy to infect infants and young children. Adults rarely get hospitalized because of Alpha virus infection. However, there are still virologists reminded that because the coronavirus may continue to mutate in the host, we must be alert to the risk of this newly discovered chimera evolving from human to human.

Haiti’s coronavirus is difficult to monitor

Another newly discovered coronavirus that infects humans is also isolated from children——

Science: Two more coronaviruses that can infect humans have been discovered(2)

However, researchers are not sure that it mainly infects children. Because this type of coronavirus belongs to the Delta classification, it has long been believed that the Delta type of coronavirus only infects birds, so it has not received much attention from clinical infectious diseases.

In 2012, this virus was reported in Hong Kong for the first time and found that it had jumped from birds to pigs. This virus can spread rapidly in pigs, cause diarrhea, and can cause death in young pigs. Haiti wiped out the local pig herd due to swine flu in the 1980s, and later introduced new pig breeds from countries such as the United States and Canada.

The virus was discovered this time because a public welfare project that researchers participated in in Haiti included free medical services in local schools. During the period 2012-2020, among the pediatric patients they received, diarrhea, respiratory infections and high fever without a specific cause occurred more frequently.

Beginning in May 2014, they began to retain tissue samples from children with unspecified high fever. In this batch of samples, they screened and found that 3 children were infected with the above, which should only be in birds. The Delta virus, Hu-PDCoV, spread from pigs. Of the three children, two live in the countryside close to the city, and one lives in the mountainous area far from the city. According to the researcher’s investigation, from the perspective of the living environment, all three children have difficulty in contact with pigs, so it is impossible to confirm that the virus is From what kind of host it was transmitted to them, it is impossible to confirm whether it is caused by human-to-human transmission.

During the genetic comparison of the viruses, they found that the three infected virus strains came from pigs in different regions, some from Tianjin, China, and some from Arkansas, USA. They may spread independently to Haiti and infect patients. Researchers therefore believe that this virus spreads very quickly among animals.

In addition to fever, the three children also developed cough, but no diarrhea was reported, only abdominal pain symptoms were recorded. Researchers estimate that this virus is also not very virulent, but it is impossible to determine the extent of its prevalence in Haiti. In the current new crown epidemic, Haiti has a high rate of new crown infection, but the number of severe cases reported is low. The researchers speculate that it may be due to the early epidemic of coronaviruses such as Hu-PDCoV in Haiti, and the local people have developed immunity to the coronavirus, thus reducing the incidence of severe illness. However, the population structure of Haiti is young, which may also be the reason for the lack of reports of severely ill patients. .

The paper itself believes that Hu-PDCoV cannot pose a major threat to human health for the time being, but a coronavirus expert at Ohio State University and Linda Saif, who isolated the Delta coronavirus from pigs that year, pointed out It is necessary to go to Haiti to test the antibodies of adults and children. If it can be confirmed that this virus can indeed infect people, it can be regarded as a threat that can trigger a pandemic.

In response to these two new discoveries, Science pointed out that comparing the cross-species attributes of the coronavirus and its different infectivity between species (for example, the same type of coronavirus is safe in birds, but pigs Infection will lead to death), human attention and research on the coronavirus is very lacking.