A woman returning to China from the United States took a coronavirus with her and triggered an outbreak that eventually infected at least 71 people, the researchers reported on Tuesday.
It began with an elevator ride, the researchers reported in the journal Centers for Disease Control and Prevention, Emerging Infectious Diseases.
The woman returned to Heilongjiang Province from a trip to the US on March 19, about a week after the last corona virus case was diagnosed in the province. He had no symptoms and tested negative for the corona virus, but was asked to quarantine at home.
No one suspects anything is wrong until a man who has no clear connection with travelers experiences a stroke. It turned out he had been at a party with a neighbor’s relative who lived in the same building as the travelers.
When researchers in China finally put the story together, they decided that the traveler must have somehow polluted the elevator in his building. The neighbor downstairs, who used the same elevator, was also infected, and he then infected his mother and her boyfriend. They go to a party and infect stroke patients and their sons.
The stroke patient and his two sons went to two hospitals. At least 28 people were infected in the first hospital and 20 more infected when he was transferred to the second facility.
When the Chinese Center for Disease Control and Prevention investigated the genetics of the virus found in this new outbreak, they found that it was different from the types previously seen in China. Viruses in patients are genetically identical or at least very similar, which makes them believe that the virus originated from abroad.
When the investigators learn that the neighbor of one of the cases has just returned from abroad, they test it again. He is not currently infected but has antibodies to the virus, indicating a previous infection. They pointed to the A0, which meant he was the first case. “Therefore, we believe A0 is an asymptomatic carrier and that B1.1 (its neighbor) is infected by contact with surfaces in the elevator in the building where they both live,” they wrote. The other occupants in the building were all declared negative.
“On April 22, 2020, A0 remained asymptomatic, and a total of 71 positive cases of SARS-CoV-2 were identified in the cluster,” the researchers wrote.
“Our results illustrate how a single asymptomatic SARS-CoV-2 infection can lead to widespread community transmission.”
