University of Arizona: The Hypotheses on the Origin of the US Coronavirus Epidemic Challenged

By Iliriana Bisha Tagani MD | Published on September 12, 2020
Reviewed By Iliriana Bisha Tagani MD | On: September 13, 2020

A team of researchers from the University of Arizona in Tucson traced Covid-19’s journey through Europe and North America. The study showed that the first infections were successfully contained, but subsequent outbreaks gave rise to the pandemic.

Coronavirus

Could the spread of the Covid-19 epidemic in Europe and the United States have been prevented?

An American study carried out by a team of researchers from the University of Arizona Tucson with the support of 13 research institutes in the United States, Canada, Belgium, and the United Kingdom and published on 10 September in the scientific journal Science reports on some scenarios explaining the dynamics of this pandemic.

The study combines evolutionary genomics of coronavirus samples with computer simulations of epidemics, as well as detailed travel reports. “This allowed us to re-run the tape of how the epidemic unfolded, over and over again, and then check the scenarios that emerge in the simulations against the patterns we see in reality,” says Michael Worobey, one of the main authors of the study.

United States: Seattle and Canadian tracks excluded

This study dissected two previous preferred scenarios to explain the spread of the virus in the United States. The first hypothesis estimates that a Chinese citizen flying from Wuhan (Hubei, China) to Seattle on January 15 caused the cluster of the state of Washington and its subsequent spread. Impossible according to the authors of the article. Even though this person has the oldest sequenced Covid-19 genome in the country, it is too different from the genes that appeared six weeks later in the same state. Scientists are more confident that the cluster was created by contamination in early February or earlier.

They also reject the idea that the virus was taken to Washington by someone from the bordering state of British Columbia in Canada. Today, they estimate that the west coast of the United States has been directly infected by a case imported from China since tens of thousands of American citizens and visa holders have traveled from China to the U.S. even after the travel ban came into force.

Several clusters were controlled through testing and isolation

The researchers say there was another infection vector of the country on the east coast, allegedly infected by a case imported from Italy. However, they have difficulty explaining the origin of this contamination in Europe. Still, they have excluded the possibility of Bavarian contamination of the European Union. Although on January 20th of this year an employee of a Bavarian car company with Covid-19 returned from China and infected 16 colleagues, no further cases appear to have been reported. “An impressive response of rapid testing and isolation has prevented the epidemic from spreading further,” say the researchers.

“Our research shows that early intervention and effective detection can have a huge impact, both in preventing pandemics and fighting them as soon as they occur,” Worobey says. Although the epidemic eventually went out of control, some victories have been achieved that showed us that extensive testing and cases tracing are powerful weapons.