A night owl at last year’s carnival celebration could have been the trigger for 50,000 cases of the corona virus, according to a new study.
The Louisiana 2020 Mardi Gras celebration is known to have turned the state into one of the earliest hotspots of the U.S. pandemic in late February.
But researchers now believe that a single person likely brought the virus to town in the weeks leading up to Fat Tuesday, causing tens of thousands of infections from people huddled together and sharing food and drinks without a mask.
They suspect that Mardi Gras “Patient Zero” infected 800 people in the two weeks between February 13th and the end of the celebrations on Ash Wednesday, February 26th.
And those 800 then spread the infection to another 50,000 people in Louisiana and neighboring states.
The team, which was made up of multiple institutions including the Scripps Research Institute, Tulane University, and Louisiana State University Health Shreveport, said the outbreak had largely gone largely undetected as no testing and mitigation measures were in place at the time.
A new study found that a single person who likely traveled from Texas brought COVID-19 to New Orleans for Mardi Gras 2020. Image: The risk of where the virus spread in the US in the first week after Mardi Gras
By Mardi Gras and Ash Wednesday, nearly 800 people were likely infected, resulting in 50,000 cases in Louisiana’s first wave. Pictured: The percentage of people who traveled to New Orleans from other states prior to Mardi Gras 2020
The samples found in New Orleans showed little genetic diversity, creating conditions similar to those found on a cruise ship where an outbreak comes from a single source. Pictured: Bourbon Street in New Orleans on Mardi Gras Day in February 2020
Studies later showed that COVID-19 exposure rates in Louisiana’s first wave were close to 10% from March 9 to May 15. Image: The Society of Saint Anne’s parade during New Orleans Carnival, February 2020
“The entire Louisiana outbreak is almost certainly being driven by the events on Mardi Gras,” study co-author Mark Zeller, a researcher at Scripps, told Times-Picayune.
‘It’s basically the snowball. As soon as it works, it just works. It’s really hard to stop. ‘
For the study, which has not yet been peer-reviewed and published on the pre-print server medRxiv.org, the team sequenced genomes of the virus from New Orleans and others during the first wave from March 9 to May 15 Locations in Louisiana.
These were then compared to genomes from the US and worldwide to determine the origin of COVID-19 in the state of Bayou.
The sample found in New Orleans showed little genetic diversity, creating conditions similar to those of a cruise ship where an outbreak comes from a single source.
“It’s the same situation,” said lead author Dr. Robert Garry, Professor of Microbiology and Immunology at Tulane Medical School, The Times-Picyaune.
Infections have been spread to other states such as Texas, Mississippi, and Alabama, but being ordered to stay home prevented the virus from spreading further (see above).
‘A cruise ship, people are crammed into smaller spaces, people are in those tight spaces. Almost like a Mardi Gras Krewe, right? People spend a lot of time together, in the balls, in those narrow spaces. ‘
They also looked at mobility data to find out who was traveling to and from New Orleans during Carnival.
Between February 14, 2020, when the celebration began and February 25, Mardi Gras day, more than one American visited the city.
The first case of COVID-19 in Louisiana was reported on March 9th. In contrast to early outbreaks in New York and Washington, the researchers found that Patient Zero was not from Europe or Asia, but from someone traveling domestically.
Analysis found that the sick person was likely from Texas, which was more than twice as likely as the next most likely state that was the source.
This is because as of February 2020, 13 percent of trips to New Orleans and 35 percent of trips to Shreveport, a city in northwest Louisiana, were passengers from Texas.
About 800 people were infected the following day, Ash Wednesday, which spread the virus to others and resulted in about 50,000 confirmed cases, mostly in Louisiana during the first wave over the next several months.
“The rapid nature of the early COVID-19 epidemic in New Orleans likely resulted in thousands more cases, backed by seroprevalence studies showing exposure rates of nearly ten percent by May 15, 2020 in New Orleans,” the authors wrote.
‘Compared to neighboring states that didn’t experience the same explosive first waves as Louisiana, the CDC estimated … that seroprevalence in Louisiana was 35 to 134 percent higher than other states in the southern United States. ‘
And while the New Orleans tribe led to infections in other parts of Louisiana and other southern states, including Texas, Mississippi, and Alabama, orders to stay at home appeared to help spread the virus to other states.
This year New Orleans will close bars February 12-17 and no operations will be allowed to sell take-away alcoholic beverages. Pictured: A group of revelers on a balcony toss pearls to the crowd down on Bourbon Street on Mardi Gras day in February 2020
“I think New Orleans had the largest increase in patients in the world in March,” Zeller told Times-Picayune.
‘It’s just very unfortunate timing. If Carnival had been two or three weeks earlier, it might not have resulted in so many cases. ‘
This year Mardi Gras and Mardi Gras will be very different.
The bars will be closed from February 12th to 17th and no establishment such as restaurants may sell alcoholic beverages to take away.
Pedestrians and vehicles are not permitted on some of the city’s most popular streets between 7:00 p.m. and 3:00 a.m., and there are no parking zones.
Indoor gatherings are limited to a maximum of 10 people and outdoor gatherings are limited to a maximum of 25 guests.
“When students crowd on Bourbon Street, many of these people don’t get seriously ill,” said Dr. Jeremy Kamil, professor of microbiology and immunology at LSU Health Shreveport, told Times-Picayune.
“But when you go home and visit Grandma, or if you pass it on to someone else who passes it on to someone who works in a nursing home or is a prison clerk, then suddenly you are indirectly in a chain of events that you are now in participated in the deaths of 90 people in some way. ‘