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Monday, February 17, 2025

Pandemic mystery: Scientists focus on COVID’s animal origins

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1165 days ago
20211210
FILE - Members of a World Health Organization team are seen through a window wearing protective gear during a field visit to the Hubei Animal Disease Control and Prevention Center for another day of field visit in Wuhan in central China's Hubei province, on Feb. 2, 2021. Nearly two years into the COVID-19 pandemic, the origin of the virus tormenting the world remains shrouded in mystery. (AP Photo/Ng Han Guan, File)

FILE - Members of a World Health Organization team are seen through a window wearing protective gear during a field visit to the Hubei Animal Disease Control and Prevention Center for another day of field visit in Wuhan in central China's Hubei province, on Feb. 2, 2021. Nearly two years into the COVID-19 pandemic, the origin of the virus tormenting the world remains shrouded in mystery. (AP Photo/Ng Han Guan, File)

By LAU­RA UN­GAR-As­so­ci­at­ed Press

Near­ly two years in­to the COVID-19 pan­dem­ic, the ori­gin of the virus tor­ment­ing the world re­mains shroud­ed in mys­tery.

Most sci­en­tists be­lieve it emerged in the wild and jumped from bats to hu­mans, ei­ther di­rect­ly or through an­oth­er an­i­mal. Oth­ers the­o­rize it es­caped from a Chi­nese lab.

Now, with the glob­al COVID-19 death toll sur­pass­ing 5.2 mil­lion on the sec­ond an­niver­sary of the ear­li­est hu­man cas­es, a grow­ing cho­rus of sci­en­tists is try­ing to keep the fo­cus on what they re­gard as the more plau­si­ble “zoonot­ic,” or an­i­mal-to-hu­man, the­o­ry, in the hope that what’s learned will help hu­mankind fend off new virus­es and vari­ants.

“The lab-leak sce­nario gets a lot of at­ten­tion, you know, on places like Twit­ter,” but “there’s no ev­i­dence that this virus was in a lab,” said Uni­ver­si­ty of Utah sci­en­tist Stephen Gold­stein, who with 20 oth­ers wrote an ar­ti­cle in the jour­nal Cell in Au­gust lay­ing out ev­i­dence for an­i­mal ori­gin.

Michael Worobey, an evo­lu­tion­ary bi­ol­o­gist at the Uni­ver­si­ty of Ari­zona who con­tributed to the ar­ti­cle, had signed a let­ter with oth­er sci­en­tists last spring say­ing both the­o­ries were vi­able. Since then, he said, his own and oth­ers’ re­search has made him even more con­fi­dent than he had been about the an­i­mal hy­poth­e­sis, which is “just way more sup­port­ed by the da­ta.”

Last month, Worobey pub­lished a COVID-19 time­line link­ing the first known hu­man case to the Hua­nan Seafood Whole­sale Mar­ket in Wuhan, Chi­na, where live an­i­mals were sold.

“The lab leak idea is al­most cer­tain­ly a huge dis­trac­tion that’s tak­ing fo­cus away from what ac­tu­al­ly hap­pened,” he said.

Oth­ers aren’t so sure. Over the sum­mer, a re­view or­dered by Pres­i­dent Joe Biden showed that four U.S. in­tel­li­gence agen­cies be­lieved with low con­fi­dence that the virus was ini­tial­ly trans­mit­ted from an an­i­mal to a hu­man, and one agency be­lieved with mod­er­ate con­fi­dence that the first in­fec­tion was linked to a lab.

Some sup­port­ers of the lab-leak hy­poth­e­sis have the­o­rized that re­searchers were ac­ci­den­tal­ly ex­posed be­cause of in­ad­e­quate safe­ty prac­tices while work­ing with sam­ples from the wild, or per­haps af­ter cre­at­ing the virus in the lab­o­ra­to­ry. U.S. in­tel­li­gence of­fi­cials have re­ject­ed sus­pi­cions Chi­na de­vel­oped the virus as a bioweapon.

The con­tin­u­ing search for an­swers has in­flamed ten­sions be­tween the U.S. and Chi­na, which has ac­cused the U.S. of mak­ing it the scape­goat for the dis­as­ter. Some ex­perts fear the pan­dem­ic’s ori­gins may nev­er be known.

FROM BATS TO PEO­PLE

Sci­en­tists said in the Cell pa­per that SARS-CoV-2, which caus­es COVID-19, is the ninth doc­u­ment­ed coro­n­avirus to in­fect hu­mans. All pre­vi­ous ones orig­i­nat­ed in an­i­mals.

That in­cludes the virus that caused the 2003 SARS epi­dem­ic, which al­so has been as­so­ci­at­ed with mar­kets sell­ing live an­i­mals in Chi­na.

Many re­searchers be­lieve wild an­i­mals were in­ter­me­di­ate hosts for SARS-CoV-2, mean­ing they were in­fect­ed with a bat coro­n­avirus that then evolved. Sci­en­tists have been look­ing for the ex­act bat coro­n­avirus in­volved, and in Sep­tem­ber iden­ti­fied three virus­es in bats in Laos more sim­i­lar to SARS-CoV-2 than any known virus­es.

Worobey sus­pects rac­coon dogs were the in­ter­me­di­ate host. The fox-like mam­mals are sus­cep­ti­ble to coro­n­avirus­es and were be­ing sold live at the Hua­nan mar­ket, he said.

“The gold-stan­dard piece of ev­i­dence for an an­i­mal ori­gin” would be an in­fect­ed an­i­mal from there, Gold­stein said. “But as far as we know, the mar­ket was cleared out.”

Ear­li­er this year, a joint re­port by the World Health Or­ga­ni­za­tion and Chi­na called the trans­mis­sion of the virus from bats to hu­mans through an­oth­er an­i­mal the most like­ly sce­nario and a lab leak “ex­treme­ly un­like­ly.”

But that re­port al­so sowed doubt by peg­ging the first known COVID-19 case as an ac­coun­tant who had no con­nec­tion to the Hua­nan mar­ket and first showed symp­toms on Dec. 8, 2019. Worobey said pro­po­nents of the lab-leak the­o­ry point to that case in claim­ing the virus es­caped from a Wuhan In­sti­tute of Vi­rol­o­gy fa­cil­i­ty near where the man lived.

Ac­cord­ing to Worobey’s re­search, how­ev­er, the man said in an in­ter­view that his Dec. 8 ill­ness was ac­tu­al­ly a den­tal prob­lem, and his COVID-19 symp­toms be­gan on Dec. 16, a date con­firmed in hos­pi­tal records.

Worobey’s analy­sis iden­ti­fies an ear­li­er case: a ven­dor in the Hua­nan mar­ket who came down with COVID-19 on Dec. 11.

AN­I­MAL THREATS

Ex­perts wor­ry the same sort of an­i­mal-to-hu­man trans­mis­sion of virus­es could spark new pan­demics — and wors­en this one.

Since COVID-19 emerged, many types of an­i­mals have got­ten in­fect­ed, in­clud­ing pet cats, dogs and fer­rets; zoo an­i­mals such as big cats, ot­ters and non-hu­man pri­mates; farm-raised mink; and white-tailed deer.

Most got the virus from peo­ple, ac­cord­ing to the U.S. Cen­ters for Dis­ease Con­trol and Pre­ven­tion, which says that hu­mans can spread it to an­i­mals dur­ing close con­tact but that the risk of an­i­mals trans­mit­ting it to peo­ple is low.

An­oth­er fear, how­ev­er, is that an­i­mals could un­leash new vi­ral vari­ants. Some won­der if the omi­cron vari­ant be­gan this way.

“Around the world, we might have an­i­mals po­ten­tial­ly in­cu­bat­ing these vari­ants even if we get (COVID-19) un­der con­trol in hu­mans,” said David O’Con­nor, a vi­rol­o­gy ex­pert at the Uni­ver­si­ty of Wis­con­sin-Madi­son. “We’re prob­a­bly not go­ing to do a big gi­raffe im­mu­niza­tion pro­gram any time soon.”

Worobey said he has been look­ing for ge­net­ic fin­ger­prints that might in­di­cate whether omi­cron was cre­at­ed when the virus jumped from hu­mans to an an­i­mal, mu­tat­ed, and then leaped back to peo­ple.

Ex­perts say pre­vent­ing zoonot­ic dis­ease will re­quire not on­ly crack­ing down on il­le­gal wildlife sales but mak­ing progress on big glob­al prob­lems that in­crease risky hu­man-an­i­mal con­tact, such as habi­tat de­struc­tion and cli­mate change.

Fail­ing to ful­ly in­ves­ti­gate the an­i­mal ori­gin of the virus, sci­en­tists said in the Cell pa­per, “would leave the world vul­ner­a­ble to fu­ture pan­demics aris­ing from the same hu­man ac­tiv­i­ties that have re­peat­ed­ly put us on a col­li­sion course with nov­el virus­es.”

‘TOX­IC’ POL­I­TICS

But fur­ther in­ves­ti­ga­tion is stymied by su­per­pow­er pol­i­tics. Lawrence Gostin of George­town Uni­ver­si­ty said there has been a “bare-knuck­les fight” be­tween Chi­na and the Unit­ed States.

“The pol­i­tics around the ori­gins in­ves­ti­ga­tion has lit­er­al­ly poi­soned the well of glob­al co­op­er­a­tion,” said Gostin, di­rec­tor of the WHO Col­lab­o­rat­ing Cen­ter on Na­tion­al and Glob­al Health Law. “The pol­i­tics have lit­er­al­ly been tox­ic.”

An AP in­ves­ti­ga­tion last year found that the Chi­nese gov­ern­ment was strict­ly con­trol­ling all re­search in­to COVID-19′s ori­gins and pro­mot­ing fringe the­o­ries that the virus could have come from out­side the coun­try.

“This is a coun­try that’s by in­stinct very closed, and it was nev­er go­ing to al­low un­fet­tered ac­cess by for­eign­ers in­to its ter­ri­to­ry,” Gostin said.

Still, Gostin said there’s one pos­i­tive de­vel­op­ment that has come out of the in­ves­ti­ga­tion.

WHO has formed an ad­vi­so­ry group to look in­to the pan­dem­ic’s ori­gins. And Gostin said that while he doubts the pan­el will solve the mys­tery, “they will have a group of high­ly qual­i­fied sci­en­tists ready to be de­ployed in an in­stant in the next pan­dem­ic.”

COVID-19


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