Washington DC - Anthony Fauci called Kansas Senator Roger Marshall a "moron" on Tuesday after a tense exchange over Fauci’s financial disclosures, a sign of the increasing hostility between conservatives and one of the nation’s top Covid-19 experts.

Toward the end of a more-than-three-hour Senate Health Committee meeting, Marshall pointed to Fauci’s government salary of more than $400,000 and asked whether he would make his financial disclosure available to the public.

Fauci is a government employee and his financial disclosure forms are available to the public, who can access them through a Freedom of Information Act request.

"Wouldn’t you agree with me that you see things before members of Congress would see them, so that there’s an air of appearance that maybe some shenanigans are going on," Marshall said. "I assume that’s not the case."

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When Fauci called Marshall "misinformed" and said his financial disclosure is public information and available upon request, Marshall said his office had been unable to find the information. As Kansas Senator Jerry Moran prepared to ask a question, Fauci was caught on the microphone saying "what a moron" and "Jesus Christ."

In a press release after the hearing, Marshall doubled down and said Fauci was "clearly distraught by the line of questioning."

"Calling me a moron during a Senate hearing may have alleviated the stress of the least trusted bureaucrat in America, but it didn’t take away from the facts," Marshall said.

The National Institute of Allergy and Infectious Diseases, which is headed by Fauci, did not immediately respond to a request for comment.

Fauci was testifying with Rochelle Walensky, director of the Centers for Disease Control, and Janet Woodcock, acting commissioner of the US Food and Drug Administration, about the current surge of Covid-19 cases spreading through the country as a result of the Omicron variant.

Throughout the pandemic, Fauci has been a target of conservatives who have chafed at the way the government has handled health restrictions.

But nearly two years into the pandemic, tension has ratcheted up between Fauci and conservatives in Congress, where there is a partisan divide over who wears masks in the hallways and in the chamber.

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Senator Rand Paul, who has been a frequent critic and was previously suspended from YouTube for false claims over masks, has called Fauci "a lead architect" of the government’s response to the virus, from shutting down businesses at the beginning of the pandemic to urging people to wear a mask and get vaccinated.

Earlier in the committee hearing, Marshall, an obstetrician and gynecologist, questioned Fauci about his role in authorizing "gain of function" research, a type of experiment where scientists change a virus to make it more potent as a way to study its effects.

Marshall has said he would like a ban on gain of function research and has made investigating the origins of Covid-19 a core platform for his first year in office.

Fauci also clashed with Paul over an email exchange between him and former director of the National Institutes of Health Francis Collins, in which Collins and Fauci discussed how to combat what they called a "fringe" narrative about the pandemic raised by epidemiologists at prestigious universities.

In response, Fauci held up a print-out of Paul’s Senate campaign website, where there is a picture of Fauci next to the text "Fire Dr. Fauci" and several buttons where people can make donations to the campaign.

Fauci talked about how he has gotten death threats after similar exchanges with Paul and said a man who was arrested driving from Sacramento to Washington, DC with an AR-15 and ammunition said he was going there to kill Fauci.

"He’s doing this for political reasons," Fauci said.

Fauci has often drawn the ire of activists. In the 1980s, he was among those criticized for the government’s slow response to the AIDS epidemic. Members of ACT UP burned him in effigy outside the NIH building during one protest.

But Fauci, who later became friends with some ACT UP leaders, has drawn a distinction between activists fighting for more resources for people with the disease and those who have criticized him for public health measures intended to decrease the spread of the virus.