Luke Letlow, a congressman-elect from Louisiana, died of covid-19 on Tuesday at a hospital in Shreveport, according to state officials.

Letlow, 41, won a runoff earlier this month to represent the state’s 5th Congressional District, succeeding his former boss, Rep. Ralph Abraham (R-La.), who did not run again after three terms in Congress.

Letlow is the highest-ranking U.S. politician to die of covid-19, which has killed more than 337,000 Americans. He was scheduled to be sworn into office on Sunday.

Letlow announced that he had tested positive for the novel coronavirus on Dec. 18, the Monroe News-Star reported, and isolated at his home in Richland Parish in northeastern Louisiana. By the next day, he was admitted to the hospital and later transferred to Ochsner LSU Health in Shreveport.

He is survived by two young children and his wife, Julia Barnhill Letlow, the News-Star reported.

State and national political leaders mourned his death on Tuesday night.

“COVID-19 has taken Congressman-elect Letlow from us far too soon,” said Louisiana Gov. John Bel Edwards (D), in a statement shared on Twitter. “I am heartbroken that he will not be able to serve our people as a U.S. Representative, but I am even more devastated for his loving family.”

Letlow was a native of Start, La., a town of about 900 people, and graduated from Louisiana Tech University before launching his political career as a staffer for Bobby Jindal (R), who went on to become a U.S. congressman and then Louisiana’s governor, the News-Star reported. When Abraham was elected to Congress in 2015, Letlow joined him as chief of staff.

In the race to succeed Abraham, Letlow was the establishment Republican, earning endorsements from his former boss and heavily outraising his opponents, the Associated Press reported. He took the most votes in a nine-candidate field in November, then bested Republican state Rep. Lance Harris in a Dec. 5 runoff.

As the coronavirus ravaged Louisiana, Letlow urged residents to follow social distancing guidelines and to listen to doctors, noting that Abraham, a physician, had returned to Louisiana to help treat covid-19 patients.

But photos on his Twitter page show he had an inconsistent record of wearing masks while campaigning, sometimes covering his face at meet-and-greets but also speaking indoors without a mask on to rooms of mask-free residents. At a candidate forum in October, Letlow urged the state to ease pandemic restrictions, saying, “We’re now at a place if we do not open our economy, we’re in real danger.”

After his symptoms worsened earlier this month, Letlow was first taken to St. Francis Medical Center in Monroe, where he sounded a hopeful note on Dec. 21, tweeting that he was “confident” in his recovery. Two days later, he was taken to a Shreveport hospital and placed in an intensive care unit, where he was treated with remdesivir and steroids, according to a statement from his office.

This week, he was in critical condition but showing signs of recovery, G.E. Ghali, the chancellor of LSU Health Shreveport, told the Advocate. But on Tuesday, he suffered a “cardiac event” and died, Ghali said. Asked whether any underlying conditions might have contributed to his death, Ghali said, “None. All covid related,” the Advocate reported.

Letlow’s death comes as coronavirus cases and fatalities are rising in Louisiana. On Tuesday, the state recorded more than 3,900 new cases and 61 deaths, according to data compiled by The Washington Post, a 185 percent jump over the average number of deaths in the past seven days. In all, the state has had more than 304,000 cases and 7,397 deaths.

After Letlow’s death, Jindal recalled his former staffer’s “passion for service” in the years they worked together.

“I first met Luke when he was still a college student, and spent countless hours with him in his truck driving the back roads of Louisiana,” Jindal wrote on Twitter. “His passion for service has been a constant throughout his life.”

House Speaker Nancy Pelosi (D-Calif.) also noted Letlow’s devotion to public service.

“Congressman-elect Letlow was a ninth generation Louisianan who fought passionately for his point of view and dedicated his life to public service,” Pelosi said in a statement. “As the House grieves Congressman-elect Letlow’s passing, our sorrow is compounded by the grief of so many other families who have also suffered lives cut short by this terrible virus.”

Louisiana’s congressional delegation, including House Minority Whip Steve Scalise (R), released a joint statement praising Letlow’s “positive spirit.”

“We are devastated to hear of Luke Letlow’s passing. Luke had such a positive spirit, and a tremendously bright future ahead of him,” the statement said. “More than anything, Luke was a loving husband, father, brother, and son, and his family — like so many others who have been affected by this evil disease — needs our prayers.”

House Minority Leader Kevin McCarthy (R-Calif.) said he spoke to Letlow’s family after his death.

“Our hearts break tonight as we process the news of Congressman-elect Luke Letlow’s passing,” he wrote on Twitter. “I spoke with his wife, Julia. Judy and I are praying for her and their two young children during this terrible time.”