SIOUX FALLS, S.D. (AP) — Sen. John Thune was consulting with his doctor in his home state of South Dakota on Thursday after leaving Washington, D.C., a day earlier because he felt ill.

Thune, the Senate majority whip, was told by doctors to self-monitor and that he didn't need to take additional action, according to a Wednesday night update from spokesman Ryan Wrasse. Thune flew home on a chartered flight, accompanied by one member of his security detail. He also took the precaution of wearing a mask on the flight.

Thune is 59. His office declined to say whether he would be tested for COVID-19 or who paid for the flight. Wrasse tweeted later Thursday that Thune had improved Thursday morning.

South Dakota's other senator, Republican Mike Rounds, is self-isolating at his family farm in South Dakota following the vote on a $2.2 trillion fiscal package aimed at shoring up the nation’s economy.

Rounds told reporters Thursday he is taking the precaution in part because his wife, Jean, is at higher risk for COVID-19 following her treatment for cancer. He said he is not feeling symptoms but plans to take the precaution for seven to 10 days.

Kentucky Sen. Rand Paul announced Sunday that he had tested positive for the coronavirus. He kept working for six days after getting tested, saying he had no symptoms.

For most people, the coronavirus causes mild or moderate symptoms, such as fever and cough that clear up in two to three weeks. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia and death.