Kay Hagan
Twitter/Kay Hagan

Kay Hagan, the former senator of the U.S. state of North Carolina, died on Monday at the age of 66. In a statement, Hagan's family revealed she died of encephalitis, or brain inflammation, caused by Powassan virus -- a rare virus spread through tick bites.

According to reports, Hagan was in Washington when she fell ill and was first diagnosed with the virus in 2016. Hagan, a Democrat from North Carolina who beat Republican Senator Elizabeth Dole in 2008, was hospitalized at an Atlanta rehabilitation hospital for about six months in 2016 before beginning outpatient treatment.

"We are deeply grateful for the support shared with our family as Kay worked to regain her strength these last few years after her illness, and we appreciate your continued prayers," her family said in the statement. "Kay meant everything to us, and we were honored to share her with the people of North Carolina whom she cared for and fought for so passionately as an elected official. Most of all, we already miss her humor and spirit as the hub of our family, a role she loved more than anything. Nobody could light up a room and make people feel welcome like Kay."

Hagan is survived by her husband, Chip Hagan, and her children, Tilden, Jeanette, and Carrie.

Several people, including U.S. presidential hopeful Amy Klobuchar, posted on Twitter after the news of her death.

"We lost my good friend Kay Hagan today. She was one bright yellow ray of sunshine for everyone she touched—the Senate, her beloved state of NC, her friends. As she struggled the last few years, Chip & their kids were always at her side. Look up at the sun & think of Kay today," Klobuchar wrote.

NBC News political reporter Jonathan Allan tweeted a photo of Hagan holding his child, writing: "Shortly after the birth of our son, Sen. Kay Hagan dropped by our house to check on my wife — who worked for her then — and meet the baby. No fanfare, no staff, just a few minutes of quiet celebration of our new joy. We're saddened to hear of her passing."