Bre Payton, a writer for a conservative online newsmagazine and a guest commentator on the Fox News Channel, died on Friday in San Diego. She was 26.

Her death was confirmed by the online newsmagazine, The Federalist. Ms. Payton had the H1N1 flu, also known as the swine flu, and encephalitis, according to her family.

Ms. Payton started writing for The Federalist in April 2015. The site said she quickly became a “rising star” who was regularly featured on Fox News Channel and Fox Business Channel.

“From the moment we started talking I realized she was a potential star,” Ben Domenech, the publisher of The Federalist, said in an essay on Saturday. “She was raw, yes, but that could be honed. She was eager to learn, to write, and to go places — not because of ambition, but because she wanted to change the world.”