Longtime Fox News anchor John Roberts, 68, is currently battling a serious case of malaria.

In an interview with PEOPLE Magazine, Roberts opened up about his health scare and the moment he realized he had contracted the mosquito-borne illness on Monday, August 25.

“I had been hurting from the top of my head to the tip of my toes. Literally everywhere. I was also beset with uncontrolled shivering all during my show,” Roberts told PEOPLE. “Initially, I thought it was just muscle cramps and aches. But when I started shivering, I started to lean toward the flu.”

He knew something was seriously wrong when his bloodwork showed low levels of both platelets and white blood cells. “My rheumatologist told me to go to the ER,” Roberts recalled.

It was at the hospital where he received the official diagnosis. “I thought, ‘Of course you have malaria… You never do anything in small measures.’ But I was a little scared,” he admitted. “Malaria can be deadly if left unchecked.”

“I don’t know exactly how ‘severe’ it was from a medical classification, but it sure felt severe,” he added. “I have never felt that sick in my life.”

Roberts believes he contracted the illness while vacationing in Indonesia, where he spent two weeks before returning to the U.S. in early August. Although he doesn’t remember being bitten, his symptoms began about 10 days after coming home.

Malaria, a disease spread by mosquitoes, is most common in tropical and subtropical regions. Symptoms often include fever, chills, headaches, body aches, fatigue, and sometimes gastrointestinal issues like nausea, vomiting, or diarrhea. These symptoms typically appear within one week to one month after exposure.

During his hospital stay, Roberts was treated with IV artesunate—the standard U.S. treatment for severe malaria. He called it the “big gun” in the fight against the parasite.

“Yesterday [Aug. 27] was a down day,” he admitted. “I felt horrible all day. I also have wild swings in temperature every hour. I’ll be shivering and shaking like a leaf… the next I’ll be sweating.”

Despite the ordeal, Roberts is expected to return to work on Tuesday, September 2.

In his first social media post about the diagnosis, Roberts thanked Trace Gallagher for filling in on America Reports while he recovered. “I somehow came down with a severe case of Malaria,” he wrote on X (formerly Twitter). “I can honestly say that I am the only person in the hospital with Malaria. In fact, one of my doctors said I’m the first case he has ever seen. Thanks to the folks at @InovaHealth for their expertise and compassion…!”

Dr. Jeffrey Horelick also weighed in, offering personal insight into the severity of malaria.