This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

(CNN) – The father of a 14-year-old boy now recovering from a coronavirus-related syndrome says all the symptoms began with a slight fever and some rashes on his son’s hands in mid-April.

The condition, which doctors are calling multisystem inflammatory syndrome in children, has shown up in children across the US — and internationally.

“We dismissed it,” John McMorrow told CNN’s Don Lemon Monday night. “We spoke to his pediatrician and he gave us some antibiotics, he had a slight fever. But within five days it blew up to be a lot more than that.”

Jack McMorrow said he didn’t think his symptoms had anything to do with coronavirus because it all began with a sore throat.

But days later, he was hospitalized with heart failure and his fever was so high he “couldn’t move anything.”

“Even for others to move my limbs at all, it was painful,” he said. “The only way I could describe it is that it felt like almost electricity or fire coursing through my veins.”

Doctors across the country have been investigating similar cases in at least 150 children, most of them in New York. The condition seems to be affecting youth after they’ve had a bout with coronavirus, doctors said last week.

“This multisystem inflammatory syndrome is not directly caused by the virus,” Dr. Jeffrey Burns, a critical care specialist at Boston Children’s Hospital, told CNN. “The leading hypothesis is that it is due to the immune response of the patient.”

Similar cases have been reported internationally, including in the United Kingdom and Italy.

Positive for both virus and antibodies

McMorrow’s doctor, Dr. Thomas Connors, from NewYork-Presbyterian Morgan Stanley Children’s Hospital, told Lemon Monday when he became involved the teen was experiencing a high fever, high heart rate, and low blood pressure.

“He was showing signs of having shock,” Connors said and added the boy had no known pre-existing conditions.

McMorrow tested positive for both coronavirus and antibodies.

“It shows us two different things, two different aspects of this infection,” the doctor said.

“When you have an active infection and especially one that is transmitted by the respiratory tract, you can find it first in your upper respiratory tract, in the nose, and in the throat,” he said. “After you’ve had an infection what you hope will happen (is that) your immune system will develop protection to it if you see it again and the most common thing to look for protection is antibodies.”

McMorrow’s test results showed the teenager had a previous infection or enough time with the disease to develop antibodies but also still had an active strain of the virus in his nose, according to the doctor.

Click here for more stories on Pediatric Multisystem Inflammatory Syndrome