Fox News Washington correspondent Kristin Fisher joined "The Story" Wednesday to discuss her now-viral tweet about her father -- a Texas emergency room physician who is on the front lines of the coronavirus pandemic.

"I had been talking to him on the phone almost daily about the virus, but there was something about seeing him in the mask and the gloves ... it just really hit me, and I got really scared for my dad," Fisher said.

On Monday, Fisher posted a photo that her dad texted her that showed him sporting a lab coat, mask and gloves. Fisher told her Twitter followers that she "burst into tears the second" she saw the photo, a reaction that came seemingly "out of nowhere."

An error occurred while retrieving the Tweet. It might have been deleted.

"I called him to say I was worried about him, but could barely speak as I fought to keep my voice steady," she wrote. "I think we all have a moment where the gravity of what’s happening finally hits us. This was mine."

Joining his daughter on "The Story," Dr. William Fisher said he was "surprised" by Kristin's post, but explained her concern is valid.

"When I read what she said, I teared up, too. I was so surprised. It was such a wonderful thing to read.," Dr. Fisher told MacCallum. "She is right to be concerned."

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"All health care workers are at increased risk, but we do the best we can, and every patient that I see with similar symptoms is a potential Covid-19 patient, so we have to treat everybody as though they are infected ... and that is what we are doing."

Kristin Fisher said her father's age makes him vulnerable to the virus, but he "loves his job and will never retire."

"I know he is the youngest 73-year-old in the world. He has the immune system of somebody who has been working in emergency rooms for 40-plus years, but when you hear the stats about how this virus affects people who are older, it really hit me," she told MacCallum.

"It's like walking into a dark forest with a patient behind every tree."
— Dr. William Fisher. 'The Story'

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Asked how his team is handling the outbreak, Dr.Fisher said the situation is "unusual," and compared it to "walking into a dark forest with a patient behind every tree."

"They all have similar symptoms. Some have the flu, some have a cold. And some have Covid-19, and there's no way to tell," he explained. "We have to treat them all as though they are infected, and it's a little different to have that situation, but that's what we do."

"The way we have transitioned from a peacetime to a wartime setting in the last two weeks has been remarkable."
— Dr. William Fisher, 'The Story'

Dr. Fisher added that while his hospital has not yet secured test kits and patients must be tested by an outside facility, the federal government has done an "excellent job" responding to the crisis.

"The way we have transitioned from a peacetime to a wartime setting in the last two weeks has been remarkable," he said. "It took four to six months to get this far after Pearl Harbor. I think an excellent job is being done, it's just the magnitude of the problem is so great, it takes time."

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Kristin Fisher said she related to the fear and concern felt by families of doctors and nurses responding to the crisis head-on.

"Just looking at my father, this past 24, 48 hours, it's really made me think, 'If I'm feeling this about my dad, how many other people who have family members who are nurses, doctors, other people who work in hospitals, how many of them are dealing with similar thoughts and fears?'" she said.