Rachel Scott's son Braden was 5 years old when he was diagnosed in 2016 with acute flaccid myelitis, or AFM, a rare, rapid-onset neurological disease affecting the spinal cord leading to paralysis.
Josh and Gretchen Trimble's youngest daughter, Opal, was just 4 months old when she was diagnosed with AFM, one of the youngest patients ever to be diagnosed with the disease.
Now, as the Centers for Disease Control and Prevention (CDC) warns about a potential AFM outbreak this fall, these parents are speaking out about what they want others to know about the rare but potentially lethal disease.
AFM tends to come in two-year cycles, which is why the CDC is alerting people to be on the lookout for it now, according to Dr. Jennifer Ashton, ABC News chief medical correspondent.
"In medicine we have a saying, 'An increased risk of a rare event is still a rare event,'" she said. "But if it happens to your child, it is a big deal."
Here are five things to know.
When Gretchen Trimble dropped Opal off at day care one day in February of last year, she said she remembers thinking that morning how Opal was happy and pleasant.
A few hours later, Trimble was called to pick Opal up from day care because of her poor health. A few days after that, Opal was in the pediatric intensive care unit and diagnosed with AFM.
"The onset of it was just so sudden," said Trimble. "When I got the call from the day care and I went to pick her up, I was just blown away that she not only was acting so sick, but it was such a drastic difference from that morning. She was showing no signs of any kind of symptoms."
Scott's son, Braden, had a cold that Scott said at first was nothing unusual.
"All of my kids just had a mild cold, runny noses and nothing major," said Scott. "For everybody, the cold passed and then about a week later Braden started having these signs of paralysis and weakness."
Experts say seeking medical attention right away could make all the difference.
Symptoms of AFM include sudden arm or leg weakness, difficulty walking, limb pain, back pain or neck pain. AFM can cause paralysis over the course of hours or days, which may require a ventilator for breathing. It most commonly affects young children.
MORE: CDC expects 2020 outbreak of life-threatening AFM in childrenMost children with AFM will have a fever or respiratory illness about six days before weakness occurs. But why some children get AFM and some don't isn't yet clear.
Braden's first symptoms of AFM were difficulty swallowing. Scott, who had never heard of AFM, said she and her husband thought their son had a sore throat and attributed his weakness to the fact that he was not eating.
"Had [AFM] been something that we'd heard of before or seen in the news, it would have set off a red flag for us and our doctors," said Scott. "None of our doctors were considering [an AFM diagnosis] until he had stopped breathing and was intubated."
Scott stressed that parents need to pay close attention to their child's symptoms, even as an AFM outbreak could overlap with the coronavirus pandemic.
MORE: Father, daughter have touching 'heartbeat' ritual as she recovers from rare illness"The most important thing, especially right now when people are fearful of going into medical facilities and are trying to avoid places where sick people are congregated, if your child is experiencing any limb weakness, any facial drooping, any trouble swallowing, a cold or fever, that is a medical emergency and you need to go to the emergency room immediately," she said. "You cannot avoid seeking treatment out of fear of COVID-19."
Because AFM is so rare, it is still a disease that doctors are learning more about.
Scott's and Trimble's children were each diagnosed and treated for other illnesses before being diagnosed with AFM.
They were also each finally diagnosed with AFM after doctors ordered an MRI, which is what the CDC recommends health care providers order to distinguish AFM from other neurological conditions.
"I go back often playing the could have, should have, would have game," Trimble said of the several days it took for a doctor to order an MRI for Opal.
"What was crazy to us, because it's a one-in-a-million disease, that it was a learning experience for our doctors too," she said. "I would encourage parents to ask questions and know that doctors aren't going to have all the answers."
Opal spent seven weeks in the PICU, where her parents were told she had a 30% chance of recovery. She then spent another several months at the Children's Center Rehabilitation Hospital in Bethany, Oklahoma, where she got treatment the Trimbles credit with her recovery.
She was paralyzed from the neck down at diagnosis and now, nearly two years later, has full movement in her upper body and is regaining movement in her lower body, according to Trimble.
"Don't give up hope, that's my encouragement to parents," she said. "Just expect big things from your child and position them and give them the resources that can foster that and know that there is always hope and there are always things to be thankful for."
Likewise, Scott's son Braden continues to make improvements every day, four years after his diagnosis. He is able to walk short distances, has full use of one arm and had his tracheotomy tube removed last year, though he still relies on a feeding tube for much of his nutrition.
"It's been a heartbreaking and devastating thing for my family, but it's not the end of the world," said Scott. "Braden is happy. He has a great life. It's not a death sentence."
Both Trimble and Scott cited the need for support while confronting a disease that is so rare.
"Even though the numbers are small, for the families that it does impact, it's life-changing," said Trimble, who shares her family's journey on Facebook.
Scott, who also shares Braden's journey on Facebook added, "It's a very real thing that we're living with and it's something that parents need to be aware of before it's something that their kid is dying from."
The CDC has a resource page for people to find out more about AFM.
The Acute Flaccid Myelitis Association is a nonprofit organization that offers more information about AFM, as well as resources and support for parents.