LOS ANGELES (CBSLA.com) — Experts fear an outbreak as children across the country are being attacked by the rare, polio-like enterovirus, right as flu season is set to begin.

The respiratory illness, which started in California, is causing great concern.

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One local 3-year-old victim named Lucian has dealt with the virus since he was 11 months old. Lucian has a paralyzed left leg, while his right leg is in a slow recovery.

Lucian’s mother, Erin, underwent years of tests before she was finally informed that her son has enterovirus.

“We did not get our official polio-like diagnosis until March of this year,” Erin said. “So, almost two years.”

A total of 443 people throughout 40 states and the District of Columbia have confirmed illnesses caused by enterovirus, according to the Centers for Disease Control. All but one of these victims are children.

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“And then it can become a persistent infection in the lungs,” infectious disease expert John Chia said. “Or it can go through the blood stream and reach the central nervous system. That’s how I think poliomyelitis occurred in those cases.”

While most don’t get sick or only show a mild illness, infants and people with weakened or compromised immune systems have a greater risk of getting very sick or may even become paralyzed.

Erin, meanwhile, who says her son was healthy at the time he contracted enterovirus, urges parents to trust their instincts if they feel or see something that isn’t right.

“Pay attention. I’ll kick myself in the fanny the rest of my life, thinking, if I had maybe pursued that a little bit stronger, would the outcome have been different?”

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The CDC has not connected any deaths to the virus but says victims admitted into hospitals showed symptoms of asthma, as well as previous wheezing.