This fall, enterovirus 68 (EV-68) has been responsible for the hospitalization of hundreds of children throughout the United States. As if an outbreak of a virus which causes severe respiratory complications in young children wasn’t bad enough, experts now believe they identified an even more worrying symptom of the virus: paralysis. Although this jump from coughing to paralysis is rare, it’s not unheard of — but how exactly does a virus infect the nervous system?

The enterovirus 68 has been reported in at least 40 states and confirmed in at least 277 people, according to the Centers for Disease Control and Prevention (CDC). Those infected with the virus may exhibit symptoms, such as sniffling, coughing, fever, and muscle aches. In patients with asthma, especially young children, EV-68 can spur respiratory issues severe enough to land them in the hospital.

In a mysterious twist of events, four children hospitalized with EV-68 have also exhibited symptoms of minor paralysis, ABC News reported. Earlier this year, two more children experiencing paralysis also tested positive for the virus, Medical Daily reported. Although not yet proven, doctors believe this connection is not pure coincidence.

Investigators from the CDC are currently looking for a link between EV-68 and paralysis. This is not the first time a virus has been found to cause paralysis in patients. Polio is without doubt the most recognized paralysis-causing virus. The virus enters the body and infects the bloodstream in order to reach the nervous system.

Once inside the nervous system, the virus multiplies and destroys nerve cells which activate skeletal muscles. This cell damage is irreversible and causes a loss of muscle function, which we see as paralysis. "Although poliovirus has been eradicated from most of the globe, other viruses can also injure the spine, leading to a polio-like syndrome,” Dr. Keith Van Haren from Stanford University explained in a press release earlier this year. Dr. William Schaffer, an infectious disease expert at Vanderbilt University School of Medicine, agreed with Van Haren's conclusion, telling ABC News that "From time to time other enteroviruses can behave very sporadically like the polio virus. … The leading candidate is indeed this enterovirus 68.”

The CDC is currently conducting a test to see whether the virus is present in patients’ spinal fluid. This would prove that the virus was, in fact, causing the paralysis. The test will take up to a week. Unfortunately, as ABC News reported, the enterovirus 68 often fails to show up in lab tests, even when present.

If doctors prove the virus is behind the paralysis, parents can be reassured that this symptom is quite uncommon. "It's a pretty rare complication and not unexpected with this kind of viruses," Dr. Larry Wolk, the chief medical officer and executive director of Colorado Department of Public Health and Environment, told ABC News. "You hear about this nine with this complication, what you're not hearing about is that thousands or hundreds of thousands" just have a cold.