STANFORD, Calif. — An extremely rare, polio-like disease has appeared in more than a dozen California children within the past year, and each of them suffered paralysis in one or more arms or legs, Stanford University researchers say. But public health officials have not identified any common causes connecting the cases.
The illness is still being investigated and appears to be very unusual, but Dr. Keith Van Haren at Lucile Packard Children’s Hospital at Stanford University warned Monday that any child showing a sudden onset of weakness in their limbs or symptoms of paralysis should be immediately seen by a doctor.
‘‘The disease resembles but is not the same as polio,’’ he said. ‘‘But this is serious. Most of the children we’ve seen so far have not recovered use of their arm or their leg.’’
But doctors are not sure if it is a virus or something else, he said. Van Haren said he has studied five cases from Monterey up through the San Francisco Bay Area, including two that were identified as the disease enterovirus-68, which is from the same family as the polio viruses. He said there have been about 20 cases statewide.
‘‘We want to temper the concern, because at the moment, it does not appear to represent a major epidemic but only a very rare phenomenon,’’ he said, noting similar outbreaks in Asia and Australia.
But for some children, like Sofia Jarvis, 4, of Berkeley, rare does not mean safe.
She first developed what looked like asthma two years ago, but then her left arm stopped moving, and it has remained paralyzed ever since.
‘‘You can imagine. We had two boys that are very healthy, and Sofia was healthy until that point,’’ said her mother, Jessica Tomei. ‘‘We did not realize what we were in store for. We did not realize her arm would be permanently paralyzed.’’
Van Haren said polio vaccines do not protect children from the disease.