Tuesday, February 25, 2014 'Polio-Like Illness' in California Children Still a Mystery The "polio-like illness" found in 5 California children "appears to be very, very rare," according to the author of a study on these cases, but could point to an "emerging" infectious syndrome. In a recent press release the study's authors stated that 20–25 similar cases are now being investigated. The illnesses involve paralysis of 1 or more limbs with rapid onset and a peak in severity at about 2 days. Of the 5 children affected, 3 had respiratory illnesses before the polio-like symptoms began. All 5 had been vaccinated against the polio virus. Despite treatment, the children's symptoms did not improve, and though all are still alive none returned to normal limb function after 6 months. The children who experienced the illness were clustered in California over a 1-year period. Of the 5 children, 2 tested positive for enterovirus-68, which the US Centers for Disease Control and Prevention describes as a "very common" virus that tends to produce few or "very mild" signs of illness. Rarely, however, the virus can produce myocarditis, pericarditis, encephalitis, and paralysis. Providers were unable to find a cause for the illness in the other 3 children. The study of the 20–25 additional cases is focused on children with paralysis of 1 or more limbs and abnormal MRI scans, with no presence of botulism or Guillain–Barré syndrome—2 conditions that can also generate polio-like symptoms. The study will be discussed in detail in a case study that will be presented at the American Academy of Neurology's annual meeting April 26–May 3.