Last year 118 children were paralyzed in the U.S. The only association (for most of the children) was a recent respiratory infection. At the time, enterovirus D68 was targeted, but less than 20% of the children had the virus present at the time of testing.
A recent report of the CDC cites Enterovirus C105 as another possible cause. The enterovirus C family includes 11 enteroviruses (previously Coxsackie A viruses) as well as the polioviruses. The most recent report is of a six-year-old girl who lost function in her right arm after a respiratory infection. Enterovirus C105 was found in her respiratory tract, and her MRI showed swelling in her spinal column.
Although the patient was started on immunoglobulin treatment, it had little effect. She has gradually regained the use of her arm over the eight months since her infection. (report here)