"The CDC has confirmed 182 cases of AFM so far this year.
Outbreaks have occurred most frequently in the summer and fall."
Possibly a correlation with illegal immigrant travel ?
Many diseases can be followed by the school calendar.
Most patients had onset of AFM between August and October, with increases in AFM cases every two years since 2014. At this same time of year, many viruses commonly circulate, including enteroviruses, and will be temporally associated with AFM.
https://www.cdc.gov/acute-flaccid-myelitis/about-afm.html
This indicates that the vector is an insect or an animal with population variation every second year.