This study is designed to gain a better understanding and natural history of acute flaccid myelitis (AFM).

This study will include reviewing medical records to record information about the medications taken to treat AFM and your social history (smoking, alcohol and drug use). The results of lab tests, imaging studies and tests will also be collected to determine if you have any damage to your nerves that are done by your clinical care team to diagnose your AFM.

Samples from Mouth, nose, stool and blood will be collected as a part of this study. Any remaining spinal fluid that is in the lab from the spinal tap from clinical labs will also be collected. A neurological exam and tests to determine issues with muscles, functionality and strength after being diagnosed with AFM will also be performed as a part of this study.

Patients who previously had been treated with either intravenous ganciclovir or oral
valganciclovir as an infant or toddler, either as part of a previous Collaborative Antiviral Study Group (CASG) study or through routine clinical care at a current or former CASG study site, will be offered enrollment on this retrospective follow-up study.