We agree with Spencer that a causative environmental agent should be able to trigger the tau pathology observed in post-mortem studies of nodding syndrome.1 However, it is possible that O. volvulus microfilaria, secretory/excretory products or endosymbionts, including viruses, could occasionally cross the weakened blood-brain barrier of young children causing neuroinflammation, resulting in epilepsy and tau deposits.10 Here, MAPT is linked to epilepsy.