Singed poison's interaction with on hit spells (such as spellvamp/ rylais)

So on the wiki for singed's Q ... it says..

'' Poison Trail is a toggled point blank area of effect ability. CLOUD RADIUS: 20

Applies spell effects as an area of effect ability. Hextech Revolver item.png Spell vamp is reduced to one-third effectiveness. Will of the Ancients item.png Will of the Ancients will heal you for 5% of the raw damage dealt. Rylai's Crystal Scepter item.png Rylai's Crystal Scepter will apply a 40% Slow icon slow for 1 second.

Applies spell effects as a damage over time ability. Hextech Revolver item.png Spell vamp is fully applied. Will of the Ancients item.png Will of the Ancients will heal you for 15% of the raw damage dealt. Rylai's Crystal Scepter item.png Rylai's Crystal Scepter will apply a 20% Slow icon slow for 1 second. ''

so.. for rylai, i get it, it will slow 40 for 1 sec then 20 and on

what about for spell vamp?