Visit a nurse following onset of tetanus (6)
I believe the answer is:
attend
'visit' is the definition.
(I've seen this before)
'a nurse following onset of tetanus' is the wordplay.
'nurse' becomes 'tend' (tend can mean to nurse or look after).
'following' says to put letters next to each other.
'onset of' suggests taking the first letters.
The first letter of 'tetanus' is 't'.
'tend' put after 't' is 'ttend'.
'a'+'ttend'='ATTEND'
(Other definitions for attend that I've seen before include "Being 16 [LISTEN]" , "Escort (someone)" , "Be there ? pay attention" , "Listen closely" , "Be present at, or accompany" .)