Travel bug ultimately stops Pierre running country (13)
I believe the answer is:
peregrination
'travel' is the definition.
(peregrination is wandering around)
'bug ultimately stops pierre running country' is the wordplay.
'ultimately' says to take the final letters.
'stops' is an insertion indicator (stopping can mean blocking a gap).
'running' indicates an anagram (the letters run around to different places).
'country' becomes 'nation' (synonyms).
The last letter of 'bug' is 'g'.
'pierre' is an anagram of 'pereri'.
'g' going inside 'pereri' is 'peregri'.
'peregri'+'nation'='PEREGRINATION'
(Other definitions for peregrination that I've seen before include "Long meandering journey" , "Globe-trotting" , "wandering" , "Travelling about" .)