Parasite seen in experimental test tubes (but eradicated) (6)
I believe the answer is:
tsetse
'parasite' is the definition.
(biting fly found in tropical Africa)
'experimental test tubes but eradicated' is the wordplay.
'experimental' indicates anagramming the letters.
'eradicated' indicates named letters should be taken away.
'test'+'tubes'='testtubes'
'testtubes' with 'but' taken out is 'esttes'.
'esttes' is an anagram of 'TSETSE'.
'seen in' is the link.
(Other definitions for tsetse that I've seen before include "bloodsucker" , "carrier of disease" , "source of sleeping sickness" , "African transmitter" , "cause of sleepiness?" .)