The most common and most likely answer to this crossword clue is the 6 letter word TSETSE
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More clues leading to the result TSETSE
- Fly first-class twice - not second class - and back.
- Bug transmitters in trustee's banks
- Insect collections kept in ether regularly
- Fly back east twice, having mislaid articles
- Superintendent sets example, arresting sucker
- Set out to catch regular fly
- . Fly by night, finally getting directions over Spain
- One gets off to a flying start participating in three sets
- Cause of disease in cattle? Tribe has groups replacing bone
- Scenery fills empty theatre: one with wings
Buddy explains!

The straight part
We know that "Parasite" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case parasite = tsetse.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TSETSE mean?
TSETSE noun- Any fly of the genus Glossina, native to Africa, that feeds on human and animal blood; known primarily as a carrier of parasitic trypanosomes.