The most common and most likely answer to this crossword clue is the 9 letter word EPIDEMICS
I've seen this crossword clue in The Daily Telegraph
E
P
I
D
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M
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Buddy explains!

The straight part
We know that "Outbreaks" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case outbreaks = epidemics.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 EPIDEMICS mean?
EPIDEMICS noun- A widespread disease that affects many individuals in a population.
- An occurrence of a disease or disorder in a population at a frequency higher than that expected in a given time period.