Think about Jack, possibly, at home getting fungal infection (10)

'fungal infection' is the definition.
(disease affecting insects)

'think about jack possibly at home' is the wordplay.
'think' becomes 'muse' (musing is a kind of thinking).
'about' means one lot of letters goes inside another.
'jack possibly' becomes 'card' (jack is a type of playing card).
'at home' becomes 'in' (similar in meaning).
'card'+'in'='cardin'
'muse' going around 'cardin' is 'MUSCARDINE'.

'getting' is the link.