Complex sentence: Apart from viral infection, other infections such as bacterial infections can cause parotitis (acute suppurative parotitis or chronic parotiti) as may blockage of the duct, whether from salivary duct calculi or external compression.
Split into simpler sentences: Apart from viral infection, other infections such as bacterial infections can cause parotitis (acute suppurative parotitis or chronic parotiti). These infections may cause blockage of the duct by salivary duct calculi or external compression.