The paramecium would not be able to get rid of excess water so the cell would burst.
FUNCTION OF THE CONTRACTILEVACUOLE:
The contractilevacuole is an organelle present in protist organisms like paramecium, amoeba etc.
The contractilevacuole functions to regulate water balance in the cells of organisms that they are found. Contractilevacuole performs this function by storing excess water and expelling the out of the cell.
Hence, if a disease affected a paramecium's contractilevacuoles, stopping the normal functioning of the vacuoles, the paramecium would not be able to get rid of excess water so the cell would burst.