Another five cases of mumps have been confirmed in Toronto, bringing the total to 22 this year.
Toronto public health officials say the virus has hit mostly people between the ages of 18 and 35 who frequented bars in the western part of downtown.
Clusters of mumps have also emerged in the Prairies and Western Canada.
Public health officials say the outbreaks serve as a reminder of the importance of proper immunization, adding that young adults should make sure they're received two doses of the measles-mumps-rubella (MMR) or measles-mumps-rubella-varicella (MMRV) vaccines.
The mumps virus spreads through coughing, sneezing, and coming into contact with a person's saliva by sharing drinks or utensils, food or water bottles, or by kissing.
Public health officials say crowded environments, such as dorms and classrooms, are particularly susceptible to outbreaks.
with a file from Siobhan Morris