Ottawa has reported its first cases of measles in six years, an adult and a child who were infected while traveling abroad, Ottawa Public Health reported.

The risk to the public remains low, but possible transmission may have occurred in two public places. Anyone who has been in contact with the sick and is experiencing symptoms — fever, cough, runny nose, rash, red eyes — is advised not to visit a clinic without calling first.

Measles is a highly contagious viral disease. The only reliable way to protect yourself is vaccination, OPH reminds.

Means, the largest measles outbreak in 30 years continues across Ontario. In the past week alone, 233 new cases have been reported. Most of the cases are unvaccinated children (86.8%).

The Southwestern Public Health region is the most affected, with 181 cases per 100,000 people. The spread of the infection continues due to the lack of herd immunity among unvaccinated groups of the population.