03/10/2015 03:55 EDT | Updated 05/10/2015 05:59 EDT

Number of measles cases in Quebec jumps to 80 northeast of Montreal: report

JOLIETTE, Que. - There are reports of a spike in the number of people with measles northeast of Montreal.

The reports say the number of cases in the Lanaudiere region is up to 80, a significant jump from 32 at the end of February.

The health department in the region is refusing to answer queries about the number.

A staff member said the situation was evolving but would not confirm any figures until a news conference scheduled for Wednesday morning in Joliette.

The CBC says all of the cases involve unvaccinated children and adults and are traced to an outbreak at a California amusement park.

All the Quebec cases have been centred in the Lanaudiere region and are part of one chain of transmission that started when a person who became infected at Disneyland returned to the province.

In late February, Quebec health authorities said several dozen other people were under observation because measles have a two-week incubation period.

There have also been 18 cases of measles confirmed in Ontario and a single case in Manitoba.