As southern Alberta battles its worst measles outbreak in decades, some doctors are warning the virus is more rampant than the case counts show and they’re now struggling to keep up with demand.

As of midday Wednesday, 628 cases had been confirmed in Alberta since the outbreaks began in March.

The last time the province reported more cases was 1987, when 690 cases were confirmed.

“Unfortunately I think, for at least parts of the province, this is no longer controllable,” said Craig Jenne, a professor in the department of microbiology, immunology and infectious diseases at the University of Calgary.