Vancouver Coastal Health has alerted parents whose kids attend Ecole Laura Secord Elementary in Vancouver, after a student tested positive for pertussis, better known as whooping cough.
In a letter, it warns other students may have been exposed between February 7 and March 7.
Two more cases of whooping cough have been confirmed on Vancouver Island.
Island Health says a person at Saanich's Mount Douglas Secondary School has caught the contagious respiratory infection.
It did not say whether the person is a student, teacher or support staff member.
The health authority confirms an adult in Duncan has also been infected but calls this case "well contained."
It is reminding people to check their vaccination history.
What is whooping cough?
Whooping cough is a highly contagious disease of the lungs and throat that spreads when the sick person coughs or sneezes.
It usually takes seven to ten days for someone who’s been infected to show symptoms, but it may take as long as 21 days. It begins like a typical cold, but one to two weeks later a cough develops that ends with a distinctive whooping sound when the patient breaths in.
The cough can last up to two months and can be life-threatening for babies.
Coastal Health is asking anyone with a child under the age of one who spent time at Ecole Laura Secord in the past month to contact their health care provider.
Like measles, whooping cough is preventable through vaccination.
With files from CTV Vancouver Island
