Island Health is waiting on test results to determine exactly which strain of cholera bacteria was responsible for a small outbreak on Vancouver Island.

Medical health officer Shannon Waters says up to four people became ill after harvesting herring eggs along the central island coast.

She says the incidents are extremely unusual, but cholera cases from contaminated shellfish have also been recorded in the United States.

Island Health says anyone who has harvested herring eggs between French Creek and Qualicum Bay should not consume them,, and should contact Island Health.