The measles outbreak reported in British Columbia last week has expanded to 26 confirmed cases, including three in the interior.

Ritinder Harry, spokeswoman for the B.C. Centre for Disease Control, told ctvbc.ca that of the infected, 14 were unimmunized and 12 have unknown vaccination history.

"It could be that they received one dose and didn't go in for the second, or that they don't remember," she said.

Harry says the risk to the general population is low because most children receive both of the necessary doses of measles vaccine before their second birthday -- but anyone unsure of their immunization history is advised to check with their family physician.

"Check your records," Harry said. "If you are seeing symptoms of measles, call the B.C. helpline at 811 immediately."

The illness begins with a fever, runny nose and cough. Days later, a rash appears around the face, which then spreads to the chest and limbs. The eyes may also be red and sensitive to light.

Measles can also lead to serious health problems. One in every 1,000 infected suffers an inflammation of the brain, which can lead to convulsions, deafness or permanent mental disability. One in every 3,000 cases can result in death.

Different strains identified

The centre has identified two separate strains of the virus – one believed to have been brought in by out-of-country visitors during February or early March, the other brought home by a British Columbian man returning from India.

The bulk of the cases reported are in Metro Vancouver, but single cases have been confirmed by the Interior Health Authority in Vernon, Lillooet and Williams Lake.

Officials say the cases are not directly connected to each other, and that two of the infected have not recently travelled outside of their communities.

"Measles has not been circulating in B.C. in the past two years," Interior Health medical officer Rob Parker said in a release. "We're urging parents to review their kids' medical records."

The initial outbreak reported on March 30 consisted of 10 confirmed and four suspected cases. Eight of the cases came from a single household of unvaccinated members.

BC Children's Hospital exposure

A spokesperson for the BC Children's Hospital confirms that last Thursday about 250 people were exposed to the virus because of a suspected airflow issue.

All exposed were informed, tested and questioned. Officials say they are still investigating how and why the virus was able to escape from a room containing the hospital's only measles patient.

The hospital says there is no indication any of the exposed contracted the measles -- though the disease can take from five days to three weeks to reveal itself.

More information on measles is available at the B.C. Centre for Disease Control website.