Dozens of drug users in B.C. have been hospitalized since December because of tainted cocaine being sold on the streets, health officials say.

Tests show the cocaine is being cut with Levamisole, a drug used to de-worm livestock. The drug has also served to treat colon cancer but is no longer used on humans because of side-effects.

The drug has been detected in cocaine around the world for several years, but did not start showing up in cocaine in B.C. until December. Since then 27 people in different parts of the province have become extremely sick.

Dr. Jane Buxton of the B.C. Centre for Disease Control said the Levamisole lowers white blood cell counts and weakens the immune system of those who ingest it.

"The people who react to the Levamisole with the low white cell counts can get very serious infections.… That can be life-threatening," she said.

The tainted cocaine has been linked to deaths in other jurisdictions, though none in B.C., Buxton said, but she warns that anyone suffering from a fever after using cocaine should see a doctor.

"They've all been hospitalized and have to have certain medications and antibiotics, and the condition can occur very quickly. So one of the messages is for people who develop severe infections or fever — they should actually seek medical attention."

The cocaine is likely being bulked up in Colombia with the Levamisole, which users say looks and feels the same, before it's shipped to North America, where most of it ends up in crack, said Buxton.

Ann Livingston, with the Vancouver Area Network of Drug Users, said the risk to drug users could be reduced if police automatically publicized test results stemming from drug seizures.

"The drugs have to be analyzed to make sure they are illegal drugs, so they have their own surveillance system, but have failed to share that in a more community-minded way," said Livingston.