Canadian Blood Services to introduce second screening test for hepatitis B
September 09, 2004 PM ET

TORONTO (CP) - Canada's blood supply will undergo an additional screening test for hepatitis B - the most prevalent strain of the hepatitis virus - by next spring, Canadian Blood Services announced Thursday.

"This is another test to screen out a very small number of people who still might be infected and get missed" by the existing test, said Dr. Margaret Fearon, an executive medical director at the agency. "That small amount of virus potentially could get into the blood supply."

The agency's board of directors passed a resolution Thursday to have the additional test in place by April 15, 2005, pending Health Canada approval.

A vaccine is available for hepatitis B, and the North American blood supply has been screened for the virus for some years.

Most infected people make a full recovery and develop a lifelong immunity. But a small percentage of those infected continue to carry traces of the virus, said Fearon.

Some 90 per cent of babies born to mothers carrying the virus have a high chance of developing chronic hepatitis B later in life, according to Health Canada. That can lead to cirrhosis and cancer of the liver.

"We're just adding another layer of safety," said Fearon.

Canadian Blood Services was set up to run the country's blood supply system following a federal inquiry into the tainted-blood scandal of the 1980s and early '90s. Thousands of people were infected with HIV (news - web sites) and hepatitis C - for which there is no vaccine - when the Canadian Red Cross was slow to implement available screening tests

When they weakened those genes, staph no longer sickened worms or mice, said lead researcher Eric P. Skaar. Next step is hunting drugs to block staph's iron-stealing ability.

Where does that ancient remedy of bloodletting come in?

The discovery suggests that bloodletting, done early enough, may have slowed staph infections by starving germs of iron, National Institutes of Health (news - web sites) iron specialist Tracy Rouault wrote in a review of Skaar's research.

Nobody's suggesting bleeding staph patients today. Now derided as a nonsensical if not barbaric custom, bloodletting was abandoned in the mid-20th century after antibiotics were invented.

But the mystery persists: "How could a procedure popular for 2,500 years have really been completely worthless?" Rouault asked.

Bloodletting was used for lots of reasons, many that "didn't make good sense," she stressed. But, searching old medical texts, she found that starting in 18th-century France, certain physicians advised it only at the start of a high-fever illness. Even in 1942, medicine's leading English-language textbook advised early bleeding for high-fever pneumonia.

That can certainly describe a bad staph infection. Moreover, Rouault notes that one treatment for a different disease, malaria, is a drug that lowers iron in blood.