Disease experts warn of 'silent killer'

Parasites can damage heart tissue, nerve cells

By Sharon KirkeyCanWest News Service

Sunday, June 10, 2007

Tropical disease experts are warning of a new threat to Canada's blood supply, a "silent killer" that produces no symptoms for years while parasites slowly feed on a person's heart muscle and intestines.

Chagas disease is endemic in parts of Central and South America where it has already infected up to 20 million people and kills more than 50,000 every year.

Transmitted by blood-sucking "assassin" bugs, Chagas - named after the Brazilian doctor, Carlos Chagas, who discovered it in 1909 - can also be spread via infected blood transfusions.

Now, the parasitic infection is drifting northward because of immigration patterns and travel - including adventure and eco-tourists to such Chagas-hit areas as Colombia and parts of Brazil.

Chagas isn't a reportable illness in Canada; its prevalence is unknown. What's more, front-line doctors may know about West Nile virus or Lyme disease, but most would not know Chagas to see it, experts say. "I don't think the average primary care doc would know it [at] all," says Dr. Jay Keystone, professor of medicine at the University of Toronto.

It can take 20 years or longer for the parasite to cause sufficient damage to nerve cells and tissue in the heart to put people into heart failure. People can have strokes because of heart arrhythmias.

The disease can attack in other ways: Researchers recently reported the case of a 40-year-old man who was transferred to hospital from a Manitoba jail after a two-week history of headache, nausea, vomiting and drowsiness.

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