Could Fertility Drugs Foster Mad Cow Disease in Humans?

Vancouver, BCFor the first time anywhere, a Canadian study has revealed a potential for Creutzfeldt-Jakob disease (CJD) associated with the use of fertility drugs. A close cousin of CJD is bovine spongiform encephalopathy (BSE), more commonly known as "mad cow disease." Study authors stress that so far the danger is theoretical—and if there were a risk at all, the risk would likely be minor at best. There have been no reported cases.

But it is no guarantee of safety, study authors say.

According to a March 25 story in the Canadian Press (CP), researchers have documented the presence of prion proteins in the fertility drugs used by some 300,000 women in Canada and the United States every year in an effort to conceive. Fertility drugs are purified through a process that involves the urine of postmenopausal women.

Prion proteins are found naturally in the body and in their normal state are considered harmless. However, researchers say it is possible for these proteins to alter their configuration in spontaneous fashion. As a result of this transformation, the proteins can become infectious.

Co-author of the study is Dr. Neil Cashman, the scientific director of PrioNet Canada who holds a Canada research chair in neurodegeneration at the University of British Columbia (UBC). He stressed in the CP report that no evidence of CJD was found in any of the samples studied, nor have there been any adverse reports from the field.

"There has never been a single recognized case of Creutzfeldt-Jakob disease in a woman who received these urinary pharmaceuticals," he stressed. "So that's a good thing. It means it's not common, if there is transmission. ... So if there's a risk, it's an extremely small one."

For the study, researchers examined dozens of urine-derived drug samples from various pharmaceutical companies and batches, and found evidence of prion proteins.

The suggestion is that the drugs carry a previously unrecognized risk of contamination with the infectious agents.

Dr. Roger Pierson, a professor of obstetrics and gynecology at the University of Saskatchewan, applauded the study. And while there have been no actual reports of CJD—and the risk, in theory, is thought to be small—the data is "very sobering" nonetheless, "and they should cause all of us to have a very deep reflection on what we know, what we think we know and how we apply that information to the health of Canadians and everyone else in the world," said Pierson, a spokesman for the Canadian Fertility and Andrology Society.

"This does not mean that every woman in Canada that's had these drugs is going to get sick, or even a small proportion of them," Pierson said. "But we need to look."

The study was published in the Public Library of Science (PLoS) ONE.