vCJD: ‘Mad-cow’ variant not now a risk

Fort Wayne News Sentinel
Jennifer L. Boen

Only 3 vCJD cases in the U.S. were confirmed; all had links to U.K. beef.

Excerpt…

The news that since January four northeast Indiana residents are suspected to have died from a progressive, fatal neurodegenerative disease often mistaken for “mad-cow disease” should not overly concern residents, public health officials say.

The cluster of suspected cases of Creutzfeldt-Jakob Disease, or CJD, is not unusual, they say, and similar occurrences have been recorded in other states, including New Jersey and Wisconsin.

The disease cannot be transmitted through direct human-to-human contact.

Often, what is thought to be CJD turns out to be something else altogether, said Ryan Maddox, an epidemiologist with the U.S. Centers for Disease Control and Prevention who tracks CJD. Two years ago nine suspected cases were reported in Idaho, but after further investigation, several deaths proved to be from other causes.

“What starts out as a high number drops dramatically after an investigation is completed,” said Maddox, who is involved in the local investigation.

It will be several more weeks before autopsies are completed on two of the four suspected local cases; the other two were not autopsied.

Findings will be forwarded to the CDC, said John Silcox, spokesman for the Fort Wayne-Allen County Department of Health. The CDC’s investigation could take several more months. Between 1985 and 2005, the most recent year data is available, Allen County had five confirmed CJD deaths.

When people hear of CJD, they often jump to the conclusion it is “mad cow disease,” which is bovine spongiform encephalopathy, or BSE. The steer or cow gets infected from eating contaminated bone meal and other ground-up parts, usually neurological tissue, of BSE-infected animals.

If humans eat meat from a BSE-infected animal, they may develop variant CJD or vCJD, but only three U.S. cases of vCJD have been confirmed.

“Two had very strong ties to the United Kingdom, and in the third case, the person grew up in Saudi Arabia and was likely exposed to British meat,” Maddox said. No cases of vCJD have been recorded in which the deceased did not have ties to a country where BSE had occurred or was occurring.

Dr. Deborah McMahan, Allen County commissioner of health, said she has talked to the families of the four northeast Indiana residents suspected to have died from CJD. None traveled to or had ties to an at-risk country, she said.

The UK reported 147 human cases of vCJD between 1994 and August 2004, comprising about 98 percent of all cases known in the world during that period. When the UK changed its animal-feed requirements, cases there consistently dropped, although France has reported vCJD cases from time to time, Maddox said.

In total, about 200 known cases of vCJD have been recorded worldwide, Maddox said.

About 85 percent of all CJD cases, or one per 1 million people, are classified as classic or sporadic CJD. Another 5 percent to 15 percent of CJD cases can be attributed to inherited mutations of the prion protein gene. CJD is called a prion disease because a normal brain protein spontaneously changes into an infectious abnormal form called a prion. Two inherited forms of CJD include Gerstmann-Straussler-Scheinker syndrome and fatal familial insomnia.

“Prion diseases are not a virus, not bacteria, which distinguishes these diseases from pretty much everything else out there,” Maddox said. “There isn’t as much known about them.”

A few vCJD cases in other countries have occurred when a person received a transplant of neurological tissue such as a retina from an infected person. In 2003, the cause of death in a 62-year-old UK man with vCJD was traced back to a transfusion of vCJD-contaminated blood. Since then, the British government and the U.S. Food and Drug Administration have established deferral policies for donors who have traveled to high-risk countries.

Half of CJD victims die within six months of the onset of symptoms; 80 percent are dead within a year, Maddox said. In vCJD, exposure to the disease likely occurs many years, even decades, prior to the onset of symptoms. The symptoms with vCJD last, on average, twice as long before death.

A key difference between vCJD and sporadic CJD is the age of death. For vCJD victims, the average age is 28, compared to 68 in CJD. One of the local deaths was a man in his 70s and the other a 53-year-old man. Health officials have not released the ages of the other two.

Although CJD and/or vCJD can be diagnosed only through an autopsy, other tests can help classify a probable case of either. The patterns seen on an electroencephalogram – a test of the brain’s electrical functions – are different when CJD and vCJD are present. A cerebral spinal fluid test has proved effective in confirming CJD, but the test carries risks, Maddox said.

In 43 states, local health officials must report CJD deaths to state officials, but Indiana is not among them. McMahan has asked state officials to put CJD on the list of mandatory reportable diseases, which includes meningitis, measles and salmonella….

Full article at Fort Wayne News Sentinel.