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CJD screening may miss thousands of cases

 

By Steve Mitchell

UPI Medical Correspondent

Published 7/21/2003 3:00 PM

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WASHINGTON, July 21 (UPI) -- The federal government's monitoring system for

cases of Creutzfeldt-Jakob disease, a fatal human brain illness, could be

missing tens of thousands of victims, scientists and consumer advocates have

told

United Press International.

 

Creutzfeldt-Jakob disease or CJD can be caused by eating beef contaminated

with mad cow disease, but the critics assert without a better tracking system

it might be impossible to determine whether any CJD cases are due to mad cow or

obtain an accurate picture of the prevalence of the disorder in the United

States.

 

Beginning in the late 1990s, more than 100 people contracted CJD in the

United Kingdom and several European countries after eating beef infected with

bovine spongiform encephalopathy -- the clinical name for mad cow disease.

 

No case of mad cow has ever been detected in U.S. cattle and the Centers for

Disease Control and Prevention's monitoring system has never detected a case

of CJD due to eating contaminated American beef. Nevertheless, critics say,

the CDC's system misses many cases of the disease, which currently is

untreatable and is always fatal.

 

The first symptoms of CJD typically include memory loss and difficulty

keeping balance and walking. As the disease destroys the brain, patients rapidly

progress in a matter of months to difficulty with movement, an inability to talk

and swallow and, finally, death.

 

Spontaneously-occurring or sporadic CJD is a rare disorder. Only about 300

cases appear nationwide each year, but several studies have suggested the

disorder might be more common than thought and as many as tens of thousands of

cases might be going unrecognized.

 

Clusters of CJD have been reported in various areas of the United States

-- Pennsylvania in 1993, Florida in 1994, Oregon in 1996, New York in

1999-2000 and Texas in 1996. In addition, several people in New Jersey developed

CJD

in recent years, including a 56 year old woman who died on May 31, 2003.

Although in some instances, a mad cow link was suspected, all of the cases

ultimately were classified as sporadic.

 

People who develop CJD from eating mad-cow-contaminated beef have been

thought to develop a specific form of the disorder called variant CJD. But new

research, released last December, indicates the mad cow pathogen can cause both

sporadic CJD and the variant form.

 

" Now people are beginning to realize that because something looks like

sporadic CJD they can't necessarily conclude that it's not linked to (mad cow

disease), " said Laura Manuelidis, section chief of surgery in the neuropathology

department at Yale University, who conducted a 1989 study that found 13 percent

of Alzheimer's patients actually had CJD.

 

Several studies, including Manuelidis', have found that autopsies reveal 3

percent to 13 percent of patients diagnosed with Alzheimer's or dementia

actually suffered from CJD. Those numbers might sound low, but there are 4

million

Alzheimer's cases and hundreds of thousands of dementia cases in the United

States. A small percentage of those cases could add up to 120,000 or more CJD

victims going undetected and not included in official statistics.

 

Experiences in England and Switzerland -- two countries that discovered mad

cow disease in their cattle -- have heightened concerns about the possibility

some cases of sporadic CJD are due to consuming mad-cow-tainted beef. Both

countries have reported increases in sporadic CJD since mad cow was first

detected in British herds in 1986.

 

Switzerland discovered last year its CJD rate was twice that of any other

country in the world. Switzerland had been seeing about eight to 11 cases per

year from 1997 to 2000. Then the incidence more than doubled, to 19 cases in

2001 and 18 cases in 2002.

 

The CDC says the annual rate of CJD in the United States is one case per

million people, but the above studies suggest the true prevalence of CJD is not

known, Manuelidis told UPI.

 

Diagnosing CJD or Alzheimer's is difficult because no test exists that can

identify either disease in a living patient with certainty. So physicians must

rely on the patient's symptoms to determine which illness might be present.

Sometimes, however, the symptoms of one disease can appear similar to the other

disorder. The only way to determine the disease conclusively is to perform an

autopsy on the brain after death.

 

Unfortunately, although autopsies once were performed on approximately half

of all corpses, the frequency has dropped to 15 percent or less in the United

States. The National Center for Health Statistics -- a branch of the CDC --

stopped collecting autopsy data in 1995.

 

" If we don't do autopsies and we don't look at people's brains ... we have

no idea about what is the general prevalence of these kinds of infections and

(whether) it is changing, " Manuelidis said.

 

At the same time autopsies have been declining, the number of deaths

attributed to Alzheimer's has increased more than 50-fold since 1979, going from

857

deaths then to nearly 50,000 in 2000. Though it is unlikely the dramatic

increase in Alzheimer's is due entirely to misdiagnosed CJD cases, it " could

explain some of the increase we've seen, " Manuelidis said.

 

" Neurodegenerative disease and Alzheimer's disease have become a

wastebasket " for mental illness in the elderly that is difficult to diagnose

conclusively, she said. " In other words, what people call Alzheimer's now is

more broad

than what people used to call it, and that has the possibility of encompassing

more diseases -- including CJD. "

 

The autopsy studies that found undiagnosed CJD cases raise the question of

whether the United States " already has an undetected epidemic here, " Jeff

Nelson, director of vegsource.com, a vegetarian advocacy Web site, told UPI.

 

" What's the source of that? " Nelson asked. " Could it be the same source of

encephalitis we saw in minks? "

 

Nelson referred to an outbreak of a mad-cow-type disorder in minks in

Wisconsin in the 1980s. The origin was traced back to the animals' diet, which

included parts of so-called downer cattle -- sick cows that are unable to stand,

which often indicates a neurological disease, including mad cow. The mink

disease raised concerns about whether U.S. cattle were carrying a mad-cow-like

pathogen even prior to the U.K. epidemic that began in 1986.

 

Andrew Monjan, chief of the neuropsychology of aging program at the National

Institute of Aging -- part of the National Institutes of Health in Bethesda,

Md. -- acknowledged there has been an increase in U.S. Alzheimer's cases.

However, he told UPI, this probably is due to the aging of the population -- as

people grow older, they develop a higher risk of developing Alzheimer's.

 

" There's been no change in the number of CJD cases in the country and there

has been clearly a tracking of the unusual cases of CJD " that could be due to

mad cow disease, Monjan said. However, Terry Singletary, coordinator of CJD

Watch -- an organization founded to track CJD cases

-- says efforts to track the disease have been close to nonexistent. For

example, only 12 states require such reports. Therefore, many cases might be

going

undetected, unreported or misdiagnosed.

 

If more states made CJD a reportable illness, there would be more clusters

detected across the United States, said Singletary, who became involved with

CJD advocacy after his mother died from a form of CJD known as Heidenhain

variant. In the 18-year period between 1979 and 1996, he noted, the country saw

a

jump from one case of sporadic CJD in people under the age of 30 -- a warning

sign for a link to mad cow because nearly all of the U.K. victims were 30 years

of age or younger

-- to five cases in five years between 1997 and 2001. " That represents a

substantial blip, " he told UPI.

 

Singletary also said there have been increases in sporadic CJD in France,

Germany and Italy, all of which have detected mad cow disease in their cattle.

 

So far, the CDC has refused to impose a national requirement that physicians

and hospitals report cases of the disease. The agency has not chosen to make

CJD a reportable disease because " making it reportable is not necessarily

directly helpful in surveillance because in some states where it's reportable

you

may not get the physician to report it, " said Dr. Ermias Belay, CDC's medical

epidemiologist working on CJD.

 

Instead, the agency relies on other methods, including death certificates

and urging physicians to send suspicious cases to the National Prion Disease

Pathology Surveillance Center at Case Western Reserve University in Cleveland,

which is funded by the CDC. However, because autopsies generally are not done,

if a CJD case is misdiagnosed as Alzheimer's or dementia, a correct diagnosis

might never be determined and therefore the cause of death listed on a death

certificate might be inaccurate.

 

Belay told UPI he discounted this possibility. It is unlikely to happen, he

said, because it is easy to distinguish CJD from Alzheimer's -- the two

conditions display different symptoms.

 

Manuelidis disagreed. It can be quite difficult to determine accurately if a

patient has CJD, as evidenced by her study, in which respected and competent

neurologists and psychiatrists at Yale originally diagnosed patients with

Alzheimer's, yet were wrong at least 13 percent of the time. Another study

conducted at the University of Pennsylvania, which found 6 percent of dementia

patients actually were suffering from CJD, supports the difficulty in

distinguishing

the illnesses correctly.

 

The U. Penn. researchers concluded: " These results show that in patients

with a clinical diagnosis of dementia, the etiology (cause) cannot be accurately

predicted during life. "

 

In addition, the NPDPSC sees less than half of all the CJD cases each year,

so the CDC's investigational system not only is missing many of the

misdiagnosed CJD cases, it also is not conducting autopsies on most of the

detected

cases.

 

Belay said the CDC follows up on all cases of CJD that occur in people under

age 55, as these could be linked to variant -- mad-cow-related -- CJD. But so

far, all have turned out to be sporadic forms of the disease. About 30 cases

of the disorder occur each year in the United States in this age group, while

the remaining 270 or so are older.

 

The case of Carrie Mahan -- a Philadelphia woman who developed a brain

disorder that appeared to be CJD and died from it in 2000 at the age of 29 --

illustrates just how difficult it can be to diagnose the disease.

 

Mahan's physician, Dr. Peter Crinos of the University of Pennsylvania

Medical Center, ruled out other disorders and felt certain the young woman had

died

of CJD, a concern that raised the possibility of a link to mad cow disease

because of her young age. When neuropathologist Nicholas Gonatas, who had seen

CJD before, examined Mahan's brain after her death, he, likewise, was confident

he detected the microscopic, sponge-like holes caused by the disease. But when

he sent brain samples to the NPDPSC, the results came back negative. Gonatas,

convinced the surveillance center's finding was erroneous, sent off two more

samples, only to have them both come back negative.

 

Subsequent research, however, has shown the test used by the surveillance

center cannot rule out CJD, said Crinos, an assistant professor of neurology.

 

" There's no question that Carrie had a spongiform encephalopathy, " Crinos

said, but added although it appeared to be CJD, it is difficult if not

impossible to say if it was due to mad cow disease.

 

Crinos told UPI until the CDC implements a better tracking system, a lot of

questions will remain about CJD and cases like Carrie Mahan's. One central

question: Why are cases of what is presumed to be a rare disease popping up in

clusters in certain areas of the country? Crinos said the clustering suggests an

environmental or food-borne cause, but so far, " No one knows the answer to

that. "

 

2001-2003 United Press International

 

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