jwissmille

Date: 1997/04/05

THE UNUSUAL SUSPECTS
Laura Beil - Dallas Morning News

Heart disease doesn't usually make the Top 10 list of afflictions you
can catch. But a decade ago, most doctors probably wouldn't have
thought that ulcers were caused by anything other than the churning
stomachs of overachievers. As it turns out, the disease is triggered by
an infection almost 90 percent of the time and can be cured with
antibiotics.
"We traditionally have thought of infectious disease as being acute
diseases," said Dr. Patrick Moore of Columbia University School of
Public Health in New York. "We're now realizing that there are a broad
number of diseases that may have an infectious component.
He isn't just referring to the Ebolas, the hantaviruses and other
dramatic infirmities that have come out of hiding during this
generation. Of even broader significance, researchers say, are the
infections that may have been with us all along,. masquerading perhaps
as diabetes, multiple sclerosis or similar long-term diseases that seem
to come from nowhere.
"It sounds almost like heresy to think that chronic diseases may be
caused by infection," said Dr. Javier Nieto of Johns Hopkins University
School of Hygiene and Public Health in Baltimore.
Yet viruses and bacteria are now suspected to have a hand in several
forms of cancer, a host of unexplained inflammatory ailments like
arthritis, and even clogged coronary arteries, which threaten the lives
of more than 13 million Americans.
"Not all cancers are infectious, not all chronic diseases are
infectious, but clearly more of these diseases are infectious than we've
already found," Moore said.
Many significant findings have come recently, following an evolution on
both technology and scientific thinking, researchers say.
The search itself is easier now because scientific gumshoes have better
gadgets. Scientists can now find the footprints of bacteria and
viruses, even if the suspects themselves remain at large. And more and
more researchers are now receptive to the idea that microorganisms may
be accomplices in chronic diseases.
"People's minds are more open to the possibility, primarily because of
the ulcer story," said Dr. Bennett Lorber, an infectious-disease expert
at Temple University School of Medicine in Philadelphia.
The ulcer story began in 1983, when Barry Marshall and Robin Warren,
two maverick researchers from Royal Perth Hospital in Australia,
reported that they had found a squiggly bacterium in stomach lining, and
that the presence of this organism, known as Helicobacter pylori, seems
to have something to do with the development of ulcers.
The announcement was not well-received by generations of doctors
brought up to think that anxiety and diet were to blame for ulcers.
"I remember being at a meeting and hearing Barry Marshall present this
story and people laughed at him," Lorber said.
Medical science eventually grew to accept the idea, but not before Dr.
Marshall gulped down an H. pylori cocktail to demonstrate that the bug
could make a person sick. It did.
The idea of an ulcer-causing bacterium was unexpected, partly because
the disease didn't have an obvious pattern that suggested a spreading
infection. Other chronic diseases, however, have drawn attention to
themselves because they have patterns of attack suggestive of an
infectious disease.
"People have suspected an infectious etiology for cervical cancer for
more than 100 years," said Dr. Keerti Shah of Johns Hopkins University
School of Medicine. The cause of cervical cancer historically was
thought to be sexually transmitted, he said, because physicians had long
noticed that nuns never seems to get the disease.
In 1993, researchers from the National Cancer Institute reported that a
precancerous condition in the cervix was almost always associated with
infection with a common virus called human papilloma virus. And in
1995, Shah and his research team found the same association with
cervical cancer in a study of women worldwide.
"I think people suspected that something like this would come out,"
Shah said.
Dozens of studies, including those examining patterns of the disease in
the population, have continued to support the notion that cervical
cancer is an infectious disease. For instance, last fall, Shah led a
research project that found that women were likely to be diagnosed with
cervical cancer if their husbands reported having many sexual partners -
and especially if the men had frequented prostitutes.
If was also the telltale patterns of infectious disease that prompted
Moore from Columbia University to investigate Kaposi's sarcoma, a skin
cancer that is a common cause of illness in people with AIDS.
"The epidemiology was really that pointed us in the direction that
there was an infectious cause here," Moore said. In particular, a late
1980's study from the U.S. Centers for Disease Control and Prevention
found that gay men infected with the AIDS virus through sex were 20
times more likely to develop the cancer than AIDS patients with
hemophilia who had contracted the virus through transfusions.
"You find what you look for," Moore said. "If you're not thinking that
a disease is caused by an infectious agent, then you won't find it."
Lacking funding for the project, Moore teamed up with his wife, Dr.
Yuan Chang, who is in the school's pathology department. The pair
eventually pinpointed a foreign string of genes that belonged to a
previously undiscovered human herpes virus. Research papers published
in The New England Journal of Medicine in 1995 reported that infection
with this virus predicted which AIDS patients would develop the disease.
Perhaps nowhere has the complexity of disease been more evident than in
the search for an infections that might be related to coronary artery
diseases. The conditions develops when a waxy plaque builds up on the
inside of the artery walls. It is known that a fatty diet, smoking,
lack of exercise and many other factors fuel the buildup, but it's not
as clear what starts the process. Many scientists believe that the
conditions could develop at a site where the artery is injured - but
injured from what?
"Viruses, when they infect cells, do damage to them" said Dr. Joseph
Melnic of Baylor College of Medicine in Houston. Melnick is part of a
growing number of scientists who believe that infections with a certain
virus, called cytomegalovirus, may in many cases be the triggering
event.
The virus, CMV, is common, infecting 60 to 70 percent of the
population, and in health adults it appears to do little harm. Yet when
examining the plaques of heart patients, Melnick said, "We're finding it
in about 90 percent of the patients with atherosclerosis and about 30
percent in others" without disease.
Recent studies have been even more compelling. Last August in the
journal Circulation, researchers studies a group of people who had blood
samples frozen and stored in 1974. Among them, the people who had the
greatest thickening of their artery walls were most likely to have had
CMV infection appear at least 20 years ago. A second study, published
the same day in the New England Journal of Medicine, found that
CMV-infected patients were more likely to redevelop disease after
treatment for their first plaque buildup.