Iowa State University

Harley Moon, Veterinary Pathology, (515) 294-9327
Richard Ross, Veterinary Medicine, (515) 294-1250
Glenda Webber, Office of Biotechnology (515) 294-9818
Steve Jones, News Service, (515) 294-4778


AMES, Iowa -- The National Institutes of Health has awarded Iowa State University $772,000 to study an E. coli disease in swine that could lead to a better understanding of a devastating kidney disease in children.

In a five-year project, ISU veterinary pathologist Harley Moon will lead a group of researchers studying edema disease in young pigs. Because a vaccine exists for the swine disease, they hope to determine if a vaccine can be developed for a similar disease in children called hemolytic uremic syndrome (HUS).

Joining Moon in the research are ISU veterinary immunologist Michael Wannemuehler; veterinarian Brad Bosworth of the U.S. Department of Agriculture-Agricultural Research Service's National Animal Disease Center, Ames; and microbiologist James Samuel of Texas A&M University, College Station.

Both HUS and the swine disease are caused by the same type of E. coli bacteria that colonize the intestine and produce a toxin. The toxin is absorbed through the bloodstream and eventually damages blood vessels. Moon says edema disease of swine is the only known naturally-occurring disease, other than HUS, in which this type of intestinal infection produces vascular damage.

The E. coli. that cause edema disease in swine cannot cause disease in humans, said Moon, F.K. Ramsey Chair of Veterinary Medicine at ISU. "The mechanisms that the swine E. coli strains use to cause edema disease are the same as those used by human E. coli strains to cause HUS. This makes edema disease in swine a useful research model for HUS.

"We will look for antibodies to intervene and prevent serious damage in the pigs," Moon added. "If we can do it in swine, it's likely it can be done for children. It could spur clinical trials by medical researchers."

In humans, HUS can lead to a variety of health problems. When the E. coli bacteria begin producing toxin in the intestine, diarrhea and intestinal bleeding result. As the toxin is absorbed by the body, it binds to the kidneys.

"Once the kidneys are involved, children may experience blood clots, anemia, hemorrhages, and, in some cases, total kidney failure and death," Moon said.

"This team of research collaborators is uniquely suited for this type of research," said Richard Ross, dean of ISU's College of Veterinary Medicine. Ross called Moon, a member of the National Academy of Sciences, one of the world's foremost scientists in the study of E. coli diseases in animals.

More than 700 donors contributed in excess of $1 million to fund the Ramsey endowed chair that Moon holds. Endowed chairs are prestigious positions that enhance a university's ability to attract and retain the best scholars, Ross added. The endowment provides a revenue source to supplement college support for the teaching and research activities of the chair holder.

Ross said the research team's National Institutes of Health grant is an excellent return on the donors' investment in the endowed chair.

Using molecular biology and other laboratory techniques, the research team will determine the windows of opportunity for intervening in the HUS infection process.

"We know that full-blown HUS usually does not develop until a few days after the initial diarrhea," Moon said, "but we don't know the best time to block the toxin with antibodies before it enters the body's system and causes irreversible kidney damage."

The researchers hope to learn whether some children might suffer from a milder subclinical form of HUS that has no visible symptoms but is thought to impair growth. Moon said that data documenting this type of infection in pigs suggests that it also might impair growth in children.

The researchers also want to be able to predict the severity of HUS in children.


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