WEDNESDAY, May 24, 2006 (HealthDay News) -- The discovery that seven organ-transplant recipients died from a rodent-borne infection shows the need for a tracking system for early detection of problems involving donors and transplant patients, investigators say.
The deaths occurred separately, four in Wisconsin in 2003 and three in Rhode Island and Massachusetts in 2005. An intensive research effort was needed to determine that the cause was lymphocytic choriomeningitis virus (LCMV), which is carried by hamsters and other rodents.
In the 2005 cluster, infection was eventually traced to a hamster the 45-year-old organ donor had purchased weeks before her death from brain hemorrhage. The source of LCMV infection for the 2003 cluster remains a mystery.
The medical detective hunt began at Rhode Island Hospital, where two of the infected persons were treated, according to a report in the May 25 issue of the New England Journal of Medicine.
"It only became apparent that the link was the donor in these two gentlemen when they both came in with the same symptoms," said Dr. Staci A. Fischer, a physician in infection diseases for the hospital's transplant service. "They were negative for the usual things that cause their symptoms, such as diarrhea, and we began inquiring at the New England Organ Bank how other recipients were doing. That started the detective work."
That work was widespread -- the journal report comes under the names of more than 20 people working at seven different facilities, most notably, the U.S. Centers for Disease Control and Prevention, but also physicians in Boston and Wisconsin.
"Once I spoke to the physicians in the other hospital, it was evident that their recipients were quite ill as well," Fischer said. "Tissue and blood samples were shipped urgently to the CDC to see if they could make a diagnosis."
The CDC was primarily responsible for identifying the cause of the infection, she said. LCMV infection can occur in humans, triggering a form of meningitis that usually does not cause much damage. "There are not severe consequences other than in pregnancy," Fischer said. "Usually people recover without difficulty."
But it was different for the transplant recipients. Their symptoms included abdominal pain, mental problems, diarrhea and kidney failure. Of the eight people who were infected, only one survived after being given an antiviral drug.
The researchers aren't recommending that people who have hamsters or other rodents as pets be forbidden to donate organs. "There are 92,000 people on the [organ] waiting list, and diminishing the donor pool is not what anyone wants to do because the risk is low," Fischer said.
Instead, it may be helpful to ask prospective donors about their exposure to rodents -- not to exclude them but to provide information to doctors in case of complications after a transplant, she said.
Some regulation might be needed for colonies where these pets are bred, said Dr. Clarence J. Peters, who wrote an accompanying editorial in the journal. He worked at the CDC for 10 years and now is professor of pathology, microbiology and immunology at the University of Texas Medical Branch at Galveston.
Peters said he is philosophically opposed to government regulation, but it might be wise to run periodic tests of animal colonies to determine whether the LCMV infection is present, since it can spread rapidly from animal to animal.
While LCMV rarely causes death in healthy individuals, it is "a very unpleasant illness" that, among other problems, can make people abnormally sensitive to light, Peters said.
"Anyone with central nervous system symptoms should be asked about rodent exposure in general," he said. "We always joke about the infectious-disease physician who asks, 'Has your pet bat been well?'"
More information
The U.S. Centers for Disease Control and Prevention offers tips on avoiding LCMV infection from pets.
