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CDC confirms presence of amoeba in transplant donor, recipient

Published on Friday, December 18, 2009

Published in Press Releases on December 18, 2009 (PDF)

An unprecedented case involving possible transmission of an organism from organ donor to recipients has been the focus of an intense medical search involving the University of Mississippi Medical Center, the Centers for Disease Control and Prevention and the Mississippi State Department of Health.

The effort launched recently following the illnesses of two transplant recipients who received organs from the same donor. Both of those patients are now critically ill.

Some time ago, UMMC admitted a patient who exhibited neurological symptoms. During a week-long hospitalization that included a battery of medical tests and interventions, physicians arrived at a diagnosis of an autoimmune disorder in which the body's immune system attacks its own cells and tissues. Subsequently, the patient died in the hospital.

The family decided to donate the patient's organs. Tests were carried out to determine the presence of a transmissible disease, and none was found. Also, no instance of transmission of an autoimmune disorder has been found in medical literature.

The organs were deemed suitable for transplant and were accepted by the Mississippi Organ Recovery Agency. Four recipients received four organs at medical centers in three states.

Two of the recipients have developed symptoms resembling those experienced by the donor. The other two recipients have exhibited no symptoms of concern to date.

On Thursday, the CDC confirmed the presence of a type of amoeba in the donor based on their highly sophisticated laboratory analysis of samples from the donor. This organism is extremely difficult to detect and diagnose, in part because it is extremely rare, with fewer than 70 known cases occurring in the United States since it was first identified in 1986. The CDC confirmed today the presence of the amoeba in one of the recipients.

It appears this would be the first recorded case of transmission of the organism via organ transplantation.

Balamuthia mandrillaris is the parasitic soil amoeba believed to be the cause of the illnesses. It is unknown how the amoeba enters the body but it is thought to enter through the respiratory tract or breaks in the skin.

Medical authorities have no reason to suspect that any other individuals are at risk from this transmission event.

"The families of the donor and the recipients have been notified of this situation," said Dr. William Cleland, chief medical officer of UMMC's hospitals and health system. "We feel nothing but compassion for what they and their loved ones are experiencing."