Nancy A. Melville

September 01, 2015

ATLANTA — Strict adherence to screening guidelines for organ transplantation and effective communication can prevent the spread of Strongyloides stercoralis, according to research from the New York Organ Donor Network.

The intestinal parasite is carried by an estimated 100 million people around the world. It's prevalence is endemic in tropical and subtropical regions, particularly South American and some parts in Africa.

Infection can lead to diarrhea, abdominal pain, and skin manifestations. Although immunocompetent individuals often experience no symptoms, infection in immunocompromised patients, such as solid organ transplant recipients, can result in severe illness or death.

"Timing and direct communication between organ procurement organizations and transplant centers is critical to preventing morbidity and mortality associated with donor-derived infection," said Francisca Abanyie, MD, from the division of parasitic diseases and malaria at the Center for Global Health, Centers for Disease Control and Prevention, in Atlanta.

She and her team assessed outcomes in patients who received organs from three different donors infected with S stercoralis. Dr Abanyie presented the results here at the International Conference of Emerging Infectious Diseases.

Strongyloides Stercoralis

Guidelines from the American Society for Transplantation recommend that transplant candidates and donors with epidemiologic risk factors or unexplained eosinophilia be evaluated for Strongyloides.

In addition, the Organ Procurement and Transplantation Network requires donor recovery hospitals to communicate a donor's test results that could be relevant to acute patient care "as soon as possible" to transplant programs, tissue banks, and other organizations involved in receiving organs or tissue.

But some cases are falling through the cracks.

In the first case described by Dr Abanyie, a 36-year-old man born in the United States received a left kidney and a pancreas. He began to experience nausea and other symptoms 5 weeks after transplantation. His immunosuppression was then decreased and he subsequently developed bacteremia. The two organs were ultimately removed.

The donor was a 21-year-old man who had emigrated from Mexico 6 years before the procedure and who had died in a motor vehicle accident from head trauma. Even though Strongyloides is endemic in Mexico, the donor was not screened; he was thought not to be at risk for infection. However, on subsequent testing, his serum was found to be positive for Strongyloides.

Four other recipients of organs or tissue from this donor received prophylaxis and, to date, have not developed infection.

"The lesson from this investigation is that screening of patients from endemic areas is very important in preventing infection to transplant recipients," Dr Abanyie explained.

In the second case she described, a 73-year-old man born in the United States who received a right lung developed diarrhea and anorexia 6 weeks after transplantation. His pretransplant serum was negative for Strongyloides antibodies, but after transplantation, his skin and stool tests were positive for Strongyloides. Despite treatment, he died 67 days after transplantation.

The donor was a 36-year-old homeless man who was born in El Salvador but who had lived in the United States for 14 years. He died after suffering a subarachnoid hemorrhage in a fall. The donor was determined to be at high risk because of the country of his birth and screened positive for Strongyloides.

Unfortunately, not all of the necessary steps were taken to communicate this critical information. The screening results were posted on the donor network used by organ procurement centers, but the information was not directly communicated to the recipient's center.

A 40-year-old woman who received a left lung from this donor developed some of the same symptoms 6 to 7 weeks after transplantation. She also tested positive for Strongyloides and, after developing acute respiratory distress syndrome, died 9 weeks after transplantation.

Three other recipients of organs from this donor were treated with prophylaxis and, to date, have experienced no signs of infection.

"The lesson here is that results should be directly communicated from the organ procurement organization to the transplant centers. In this case, those steps might have saved the lives of two of these organ recipients," Dr Abanyie said.

In the third case she described, a 45-year-old man who was born in Puerto Rico and who had lived in New York City for 7 years died from complications related to a stroke.

He was identified as being at high risk because of his country of birth, was tested, and was found to have Strongyloides antibodies at the time of organ procurement.

The positive results were communicated directly to the transplant centers and the four organ recipients were given prophylaxis. To date, they have shown no clinical infections.

"This is a great example of what should be done," Dr Abanyie said. "Pretransplant screening was performed and the results were directly communicated to the transplant centers, allowing for provision of prophylactic therapy to the recipients and, therefore, preventing donor-derived Strongyloides."

Failure to Screen

One reason for failure to perform appropriate screening might simply be a lack of awareness that candidates are at risk, said Dr Abanyie, who was involved in a report of other cases of donor-derived S stercoralis infection that was published earlier this year (Am J Transplant. 2015;15:1369-1375).

"Strongyloides is endemic in only certain parts of the world — such as Mexico, parts of South America, Puerto Rico, West and Central Africa, and some parts of the United States — so it's not appropriate that everyone be screened," she told Medscape Medical News. "That may be a factor — actually knowing where the disease is endemic and who to test for infection."

Another issue is that donor-derived infections are not all that common, said Michael Ison, MD, from the Feinberg School of Medicine and the Comprehensive Transplant Center at Northwestern University in Chicago.

"The issue of donor-derived infections is an emerging topic in the field of transplant infectious diseases," he told Medscape Medical News.

In the 10 years since the requirement to report potential donor-derived disease transmission was established by the Organ Procurement and Transplantation Network and the United Network for Organ Sharing, there have been nearly 1500 reports to the organ vigilance system, resulting in confirmation of disease transmission in 317 recipients.

Of those, 92 (29%) recipients with confirmed transmission died from the transmitted infection, he reported.

"This suggests that while this may be a clinically significant event, it still is an incredibly rare event, complicating just over 0.1% of all organ transplants," he pointed out.

Safe, Effective Treatment

There might be a lack of awareness that safe and effective therapy, generally ivermectin, can be given to the donor and recipient to significantly reduce the risk for disease transmission. Such therapy can be administered safely after the transplant procedure, and is safe even in the instance of a false-positive result, Dr Ison explained.

"The only downside to broader screening is that centers may choose not to use a donor because they do not understand the implications of the testing," he said. "Nonetheless, there are clear guidelines on the management of Strongyloides in donors and recipients, and I, personally, would be comfortable using any donor, even if they had a positive Strongyloides screening test."

In fact, Dr Abanyie pointed out that since 2010, of the more than 1400 potential donors screened at the LiveOnNY organ procurement center, 315 were tested for Strongyloides on the basis of known risk factors. Of the 16 found to be positive, 13 were determined to be suitable donors.

From these 13 donors, 35 people received organs, mainly kidneys and livers. The majority received prophylactic therapy, and "none of these patients, to date, have had infection due to Strongyloides. This is an example of a success story," Dr Abanyie said.

The LiveOnNY experience "shows that targeted donor screening and the provision of prophylactic therapy can avert infection in recipients of organs from seropositive donors," she explained.

Dr Abanyie and Dr Ison have disclosed no relevant financial relationships..

International Conference on Emerging Infectious Diseases (ICEID). Presented August 26, 2015.

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