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Transplant travails: West Nile and HCV outbreaks
First West Nile cluster, HCV window’ donor
The first recognized transmission of West Nile virus by organ transplantation and an unusual hepatitis C outbreak in organ recipients were both recently described in Washington, DC, at the annual conference of the Society for Healthcare Epidemiology of America.
"West Nile virus can be transmitted by organ transplantation and blood transfusion," reported Martha Iwamoto, MD, MPH, a medical epidemiologist at the Centers for Disease Control and Prevention (CDC). "Immunosuppressed organ recipients may be at risk for more severe West Nile virus disease."
In August 2002, recipients of organs from a common donor developed fever with mental status changes.1 Transmission of West Nile virus through organ transplantation was suspected. The CDC reviewed medical records, conducted interviews, and collected blood and tissue samples for testing using a variety of assays. People who donated blood to the organ donor were identified and tested for West Nile virus.
The investigators identified West Nile virus infection in the organ donor and all four organ recipients. Three of the organ recipients developed encephalitis, and one developed febrile illness. Three recipients seroconverted with West Nile virus antibody, and one recipient had brain tissue positive for West Nile virus. Organ donor serum specimens collected before and immediately following blood transfusions showed no evidence of West Nile virus. However, serum and plasma samples obtained at organ recovery were positive by nucleic acid testing and viral culture. The organ donor received blood transfusions from 63 donors. Blood donor look-back and follow-up testing identified one donor who was viremic at blood donation and developed West Nile virus during the two months following blood donation.
"Blood from this donor was the last component that the organ donor received," Iwamoto said. West Nile virus infection should be considered in patients who develop fever and encephalitis following transplantation or transfusion, she urged.
Slipping through the window
In another transplant-related outbreak reported at SHEA, hepatitis C virus was transmitted to at least nine transplant recipients from a single organ donor in the classic "window period" prior to antibody production.
"It is possible that an infected donor may go undetected," said Pritti Patel, MD, MPH, medical epidemiologist in the division of viral hepatitis at the CDC.
"[There is a] window period between infection and the development of antibodies to the virus," Patel added. "During an eight-week period of time, the individual is capable of transmitting an infection but would test negative for HCV."2
In May 2002, a tissue graft recipient developed acute HCV six weeks following transplantation. At the time of death in October 2000, the donor was HCV-negative. However, an investigation initiated in July 2002 indicated that stored donor serum was HCV RNA-positive and transmission to graft recipients had occurred.
"Donor serum is tested for antibody to HCV using an enzyme immunoassay," Patel said. "HCV RNA testing is not routinely preformed [because] the results of this test may not be available in time for organ transplantation."
Findings thus far in the ongoing investigation indicate 44 grafts from the HCV-infected donor were transplanted into 40 recipients. Of those, 34 received tissues and six received organs. Cases occurred in all three organ recipients for whom serum specimens were available. Transmission also occurred to six graft patients, including recipients of saphenous veins, tendons, and tendons with bone. No cases occurred in recipients of skin or irradiated bone. The donor was the likely source of HCV infection for at least nine recipients of organs and tissues, Patel noted. Although transmission from anti-HCV-negative tissue donors is likely uncommon, enhanced donor screening and improved viricidal tissue processing should be considered, she said.
1. Iwamoto M, Jernigan DB, Guasch A, et al. Transmission of West Nile virus from an organ donor to four transplant recipients. Latebreaker abstract. Presented at the annual conference of the Society for Healthcare Epidemi-ology of America. Washington, DC; April 2003.
2. Patel PR. Tugwell BD, Williams IT, et al. Hepatitis C virus (HCV) transmission from an antibody-negative organ and tissue donor: Further epidemiologic findings and genetic analysis. Abstract 237. Presented at the annual conference of the Society for Healthcare Epidemiology of America. Washington, DC; April 2003.