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Possible West Nile Virus transmission through organ transplantation

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UNOS News Bureau

(804) 782-4730

newsroom@unos.org

The Health Resources and Services Administration, (HRSA) Office of Special Programs, is issuing this alert to organizations associated with organ transplantation about a suspected case of transmission of West Nile virus through organ transplantation. In addition, this alert notice provides a summary of the current status of the ongoing investigation of this case.

The investigation has focused on a cluster of cases of West Nile virus infection through transplantation of organs from one donor. The organ donor received multiple blood transfusions prior to death and testing of the donor demonstrated evidence of West Nile virus infection. All four of the persons who received organs from the single donor became infected with the West Nile Virus; one died and two remain hospitalized and one is recuperating at home.

Organ transplantation has not been confirmed as the route of the recipients' West Nile virus infection. However, the Center for Disease Control and Prevention (CDC) has confirmed infection in all four recipients in this case. CDC has indicated that the donor most likely became infected with the West Nile virus through a mosquito bite or via blood transfusion shortly before organ donation. HRSA recommends all organizations associated with organ transplantation keep current on this matter and be prepared to implement precautionary procedures that may be recommended by federal and state health authorities.

        • To date, CDC and the Food and Drug Administration (FDA) have found insufficient information to recommend changes to existing organ or blood donor screening and testing practices. As a precaution, the remaining blood products from blood donors whose blood was given to the organ donor have been voluntarily withdrawn from use.
        • Clinicians caring for organ transplant patients with febrile illnesses - particularly patients with unexplained meningitis or encephalitis in the weeks following transplant -- should consider West Nile virus infection as a possible cause of the illness.
        • West Nile infection can be detected by IgM antibody in cerebrospinal fluid (CSF) or serum samples by MAC-ELISA. Laboratory evaluation of the CSF in the organ recipients may not be consistent with common findings in patients with encephalitis (such as pleocytosis and elevated protein). According to CDC, clinicians who suspect West Nile Virus can obtain rapid testing at State laboratories through State and local health departments.

Status of Investigation:

The CDC, the FDA, the Georgia State Division of Public Health, and the Florida Department of Health are continuing to investigate how the four organ recipients became ill. All four showed symptoms of viral infection after the transplant. The onset of their illness occurred 17 to 18 days after transplant, which is longer than the typically observed incubation period of 3 to 14 days for the West Nile Virus. Each of the four organ recipients demonstrated clinical symptoms and/or laboratory test results consistent with a West Nile infection.

It is not known how the donor was infected. It is most likely that the donor may have acquired the West Nile virus through a mosquito bite or through blood transfusions that she received prior to removal of the organs. It is also not certain how the organ recipients were infected. The organ recipients were most likely infected through mosquito bites or through the transplanted organs. Laboratory tests are underway to determine whether West Nile Virus was present in the organ donor or in the blood of donors whose blood products were used in the transfusions. West Nile Virus infection in organ transplant or blood transfusion recipients has not been previously reported and the risk for acquiring West Nile Virus infection from donated organs or blood is not known. As stated above, present information is insufficient to indicate changes to existing organ or blood donor screening and testing practices.

Additional information from CDC and FDA about the West Nile Virus and organ transplantation:

        • Although there are no data about the stability of West Nile Virus in refrigerated blood or blood components, flaviviruses such as West Nile in general are known to survive over long periods in fluids with high protein content and would be expected to have good stability in blood.
        • West Nile Virus is a lipid-enveloped virus and is expected to be destroyed during the viral inactivation procedures used in the plasma derivative manufacturing process. Therefore, there should be minimal risk of transmission to recipients of manufactured plasma products.
        • Most West Nile Virus infections are mild and present no symptoms to the infected person. In the general population, 20 percent of those infected develop a mild illness and approximately 1 in 150 infections result in severe neurological disease. Organ transplant recipients, however, have weakened immune systems and may be at greater risk of severe disease if infected. The risk of infection by West Nile Virus for organ transplant recipients has not been calculated.
        • As stated earlier, the typical West Nile incubation period is thought to range from 3 to 14 days, but the onset of illness for the four transplant recipients began as late as 17 to 18 days after transplantation of the organ.
        • Symptoms in the four transplant patients under investigation started as fever unresponsive to antimicrobial therapy, headache, backache and non-specific respiratory symptoms. Three patients developed progressive decline in mental status and required mechanical ventilation. The patient who died succumbed from brain stem herniation. Although not observed in recent outbreaks, myocarditis, pancreatitis and fulminant hepatitis have been described in West Nile Virus infections.
        • Treatment is primarily supportive. Ribavirin in high doses and interferon alpha-2b were found to have some activity against West Nile Virus in vitro, but no controlled studies have been completed on these drugs or other medications in the management of West Nile Virus encephalitis.

HRSA is advising all OPOs and transplant centers to be alert to the risks of West Nile Virus and to be aware of all daily updates provided by the CDC and FDA.

Resources for Updated Information:

The following Internet-based resources provide additional information about West Nile and will continue to be updated as more becomes known in this ongoing investigation.

The most recent CDC Press Release and the updated status of its investigation can be found on its Web site: http://www.cdc.gov

A full description of the clinical features and diagnostic test options for West Nile virus infection can be found on the CDC Web site: http://www.cdc.gov/ncidod/dvbid/westnile/resources/fact_sheet_clinician.htm

A FDA alert regarding West Nile virus and blood safety can be found on its Web site: http://www.fda.gov

HRSA will continue to monitor the situation with the CDC and the FDA and provide periodic updates to the transplant community.