West Nile Virus Transmission Through Organ Transplantation

The Health Resources and Services Administration (HRSA), Office of Special Programs, is issuing this alert to organizations associated with organ transplantation as a reminder of the potential for transmission of West Nile virus (WNV) through organ transplantation. In addition, this alert notice directs the organ transplant community to the most current sources of information and guidance.

In August 2002, four organ transplant recipients became infected with WNV after receiving organs from the same donor. An investigation led by the Centers for Disease Control and Prevention (CDC) determined that the organ donor acquired WNV from blood transfused shortly prior to organ donation. One organ recipient developed WNV fever. The other three recipients developed encephalitis; one died as a result of brain herniation.
The magnitude of the risk of acquiring West Nile virus infection from donated organs has not been determined. Currently, there is no FDA-approved screening test for WNV. Information remains insufficient to recommend specific changes to existing organ donor screening and testing practices. HRSA recommends that all organizations associated with organ transplantation remain vigilant in evaluating potential donors and be prepared to implement precautionary procedures that may be recommended by Federal and State health authorities.

On May 1, 2003, the Food and Drug Administration (FDA) issued a revised guidance for assessment of blood donor suitability. One new recommendation is to ask blood donors a specific question about history of fever with headache within one week prior to donation; donors who answer ”yes” should be deferred for 28 days from the date of the interview. HRSA recommends that OPOs and transplant centers review this guidance and consider whether similar measures are appropriate or applicable in the setting of organ donation and transplantation.

FDA has been working with industry to facilitate the development of tests for WNV for blood donor screening. WNV nucleic acid amplification tests are currently available to blood banks nationwide for investigational use in blood donor screening. HRSA is exploring the applicability of these screening tests in the setting of organ donation. The investigational blood donor screening procedure has successfully identified the first human WNV infection in an asymptomatic blood donor.

FDA just approved the first diagnostic test for WNV. This blood test is an IgM Capture ELISA and is intended for use in patients with clinical symptoms consistent with viral encephalitis or meningitis. Positive test results must be confirmed by an additional test or by using current CDC diagnostic guidelines. The WNV diagnostic test should be available later this year, and can be purchased by any accredited laboratory. Patients with symptoms of encephalitis or meningitis generally would not be considered for organ donation. However, this test may be valuable in evaluating transplant recipients who develop clinical symptoms suggestive of WNV infection. Note that this new IgM test is not intended for screening blood or organ donors.

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

• Laboratory evaluation of the cerebrospinal fluid (CSF) in organ recipients may not be consistent with common findings in patients with encephalitis (such as pleocytosis and elevated protein). IgM antibody to WNV can be detected in CSF or serum samples by ELISA. Clinicians who suspect WNV can obtain rapid testing at state laboratories through state and local health departments, or can use the new WNV diagnostic test when it becomes available.
• Clinicians caring for organ transplant recipients with febrile illnesses - particularly patients with unexplained meningitis or encephalitis in the weeks following transplant--should consider WNV as a possible cause of the illness.
• Most WNV infections are mild and present no symptoms in 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. The risk of fatal encephalitis in cases of severe disease is about 1 in 1000. Organ transplant recipients, however, have weakened immune systems and may be at much greater risk of severe disease if infected.
• The WNV incubation period is generally thought to range from 2 to 14 days, but the onset of illness for the four infected transplant recipients ranged from 7 to 17 days after transplantation of the organ.
• Patients with diagnosed WNV infection who have received blood transfusions or organs within the 4 weeks preceding the onset of symptoms should be reported to CDC through state and local public health authorities.
• Cases of WNV infection in individuals who had onset of symptoms within 2 weeks after blood or organ donation should be reported to CDC through state and local public health departments.

HRSA is advising all OPOs and transplant centers to be alert to the risks of WNV and to frequently check CDC and FDA web sites for updated information.

Resources for Updated Information

• Updated WNV case count, CDC Press Releases, and telebriefing transcripts (CDC)
• Fact Sheet: Clinical features, diagnostic testing and reporting requirements (CDC)
• The FDA Guidance for Industry: Revised Recommendations for the Assessment of Donor Suitability and Blood and Blood Product Safety in Cases of Known or Suspected West Nile Virus Infection (FDA)
• West Nile virus blood safety and general information (FDA)
• American Association of Blood Banks press release on national testing of blood for West Nile virus (not a U.S. Government Web site)

HRSA will continue to work with the CDC, FDA, and the transplant community to minimize the risks of transmission of WNV through organ transplantation.