Organ Transplantation

Risk from transplanted organs

The risk of being infected with West Nile virus from a transplanted organ is low.

The following can affect your chances of being infected with West Nile virus from a transplanted organ:

• Time of year. Infection risk increases during months when mosquitoes are most active (June through October).
• Number of West Nile virus disease (West Nile) cases in a year
• Where the organ donor lives
  

Testing organ donors

Unlike blood donors, not all organ donors are tested for West Nile virus. However, most centers screen living donors and some centers screen deceased donors for West Nile virus. Organ donors might not be tested because of the time it may take to get results. Current tests for West Nile virus may not work well for all organ donors.

Donation after infection

You can still be an organ donor if you have had West Nile in the past. A small number of patients have been infected with West Nile virus from transplanted organs. However, those organs came from donors who were recently infected with West Nile virus and still had virus in the blood or tissues at the time of donation.

Risk of severe illness

Organ transplant recipients are generally at higher risk of severe West Nile illness because they take medications that can weaken the immune system. Seventy-five percent of transplant recipients who become infected develop severe illness. This is much higher than the risk among most people who do not have weakened immune systems and are infected by mosquito bite (less than 1%).