Microsporidiosis acquired through solid organ transplantation: a public health investigation.

Background: Encephalitozoon cuniculi, a microsporidial species most commonly recognized as a cause of renal, respiratory, and central nervous system, infections in immunosuppressed patients, was identified as the cause of a temporally associated cluster of febrile illness among 3 solid organ transplant recipients from a common donor. Objective: To confirm the source of the illness, assess donor and recipient risk factors, and provide therapy recommendations for ill recipients. Design: Public health investigation. Setting: Two transplant hospitals and community interview with the deceased donor's family. Patients: Three transplant recipients and the organ donor. Measurements: Specimens were tested for microsporidia by using culture, immunofluorescent antibody, polymerase chain reaction, immunohistochemistry, and electron microscopy. Donor medical records were reviewed and a questionnaire was developed to assess for microsporidial infection. Results: Kidneys and lungs were procured from the deceased donor and transplanted to 3 recipients who became ill with fever 7 to 10 weeks after the transplant. Results of urine culture, serologic, and polymerase chain reaction testing were positive for E. cuniculi of genotype III in each recipient; the organism was also. identified in biopsy or autopsy specimens in all recipients. The donor had positive serologic test results for E. cuniculi. Surviving recipients received albendazole. Donor assessment did not identify factors for suspected E. cuniculi infection. Limitation: Inability to detect organism by culture or polymerase chain reaction in donor due to lack of autopsy specimens. Conclusion: Microsporidiosis is now recognized as an emerging transplant-associated disease and should be considered in febrile transplant recipients when tests for routinely encountered agents are unrevealing. Donor-derived disease is critical to assess when multiple recipients from a common donor are ill.