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Background Invasive fungal infections are a major cause of morbidity and mortality among solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients, but few data have been reported on the epidemiology of endemic fungal infections in these populations. Methods Fifteen institutions belonging to the Transplant-Associated Infection Surveillance Network prospectively enrolled SOT and HCT recipients with histoplasmosis, blastomycosis, or coccidioidomycosis occurring between March 2001 and March 2006. Results A total of 70 patients (64 SOT recipients and 6 HCT recipients) had infection with an endemic mycosis, including 52 with histoplasmosis, 9 with blastomycosis, and 9 with coccidioidomycosis. The 12-month cumulative incidence rate among SOT recipients for histoplasmosis was 0.102%. Occurrence of infection was bimodal; 28 (40%) infections occurred in the first 6 months post transplantation, and 24 (34%) occurred between 2 and 11 years post transplantation. Three patients were documented to have acquired infection from the donor organ. Seven SOT recipients with histoplasmosis and 3 with coccidioidomycosis died (16%); no HCT recipient died. Conclusions This 5-year multicenter prospective surveillance study found that endemic mycoses occur uncommonly in SOT and HCT recipients, and that the period at risk extends for years after transplantation.

Post-transplantation histoplasmosis may be acquired via inhalation, may result from endogenous reactivation, or may be derived from the allograft. The Histoplasma and Aspergillus enzyme-linked immunoassays are increasingly being relied upon for rapid diagnosis of fungal infections, especially in immunocompromised patients. We describe 4 cases of solid organ transplant recipients who had histoplasmosis and a falsely positive Aspergillus galactomannan (GM) obtained from the serum or bronchoalveolar lavage (BAL) fluid. We also report our experience, testing for Histoplasma antigen (Ag) in specimens positive for Aspergillus GM. From January 2007 through December 2010, of 2432 unique patients who had positive Aspergillus GM tests, 514 (21%) were tested for Histoplasma Ag, and 27 were found to be positive. Most specimens that tested positive for both Aspergillus and Histoplasma were obtained by BAL. False-positive tests for Aspergillus GM can occur in immunosuppressed patients who have histoplasmosis, and may obscure the correct diagnosis.

West Nile virus (WNV), a single-stranded RNA flavivirus, has spread across the United States since arriving in 1999. While asymptomatic or self-limited in a majority of patients, WNV can cause a severe neuroinvasive disease, which occurs more often in transplant recipients with chronic immunosuppression. Diagnosis of acute WNV infection usually relies on serologic identification of immunoglobulin M (IgM) specific for the virus. We report a fatal case of naturally acquired WNV encephalitis in a renal and pancreas transplant recipient who was seronegative for WNV-specific IgM but had detectable WNV RNA by nucleic acid amplification testing (NAAT) several weeks after the onset of symptoms. This case demonstrates the importance of using both serologic assays and NAAT for WNV in transplant recipients with the clinical suspicion of encephalitis.

A.G. Freifeld, J. Meza, B. Schweitzer, L. Shafer, A.C. Kalil. A.R. Sambol. Seroprevalence of West Nile virus infection in solid organ transplant recipients. Transpl Infect Dis 2010: 12: 120–126. All rights reserved Background. Of people infected with mosquito-borne West Nile virus (WNV)