Development of a Murine Model of Cerebral Aspergillosis

Central nervous system (CNS) Aspergillus infection has a mortality rate in humans that approaches 95%. Because no animal models are available for studying this infection, we sought to develop a murine model of CNS aspergillosis. Inconsistent data were obtained for nonimmunosuppressed CD-1, C57BL/6, and DBA/2N mice after infection by midline intracranial injection of Aspergillus fumigatus. CD-1 mice given cyclophosphamide to produce immunosuppression had continuous pancytopenia. Dose-finding studies in CD-1 mice showed that infection with 5 x 106 conidia/mouse consistently caused 100% mortality by day 5-8; no mice died before day 3. Histologic examination of samples of brain tissue showed focal abscesses containing Aspergillus hyphae. Fungus burdens in brain were higher than those in other organs, although Aspergillus disseminated to the kidneys and the spleen. The model we established provides an opportunity to study immune responses to and therapeutic options for CNS disease in an immunologically defined, genetically manipulable, and inexpensive species.