Animal models of zygomycosis - Absidia, Rhizopus, Rhizomucor, and Cunninghamella

Infections caused by zygomycetes, which have been incrasing in recent years , are known for their difficulty of diagnosis and treatment. Because little is known about this fungus and its infection, vigorous research is now in serious demand. As in many other systemic mycoses, animal model studies are essential in the investigation of zygomycosis, particularly for the study of pathogenesis, diagnosis and treatment. Unfortunately, such studies have been limited when compared with those of aspergillosis. To help investigati ng the disease, here in this review article, the profile of human zygomycos is is briefly described, followed by a review of the heretofore used animal models of zygomycosis. Among clinically important zygomycetes causing human infection, animal mode ls are available for Absidia corymbifera, Rhizopus oryzae, R. microsporus v ar. rhizopodiformis, Rhizomucor pusillus and Cunninghamella bertholletiae. Mice are the most commonly used animals, but models using guinea pigs and r abbits are also available. Pretreatment of animals with cyclophosphamide, c orticosteroid, alloxan or streptozocine is frequently done to create an imm unocompromised state. Treatment with desferrioxamine, an iron chelator, is also used to make animal models. In terms of the route of infection, the ai rborne route is used for pathophysiological studies in pulmonary infection models, but sometimes intravenous injection is preferred, particularly for antifungal drug studies. When pathophysiological analysis is the purpose of the study, the animals must be cautiously examined both histopathologicall y and mycologically. For the most part, zygomycosis model studies can be performed in a similar manner to those of aspergillosis. However, Aspergillus spp. and zygomycetes are completely different fungi, and researchers should be aware of the spe cific, critical aspects when handling zygomycosis models, such as homogeniz ation of infected organs and staining of pathological samples.