Association Between the Human Pathogen Sporothrix schenckii and Sphagnum Moss

Abstract

The discipline of medical mycology can be divided into a study of: 1) mycoses (fungal infections of man and other animals); 2) mycotoxicoses (toxic fungal metabolites); 3) mycetismus (mushroom poisoning); and 4) fungal allergies (Rippon, 1988; see also Chapter 11). The mycoses are subdivided on the basis of the extent of invasion of the host and on the basis of the innate virulence of the etiologic agents, i.e., primary pathogens or opportunistic pathogens (Table 12.1). The primary pathogens are those that readily cause infection in the normal (healthy) host, whereas the opportunistic pathogens such as Candida albicans and Aspergillus fumigatus typically only infect an immunocompromised or otherwise debilitated host. The medically important fungi are noted for demonstrating specific ecological habitats and geographical distributions. Cryptococcus neoformans, the etiological agent of cryptococcosis and a major pathogen in immunosuppressed patients, is associated with pigeon guano and is distributed throughout the world. Other examples include Coccidioides immitis in the soil of the San Juaquin Valley, California; Histoplasma capsulatum in starling, chicken, and bat guano, and Sporothrix schenckii in sphagnum moss. Epidemics have been caused by all of these fungi.