Chapter 91 – Sporotrichosis

Publisher Summary This chapter describes the various animal models used for sporotrichosis. Sporotrichosis is a chronic mycotic disease of humans and animals. Sporotrix sckenckii, the etiological agent of sporotrichosis, is a dimorphic fungus (mold and yeast phase) which occurs naturally on vegetation or as a soil saprophyte. This mycosis develops after the traumatic introduction of S. sckenckii into the dermis. Clinically, classical sporotrichosis is usually seen as an ascending lymphangitis of the extremities following the development of the primary lesion (shunt) at the site of inoculation. The various animal species, which are used for this model include mice, guinea-pigs and hamsters. The mice strains used in this model include BALB/c, 4.5 months of age, weighing 20 g, male NYLAR mice weighing 18–20 g, Swiss mice weighing 18–25 g, and female and male ICR Swiss albino mice. Goldhamster Mesocricetos auratus, male Hartley strain weighing 500–700 g, and male albino guinea pigs are also used. In most of the experiments, the animals are normally housed at room temperature with water and food ad libiturn without special precautions. Two different forms of inoculum are used, for virulence studies conidia are inoculated, whereas the yeast form of S. sckenckii is mainly used in chemotherapeutic studies. Mice or guinea-pigs are inoculated intracutaneously with 0.1–0.2 ml of conidia suspension into the dorsal portion of the right foot. Guinea-pigs receive an intradermal injection of conidia in 0.1 ml saline on the shaved dorsal area of the animals. Guinea-pigs are infected in the left testicle with yeast cells of S. schenckii in a volume of 0.25 ml saline. S. sckenckii affects bone, joints and most organs like kidney, liver, spleen, lung and testes. The in vivo growth rate is the highest in the testes. The course of disseminated infection is monitored by mortality data, macroscopical, and radiological examination of the bone and joint involvement, and by histological and cultural examination of inner organs, mainly spleen and liver.