Estudo de casos espontâneos de esporotricose canina e felina, e avaliação da melanina em células de Sporothrix schenckii em modelo murino

Abstract

Sporotrichosis is a zoonotic mycosis, caused by dimorphic fungus Sporothrix schenckii, that attacks the man and several animal species, especially domestic felines. Among the factors of patogenicity of the fungus, stands out the melanin presence. This work had as objective: to study spontaneous cases of esporotricose in canine and felines, evaluating the aspects clinical, epidemic, pathological and therapeutic; to evaluate the melanin presence, in transition cells and yeasts of isolated pigmented and albino mutants of Sporothrix schenckii; and to compare the development of experimental sporotrichosis produced for isolated pigmented and albino mutants. Spontaneous case study: They were studied cases of feline and canine esporotricose diagnosed by the Laboratório de Micologia (FV-UFPel) during the period from 2002 to 2006, we which it was observed the main forms clinics of the sporotrichosis, that it resulted in cutaneous disseminated in felines and canine, besides, it was obtained the isolation of the fungus in testicles without lesions from feline with cutaneous sporotrichosis. The treatment of the animals was accomplished with itraconazol, in the dosage of 10mg/kg/dia, orally, being obtained the clinical cure of 50% of the felines and 100% of the dogs. Experimental sporotrichosis: 60 albino mice divided in two groups, MEL+ and MEL -, they were inoculated subcutaneously in the paw pads, with pigmented conidia and albino mutants, respectively. Samples of tissues of the inoculation site were obtained by biopsy for study mycological, histopathological and ultrastructural. All the animals developed characteristic lesions of sporotrichosis in the inoculation point, being observed significant differences in second, third and fifth week of the experiment. The animals of the group MEL- demonstrated ulcerate in the paw pad in the second week of the experiment (p<0,01) while the group MEL+ stayed with edema and nodule. In the weeks, three and five, the group MEL+ demonstrated lesions in other corporal areas and increase of volume of the lymph node popliteal (p<0,05). Histopathology showed that isolated pigmented incite inflammatory reponse less accentuated, that it allows the invasion and spread of the agent. The study ultrastructural showed that the fungus synthesizes melanin in the yeasts form, and that pigmented conidia lose the melanin layer during the transition period. It was observed, the increase of cases of sporotrichosis in felines and the occurrence of the mycosis in dogs, alerting for the zoonotic risk and the importance of the diagnose differential for the appropriate treatment of the mycosis, emphasizing the effectiveness and safety of the therapy with itraconazol in the dose of 10mg/kg/dia. In the experimental sporotrichosis it was observed that differences exist in the initial period of the development of the disease among groups inoculated with conidia pigmented and albino mutant, since the conidia lose the melanin layer during the transition period and when in the form leveduriforme, both isolated they are capable to synthesize melanin in vivo.