Rhizopus microsporus segmental enteritis in a cow

Cutaneous Mucormycosis in Buffalos in the Brazilian Amazon Biome

This is the first description of cutaneous mucormycosis in buffalo in the Brazilian Amazon biome. All buffalo showed apathy, inappetence, weight loss, reluctance to move, and prolonged sternal decubitus. Of the four affected animals, two died 15 and 30 days after the appearance of clinical signs. In the initial phase, the skin lesions were rounded areas with dry central regions, sensitive to palpation, with protruding edges and diameters ranging from 8 cm to 15 cm. These areas of necrosis were isolated or coalescing and present mainly on the limbs and sides. In an advanced stage of the disease, there was detachment of the skin from the necrotic areas with extensive wound formation, which sometimes exposed the subcutaneous tissue. The histopathology of the skin showed a multifocal inflammatory infiltrate composed of intact and degenerated eosinophils surrounded by epithelioid macrophages. At the center of these areas was a focally extensive area of epidermal ulceration characterized by intact and degenerated neutrophils, the necrosis of epithelial cells, and the accumulation of fibrin and erythrocytes. The mycological culture was positive for Rhizopus sp. The diagnosis of cutaneous dermatitis caused by Rhizopus sp. was based on clinical signs, macroscopic and histopathological findings, and the identification of the fungus by mycological and molecular techniques.

A case of feline gastrointestinal eosinophilic sclerosing fibroplasia associated with fungal colonisation: endoscopic features, treatment and follow-up

Case summary

A 5-year-old castrated male domestic shorthair cat presented with a 3-month history of weight loss, chronic diarrhoea and vomiting. Examination revealed a large proximal duodenal lesion eventually diagnosed as feline gastrointestinal eosinophilic sclerosing fibroplasia (FGESF) associated with fungal filaments. Histological examination was performed following endoscopic biopsy. Direct examination and mycological culture of the duodenal biopsies revealed the presence of a siphomycetous fungus, which was further identified as Rhizopus microsporus. Treatment with prednisolone and ciclosporin for 3 months led to complete resolution of the clinical signs and marked improvement of the endoscopic lesions. Specific fungal treatment with amphotericin B was poorly tolerated.

Relevance and novel information

To the best of our knowledge, this is the first report of the characterisation of a siphomycetous fungus associated with FGESF lesions, and the first endoscopic description and diagnosis of FGESF without surgical biopsies. We hypothesise that the presence of R microsporus occurred because of disrupted mucosal integrity.

A global view on fungal infections in humans and animals: opportunistic infections and microsporidioses

After cardiovascular diseases, infectious diseases are the second most common cause of death worldwide. Although these infections are caused mainly by viruses or bacteria, a systematically growing prevalence of human and animal opportunistic fungal infections is noticeable worldwide. More attention is being paid to this problem, especially due to the growing frequency of recalcitrant and recurrent mycoses. The latter are classically divided into superficial, which are the most common type, subcutaneous, and systemic. This work discusses opportunistic fungal pathogens without proven horizontal transmission between different animal species including humans and microsporidia as spore-forming unicellular parasites related to fungi; however, with a yet undetermined taxonomic position. The review also mentions aetiological agents, risk factors, epidemiology, geographical distribution, and finally symptoms characteristic for individual disease entities. This paper provides insight into fungal infections from a global perspective and simultaneously draws attention to emerging pathogens, whose prevalence is continuously increasing. Finally, this work also takes into consideration the correct nomenclature of fungal disease entities and the importance of secondary metabolites in the pathogenesis of fungal infections.

Systemic mucormycosis caused by Rhizopus microsporus in a captive bottlenose dolphin

A 6-year-old female bottlenose dolphin (Tursiops truncatus) kept in dolphinarium died after a 3.5-month period of lethargy and inappetence despite antibiotics and supportive care. At necropsy, gross findings included diffuse varying-sized nodules in the lungs and scattered nodules throughout the heart, spleen, mesenteric and hilar lymph node and kidney. Microscopically, the lesions were characterised by disseminated fungal pyogranulomas with numerous intralesional Mucor-like fungi. The fungi structures were demonstrated by Periodic acid-Schiff and Gomori methenamine silver stain. Molecular analyses of the fungi were Rhizopus microsporus by PCR sequencing 18S ribosomal RNA gene. Ziehl-Neelsen stain failed to show acid-fast bacterial infection. Based on pathological and molecular examination, systemic granulomatous mucormycosis was diagnosed. To our knowledge, this is the first reported case of systemic mucormycosis caused by Rhizopus microsporus in bottlenose dolphin.