Zygomycosis caused by Conidiobolus coronatus in a llama (Lama glama).

Abstract

Zygomycosis is a unifying term that includes a diverse group of mycotic diseases caused by fungi of the class Zygomycetes. The pathogenic zygomycetes are grouped in the orders Entomophthorales and Mucorales; disease in animals is caused by members of the genera Basidiobolus and Conidiobolus (entomophthoramycosis) and Ahsidia, Mortierella, Mucor, and Rhizopus (mucormycosis).2 j-’” Members of the order Mucorales cause disseminated disease with hyphal angioinvasion, and members of the order Entomophthorales cause localized subcutaneous granulomas characterized by marked deformation of infected tissues. In the horse, subcutaneous zygomycosis affects the skin of the limbs, head, chest, neck, and nasal epithelium. Entornophthora coronatus (Conidiobolus coronatus) is isolated from the nasal area,’->.’ and Mucor pusillus, Basidiobolus haptosporus, and Basidiobolus ranarum are isolated from subcutaneous tissues.’.’ Pythium insidiosurn, formerly Pythium (Hyphomyces) destruens, an aquatic fungus-like organism, is a cause of equine “phycomycosis,” a subcutaneous granulomatous disease of the distal extremities in the The term “phycomycosis” is obsolete because it has no taxonomic equivalent. Pythium spp., formerly in the class Phycomycetes, kingdom Fungi, have been reclassified into the kingdom Protista, phylum Mastigomycota, class Oomycetes. Other members of the former class Phycomycetes have been reclassified into the division Chytridiomycota or Zygomycota of the kingdom Fungih In The purpose of this communication is to describe a case of deformative and obstructive nasal entomophthoramycosis (zygomycosis) caused by C. coronatus in a llama (Larna glama) and to compare and contrast the disease in llamas with that described in the horse. A 3-year-old intact female llama was presented to the University of Illinois Veterinary Teaching Hospital with a 2-year history of sneezing and a 6-month history of nasal discharge, swollen nares, weight loss, and lethargy. Affected skin, extending rostrad from the incisive notch and covering the muzzle and upper lip, was firm, nodular, mildly hyperemic, and covered by multifocal crusts, with some focal erosions and ulcerations (Fig. 1). The nares contained a green-brown exudate. The lesion did not respond to treatment with topical Panalog@ (Solvay Veterinary, Princeton, NJ) and cleansing with Betadine@ (Purdue Frederick Co., Nonvalk, CT). The llama developed dyspnea and stridor attributed to partial stenosis of the external nares caused by swelling and accumulation of exudate and nasal discharge. Minimal exercise resulted in open-mouth breathing. Results of hematologic evaluation, serum biochemical analyses, and radiographs of the skull and thorax were normal. Endoscopic examination of the nares and nasal passages was normal except for the lesion involving the external nares. Punch biopsies were submitted for histopathologic, mycologic, and bacteriologic examinations. In accordance with an initial diagnosis of cutaneous zygomycosis or pythiosis, intravenous sodium iodide therapy was initiated. The llama was nonresponsive and was euthanatized because of its deteriorating condition. No other lesions were noted at necropsy. Sections of skin from the lateral wing of the right nostril were fixed in 10% neutral buffered formalin, embedded in paraffin, sectioned at 4 pm, and stained with hematoxylin and eosin (HE). Microscopically, the deep dermis contained multiple distinct and coalescing granulomas surrounded by fibrovascular connective tissue (Fig. 2). Granulomas consisted of a central necrotic core of cell debris, intensely eosinophilic material, and degenerate and nondegenerate eosinophils and neutrophils that were surrounded by large numbers of epithelioid macrophages and variable numbers of multinucleate giant cells. Giant cells were more prominent in less organized granulomas. Large numbers of eosinophils and fewer neutrophils, lymphocytes, and plasma cells were admixed with the macrophages in the surrounding connective tissue. Perivascular accumulations of small to moderate numbers of lymphocy tes and plasma cells were present at the deep maIgins of the lesion. Within the core of the granulomas and within multinucleate giant cells were 6.0-12.5-pm round and elongated channels or clear spaces. These spaces were interpreted as unFig. 1. Nostrils; llama with subcutaneous mycosis. The nostrils are partially deformed and have multifocal alopecia, ulceration, and crust formation (small arrowheads). The nares (arrows) are partially occluded by an exudate, debris, and nasal discharge.