Doenças fúngicas em bovinos e asininos.

Abstract

This thesis, presented to the Graduate Program of Veterinary Medicine of the Federal University of Campina Grande, is divided into three chapters, each chapter being represented by one scientific article. In the first chapter we describe the fungal diseases in cattle diagnosed in the Sertão of Paraiba, Northeast Brazil, emphasizing the epidemiological, clinical and pathological aspects. For that, a retrospective study of bovine necropsies performed from January 2003 to December 2015 was carried out, selecting suspected or confirmed cases of fungal diseases. From these protocols was collected information on breed, sex, age, time of disease evolution, clinical signs, and lesion of locations, macroscopic and microscopic changes. The diagnosis was established based on the morphotinorial characteristics of the agent, hematoxylin and eosin staining, impregnation by Grocott's methenamine silver nitrate, periodic acid of Schiff and Alcian Blue, as well as Immunohistochemistry to confirmation the agent in some cases. Of 817 bovine necropsies, 11 were diagnosed fungal diseases, representing 1.34%. The fungal infections diagnosed in order of frequency were zygomycosis (6 cases), aspergillosis (3 cases), candidiasis (1 case) and cryptococcosis (1 case). Of the six cases of zygomycetes infections, five were classified as Mucorales and one Entomophothorales. Of the five cases of Mucorales, two presented lesions in several organs, including the pre-stomach, abomasum, kidneys, heart, besides the diaphragm and the encephalon. In one case the lesions were restricted to the rumen, reticulum and abomasum and in the other two, there were lesions in the brain and in the skin. In bovine 3, positive immunostaining was observed for Rhizopus arrhizus and in bovine 6 for Conidiobolus lamprageus. Of the three cases of aspergillosis, one affected the upper respiratory tract, another abomasum and one the brain, respectively. In two cases, fungal infection occurred secondary to primary viral disease such as malignant catarrhal fever and bovine viral diarrhea. A case of Candida albicans infection was diagnosed in a 20-day-old calf, affecting the pre-stomachs, after the use of antibiotic therapy and corticosteroids. Additionally, a case of Cryptococcus neoformans var. Grubii In a bovine with lesions restricted to the encephalon. In the second chapter we describe the epidemiological, clinical and pathological aspects of three cases of cutaneous pythiosis in cattle diagnosed in the semi-arid state of Paraiba and Ceara States and along the coast of Sergipe, Northeast Brazil. Epidemiological and clinical data were obtained during visits to farms with suspected cases of the disease. A biopsy of the lesions of each animal was performed. The disease occurred in adult and calves that had contact with water accumulated in dams or irrigation channels. Clinically, lesions were observed mainly on the skin of the thoracic and/or pelvic limbs, characterized by flat and irregular ulcerated areas or nodules of varying sizes, some with fistulated tracts, which cut deep into the subcutaneous tissue. In one case there was involvement of superficial lymph nodes. Histologically, pyogranulomatous inflammation was associated with hyphae not stained by H.E, which were impregnated by GMS. The diagnosis of Pythium insidiosum was confirmed by IHC. In the third chapter we describe the epidemiological, clinical-pathological, immunohistochemical and molecular aspects of a case of cutaneous pythiosis in donkey in Brazil. It was a donkey, female, adult mixed breed, pregnant woman who presented nodular skin lesions, multifocal and disseminated, with 30 days of evolution. This animal was raised in an area of native pasture (caatinga), but grazed in an area of abundant green vegetation around a pond. Macroscopically, nodules ranged from 1-11 cm in diameter, some with irregular ulcerated surface draining bloody secretion and others covered by skin, both distributed mainly on the skin of the limbs, ventral region of the chest and mammary gland. On the cutting surface, there were discrete yellowish nodules, multifocal to coalescent and occasionally small cavitations with discrete kunkers. Microscopically, there was ulcerative and nodular dermatitis and pyogranulomatous nodular folliculitis associated with myriad negative images of hyphae, impregnated by GMS. Immunohistochemistry obtained strong immunostaining of the hyphae in brown and from the paraffin material the DNA of Pythium insidiosum was extracted. After confirming the diagnosis, excision was performed only on large skin lesions, treated as second intention wounds, which were completely healed 30 days after surgery. Small cutaneous lesions regressed spontaneously in approximately 60 days. Fungal infections occur sporadically in cattle with varied clinical and pathological presentations, and their occurrence may be influenced by primary viral, metabolic and/or iatrogenic diseases. Cutaneous pythiosis occurs in cattle and donkey in the Northeast region. In addition, it may experience spontaneous healing and should be included in the differential diagnosis of skin diseases in these species.