Parasitic lesions in fish in the Federal District, Brazil

Brazil has a vast territory and favorable climatic conditions that allow the cultivation of freshwater fish. The intensification of the productive system can cause an imbalance in the aquatic environment as a result of poor water quality, nutritional deficiencies and infectious or parasitic diseases. The laboratory diagnosis and the determination of the prevalence of the main lesions, which occur in a certain region, help to guide towards the etiological diagnosis. This study aimed to describe the main parasitic lesions in fish in the routine at the Veterinary Pathology Laboratory of the Universidade de Brasília (UnB). All records of fish with parasitic lesions were recovered. Those cases in which there was an intralesional parasite and which presented lesions compatible with the parasite were included. The screening of ectoparasites was done by scraping the superficial mucus from the gills and skin. Organ sections were routinely processed for histopathologyand stained with hematoxylin-eosin (HE). In some records, parasitological identification was carried. The information was divided into the species of the affected fish, epidemiology of the outbreak (water quality, temperature, type of breeding), lesion distribution, etiology and macroscopic and microscopic changes. The resulting data was organized in absolute frequency and percentage. In this study, 22 cases were counted, between individual deaths and outbreaks, totaling 83 necropsied teleost fish. Inflammatory changes of parasitic origin were seen in 13/22 (59%) of the cases had lesions of parasitic origin. Skin lesions and gills were the most relevant. Macroscopically, red areas or spots of hyperemia or hemorrhage on the body surface were the most prevalent findings. Under microscopy, proliferative gill inflammation was the most relevant diagnosis. Pscinoodinium pilullare (Dinoflagellida), Ichthyophthirius multifiliis (Ciliophora), and monogenetic worms (Monogenea) were the main parasites found. Trichodina sp. (Ciliophora), Ichtyobodo sp. (Kinetoplastida), Amoebas, and Chilodonella sp. (Ciliophora), were seen in fewer numbers. An unusual case suggestive of parasitism by Eustrongylides sp. (Nematoda), in a pirá-brasília (Simpsonichthys boitonei), specimen has been recorded. The diagnoses were based on epidemiology, anatomopathological and parasitological findings. The most frequent and significantly lethal lesion in the study was proliferative and / or hyperplastic branchitis. Proliferative branchitis with lamellar epithelial hyperplasia (LEH) is a response to some type of chemical or mechanical injury to the gill epithelium in order to protect the capillaries from further damage or microbial penetration. However, it also increases the diffusion distance between capillaries and the environment and, therefore, hinders breathing, excretory and osmoregulatory functions. Protozoan infections and monogenetic worms in general generated LEH and skin lesions of mechanical origin. Secondary bacterial infection, were observed in this parasitosis determining the cause of death of the fish. Its pathogenicity comes from the lesions caused by the colonization and histophagy of the epithelial surfaces, mainly gills and skin, causing epithelial proliferation, lamellar cell fusion, epithelial cell degeneration and necrosis forming several ulcers in the epithelium after the release of mature trophies. The pathogenesis of parasitism by Eustrongylides spp. is considerable when there is a large quantity of these larvae that can cause intestinal obstruction, rupture and compression of viscera, of greater importance in small fish. The main parasites of necropsied fish were protozoa and monogenetic worms, which mainly cause branquitis and dermatitis in varying grades.(AU)

Adenoma of the gallbladder in a mongoose (Mungos mungo) / Adenoma de vesícula biliar em mangusto (Mungos mungo)

ABSTRACT: Primary gallbladder neoplasms occur infrequently in domestic animals and rarely in wild animals. This article describes a case of gallbladder adenoma in a mongoose ( Mungos mungo) in captivity. Grossly, the gallbladder was moderately distended with a smooth capsular surface. Necropsy showed an irregular, soft, whitish nodule 0.8cm in diameter. Microscopic examination of the nodule showed proliferation of epithelial cells, which projected from the mucosa and formed papillary projections supported by a sparse fibrovascular stroma. Neoplastic cells were well differentiated with mild anisocytosis and anisokaryosis. Based on these histopathological findings, adenoma of the gallbladder was diagnosed.

RESUMO: Neoplasmas primárias de vesícula biliar são incomumente descritas em animais domésticos e, raramente, afetam animais silvestres. Este trabalho tem por objetivo descrever um caso de adenoma de vesícula biliar em mangusto ( Mungos mungo) mantido em cativeiro. Macroscopicamente, a vesícula biliar estava moderadamente distendida, com superfície lisa e, em seu interior, havia um nódulo esbranquiçado, irregular, macio, de 0,8cm de diâmetro. Microscopicamente, havia proliferação neoplásica, epitelial, bem diferenciada, com projeções papilares da mucosa contendo células cilíndricas. Observou-se anisocitose e anisocariose leve. Com base nos achados histopatológicos, foi firmado o diagnóstico de adenoma de vesícula biliar.