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)

Carcinoma bronquíolo-alveolar difuso em um cão: aspectos clínico-patológicos e imuno-histoquímicos / Diffuse bronchioloalveolar carcinoma in a dog: clinicopathological and immunohistochemical findings

Um cão Poodle, 12 anos de idade, demonstrou marcada dispneia. Na radiografia, havia comprometimento difuso do pulmão e foi feito diagnóstico de pneumonia intersticial. Na necropsia, o pulmão continha múltiplos e pequenos nódulos coalescentes. Histologicamente, os nódulos eram compostos por células epiteliais cuboides ou colunares baixas atípicas, que eram PAS-negativa. A avaliação imuno-histoquímica revelou positividade para citoceratina, fator 1 de transcrição da tireoide (TTF-1) e apoproteína A surfactante (SP-A). O tumor foi negativo para vimentina e cromogranina A. As áreas necróticas não marcaram para TTF-1 e SP-A. Com base nos achados histopatológicos e imuno-histoquímicos, foi realizado o diagnóstico de carcinoma bronquíolo-alveolar não mucinoso com envolvimento difuso do pulmão. Essa é uma forma rara de apresentação desse tumor que pode mimetizar pneumonia na avaliação clínica e radiográfica. O diagnóstico definitivo é baseado na histopatologia e imuno-histoquímica.

A 12-year-old poodle dog was presented with a history of severe dyspnea. Radiology revealed diffuse pulmonary lesion which was diagnosed as interstitial pneumonia. At necropsy there were multiple small coalescent nodules distributed throughout the lung parenchyma. Histologically the nodules consisted of cubic to low columnar atypical epithelial cells which were PAS-negatives. In the immunohistochemistry reaction this cells were marked for cytokeratin, TTF (thyroid transcription factor)-1 and surfactant apoprotein A (SP-A). The neoplastic cells were negative for vimentin and cromagranine A. The necrotic areas were not marked for TTF-1 and SP-A. Based of the histopathological and immunohistochemistry findings a diagnosis of non-mucinous bronchioloalveolar carcinoma with diffuse involvement of the lung was made. This is a rare form of presentation for this tumor, and it can mimetize pneumonia on clinical and morphological examination. A definitive diagnosis for this condition should be based on histopathology and immunohistochemistry.

Pênfigo foliáceo em cabra Boer / Pemphigus foliaceous in a Boer goat

Pênfigo foliáceo é uma doença auto-imune crônica da pele observada com freqüência em cães e, com menor freqüência, em outras espécies animais. Neste trabalho é descrito um caso desta enfermidade no semi-árido da Paraíba, em uma cabra da raça Boer, que apresentava lesões crônicas de pele com extensas áreas alopécicas irregulares, esfoliativas, com crostas amareladas e bilaterais que afetavam a região dorsal da escápula, do tórax, do dorso, da parede do abdominal, da garupa, dos membros pélvicos e da cauda. No rodete coronário, havia espessamento da pele e lesões crostosas. Microscopicamente foram observadas hiperqueratose, espongiose e pústulas intracorneais ou subcornais afetando epiderme e infundíbulos. Nas pústulas, havia grande quantidade de neutrófilos, eosinófilos e células acantolíticas. Na derme, havia acentuada congestão e moderado infiltrado inflamatório composto por eosinófilos, raros plasmócitos, linfócitos e macrófagos, principalmente na periferia de capilares e nos folículos pilosos. Os achados macro e microscópicos são característicos de pênfigo foliáceo. Esta enfermidade é rara em caprinos e, provavelmente, este seja o primeiro relato da doença no Brasil.

Pemphigus foliaceous is an autoimmune disease of the skin affecting mainly dogs and, with less frequency, other domestic species. A case of this disease is reported in the semiarid of Paraiba, Brazil, in a Boer goat with chronic skin lesions with extensive bilateral exfoliatives areas of alopecia, with yellowish crusts affecting the dorsal scapular region, thorax, abdominal wall, croup, hindlimbs and tail. On the coronary band of the hoofs, thick crusts were observed. Microscopiacally, there were hyperkeratosis, spongiosis, intracorneal and sucorneal pustules affecting the epidermis and follicular infundibula. Large number of neutrophils, eosinophils and acantholitic cells were observed in the pustules. The dermis had congestion and mild infiltration of eosinophils, rare plasma cells, lymphocytes and macrophages, mainly in the periphery of follicles. Gross and histologic lesions are characteristic of pemphigus foliaceous, an uncommon disease of goats. This seems to be the first report of pemphigus foliaceous in goats in Brazil.