Lesões granulomatosas encontradas em bovinos abatidos para consumo / Granulomatous lesions found in cattle slaughtered for meat production

RESUMO

Com o objetivo auxiliar profissionais médico-veterinários no reconhecimento das lesões de bovinos encontradas na linha de inspeção de carnes em matadouros frigoríficos, três condições granulomatosas de bovinos foram pesquisadas e suas semelhanças e diferenças avaliadas. Essas três condições granulomatosas foram actinobacilose (causada por Actinobacillus lignieresii), actinomicose (causada por Actinomyces bovis) e mastite estafilocócica (causada por Staphylococcus aureus). Em 505 lesões encontradas em bovinos abatidos para consumo humano, 40 eram uma dessas três lesões granulomatosas 24 eram actinobacilose, 10 eram actinomicose e seis eram mastite estafilocócica. De um modo geral, os aspectos macro e microscópicos dessas três lesões eram bastante semelhantes, mas suas localizações ajudavam a presumir sua etiologia. A. lignieresii afetou tecidos moles, principalmente língua e linfonodos da cabeça; A. bovis afetou o tecido ósseo, principalmente o da mandíbula; e S. aureus teve a glândula mamária como o tecido alvo. Histologicamente, os granulomas resultantes da infecção por qualquer um desses três agentes continham uma estrutura amorfa, eosinofílica, com clavas irradiadas, localizada centralmente; essa estrutura era rodeada por neutrófilos íntegros e degenerados, que, por sua vez, eram cercados por um manto de macrófagos epitelioides e ocasionais células gigantes multinucleadas. Esses mantos de macrófagos eram irregularmente infiltrados por linfócitos e plasmócitos que tendiam a se acumular na periferia da lesão, que era cercada por uma cápsula de tecido conjuntivo...

ABSTRACT

In order to help professionals of veterinary medicine in recognizing bovine lesions found during meat inspection at slaughterhouses, three granulomatous conditions of cattle were researched and their morphological similarities and differences were assessed. These three granulomatous conditions were actinobacillosis (caused by Actinobacillus lignieresii), actinomycosis (caused by Actinomyces bovis) and staphylococcal mastitis (caused by Staphylococcus aureus). Out of 505 lesions found in cattle slaughtered for human consumption, 40 were one of the three granulomatous conditions 24 were actinobacillosis, 10 were actinomycosis and six were staphylococcal mastitis. Overall the gross and histological features of these three diseases are quite similar but their location helps give away the etiology. A. lignieresii affected soft tissues, mainly those of tongue and lymph nodes of the head region; A. bovis affected bone tissue mainly that of the mandible; and S. aureus main targeted tissue was the mammary gland. Histologically the granuloma resulting from the infection with either one of these three causal agents contained centrally located amorphous, eosinophilic, club like structures surrounded by viable and dead neutrophils. These were surrounded by a mantle of epithelioid macrophages and occasional multinucleated giant cells. These macrophage mantles were irregularly infiltrate by lymphocytes and plasma cells which tended to accumulate to the periphery of the lesion which, in turn, was fenced by a fibrous connective capsule. Given the employment of adequate techniques the causative the agent could be seen within or surrounding the clublike structures in each the three types of granulomatous lesions. In the case of staphylococcal mastitis, intralesional cocci were observed both in HE and Gram stained preparations, in the latter as gram-positive cocci...