BACKGROUND Non-human primates contribute to the spread of the yellow fever virus (YFV) and the establishment of transmission cycles in endemic areas. OBJECTIVE To describe the severe histopathological aspects of YFV infection, 10 squirrel monkeys were infected with YFV and blood, brain, liver, kidney, spleen, heart, lung, lymph node and stomach were collected at 1-7, 10, 20 and 30 days post-infection (dpi). METHODS Histopathological analysis and detection of the genome and viral antigens and neutralising antibodies were performed by RT-PCR, immunohistochemistry and neutralisation test, respectively. FINDINGS Only one animal died from the experimental infection. The genome and viral antigens were detected in all investigated organs (1-30 dpi) and the neutralising antibodies from seven to 30 dpi. The brain contained perivascular haemorrhage (6 dpi); in the liver, midzonal haemorrhage and lytic necrosis (6 dpi) were observed. The kidney had bleeding in the Bowman’s capsule and tubular necrosis (6 dpi). Pyknotic lymphocytes were observed in the spleen (1-20 dpi), the lung had haemorrhage (2-6 dpi), in the endocardium it contained nuclear pyknosis and necrosis (2-3 dpi) and the stomach contained blood in the lumen (6 dpi). MAIN FINDINGS Squirrel monkeys reliably reproduced the responses observed in human cases of yellow fever and, therefore, constitute an excellent experimental model for studies on the pathophysiology of the disease.

O objetivo do presente relato é descrever um caso de formação cicatricial exuberante, característica de queloide e configuração pseudo-tumoral em um jacaré-açu (Melanosuchus niger), macho, com idade estimada de 60 anos, pertencente ao Parque Zoobotânico do Museu Emílio Goeldi, situado em Belém, Pará, Brasil. A alteração manifestou-se no membro posterior direito, envolvendo as duas falanges distais do dedo lateral e mediu 12,4cm na maior largura. A neoformação foi removida cirurgicamente e amostras foram processadas e analisadas por histopatologia, que revelou crescimento constituído por tecido conjuntivo fibroso de morfologia habitual, estando estruturalmente maduro nas áreas mais centrais.

The objective of this note is to describe a case of exuberant scarring formation, with keloid characteristics and pseudo-tumoral configuration in a male Black caiman (Melanosuchus niger), with an estimated age of 60 years, belonging to the Zoobotanical Park at the Emílio Goeldi Museum, located in Belém, Pará, Brazil. The alteration appeared on the right posterior limb involving two distal phalanges of the lateral digit and measured 12.4cm at the greatest width. The keloid tissue was surgically removed and samples were processed and analyzed histopathologically, revealing growth made up of fibrous connective tissue with the habitual morphology, which was structurally mature in the more central areas.

O Saimiri sciureus é um primata não humano existente na região amazônica e não consta na lista de animais em perigo de extinção, de acordo com o IBAMA. Neste trabalho, sistematizou-se os ramos colaterais viscerais da aorta abdominal de seis animais sendo três machos e três fêmeas, os quais tiveram o sistema circulatório preenchido com látex Neoprene, adicionado de contraste radiográfico. O resultado observado foi que a aorta abdominal emitiu ventralmente, como ramo colateral visceral, a artéria celíaca, que se trifurcou nas artérias gástrica esquerda, hepática e lienal. Os ramos da artéria celíaca promovem a irrigação do estômago, duodeno, fígado, pâncreas e baço. A seguir, a aorta abdominal emitiu a artéria mesentérica cranial, de calibre maior que a artéria celíaca e justaposta caudalmente. A artéria mesentérica cranial emitiu ramos que vascularizaram a parte final do duodeno, pâncreas, jejuno, íleo, ceco, cólon maior e cólon menor. A aorta abdominal emitiu lateralmente as artérias renais direita e esquerda. A artéria adrenal esquerda surgiu como um ramo colateral direto da artéria celíaca e a artéria adrenal direita surgiu da artéria renal direita. A artéria mesentérica caudal foi emitida da superfície ventral da aorta abdominal, logo abaixo das artérias renais. Em L6, a aorta abdominal se bifurcou, dando origem às artérias ilíacas externas direita e esquerda e estas deram origem à artéria ilíaca interna e femoral direita e esquerda. As artérias testiculares ou ováricas tiveram origem na artéria ilíaca interna. A continuidade da aorta abdominal deu origem à artéria sacral mediana e a continuidade desta é chamada de artéria caudal mediana. O estudo da espécie em questão é de suma importância para gerar conhecimentos a respeito dos primatas não humanos existentes em nosso país. Dessa forma, pode-se dizer que o Saimiri sciureus é um importante modelo biológico para o desenvolvimento de pesquisas biomédicas.

The Saimiri sciureus is a non human primate that exists in the amazon region, which is not in the list of endangered animals according to IBAMA. So, this research systemized the collateral branches visceral of the abdominal aorta of these animals. It was used six animals, three males and three females, which had the circulatory system filled with latex Neoprene added of radiographic contrast. The results showed that the abdominal aorta ventrally emitted a collateral visceral branch called celiac artery, which originates three branches: left gastric, hepatic and lienal arteries. The branches of the celiac artery promoted the irrigation of the stomach, duodenum, liver, pancreas and spleen. Then the abdominal aorta emitted the cranial mesenteric artery, which was of a larger size than the celiac artery and was caudally juxtaposed. The cranial mesenteric artery supply branches that irrigate the final portion of the duodenum, pancreas, jejunum, ileum, cecum and colon. Abdominal aorta emitted laterally the right and left kidney arteries. The left adrenal artery as a collateral branch of the celiac artery and the right adrenal artery has been originated in the right renal artery. The mesenteric caudal artery was emitted from the ventral surface of the abdominal aorta, below the kidney arteries. In L6, abdominal aorta has two derivations to origin the right and left external iliac arteries and these had given origin to the internal iliac and femoral artery right and left. The testicular or ovary arteries were emitted in internal iliac arteries. Of the abdominal aorta led to origin the sacral median artery and in this sequence there is the caudal median artery. The study of this specie is very important to generate knowledge about non human primates existing in our country. It can be said that Saimiri sciureus is an important biological model for development of biomedical researches.