Hematological and serum biochemistry evaluation in howler monkeys (Alouatta caraya) and capuchin monkeys (Sapajus apella): A comparative study.

BACKGROUND: Evaluation of blood parameters in captive non-human primates (NHPs) is crucial for monitoring their health and ensuring that their environment meets their physiological requirements. METHODS: We performed hemogram, serum biochemistry, and parasitological exams in 20 howler monkeys and 21 capuchin monkeys. RESULTS: In both species, over 50% of the individuals presented at least one parasite. There was a negative effect of age on red blood cell (RBC), white blood cell, platelets, total protein, globulin, and alkaline phosphatase, and a positive effect on the A:G ratio, gamma-glutamyl transferase, and mean platelet volume (MPV). Capuchin monkeys presented the highest platelets and alanine aminotransferase (ALT) values and howler monkeys presented the highest MPV, aspartate aminotransferase, ALT, amylase, glucose, bilirubin, and triglycerides values. We observed an interaction between species and sex on RBC, Htc, mean corpuscular hemoglobin concentration, and cholesterol. CONCLUSIONS: Species differences found in blood parameters may reflect differences in physiological adaptations associated with ecological and morphological traits and are clinically relevant for evaluating animal health and the suitability of breeding programs.

Experimental Yellow Fever in the Squirrel Monkey (Saimiri spp.): Hematological, Biochemical, and Immunological Findings.

Between 2016 and 2018, Brazil experienced the largest sylvatic epidemic of yellow fever virus (YFV). Despite to the magnitude and rapid spread of the epidemic, little is known about YFV dispersion. The study evaluated whether the squirrel monkey is a good model for yellow fever (YF) studies. Methods: Ten animals were infected with 1 × 106 PFU/mL of YFV, with one negative control. Blood samples were collected daily during the first 7 days and at 10, 20 and 30 days post infection (dpi) for detection of viral load and cytokines by RT-qPCR; measurements of AST, ALT, urea and creatinine were taken; IgM/IgG antibodies were detected by ELISA, and hemagglutination inhibition and neutralization tests were performed. The animals exhibited fever, flushed appearance, vomiting and petechiae, and one animal died. Viremia was detected between 1 and 10 dpi, and IgM/IgG antibodies appeared between 4 and 30 dpi. The levels of AST, ALT and urea increased. The immune responses were characterized by expression of S100 and CD11b cells; endothelial markers (VCAM-1, ICAM-1 and VLA-4), cell death and stress (Lysozyme and iNOS); and pro-inflammatory cytokines (IL-8, TNF-α, and IFN-γ) and anti-inflammatory cytokines (IL-10 and TGF-ß). The squirrel monkeys showed changes similar to those described in humans with YF, and are a good experimental model for the study of YF.

Zika Virus Infection Damages the Testes in Pubertal Common Squirrel Monkeys (Saimiri collinsi).

During the Zika virus (ZIKV) outbreak and after evidence of its sexual transmission was obtained, concerns arose about the impact of the adverse effects of ZIKV infection on human fertility. In this study, we evaluated the clinical-laboratory aspects and testicular histopathological patterns of pubertal squirrel monkeys (Saimiri collinsi) infected with ZIKV, analyzing the effects at different stages of infection. The susceptibility of S. collinsi to ZIKV infection was confirmed by laboratory tests, which detected viremia (mean 1.63 × 106 RNA copies/µL) and IgM antibody induction. Reduced fecal testosterone levels, severe testicular atrophy and prolonged orchitis were observed throughout the experiment by ultrasound. At 21 dpi, testicular damage associated with ZIKV was confirmed by histopathological and immunohistochemical (IHC) analyses. Tubular retraction, the degeneration and necrosis of somatic and germ cells in the seminiferous tubules, the proliferation of interstitial cells and an inflammatory infiltrate were observed. ZIKV antigen was identified in the same cells where tissue injuries were observed. In conclusion, squirrel monkeys were found to be susceptible to the Asian variant of ZIKV, and this model enabled the identification of multifocal lesions in the seminiferous tubules of the infected group evaluated. These findings may suggest an impact of ZIKV infection on male fertility.

Effect of age and sex in renal function by ultrasound and serum chemistry in two primate species (Alouatta caraya and Sapajus apella).

BACKGROUND: Comparative studies of kidney morphophysiology in nonhuman primates can help us investigate interspecies differences in growth and aging patterns. METHODS: We tested the effect of age and sex in renal morphophysiology in 21 Alouatta caraya and 21 Sapajus apella (age range = 0.5-26 years) by ultrasound, red blood cell (RBC) count, and kidney function tests. RESULTS: A. caraya had greater growth rate and absolute renal volume than S. apella, but the latter showed a greater relative renal volume and RBC count. There was a negative relationship between RBC and age, a positive relationship between creatinine and body mass, and an apparent negative relationship between creatinine and age only in S. apella. CONCLUSIONS: Our results indicate that A. caraya has a faster aging mechanism than S. apella, and the higher relative kidney volume in S. apella is suggestive of high metabolic demands in this species.

Hepatic lesions in captive owl monkeys (Aotus infulatus) with ultrasonographic "starry sky" liver.

BACKGROUND: The "starry sky" (SK) liver is ultrasonographic pattern characterized by multiple hyperechogenic foci in hepatic parenchyma. The study aimed to characterize the microscopic hepatic lesions in captive owl monkeys with SK liver. METHODS: Thirty-seven clinically healthy owl monkeys had their liver scanned and 18 of them had liver biopsy. Animals with SK and peliosis hepatis (PH) were subjected to immunohistochemical and molecular screening for Bartonella spp. RESULTS: SK liver occurred in 59.4% (22/37) of the owl monkeys. Biopsied animals showed steatosis, hydropic degeneration, hemosiderosis, PH, and multifocal granulomatous hepatitis. Two monkeys had SK, granulomatous hepatitis, and PH which were negative for Bartonella spp. CONCLUSIONS: PH and granulomatous hepatitis associated with hepatocellular degenerative lesions may present as hyperechoic nodular liver lesions consisted of SK liver; therefore, concomitant occurrence of two lesions or more contributed to the hepatic SK pattern among owl monkeys and such cases might be clinically monitored.

Histopathological lesions of congenital Zika syndrome in newborn squirrel monkeys.

The absence of an adequate animal model for studies has limited the understanding of congenital Zika syndrome (CZS) in humans during the outbreak in America. In this study, we used squirrel monkeys (Saimiri collinsi), a neotropical primate (which mimics the stages of human pregnancy), as a model of Zika virus (ZIKV) infection. Seven pregnant female squirrel monkeys were experimentally infected at three different gestational stages, and we were able reproduce a broad range of clinical manifestations of ZIKV lesions observed in newborn humans. Histopathological and immunohistochemical analyses of early-infected newborns (2/4) revealed damage to various areas of the brain and ZIKV antigens in the cytoplasm of neurons and glial cells, indicative of CZS. The changes caused by ZIKV infection were intrauterine developmental delay, ventriculomegaly, simplified brain gyri, vascular impairment and neuroprogenitor cell dysfunction. Our data show that the ZIKV infection outcome in squirrel monkeys is similar to that in humans, indicating that this model can be used to help answer questions about the effect of ZIKV infection on neuroembryonic development and the morphological changes induced by CZS.

Prenatal disorders and congenital Zika syndrome in squirrel monkeys.

During the Zika virus (ZIKV) outbreak in Brazil (2015-2016), the clinical manifestations associated with its infection were complex and included miscarriage and congenital malformations, not previously described. In this study, we evaluated the prenatal conditions of pregnant female squirrel monkeys (Saimiri collinsi) infected during different gestational thirds (GTs) and assessed all clinical aspects, diagnostic imaging, viremia and the immune response. In our study, 75% of the infected animals in the 1st GT group had significant clinical manifestations, such as miscarriage and prolonged viremia associated with a late immune response. Consequently, their neonates showed fetal neuropathology, such as cerebral hemorrhage, lissencephaly or malformations of the brain grooves, ventriculomegaly, and craniofacial malformations. Thus, our study demonstrated the relevance of pregnant squirrel monkeys as a model for the study of ZIKV infection in neonates due to the broad clinical manifestations presented, including the typical congenital Zika syndrome manifestations described in humans.

Ultrasonography-guided oocyte recovery in owl monkeys (aotus azarai infulatus).

The study evaluated an echo-guided oocyte recovery technique in owl monkeys. Twelve females were selected for the transabdominal ovum retrieval technique. This procedure collected twenty-six follicles, of which nine oocytes were recovered, without harm to the animals. The technique is feasible and is a minimally invasive protocol for neotropical primates.

Hematological and biochemical parameters of Spix's Saddleback Tamarin (Leontocebus fuscicollis) raised in captivity.

The Spix's Saddleback Tamarin, Leontocebus fuscicollis is widely distributed across the Amazon region, but is endangered. This species is serving an important role in biomedical research in captivity. However, reference values for hematological and biochemical parameters are required for the proper characterization of the species. It was therefore the objective of our research to establish these parameters taking into consideration sex and body mass differences in healthy adult Spix's saddleback tamarins. Collecting 2 mL of blood from each individual, 20 animals were examined (7 males, 13 females), and hematological and biochemical parameters were determined using commercial kits. Of the sixteen variables measured, only red blood cell (RBC), hemoglobin (Hb) and hematocrit (Ht) values were significantly higher in males (7.12 ± 0.98 106/mm, 14.98 ± 1.25 g/dL and 48.71 ± 4.91%, respectively), while red cell distribution width (RDW) was higher in females (14.58 ± 1.89%). Of the biochemical parameters measured, only gamma-glutamyl transferase (GGT) enzyme showed higher activity in females (8.08 ± 4.87 U/L), and a high glucose concentration range was observed (102.0 to 521.0 mg/dL) for both sexes. These parameters established with reference ranges for healthy adults provide a reliable reference source for the interpretation of laboratory housed saddleback tamarin.

Anatomopathological lesions of infection caused by Platynosomum illiciens (Braun, 1901) in Neotropical primates kept in captivity.

This study described the hepatobiliary anatomopathological lesions associated with trematode Platynosomum illiciens parasitism in Neotropical primates kept in captivity. In the evaluated organs, we observed portal fibrosis, biliary epithelial hyperplasia, and inflammatory reaction with a predominance of lymphocytes and plasmocytes, and in some cases infiltration of eosinophils and neutrophils.

Experimental yellow fever virus infection in the squirrel monkey (Saimiri spp.) I: gross anatomical and histopathological findings in organs at necropsy.

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.

Experimental yellow fever virus infection in the squirrel monkey (Saimiri spp. ) I: gross anatomical and histopathological findings in organs at necropsy

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.

Pelvimetry in Squirrel Monkeys (Saimiri scireus Linnaeus, 1758) / Pelvimetria em macacos-de-cheiro (Saimiri scireus Linnaeus, 1758)

Saimiri sciureus is a neotropical primate widely used in research. However, there are still difficulties regarding their reproduction in vivaria due to the high incidence of dystocia. Dystocia in primates can be caused by cephalopelvic disproportion and in Squirrel Monkeys, pregnancy of large fetuses were reported. This paper describes pelvimetry data of adult females and subadults in specimens of Squirrel Monkeys, from a research colony of Para, Brazil. Pelvic radiographs were obtained in ventrodorsal projections and the following measurements were taken: superior bi-iliac diameter (SBID); inferior bi-iliac diameter (IBID); bi-iliac average diameter (BIAD); right diagonal diameter (RDD); left diagonal diameter (LDD); sacro-pubic diameter (SPD); Based on the obtained diameters, the entrance area of the pelvis (EAP) was also calculated. The average values of the pelvic diameters and EAP in adult females were SBID 1.714cm, BIAD 1.957cm, IBID 1.686cm, RDD 2.771cm, LDD 2.764cm, SPD 2.543cm and EAP 3.9056cm2; and subadult females: 1.588cm SBID, 1.850cm BIAD, 1.625cm IBID, 2.50cm RDD, LDD 2.474cm, 1.95cm SPD and 2.8293 cm2 EAP. Saimiri sciureus pelvis is characterized as dolichopelvic. There was statistical significance between the values for adult females and subadults to SBID, BIAD, RDD, LDD, SPD and EAP. The values of SBID and IBID were lower when compared to the published data for the same species. The result found on this paper will serve as a basis for future studies using pelvic measurements and dystocia prediction of neotropical primates and comparison between different vivaria.(AU)

Saimiri sciureus é uma espécie de primata neotropical muito utilizada como animal de pesquisa. No entanto ainda há dificuldades em biotérios quanto a sua reprodução devido à alta ocorrência de distocia. A distocia em primatas pode ter origem devido à desproporção cefalopélvica, sendo que em macacos-de-cheiro é relatada a gestação de fetos grandes. O presente trabalho descreve dados de pelvimetria em espécimes de macaco-de-cheiro, fêmeas adultas e subadultas provenientes de uma colônia de pesquisa do Pará, Brasil. Foram realizadas radiografias da pelve em projeção ventrodorsal e por meio destas mensurados os diâmetros biilíaco superior (DBIS); diâmetro biíliaco inferior (DBII); diâmetro biilíaco médio (DBIM); diâmetro diagonal direito (DDD); diâmetro diagonal esquerdo (DDE); diâmetro sacro-púbico (DSP); com base nos diâmetros obtidos também foi calculada a área de entrada da pelve (AEP). Os valores médios dos diâmetros pélvicos e da AEP em fêmeas adultas foram: DBIS 1,714cm, DBIM 1,957cm, DBII 1,686cm, DDD 2,771cm, DDE 2,764cm, DSP 2,543cm e AEP 3,9056cm2; e para fêmeas subadultas: 1,588cm DBIS, 1,850cm DBIM, 1,625cm DBII, 2,50cm DDD, 2,474cm DDE, 1,95cm DSP e 2,8293 cm2 AEP. Observou-se que a pelve de Saimiri sciureus é dolicopélvica. Houve diferença estatística significativa entre os valores para fêmeas adultas e subadultas para DBIS, DBIM, DDD, DDE, DSP e AEP. Em comparação com dados da literatura de pelvimetria para S. sciureus observaram-se menores valores de DBIS e DBII. O resultado deste trabalho servirá como base para futuros estudos utilizando-se mensurações pélvicas e predição de distocia em primatas neotropicais e referência para comparação entre S. sciureus de diferentes biotérios.(AU)

Renal biochemistry variables and ultrasonographic imaging in healthy Squirrel monkeys (Saimiri collinsi).

BACKGROUND: The combined use of renal biochemistry and ultrasonographic imaging may improve the correct management of renal disease. Although renal disease is frequently observed in nonhuman primates, renal function markers have not yet been studied in Squirrel monkeys (Saimiri collinsi). OBJECTIVES: The aim of this study was to establish normal renal biochemistry variables and ultrasonographic features in Squirrel monkeys. MATERIAL AND METHODS: Renal biochemistry variables and ultrasonographic images were documented in 29 healthy Squirrel monkeys (15 males and 14 females). Urea, serum creatinine (SCr), and uric acid (UA) concentrations were measured by kinetic assay. Cystatin C (CysC) was analyzed by immunonephelometry. A multiple frequency linear array probe (5-12 MHz) was used for ultrasonographic imaging. The studied indicators of renal function were related to sex, age, and body mass. RESULTS: Serum creatinine was influenced by sex and body mass. Serum concentration of urea, UA, and CysC were not influenced by sex, age, and body mass. Ultrasonographic images provided accurate and comprehensive data for making clinical decisions for Squirrel monkeys. The total renal volume was only influenced by the body mass nested in sex and was positively correlated to body mass. Right renal volume was bigger than the left one. CONCLUSION: Normative standards for the renal evaluation, including biochemistry and ultrasonography, in the Squirrel monkey have been established correlated to age, sex, and body mass.

Influência de diferentes protocolos de contenção nosvalores do eletrocardiograma de macacos-da-noite (Aotus azarae infulatus) / Influence of different restraint protocols for the electrocardiogram values of feline night monkeys (Aotus azarae infulatus)

Macacos-da-noite são muito susceptíveis ao estresse e por isso a contenção química ou física deve ser cuidadosamente avaliada antes de qualquer procedimento. Protocolos anestésicos podem alterar alguns parâmetros fisiológicos, sendo o eletrocardiograma (ECG) um exame muito utilizado para avaliação do ritmo e da frequência cardíaca. O objetivo deste estudo foi avaliar a influência de quatro diferentes protocolos de contenção sobre o ECG realizado em Aotus azarae infulatus. Para isso foram utilizados 10 animais, machos, adultos, submetidos à contenção com a associação tiletamina/zolazepam (TZ), isoflurano (ISO), associação cetamina e midazolam (CET) e contenção física (CF). Não foram observadas diferenças nos parâmetros de ondas e complexos obtidos no ECG em todos os grupos testados, no entanto, durante a avaliação do traçado os animais do grupo CF apresentaram uma quantidade maior de alterações. Concluiu-se que os protocolos de contenção utilizados não alteraram os valores do ECG e que não foi possível considerar o grupo CF como controle devido causar mais alterações do que todos os protocolos testados.(AU)

Feline night monkeys are very susceptible to stress and therefore the physical or chemical restraint should be carefully evaluated before any procedure. Anesthetic protocols can alter some physiological parameters, and electrocardiogram (ECG) is a commonly exam used for evaluation of the rhythm and heart rate. The objective of this study was to evaluate the influence of four different protocols of restraining on ECG in Aotus azarae infulatus, in order to identify the best method of restraining in these primates. For that, we used 10 adult feline night monkeys, males, submitted to restraining protocols with the association tiletamine and zolazepam - (TZ), isoflurane (ISO), association ketamine and midazolam (CET) and physical restraint (CF). No differences were observed in the parameters wave and ECG complexes obtained in all groups tested; however, during the evaluation of the trace the animals of group CF showed a greater amount of change. It was concluded that the restraint protocols used did not change the values of the ECG, and it was not possible to consider the CF group as control due to more caused alterations than all other tested protocols.(AU)

Effect of age and sex on bone markers in Chlorocebus aethiops raised in captivity.

BACKGROUND: The objective was to evaluate the procollagen type I N-propeptide (PINP), osteocalcin (OC), ß-crosslaps (ß-CTX), and parathyroid hormone (PTH) in relation to age and sex of Chlorocebus aethiops in captivity. METHODS: Seventy-three monkeys were divided into four age groups: AG1 (juvenile); AG2 (young adult); AG3 (adult); and AG4 (senile). An electrochemiluminescence immunoassay with an Elecsys 2010 analyzer was used to determine the serum markers of bone. RESULTS AND CONCLUSIONS: Sex did not influence the results of the markers. However, the variables PINP, OC, and ß-CTX were negatively correlated with age (r = -0.643; r = -0.711; r = -0.488; P < 0.001, respectively), and PTH was correlated positively with age (r = 0.418, P < 0.001). The data obtained can be used as biomarkers of bone metabolism reference intervals in healthy C. aethiops in captivity.

Evaluation of blood pressure in feline night monkeys (Aotus azarae infulatus) under different restraint protocols.

BACKGROUND: Feline night monkeys are very susceptible to stress when handled, and because of that, the use of anesthetic and physical restraint methods should be carefully evaluated. To ensure a safer anesthesia to the animals the present study aimed to observe the influence of four restraint protocols in the blood pressure of Aotus azarae infulatus. METHODS: Blood pressure was obtained from 10 animals subjected to restraining protocols using tiletamine and zolazepam, isoflurane, ketamine and midazolam, and physical restraint and results were evaluated to determine their effect on this exam. RESULTS: Among the restraint protocols tested, the anesthetic isoflurane promoted lower blood pressure values and no differences were observed between values measured in both arms in all groups. CONCLUSION: The results of our study suggest that all restraint protocols tested significantly alter blood pressure in this species of primates.

Antiviral activity of chloroquine against dengue virus type 2 replication in Aotus monkeys.

Dengue virus (DENV) of the Flaviviridae family is a single positive-stranded RNA virus that is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. The objective of this study was to investigate the use of chloroquine (CLQ) as an antiviral drug against dengue virus in monkeys. To analyze the action of the drug in vivo, nonhuman primates groups (Aotus azarai infulatus) were inoculated with a subcutaneous injection of a virulent strain of DENV-2, treated and untreated CLQ. Blood hematological, viremia, and serum biochemical values were obtained from 16 DENV-2-inoculated, treated and untreated; four received only CLQ and one mock-infected Aotus monkeys. Monkey serum samples (day 0-10 post-inoculation) were assayed by reverse transcription polymerase chain reaction and Cytometric Bead Array for determination of viremia and inflammatory cytokines, respectively. Additionally, body temperature and activity levels were determined. In the present work, CLQ was effective on replication of DENV-2 in Aotus monkeys; a time viremia reduction was observed compared with the controls. The concentration of tumor necrosis factor alpha and interferon gamma in the serum of the animals had a statistically significant reduction in the groups treated with CLQ after infection compared with the controls. A significant decrease in systemic levels of the liver enzyme aspartate aminotransferase (AST) was also observed in the animals treated with CLQ after infection compared with the controls. These results suggest that CLQ interferes in DENV-2 replication in Aotus monkeys.

Goniometric evaluation of both forelimbs and hind limbs in two species of Neotropical monkeys.

BACKGROUND: The aim of this study was to evaluate the goniometric measurements of the forelimb and hind limb joints in two species of Neotropical primates maintained in captivity. METHODS: Eighteen intact monkeys organized into two groups were studied: Group 1-9 brown howlers (Alouatta fusca), and Group 2-9 tufted capuchins (Sapajus apella). RESULTS: Significant differences were observed in the maximum flexion of the shoulder, elbow, carpus, stifle, and tarsus (G1>G2); maximum extension and abduction of the shoulder (G1G2) and adduction (G1G2). The ROM was significantly different in all joints: shoulder (G1G2), hip (G1>G2), stifle (G1

Aggressive keloid-mimicking tumor in Melanosuchus niger in captivity / Queloide agressivo imitando tumor em Melanosuchus niger em cativeiro

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 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.