Successful treatment of Trypanoxyuris sp. infection in naturally infected southern brown-howlers (Alouatta guariba clamitans).

Southern brown-howler monkeys (Alouatta guariba clamitans) may harbor Trypanoxyuris sp., a pinworm parasite with documented fatal consequences in this species. Despite this risk, effective treatment protocols remain unclear. Therefore, the present study aimed to evaluate the efficacy of two anthelmintic protocols against natural infections in two brown-howler monkeys received at the Wild Animal Care and Rehabilitation Sector (SARAS-CAV-UDESC). The protocols utilized pyrantel pamoate & praziquantel (600.0 mg, PO, single dose) and albendazole (20.0 mg, PO, daily for 5 days). Fecal egg counts were carried out daily at the Laboratory of Parasitology and Parasitic Diseases (LAPAR-CAV-UDESC) before and after drug administration. Both treatments successfully eliminated Trypanoxyuris sp. infections. The animal treated with pyrantel pamoate & praziquantel achieved egg clearance by day 6 (144 h), demonstrating effectiveness with a single administration. Albendazole cleared the infection within 2 days of treatment, indicating its potential as a fast-acting treatment. No adverse effect were observed in the treated monkeys. These findings contribute to the development of evidence-based treatment protocols for Trypanoxyuris sp. in primates, enhancing animal health and welfare of captive and wild populations.

Morphological and molecular characterization of parabasilids isolated from ex situ nonhuman primates and their keepers at different institutions in Brazil.

Intestinal protozoa, which can be asymptomatic or cause diarrhea, dysentery and even death, are among the main agents that affect nonhuman primates (NHPs) kept under human care. Nevertheless, information on the molecular and morphometric profiles of parabasilids in the Neotropics is still scarce. In this context, the objective of this study was to isolate the Parabasalia protozoa detected in the feces of NHPs and their keepers in Pavlova and TYSGM9 media and to characterize the isolates by molecular biology and morphometry. Fecal samples from NHPs from five Brazilian institutions were analyzed. Direct examination was performed immediately after obtaining the samples. A total of 511 fecal samples from NHPs were collected, and 10.6% contained parabasilids. Regarding the handlers, of the 74 samples analyzed, three were positive. In vitro-generated parabasilid isolates were successfully obtained from all positive samples, as identified via microscopy. Isolates of the parasite were obtained both from New World NHPs, including the genera Leontopithecus, Saguinus, Leontocebus, Aotus, Saimiri, Sapajus, and Alouatta, and from the Old World primate Pan troglodytes. Forty-nine NHP isolates were molecularly identified: Pentatrichomonas hominis (16), Trichomitus batrachorum (14), Tetratrichomonas brumpti (13) and Hypotrichomonas hampli (6). The human isolates were identified as Tetratrichomonas sp. (2) and T. batrachorum (1). Visualization and morphometric analysis revealed trophozoites with piriform or rounded shapes that presented variable measurements. The isolates previously characterized as P. hominis had up to five free flagella, while T. batrachorum and Tetratrichomonas sp. had up to four free flagella, and H. hampli had a maximum of three free flagella. These morphometric characteristics corroborated the molecular identification. In general, a variety of parabasilids were observed to infect NHPs, and T. batrachorum was isolated from biological samples from both NHPs and their keepers, a finding that reinforces the susceptibility of these hosts to infections by parabasilids in Brazil.

Interspecific association between two primatespecies in an urban park / Associação interespecífica entre duas espécies de primatas em um parque urbano

As with Amazonian primates, mixed associations between species in the Atlantic Forest are also influenced by ecological factors. However, Atlantic Forest primates may face additional challenges, such as isolation pressures and fragmentation of forest habitats, which may increase the frequency of these arrangements. The main of this work is to report a sympatry with possible interaction between individuals of two species of primates of the Pitheciidae and Callitrichidae families: Callicebus nigrifrons (Spix 1823) and Callithrix aurita (É. Geoffroy Saint-Hilaire 1812) in an urban park in the south of the state of Minas Gerais. Individuals were observed interacting during foraging and displacement. The association of individuals of the two species can be explained by the low quality of the forest fragment, as it can increases the chances of obtaining food resources and configures a dilution strategy against predator attacks.

Assim como ocorre com os primatas amazônicos, as associações mistas entre espécies na Mata Atlântica também são influenciadas por fatores ecológicos. No entanto, os primatas da Mata Atlântica podem enfrentar desafios adicionais, como pressões de isolamento e fragmentação de habitats florestais, que podem aumentar a frequência desses arranjos. O objetivo deste trabalho é apresentar um relato de simpatia com possível interação entre indivíduos de duas espécies de primatas das famílias Pitheciidae e Callitrichidae: Callicebus nigrifrons (Spix 1823) e Callithrix Resumo aurita (É. Geoffroy Saint-Hilaire 1812) em um parque urbano no sul do estado de Minas Gerais. Foram observados indivíduos interagindo durante o forrageio e deslocamento. A associação de indivíduos das duas espécies pode ser explicada devido à baixa qualidade do fragmento florestal, pois pode aumentar as chances de obter recursos alimentares e configura uma estratégia de diluição de contra-ataques de predadores.

Cryopreservation of spermatozoa from black-and-gold howler monkeys (Alouatta caraya) using egg yolk-based or soy lecithin-based extenders.

There are more than 200 species and subspecies of Neotropical Primates of which more than 40% are listed as threatened by the IUCN Red List of Threatened Species. Both in situ and ex situ conservation programs can benefit from the use of assisted reproductive technologies. The objective of this study was to evaluate, for the first time, cryopreservation techniques for Alouatta caraya semen. Semen samples were collected from five adult males, analyzed, and frozen in either Test-egg yolk or Test-soy lecithin-based extenders containing either 3 or 4% glycerol. Frozen-thawed samples were analyzed at 10, 40, and 80 min post-thaw. Egg yolk-based extenders were overall better than soy lecithin-based extenders. There was no significant difference between 3 and 4% glycerol in any of the parameters analyzed, however, 4% glycerol in egg yolk-based extender produced more favorable results for total motility, intact plasma membrane, lipid peroxidation, and DNA fragmentation index. This study brought novel information on semen characteristics and cryopreservation aspects for A. caraya, which can help shape future experiments to improve the outcome of frozen-thawed sperm for this and other species of Neotropical primates.

Mediastinal T-cell lymphoma in a free-ranging brown howler monkey (Alouatta guariba clamitans).

A free-ranging brown howler monkey (Atelidae: Alouatta guariba clamitans) was necropsied and a mediastinal T-cell lymphoma and esophageal dilation were diagnosed. The case report may contribute to the differential diagnosis of neoplastic and esophageal lesions in non-human primates and highlighted the importance of surveillance of cancer in wildlife.

Phylogeography, genetic diversity, and intraspecific genetic structure of the black-horned capuchin (Sapajus nigritus).

Recent molecular studies have clarified the overarching taxonomy of capuchin monkeys, but intraspecific genetic diversity remains unexplored for most capuchin species. One example is Sapajus nigritus, the southernmost capuchin monkey, found in Brazil and Argentina; its phenotypic diversity has been recognized as two geographic subspecies, but the intraspecific genetic structure of this taxon is poorly known. Here, we sampled across most of this species' geographic distribution, producing a newly sequenced data set for genetic analyses that included 78 individuals from 14 populations. We investigated the intraspecific diversity, genetic structure, and evolutionary history using three mitochondrial markers. Our results indicated that S. nigritus populations exhibited high levels of genetic structure. We found strong support for two monophyletic clades within this species with a deep phylogenetic split, and clear separation from other related taxa. Vicariance events seem to have played a prevalent role in shaping S. nigritus genetic differentiation. The Paraíba do Sul River may have driven the deep divergence between southern and northern clades, whereas the Tietê River may have had a weaker, more recent effect on the divergence of populations within the southern clade.

IgM antibody responses against Plasmodium antigens in neotropical primates in the Brazilian Atlantic Forest.

Introduction: Zoonotic transmission is a challenge for the control and elimination of malaria. It has been recorded in the Atlantic Forest, outside the Amazon which is the endemic region in Brazil. However, only very few studies have assessed the antibody response, especially of IgM antibodies, in Neotropical primates (NP). Therefore, in order to contribute to a better understanding of the immune response in different hosts and facilitate the identification of potential reservoirs, in this study, naturally acquired IgM antibody responses against Plasmodium antigens were evaluated, for the first time, in NP from the Atlantic Forest. Methods: The study was carried out using 154 NP samples from three different areas of the Atlantic Forest. IgM antibodies against peptides of the circumsporozoite protein (CSP) from different Plasmodium species and different erythrocytic stage antigens were detected by ELISA. Results: Fifty-nine percent of NP had IgM antibodies against at least one CSP peptide and 87% against at least one Plasmodium vivax erythrocytic stage antigen. Levels of antibodies against PvAMA-1 were the highest compared to the other antigens. All families of NP showed IgM antibodies against CSP peptides, and, most strikingly, against erythrocytic stage antigens. Generalized linear models demonstrated that IgM positivity against PvCSP and PvAMA-1 was associated with PCR-detectable blood-stage malaria infection and the host being free-living. Interestingly, animals with IgM against both PvCSP and PvAMA-1 were 4.7 times more likely to be PCR positive than animals that did not have IgM for these two antigens simultaneously. Discussion: IgM antibodies against different Plasmodium spp. antigens are present in NP from the Atlantic Forest. High seroprevalence and antibody levels against blood-stage antigens were observed, which had a significant association with molecular evidence of infection. IgM antibodies against CSP and AMA-1 may be used as a potential marker for the identification of NP infected with Plasmodium, which are reservoirs of malaria in the Brazilian Atlantic Forest.

A New Assessment of Robust Capuchin Monkey (Sapajus) Evolutionary History Using Genome-Wide SNP Marker Data and a Bayesian Approach to Species Delimitation.

Robust capuchin monkeys, Sapajus genus, are among the most phenotypically diverse and widespread groups of primates in South America, with one of the most confusing and often shifting taxonomies. We used a ddRADseq approach to generate genome-wide SNP markers for 171 individuals from all putative extant species of Sapajus to access their evolutionary history. Using maximum likelihood, multispecies coalescent phylogenetic inference, and a Bayes Factor method to test for alternative hypotheses of species delimitation, we inferred the phylogenetic history of the Sapajus radiation, evaluating the number of discrete species supported. Our results support the recognition of three species from the Atlantic Forest south of the São Francisco River, with these species being the first splits in the robust capuchin radiation. Our results were congruent in recovering the Pantanal and Amazonian Sapajus as structured into three monophyletic clades, though new morphological assessments are necessary, as the Amazonian clades do not agree with previous morphology-based taxonomic distributions. Phylogenetic reconstructions for Sapajus occurring in the Cerrado, Caatinga, and northeastern Atlantic Forest were less congruent with morphology-based phylogenetic reconstructions, as the bearded capuchin was recovered as a paraphyletic clade, with samples from the Caatinga biome being either a monophyletic clade or nested with the blond capuchin monkey.

Adiponectin levels in captive Owl Monkeys (Aotus sp.).

The mean serum value of adiponectin in captive Aotus sp. is 541.99 ng/mL ± 73.05. There is no influence of sex or age, but there is a moderate positive correlation between body weight and adiponectin levels in males.

Prevalence of Platynosomum spp infection and its association with biliary lithiasis and secondary bacterial infections in free-ranging marmosets (Callithrix spp) of the Brazilian Atlantic Forest.

Platynosomosis is a parasitic disease caused by a trematode of the genus Platynosomum, a bile duct and gallbladder fluke that has been described in captive neotropical primates (New World primates; NWPs) and causes high morbidity and variable mortality. Although it is a major concern for ex-situ conservation of these animals, there are only a few studies of platynosomosis in free-ranging NWPs. Therefore, the aim of this study was to characterize platynosomosis in a free-ranging population of marmosets (Callithrix spp) from the Brazilian Atlantic Forest, focusing on the epidemiological and pathological aspects of the disease. A total of 1,001 marmosets were evaluated and on the basis of clinicoepidemiological data, histopathology, histochemistry and immunohistochemistry, we concluded that Platynosomum spp infection has a prevalence of 8.9% (confidence interval: 7.3-10.8%) in free-ranging marmosets, with a higher frequency in the Metropolitan Region of Rio de Janeiro. Infection was associated with fibrosing and proliferative cholangiohepatitis associated with biliary lithiasis (3.0% of cases) and secondary bacterial infections (14.6% of cases).

Male genital organs of the black-crowned dwarf marmoset (Callibella humilis).

This study provides the first morphological description of the male genital organs of black-crowned dwarf marmoset (Callibella humilis). Internal and external genital organs were similar to other species of non-human primates. However, some shape and size differences were noted. The penile shaft was laterally flattened and comprised of two corpus cavernosus. These were split by a septum up to the level of the glans and then merged to form a single structure. The glans penis had small, keratinized spicules arising from epidermal or dermal projections. The small, fully ossified and well-mineralized penile bone, located at the distal end of the penis, consisted of a bone matrix surrounded by sparse osteoblasts and well-developed internal osteocytes. The penile urethra was lined with columnar pseudostratified epithelium, with areas of simple cuboidal epithelium. The testes were small relative to the body compared to other primate species. The findings of this work may support comparative studies of primate reproductive ecology.

Asymmetric dimethyl arginine in captive owl monkeys (Aotus sp).

Only four of 40 animals had measurable asymmetric dimethyl arginine (ADMA) levels. The young primate had the lowest value (53.4 ng/ml) when compared with the two adults (218.8 ± 9.3 ng/ml) and the elderly one (320.5 ng/ml). The ADMA levels in this study may relate to the echocardiographic abnormalities found, and possible hypertensive individuals.

Ultrasonography of the neotropical primate female reproductive system.

The Neotropical (e. g., Aotus sp., Callithrix jacchus, Saguinus sp., Saimiri sp., and Sapajus sp.) primates are important models for biomedical research and studies on reproductive physiology and biotechnology. Consequently, studies about gynecological and obstetric ultrasonography are crucial. B-mode ultrasonography is a non-invasive imaging technique that provides real-time bidimensional or three-dimensional/four-dimensional B-mode images. In association with Doppler ultrasonography, B-mode ultrasonography can also be used to monitor the mammalian blood flow to the reproductive tract during important events such as ovulation and gestation. Thus, gynecological and obstetric ultrasonography is essential for establishing the female reproductive anatomical and physiological ovarian and uterine health status, gestational diagnosis, and fetal growth monitoring. For instance, the paper presents and discusses the state-of-the-art gynecological and obstetric ultrasonography in the Neotropical primates, species that are models for biomedical research, and some recent studies on species targets for conservation strategies for wild animal populations.

Hematological reference values for Alouatta palliata (Primates: Atelidae) and Cebus imitator (Primates: Cebidae) from the Pacific Coast of Costa Rica / Valores de referencia hematológicos para Alouatta palliata (Primates: Atelidae) y Cebus imitator (Primates: Cebidae) de la costa Pacífica de Costa Rica

Abstract Introduction: Wildlife hematological patterns are fundamental for health monitoring, and allows elucidating variations both within and between populations. Among these, hematological parameters are particularly valuable to evaluate the health status of neotropical primate species in the wild. Objective: To define hematological reference values for two species of monkeys in Costa Rica. Methods: During 2014, we collected blood samples from free-ranging mantled howler monkeys, Alouatta palliata (17 females, 18 males) and white-faced capuchin monkeys, Cebus imitator (5 females, 7 males) in seven localities of the Costa Rican Pacific coast. Results: For both species, the hematological values were higher in males, and howler monkey populations differed significantly except for platelets. Conclusions: These hematological values, which differ by sex and locality, will help evaluate the health status of these neotropical primate populations.

Resumen Introducción: Los patrones hematológicos de la vida silvestre son fundamentales para el monitoreo de la salud y permiten dilucidar las variaciones tanto dentro como entre poblaciones. Entre estos, los parámetros hematológicos son particularmente valiosos para evaluar el estado de salud de las especies de primates neotropicales en la naturaleza. Objetivo: Definir valores de referencia hematológicos para dos especies de monos en Costa Rica. Métodos: Durante el 2014 recolectamos muestras de sangre de monos aulladores de manto, Alouatta palliata (17 hembras, 18 machos) y monos capuchinos cariblancos, Cebus imitador (5 hembras, 7 machos) en siete localidades de la costa Pacífica de Costa Rica. Resultados: Para ambas especies, los valores hematológicos fueron mayores en los machos, y las poblaciones de monos aulladores difirieron significativamente con excepción de las plaquetas. Conclusiones: Estos valores hematológicos, que difieren según el sexo y la localidad, ayudarán a evaluar el estado de salud de estas poblaciones de primates neotropicales.

Isolation and genetic characterization of Toxoplasma gondii from a captive black-and-gold howler monkey (Alouatta caraya Humboldt, 1812) in Brazil.

Toxoplasma gondii was isolated in mice from different tissues of a captive black-and-gold howler monkey (Alouatta caraya) kept in a colony at the Primatology Center of Rio de Janeiro State, Brazil, and it was genotypically characterized based on using PCR-RFLP and Microsatellite Analysis (MS), later on. T. gondii was successfully isolated from inocula deriving from heart, liver and tissue pool (heart, liver, lungs, axillary lymph nodes and cerebellum) samples. The isolate was named TgBgHmBrRJ1. The high virulence of the aforementioned strain was observed in infected mice. Non-archetypal genotype (ToxoDB PCR-RFLP #206) was obtained through PCR-RFLP. This genotype had been previously described in 12 isolates from different hosts, also in Southeastern Brazil, a fact that indicates likely high circulation of this genotype in this region. The isolate was also classified as non-archetypal, based on MS genotyping, as well as presented genotypic identity close to that of strains isolated from free-range non-symptomatic chickens (TgCkBr244,245,278,279) in Espírito Santo State. It is worth emphasizing that despite the large number of reports about clinical toxoplasmosis in neotropical primates in Brazil, this is just the second isolate of this parasite ever reported in this group of animals.

Size reduction and skull shape parallelism following the evolutionary forest-to-savanna transition in Platyrrhini monkeys.

There are strong physiological and behavioral differences that allow animals to live in forests versus savannas. For example, terrestrial forest-dwelling mammals tend to be small compared to species living in savannas. Robust capuchin monkeys (genus Sapajus) are widespread in tropical South America, occurring in both forest and savanna environments, with forest species considered basal in an evolutionary context. Whether or not skull shape and size variations are associated with variation in resource use remains unknown, particularly for the two species living in savanna (Sapajus libidinosus and S. cay). Here we show that savanna species present convergent size and skull characteristics that may facilitate living in this new environment. Geometric morphometric methods were used to assess skull size and shape variation for 184 Sapajus specimens distributed across South America. We used phylogenetic generalized least squares to test size against environmental variables and multivariate morphological trajectories/partial least square analyses on the skull shape to detect shape differences in specimens between forest and savanna biomes. Our findings reveal Sapajus size reduction in the evolutionary transition from forest to savanna, a process related to increasing seasonality. Moreover, we found morphological parallelism in the skull (e.g., muzzle shortening) and (large) molars in the two savanna species, features that may facilitate the processing of harder food such as fallback resources. We associate these phenotypic differences to the evolutionary process of colonizing the savannas by primates (including early hominins), leading to morphological adaptations to tolerate stressful, seasonal environments, such as body size reduction and ingestion and mastication of tough foods.

¿Qué nos dicen los primates neotropicales bajo la mirada de la citogenética? / What do neotropical primates tell us under the look of cytogenetics?

RESUMEN Los estudios de citogenética en Primates Neotropicales (Primates: Platyrrhini) han demostrado que estos mamíferos comprenden un grupo heterogéneo a nivel cromosómico. La notable variedad de cariotipos descriptos provee evidencia significativa sobre el posible papel de los reordenamientos cromosómicos en su evolución. En el Grupo de Investigación en Biología Evolutiva (GIBE), la línea de investigación sobre el proceso de divergencia evolutiva en Platyrrhini considerando distintos aspectos de la organización del genoma se ha establecido y desarrollado de manera ininterrumpida desde hace más de 30 años. Entre los avances realizados en los últimos años se encuentra la cuantificación del tamaño del genoma en seis especies de monos caí (Cebus sp.) y dos especies de monos aulladores (Alouatta sp.) y la descripción de la composición de pares de bases en las regiones de heterocromatina constitutiva en los géneros Cebus y Ateles. Se concretaron las primeras descripciones del cariotipo y comportamiento meiótico en profase I temprana de dos especies de monos aulladores, Alouatta caraya y A. guariba clamitans. En esta última especie se identificó el primer sistema sexual de tipo pentavalente X1X2X3Y1Y2 en una especie de primate. Se caracterizó la organización de la eucromatina en términos del contenido y distribución de bases nucleotídicas AT y GC en tres especies de aulladores y en dos especies de monos caí. Estas investigaciones, entre otras, permitieron contribuir de forma original al conocimiento sobre la especiación en distintos niveles, así como sobre la arquitectura y dinámica del genoma de estos primates.

ABSTRACT Cytogenetics studies in Neotropical Primates (Primates: Platyrrhini) have shown that these mammals comprise a heterogeneous group at the chromosomal level. The remarkable variety of karyotypes described provides significant evidence on the possible role of chromosomal rearrangements in their evolution. In the Grupo de Investigación en Biología Evolutiva (GIBE), the line of research on the evolutionary divergence process in Platyrrhini considering different aspects of the organization of the genome has been established and developed uninterruptedly for more than 30 years. Among the advances made in recent years is the quantification of the genome size in six species of caí monkeys (Cebus sp.) and two species of howler monkeys (Alouatta sp.) and the description of the composition of base pairs in the constitutive heterochromatin regions in the genera Cebus and Ateles. The first descriptions were made of the karyotype and meiotic behavior in early prophase I of two species of howler monkeys, Alouatta caraya and A. guariba clamitans. In this last species, the first pentavalent-type sexual system X1X2X3Y1Y2 was identified in a primate species. The organization of euchromatin was characterized in terms of the content and distribution of AT and GC nucleotide bases in three species of howlers and in two species of caí monkeys. These, among other investigations, allowed contributing in an original way to the knowledge about speciation at different levels, as well as about the architecture and dynamics of the genome of these primates.

Lethal acute diarrhea associated with Clostridioides difficile toxin A and B in a buffy-tufted-ear marmoset (Callithrix aurita).

This is a case of lethal acute diarrhea associated with a mild neutrophilic enteritis in a buffy-tufted-ear marmoset (Callithrix aurita) with detection of A/B toxins and isolation of a toxigenic clade 3 Clostridioides difficile strain (A+ B+ CDT+ , ST5), which should be considered as a potential cause of enteritis in this species.

Environmental predictors of filarial infection in Amazonian primates: Ecological factors and primate filarial infection.

Filarial nematode infections are common in primates, but have received little attention in the Neotropics. Epidemiological data on filarial infections in primates are still too sparse to fully understand the complex of this parasitism, especially because of the difficulty in studying the ecology and epidemiology of wild primates.. We describe natural infections by Dipetalonema parasitizing 211 primates belonging to eight free-living primate genera in Amazonia, and assess the relationships between parasitic indicators and climatic (rainfall and river level), ecological (fruiting periods of plants) and biological (sex, species' body mass, group size and density) factors. The overall prevalence was 64.4% (95% CI: 64.0 - 64.9); parasitic mean abundance (N filariae per individual) and parasitic mean intensity (N filariae per infected host) of infection were 11.9 (95% CI: 8.3 - 15.6) and 18.4 (95% CI: 13.4 - 23.4) filariae/individual, respectively. Although we observed differences in parasitic parameters among primate genera, there was no correlation between parasitic parameters with density, body mass or group size. Sapajus, Cebus and Lagothrix had the highest prevalence and parasitic mean intensity. Using Lagothrix lagotricha poeppigii, the most sampled species (n = 92), as a model, we found that the number of filariae per infected host was associated with fruit production in swamp forests during the dry season, the time of food scarcity. The long periods of food shortage may cause environmental stress on primates, impairing their immune defenses and leading to increased parasite load but not affecting infection prevalence. However, the lack of information on vector ecology, key to understand risk factors associated to infection rate, prevents confirming the existence of an infection pattern dependent on food availability.

Aneurisma aórtico torácico com trombose associada em Bugio-preto (Alouatta caraya) / Thoracic aortic aneurysm with associated thrombosis in black-and-gold howler monkey (Alouatta caraya)

O aneurisma é uma dilatação anormal e permanente das artérias, resultante do enfraquecimento da parede do vaso adelgaçamento da camada média e enfraquecimento da camada elástica. Em animais, a maioria dos casos de aneurisma tem origem idiopática e são detectados acidentalmente durante a necropsia. O objetivo deste trabalho é relatar um caso de aneurisma aórtico com trombose associada em Bugio-preto(Alouatta caraya), bem como seus aspectos patológicos. O animal era adulto, macho, pertencente ao Centro Nacional de Primatas (CENP), na cidade de Ananindeua-PA, foi encaminhado para exame necroscópico para investigação da causa mortis. No histórico do animal, não constava qualquer enfermidade. O animal apresentava bom escore de condição corporal com preservação da topografia anatômica dos órgãos. Entretanto, observou-se presença de aumento de volume localizado em aorta torácica, a 1,4 cm da base do coração. Na abertura aórtica foi observado dilatações de tamanhos variados e, no interior da maior dilatação, notou-se uma estrutura de coloração vermelho escuro, aderida, de aspecto seco e superfície áspera, medindo 1,5 cm. Aneurismas aórticos em primatas não humanos não são comuns, porém já foram reportados na literatura. O diagnóstico precoce utilizando exames complementares é importante, porém, ainda há recursos não empregados na rotina veterinária tornando ainda mais difícil o diagnóstico e prevenção. Por isso, na medicina veterinária, os aneurismas são detectados acidentalmente durante a necropsia. Com base nos achados anatomopatológicos, concluiu-se que o animal veio a óbito por trombose associada a aneurisma aórtico.

An aneurysm is an abnormal and permanent dilation of the arteries, resulting from the weakening of the vessel wall.thinning of the middle layer and weakening of the elastic layer. In animals, most cases of aneurysm are idiopathic. This paper aimed to report a case of aortic aneurysm with associated thrombosis in a black-and-gold howler monkey(Alouatta caraya), as well as its pathological aspects. The animal was an adult, male, belonging to the National Primate Center (CENP), in the city of Ananindeua-PA, that was referred for necroscopic examination to investigate the causa mortis. In the animal's history, there was no disease. The animal had a good body condition score with preservation of the anatomical topography of the organs. However, there was an increase in volume located in the thoracic aorta, 1.4 cm from the base of the heart. In the aortic opening, dilations of different sizes were observed, and inside the largest dilatation, a structure of dark red color, adhered, with a dry appearance and rough surface, measuring 1.5 cm was noted in addition to dilations of different sizes. Inside the largest cavitation, a dark red structure was observed, adhered, with a dry appearance and rough surface, measuring 1.5 cm. Aortic aneurysms in non-human primates are incommon, but have been reported in the literature. Early diagnosis using complementary exams is important, however, there are still resources not used in the veterinary routine, making diagnosis and prevention even more difficult. Therefore, in veterinary medicine, aneurysms are accidentally detected during necropsy. Based on the anatomopathological findings, it was concluded that the animal died due to thrombosis associated with an aortic aneurysm.