Linear CT-scan measurements of cerebral ventricles in senile Poodle dogs.

Breed traits seem to influence the dimensions of the cerebral ventricles in dogs. The ratios between the ventricles and the brain are crucial diagnostic criteria for suspected canine cognitive dysfunction (CCD). This study aimed to establish linear computed tomography (CT)-scan measurements of the cerebral ventricles in 55 Poodle dogs aged >7 years. To this end, cross-sectional CT images were evaluated. The measurements in the whole sample were: height of the right ventricle, 6.0 ± 1.6 mm; height of the left ventricle, 5.8 ± 1.6 mm; width of the right ventricle, 6.9 ± 1.4 mm; width of the left ventricle, 7.0 ± 1.3 mm; height of the third ventricle, 3.4 ± 0.8 mm; height of the right cerebral hemisphere, 39.5 ± 2.0 mm; and height of the left cerebral hemisphere, 40.2 ± 2.6 mm. The average ventricular measurements were higher in dogs older than 11 years (p < 0.05). However, the average ratio of the ventricle height to the height of the brain did not reveal differences between age groups, sex, or antimeres. In addition, none of the images showed fused lateral ventricles. Thus, these data can assist in interpreting ventricle size in senile Poodle dogs (aged >7 years).

Características raciais parecem influenciar as dimensões dos ventrículos cerebrais em cães. As proporções entre os ventrículos e o cérebro são cruciais para os casos suspeitos de disfunção cognitiva canina (DCC). Este estudo objetivou estabelecer medidas lineares dos ventrículos cerebrais de 55 cães da raça Poodle com idade acima de sete anos. Para tal, foram avaliadas imagens de cortes transversais obtidas por tomografia computadorizada. As medidas na amostragem total foram: altura do ventrículo direito 6,0 ± 1,6 mm, altura do ventrículo esquerdo 5,8 ± 1,6 mm, largura do ventrículo direito 6,9 ± 1,4 mm, largura do ventrículo esquerdo 7.0 ± 1,3 mm, altura do terceiro ventrículo 3,4 ± 0,8 mm, altura do hemisfério cerebral direito 39,5 ± 2,0 mm e altura do hemisfério cerebral esquerdo 40,2 ± 2,6 mm. As médias das medidas ventriculares foram maiores em cães acima de 11 anos de idade (p < 0,05). Contudo, a relação entre altura ventricular e altura cerebral não revelou diferenças entre grupos etários, sexo ou antímeros. Além disso, nenhuma imagem revelou ventrículos fusionados. Assim, os dados do presente estudo podem auxiliar na interpretação das dimensões ventriculares em cães da raça Poodle acima dos sete anos de idade.

Low Occurrence of Salmonella spp. in Wild Animals in Bahia, Brazil-Population Assessment and Characterization in the Caatinga and Atlantic Forest Biomes.

Salmonella spp. are known to persist in the environment. Wild animals are believed to act as important reservoirs, with antimicrobial resistance frequently occurring in the environment. However, little is known about the role of the wildlife in Bahia as a reservoir for Salmonella in Brazil. This study aimed to isolate and characterize Salmonella spp. from wildlife in the Atlantic Forest and Caatinga biomes considering indicators such as the animal species, degree of anthropization, sampling area, and feeding habits. Convenience wildlife sampling and characterization were conducted, followed by microbiological and molecular identification of Salmonella isolates, serotyping, and antimicrobial susceptibility testing. A total of 674 fecal samples were collected from 12 municipalities during 2015-2021, and 4 were positive for the following Salmonella species: Salmonella enterica subspecies enterica serovar Agona (n = 1), Salmonella enterica subsp. enterica serogroup O:16 (n = 2), and Salmonella enterica subsp. enterica serovar Muenchen (n = 1). Antimicrobial susceptibility analysis revealed that one isolate was resistant to six antibiotics, including extended-spectrum penicillins and beta-lactamase inhibitors. These results indicated a low frequency of Salmonella spp. in the sampled forest fragments. The presence of Salmonella in wild animals increases the risk to public health and biodiversity and indicates that they can act as sentinels of environmental contamination or indicators of preservation.

Sloth's giant tick (Amblyomma varium) parasitizing free-ranging maned sloth (Bradypus torquatus) in the Atlantic Forest biome, Brazil.

Amblyomma varium is a neotropical tick popularly known as the sloth's giant tick, during the adult stage is found almost exclusively on mammals of the Bradypodidae and Megalonychidae families of the superorder Xenarthra. The maned sloth (Bradypus torquatus) is the only sloth species in danger of extinction in Brazil. This species is arboreal and descends to the ground only to perform defecation behavior. This behavior can be the determining factor for infestation and infection by different parasitic agents, including A. varium. This study reported the occurrence of A. varium found parasitizing free-living maned sloths (B. torquatus) in the Atlantic Forest biome of Northeast and Southeast Brazil. A total of 36 individuals were evaluated and more than 50% of the individuals were parasitized by ticks of the species A. varium. This study confirmed the importance of B. torquatus as a host for adults and nymphs of A. varium and reported the variation in length of the spurs on coxa IV of A. varium males.

O Amblyomma varium é um carrapato neotropical popularmente conhecido como carrapato gigante da preguiça, durante a fase adulta é encontrado quase que exclusivamente em mamíferos das famílias Bradypodidae e Megalonychidae da superordem Xenarthra. A preguiça-de-coleira (Bradypus torquatus) é a única espécie de preguiça ameaçada de extinção no Brasil. Esta espécie é arbórea e desce ao solo apenas para realizar comportamentos de defecação. Esse comportamento pode ser o fator determinante para infestação e infecção por diferentes agentes parasitários, incluindo A. varium. Este estudo relatou a ocorrência de A. varium encontrado parasitando preguiças-de-coleira (B. torquatus) de vida livre no bioma Mata Atlântica do Nordeste e Sudeste do Brasil. Foram avaliados 36 indivíduos e mais de 50% dos indivíduos estavam parasitados por carrapatos da espécie A. varium. Este estudo confirmou a importância de B. torquatus como hospedeiro para adultos e ninfas de A. varium e relatou a variação no comprimento dos espinhos da coxa IV de machos de A. varium.

Evolutionary history or function? Which preponderates in the expression of the muscle mass of the thoracic limb in wild carnivorans?

Thoracic limbs are extremely versatile and exhibit informative characteristics about habits of the Carnivora order in the wild. Despite this relevance, comparative studies with quantitative variables on thoracic limb muscles are still scarce in carnivorans. The aims of this study were to measure the mass of the intrinsic muscles of the thoracic limb of neotropical species of the Carnivora order and to establish comparative conjectures. For this purpose, 39 thoracic limbs of 10 neotropical carnivorans species were dissected. The mass of each muscle was measured on a digital scale, muscles were grouped by function, and the mass average percentage that each functional group of muscles occupied in the thoracic limb was calculated. The data of the present study was added to that available in the literature for 22 other carnivoran species. Three groups of species were considered: Canidae, Musteloidea, and Feliformia. Comparatively, the eight canid species included in this analyses concentrate muscle mass proximally in the thoracic limb to prioritize essential cursoriality. The nine musteloids had more muscle mass in the distal muscles due to the demand for versatility and manual strength, and the 14 Feliformia species exhibited an intermediate trend. The analysis of clusters revealed a great overlap of the percentage distribution of muscle mass with the phylogeny previously established for carnivorans. It could be verified that the distribution of muscle masses meets the demand of the locomotor habits of the species up to a certain level, from which phylogeny begins to limit morphological adaptations.

Os membros torácicos são extremamente versáteis e exibem características informativas sobre os hábitos das espécies da ordem Carnivora em vida livre. A despeito desta relevência, estudos comparativos com variéveis quantitativas dos músculos do membro torácico são escassos em carnívoros. Os objetivos deste estudo foram aferir a massa dos músculos intrínsecos do membro torácico de espécies neotropicais da ordem Carnivora e estabelecer conjecturas comparativas. Para este fim, foram dissecados 39 membros torácicos de dez espécies de carnívoros neotropicais. A massa de cada músculo foi mensurada em uma balança digital, os músculos foram agrupados por função e calculou-se a massa percentual média a que cada grupo funcional de músculos correspondia no membro torácico. Os dados do presente estudo foram analisados conjuntamente às informações disponíveis na literatura para outras 22 espécies da ordem Carnivora. Três grupos de espécies foram considerados: Canidae, Musteloidea e Feliformia. Comparativamente, as oito espécies de canídeos incluídas nesta análise demonstraram concentração de massa muscular mais proximalmente no membro torácico em razão dos hábitos essencialmente cursoriais. As nove espécies da superfamília Musteloidea exibiram mais massa nos músculos distais devido à maior demanda por versatilidade e força manual. As 14 espécies da subordem Feliformia apresentaram um padrão intermediário. A análise de clusters revelou nítida sobreposição entre o percentual de distribuição da massa muscular com a filogenia previamente estabelecida para a ordem Carnivora. Verificou-se que a distribuição da massa dos músculos atende à demanda dos hábitos locomotores das espécies até um certo nível, a partir do qual a filogenia começa a limitar as adaptações morfológicas.

Anatomical variations in cervical vertebrae in two species of neotropical canids: What is the meaning?

Anatomical variation in wild canids is rarely described. Altered shapes, uni- or bilaterally situated, were observed in ventral laminae of C6 and/or in C7 vertebral body of two fox species: Lycalopex gymnocercus and Cerdocyon thous. The specimens were young adults, collected dead on highways in southern Brazil. Deformities were considered anatomical variations because apparently there was no interference in function. The occurrence of such variations in two related species from the same area can suggest an environmental common cause rather than genetic issues. Future studies may deepen the understanding between cause and effect of these vertebral deformities in wild canids.

Clavicle in Carnivorans: A Forgotten Bone.

The clavicle is a bone whose development is related to the versatility of the thoracic limbs in mammals. Studies with vestigial structures are scarce and controversial, especially in the order Carnivora. The objective of this study was to verify the presence and to investigate the shape and constitution of the clavicle in neotropical carnivores. In order to do this, 108 cadavers of 19 different species were collected dead on highways and were analyzed. The clavicles were submitted to dissections, longitudinal length measurements, radiographs, histological sections and, in some cases, diaphanization. Sixteen of the 19 species had clavicles in both sides, being significantly larger (P < 0.05) and distinctly more radiopaque in the felids than in the other families. There were no macro or microscopic evidence of clavicle in the specimens of Nasua nasua (n = 6), Conepatus semistriatus (n = 2), and Conepatus chinga (n = 1). The clavicle of the males of Lycalopex gymnocercus, Galictis cuja, and Leopardus geoffroyi was significantly larger (P < 0.05). The predominating contour of the clavicles was a thin stick with cranial convexity. The histological sections demonstrated compact bone consisting of trabecula and lamellae filled by bone marrow and different levels of occupation by chondroid matrix. It can be proposed the clavicles of the order Carnivora, although vestigial and rarely absent, have their presence, constitution and shape more associated with the phylogenetic proximity and evolutionary history of the species than to the variety of movements the thoracic limbs perform in free-living conditions. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1831-1841, 2020. © 2019 American Association for Anatomy.