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The genus Bartonella (Rhizobiales: Bartonellaceae) encompasses facultative intracellular Gram-negative alphaproteobacteria that parasitize mainly erythrocytes and endothelial cells, as well as macrophages, monocytes and dendritic cells. Although they can infect numerous mammal species and arthropod vectors worldwide, reports of Bartonella infections in marsupials are scarce. In fact, such agents have only been detected in marsupials and/or associated ectoparasites in Australia and the United States of America until the present moment. The present study aimed to isolate and characterize molecularly, morphologically and phenotypically Bartonella infecting free-living marsupials sampled in the Brazilian Pantanal, the largest wetland in South America. Two marsupials were captured in December 2018 and six marsupials in February 2019, totaling eight small mammals sampled: five (62.5%) Thylamys macrurus and three (37.5%) Monodelphis domestica. All blood samples were submitted to qPCR for Bartonella spp. based on the nuoG gene, a pre-enrichment liquid culture and a chocolate agar solid culture. Bartonella sp. was isolated from 3 T. macrurus and one M. domestica. One Bartonella isolate obtained from a T. macrurus blood sample (strain 117A) that showed to be closely related to the Bartonella vinsonii complex and Bartonella machadoae was selected for whole genome sequencing using a hybrid approach based on Illumina NovaSeq and Nanopore sequencing platforms. This strain showed a genome of 2.35 Mbp, with an average C + G content of 38.8%, coding for 2013 genes, and a 29 kb plasmid with an average C + G content of 34.5%. In addition, this strain exhibited an average nucleotide identity (ANI) of 85% with Bartonella species belonging to the B. vinsonii group and 91% with B. machadoae. Phylogenomic analysis based on 291 protein coding genes shared by the genomes of 53 Bartonella species positioned this strain closely to B. machadoae. This new isolated species was named Bartonella harrusi sp. nov., which was characterized as having small capnophilic, microaerophilic and aerobic rods with an absence of pili and flagella. In conclusion, the present work describes the biochemical, phenotypic and genomic characteristics of Bartonella harrusi, a new species isolated from the T. macrurus blood samples of the Brazilian Pantanal. Finally, a review of the taxonomic classification of members of the genus Bartonella is proposed, based on the ANI values accessed by whole genome sequencing analyses.

Cassava has been widely used for animal and human nutrition. It has also been demonstrated to have antineoplastic and anthelmintic properties. Toxicity due to cassava consumption has been reported in ruminants and laboratory animals; therefore, this study aimed to investigate the toxic effects of acetone cyanohydrin, a metabolite of linamarin that is present in cassava, in Wistar rats. Six groups of five animals each were used to evaluate the toxic effects of acetone cyanohydrin administered at 25 (G1), 50 (G2), 75 (G3), 100 (G4) and 125 (G5) µmol/kg as a single oral dose. The control group received acidified water (pH 3.5). The animals were monitored after administration of acetone cyanohydrin, and clinical symptoms were recorded. Serum enzyme levels were measured to assess the kidney and liver function. During necropsy, tissue samples were collected for histopathological examination. After administration, some animals in the G2, G4, and G5 groups presented neurological symptoms such as convulsions, involuntary muscle contraction, staggering gait, motor coordination disability, prostration, and mydriasis. All of the animals in the G5 and four animals in the G4 group died seven minutes after the administration of acetone cyanohydrin. Animals in the other groups, particularly in G2, recovered from the acute phase. Biochemical analysis revealed hepatic lesions and liver dysfunction. Histopathology revealed severe lesions in both the liver and brain. In conclusion, acetone cyanohydrin has toxic effects in the liver, lung, and central nervous system in rats; however, at concentrations up to 25 µmol/kg, the animals could survive the acute phase.Index terms: Neurotoxic; hepatotoxic; cyanide; acute intoxication. RESUMOA mandioca tem sido amplamente utilizada para alimentação animal e humana. Também tem sido demonstrado que possui propriedades anti-neoplásicas e anti-helmínticas. A toxicidade devido ao consumo da mandioca tem sido relatada em ruminantes e animais de laboratório. Assim, este estudo teve como objetivo investigar os efeitos tóxicos da acetona cianidrina, um metabólito da linamarina que está presente na mandioca, em ratos Wistar. Foram utilizados seis grupos de cinco animais cada para avaliar os efeitos tóxicos da acetona cianidrina administrada a 25 (G1), 50 (G2), 75 (G3), 100 (G4) e 125 (G5) umol / kg como uma dose oral única. O grupo controle recebeu água acidificada (pH 3,5). Os animais foram monitorados após a administração de acetona cianidrina e os sintomas clínicos foram registrados. Os níveis séricos das enzimas foram medidos para avaliar a função renal e hepática. Durante a necropsia, amostras teciduais foram coletadas para análise histopatológica. Após a administração, alguns animais dos grupos G2, G4 e G5 apresentaram sintomas neurológicos como convulsões, contração muscular involuntária, andar cambaleante, incordenação motora, prostração e midríase. Todos os animais do G5 e quatro animais do G4 morreram após sete minutos da administração de acetona cianidrina. Animais dos outros grupos,...

Kinetoplastids include species economically important in agriculture, livestock, and human health. We evaluated the richness of kinetoplastids that infect small mammals in patches of unflooded forests in the Pantanal biome, an area where we hypothesize that its diversity is higher than currently recognized. Hemocultures (HC) and Next Generation Sequencing (NGS) targeting the 18S rDNA gene were employed for the detection of kinetoplastids. We grouped the positive samples into pools for each small mammal species (Monodelphis domestica, Thylamys macrurus, Oecomys mamorae, Thrichomys fosteri, Clyomys laticeps, and Holochilus chacaris). Eight parasite species were identified: Leishmania amazonensis, L. infantum; Trypanosoma cascavelli (HC + NGS), T. cruzi, T. lainsoni, T. rangeli (HC + NGS), Trypanosoma sp. DID, and Neobodo sp. The use of a tool as sensitive as NGS has increased our awareness of the diversity of kinetoplastids, as well as their host range, with emphasis on the species O. mamorae (seven kinetoplastid species, excepting T. cascavelli in a pool of nine individuals) and T. macrurus (four kinetoplastid species in a single individual). Furthermore, L. infantum and L. amazonensis infections were described in small mammals from this region for the first time. These findings make it mandatory to revisit the kinetoplastids/host associations proposed so far.

Mortalidade em pacus (Piaractus mesopotamicus) ocasionada por Pantoea agglomerans e Pseudomonas aeruginosa em tanque escavadoMortality in Pacus (Piaractus mesopotamicus) caused by Pantoea agglomerans and Pseudomonas aeruginosa in Excavated Tank ABSTRACT Background: Fish production in Brazil is growing strongly. This growth is being mainly driven by mainland aquaculture, which in 2017 produced 691.700 tons of fish. To improve production levels, fish farms have become increasingly intensive, but in these systems, the high fish densities in the ponds, the high feeding rate, and the high organic matter levels in the water can lead the fish becoming stressed. This can cause bacterial proliferation and an increase in mortality. Most species of fish-causing bacteria are saprophytes. They are found naturally in the environment and are usually responsible for secondary or opportunistic infections. This study reports on an outbreak of Pacus (Piaractus mesopotamicus) mortality at an intensive fish farm, in the municipality of Campo Grande, MS, Brazil, that used excavated tanks. Cases: The outbreak occurred at a fish farm in the municipality of Campo Grande, MS, during August, 2015. A total of 200 pacus in two tanks died after they showed the following symptoms: lethargy, anorexia, increased mucus production, and disordered swimming and water surface searching. The temperature and dissolved oxygen were measured using a digital thermometer and an oximeter, respectively, and water transparency was measured with a Secchi disc. The pH was measured using a portable digital potentiometer. The values for the water quality parameters analyzed during the mortality period were temperature, 22.5 o C; transparency, 20 cm; oxygen dissolved in the early morning 3 mg/L and at the end of the afternoon, 4.5 mg/L; pH 8.3; and toxic ammonia, 0.002 ppm. Five fishes were collected from the tank, immediately cooled to 4°C, and sent to the Microbiology and Pathology Laboratories to perform the microbiological and pathological laboratory procedures. After the replication process, the slow glucose fermentation characteristics in MacConkey Agar and other biochemical tests showed that the lactose non-fermenter bacterium was Pseudomonas aeruginosa and the fermenting bacterium was Pantoea agglomerans. A necroscopic examination revealed congestion of viscera in general and thickening of the gills; the histopathological examination showed an intense inflammatory reaction in the gills; and the liver showed congestion and dilation of the central, hepatoportal, and sinusoidal veins, marked cytoplasmic vacuolization, the presence of hemosiderin and leukocytosis, and coagulation necrosis and cholestasis foci. Discussion: The water temperature in the tanks (22.5°C) was lower than what is considered ideal for tropical fish. It ranged from 25 to 32°C. Furthermore, the pH (8.3) was close to the limit of what is considered appropriate. The mean tank flow rate at the time of death was 15 L/min, corresponding to a daily renewal rate of 1.2%, which was lower than the ...

Despite the great diversity of coccidians, to our knowledge, no coccidian infections have been described in Oecomys spp. In this context, we examined Oecomys mamorae Thomas (Rodentia: Cricetidae) from the Brazilian Pantanal for infections with enteric coccidia. Nine individuals were sampled, and one was found to be infected. The oöcysts were recovered through centrifugal flotation in sugar solution. Using morphological and morphometric features, we described a new species of Cystoisospora Frenkel, 1977. Sporulated oöcysts were ovoidal 20.0-29.1 × 16.4-23.2 (26.7 × 21.2) µm and contained two sporocysts, 12.9-19.1 × 9.4-13.9 (16.4 × 12.4) µm, each with four banana-shaped sporozoites. Polar granule and oöcyst residuum were both absent. We documented the developmental forms in the small intestine and described the histopathological lesions in the enteric tract. Our results indicate that the prevalence of Cystoisospora mamorae n. sp. in O. mamorae is low, and tissue damage in the enteric tract is mild, even in the presence of coccidian developmental stages.

Background: Melanomas are typically malignant neoplasms commonly observed in the oral cavity of dogs. The classical presentation of melanomas with characteristic melanin pigmentation is easy to diagnose; however, in some cases, the lack of melanin production in the amelanotic oral tumors cause a delay in establishing the precocious diagnosis and consequent treatment. The aim of this report was to evaluate the histopathological and immunohistochemical aspects of an oral amelanotic melanoma with osteocartilaginous formation and metastasis in a dog, in a temporal way.Case: A 10-year-old male German Shepherd dog, presenting mouth bleeding with an amelanotic melanoma located between the upper incisors was received at the Veterinary Hospital of the Catholic University Dom Bosco (UCDB), Campo Grande, MS, Brazil. The animal was clinically evaluated and radiography was performed. The tumor was surgically removed and a sample was collected for histopathological examination that revealed spindloid and some epithelioid morphological cell types surrounded by a fibromatous matrix with moderate amounts of fibrovascular stroma. Approximately 1 month after surgical removal, recovery of the tumor was observed, and a second clinical analysis and collection of sample were performed. These procedures were repeated three times showing the same histopathological characteristics added by myxoid, chondroid, fibromatous tissue, and small groups of chondrocytes as well as central areas of irregular mineralized spicules. X-ray examination revealed proliferative and lytic bone infiltration in the jaw. Immunohistochemical analysis for melanocytic differentiation markers was performed showing positivity to Melan-A, tyrosinase and HMB-45 immunoreactivity, while no S100 reactivity was detected. After 11 months of the first biopsy, pleural effusion and radiopaque disseminated nodules of 1cm in the lungs were detected by X-ray. The animal died and necropsy was conducted. Multiple masses were observed in the lung and at the parietal pleura, suggesting lung metastasis by the positivity for Melan-A.Discussion: The dog was first diagnosed with fibromatous epulis based on the observation of fibroblastic tissue and spindle cells with intense vascularization associated to the site of the tumor and its macroscopic aspect. In the subsequent follow-ups the tumor displayed malignant characteristics observed by recurrence after each surgery, as the tumor returned even larger, aggressive, and infiltrative. From the second biopsy, the histopathological analysis showed the undifferentiated character of epithelioid neoplastic cells, demonstrated by the increase of cartilage and osteoid tissue and the mineral deposit. The phenomenon of the tumor stroma to form cartilage and bone is highlighted here because myxoid change and cartilage formation were frequently observed at the site where amelanotic spindle cells were actively proliferating. It is possible that neoplastic melanocytic cells themselves were involved in the development of the osteocartilaginous areas. Although no cytoplasmic melanin pigmentation was found in the tumor fragments, specific melanocytic markers for melanoma detected neoplastic melanocytes and unmelanized melanosomes. The positive reaction for Melan-A, HMB-45, and tyrosinase in the epithelioid, spindle, and cartilaginous cell groups of the neoplasia indicated amelanotic melanoma with osteocartilaginous differentiation. The negative HMB-45, S100, and tyrosinase expression in lung metastasis may be due to the fact that melanomas express aberrant markers and are also known to display occasional loss of their classic immunophenotype. Amelanotic melanoma can be underdiagnosed due to rapid progression of the tumor allied to the dedifferentiation ability of melanocytes. Thus, the follow up study of cell morphology and immunohistochemical analysis for melanogenic factors can be important determinants in diagnosis.

Computational histomorphometry is an available and easy tool that has been used in the assessment of morphophysiological tissue changes, offering greater scientific reliability to the data, as well as facilitating the automation process. The present work aimed to describe the application of the methodology of the free software ImageJ for morphological evaluation of fish tissues. For this, micrographs of histological sections of the intestinal tract of fish stained with Periodic Acid-Schiff (PAS) were used as a model. The images were analyzed for variables of length, width, and tissue area and, number of cells or molecules. The application of computational histomorphometry demonstrated efficiency in the evaluation of histological structures of the intestine of fish supplemented with probiotics, contributing to the improvement of image analysis techniques in animal tissue models.