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Aedes albopictus is a competent vector of numerous pathogens, representing a range of transmission cycles involving unique hosts. Despite the important status of this vector, variation in its feeding patterns is poorly understood. We examined the feeding patterns of Ae. albopictus utilizing resting collections in Long Island, NY, and contextualized blood meal sources with host availability measured by household interviews and camera traps. We identified 90 blood meals, including 29 humans, 22 cats, 16 horses, 12 opossums, 5 dogs, 2 goats, and 1 each of rabbit, rat, squirrel, and raccoon. This is only the third study of Ae. albopictus blood feeding biology that quantitatively assessed domestic host availability and is the first to do so with wild animals. Host feeding indices showed that cats and dogs were fed upon disproportionately often compared with humans. Forage ratios suggested a tendency to feed on cats and opossums and to avoid raccoons, squirrels, and birds. This feeding pattern was different from another published study from Baltimore, where Ae. albopictus fed more often on rats than humans. To understand whether these differences were because of host availability or mosquito population variation, we compared the fitness of New York and Baltimore Ae. albopictus after feeding on rat and human blood. In addition, we examined fitness within the New York population after feeding on human, rat, cat, horse, and opossum blood. Together, our results do not indicate major mosquito fitness differences by blood hosts, suggesting that fitness benefits do not drive Northeastern Ae. albopictus feeding patterns.

El tlacuache de Virginia (Didelphis virginiana) es hospedero para una variedad de pulgas que pueden ser importantes vectores para la transmisión de enfermedades, incluyendo zoonosis; por lo tanto, es importante generar conocimiento sobre las pulgas que parasitan a este animal. En este trabajo, presentamos la lista de pulgas que parasitan a los tlacuaches, con la adición de una especie que no ha sido registrada previamente en D. virginiana, ni en otros marsupiales. Colectamos pulgas de tlacuaches de Virginia en el área urbana de la Ciudad de México, México, y también realizamos una búsqueda bibliográfica para determinar las especies de pulgas reportadas previamente. Encontramos registros de 26 especies de pulgas en los tlacuaches y añadimos a esta lista la especie de pulga Plusaetis sibynus. Plusaetis sibynus es una pulga común en roedores (principalmente Peromyscus y Neotoma), por lo que representa un vector potencial para la transmisión de enfermedades de estos roedores a los tlacuaches, y posteriormente a las poblaciones humanas. Se requieren más estudios para determinar el papel de esta pulga como vector de enfermedades zoonóticas.

Los tlacuaches son animales nocturnos, generalistas y oportunistas; no obstante, se conoce poco de su conducta en vida silvestre, ya que la mayoría de los estudios existentes son en cautiverio. En esta nota se reporta la conducta de Didelphis sp. en vida silvestre utilizando fotos y videos de una cámara trampa, resaltando el uso de la cola para transportar material. En el Cañón del Usumacinta, Estado de Tabasco, México, se colocó una cámara trampa el 8 de abril de 2020; se dejó funcionando y programada para tomar fotografías y videos. Se revisó el 2 de mayo del mismo año, identificando y separando los archivos correspondientes a Didelphis sp. Se identificó la conducta observada, considerando la hora y el sexo de cada individuo identificado. Se obtuvieron 209 registros de fauna silvestre, de los cuales 55 correspondieron a Didelphis sp., todos capturados durante la noche. Se identificaron 5 conductas principales dentro de las que destacan el tránsito con crías en el lomo y el transporte de material vegetal con la cola, probablemente hojas de garabato (Celtis iguanaea) para la construcción del nido. La mayoría de las conductas observadas corresponden al forrajeo; sin embargo, se reporta, por primera vez para México, el comportamiento de transportar material vegetal con la cola, presumiblemente para construir su nido. También, se reportan 3 picos de actividad durante la noche y se observa a una hembra con crías en el marsupio y posteriormente en su lomo.

La introducción de especies exóticas puede afectar negativamente a las especies nativas; por ejemplo, el perro doméstico (Canis lupus familiaris) puede aumentar su riesgo de depredación. Evaluamos el efecto de la presencia de perros y humanos sobre el comportamiento de forrajeo y uso de hábitat del fara, Didelphis pernigra, en un área exurbana en los Andes colombianos. Usamos la técnica de densidades de abandono (DDA), la cantidad de alimento dejada por un forrajeador después de explotar un parche en el que experimenta ganancias decrecientes, y que informa sobre los costos de forrajeo experimentados por un individuo, incluyendo el riesgo percibido de depredación. Medimos las DDA en experimentos en presencia de perro o humano en un área de regeneración natural de bosque andino y en una plantación exótica de Eucaliptus globulus cerca al río Bogotá en Cajicá, Colombia. Los faras utilizaron más el área de regeneración que la plantación; la plantación fue muy poco utilizada. La presencia humana redujo el forrajeo del fara en la regeneración. No se encontró efecto del perro sobre el forrajeo de los faras. Además, el forrajeo también fue afectado por la iluminación de la luna, pero su efecto dependió del periodo de la noche. Este marsupial nativo seleccionó los sitios de forrajeo dependiendo de su exposición a posibles depredadores. El fara no parece reconocer al perro como una amenaza, probablemente incrementando su vulnerabilidad al ataque de estos carnívoros.

A variety of opossum species are resistant to snake venoms due to the presence of antihemorrhagic and antimyotoxic acidic serum glycoproteins that inhibit several toxic venom components. Two virtually identical antihemorrhagic proteins isolated from either the North American opossum (D. virginiana) or the South American big-eared opossum (D. aurita), termed oprin or DM43 respectively, inhibit specific snake venom metalloproteinases (SVMPs). A better understanding of the structure of these proteins may provide useful insight to determine their mechanism of action and for the development of therapeutics against the global health concern of snake-bite envenomation. The aim of this work is to produce a recombinant snake venom metalloproteinase inhibitor (SVMPI) similar to the above opossum proteins in Escherichia coli and determine if this bacterially produced protein inhibits the proteolytic properties of Western Diamondback rattlesnake (C. atrox) venom. The resulting heterologous SVMPI was produced with either a 6-Histidine or maltose binding protein (MBP) affinity tag on either the C-terminus or N-terminus of the protein, respectively. The presence of the solubility enhancing MBP affinity tag resulted in significantly more soluble protein expression. The inhibitory activity was measured using two complementary assays and the MBP labeled SVMPI showed 7-fold less activity as compared to the 6-Histidine labeled SVMPI. Thus, the bacterially derived SVMPI with an unlabeled N-terminus showed high inhibitory activity (IC50 = 4.5 μM). The use of a solubility enhancing MBP fusion protein construct appears to be a productive way to express sufficient quantities of this mammalian protein in E. coli for further study.

Murine typhus, a neglected rickettsiosis caused by Rickettsia typhi, is a common disease in several Latin-American countries. The sylvatic life cycle of R. typhi encompasses the presence of several wild mammals, particularly opossums of the genus Didelphis and their associated fleas. Due to the colonization of wild environments by human populations, the increase in contact with opossum fleas has generated the presence of urban outbreaks of typhus. For this reason, the aim of our study was to identify the presence and diversity of Rickettsia sp. in fleas collected from opossums of an urban reserve in Mexico City. Opossums were captured from February to September 2017. For the detection of Rickettsia DNA, fragments of 800 bp of the citrate synthase (gltA) and the outer membrane protein B (ompB) were amplified. A total of 141 fleas (111 ♀, 30 ♂) of a single species (Ctenocephalides felis felis) were recovered from 31 Didelphis virginiana. Rickettsia DNA was detected in 17.7% (25/141) of the analysed fleas, recovered from seven infested opossums. The Maximum likelihood of sequences exhibited an identity of 99%-100% with sequences of R. typhi from southern United States. This work represents the first record of R. typhi in fleas from opossums in Mexico.

Mammalian pregnancy evolved in the therian stem lineage, that is, before the common ancestor of marsupials and eutherian (placental) mammals. Ancestral therian pregnancy likely involved a brief phase of attachment between the fetal and maternal tissues followed by parturition—similar to the situation in most marsupials including the opossum. In all eutherians, however, embryo attachment is followed by implantation, allowing for a stable fetal–maternal interface and an extended gestation. Embryo attachment induces an attachment reaction in the uterus that is homologous to an inflammatory response. Here, we elucidate the evolutionary mechanism by which the ancestral inflammatory response was transformed into embryo implantation in the eutherian lineage. We performed a comparative uterine transcriptomic and immunohistochemical study of three eutherians, armadillo (Dasypus novemcinctus), hyrax (Procavia capensis), and rabbit (Oryctolagus cuniculus); and one marsupial, opossum (Monodelphis domestica). Our results suggest that in the eutherian lineage, the ancestral inflammatory response was domesticated by suppressing one of its modules detrimental to pregnancy, namely, neutrophil recruitment by cytokine IL17A. Further, we propose that this suppression was mediated by decidual stromal cells, a novel cell type in eutherian mammals. We tested a prediction of this model in vitro and showed that decidual stromal cells can suppress the production of IL17A from helper T cells. Together, these results provide a mechanistic understanding of early stages in the evolution of eutherian pregnancy.

In this study, we examined whether the genetic diversity of Didelphis marsupialis is structured or their populations maintain high gene flow as expected in common species. Forty-eight Tomahawk trap...

Made available in DSpace on 2021-06-25T10:44:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Leptospirosis is a potentially fatal zoonosis caused by Leptospira bacteria. Some animal host species are adapted to specific serovars being potential carriers and environmental dispersers. From 2009 to 2011, 45 wild mammals (39 opossums Didelphis albiventris, four porcupines Sphiggurus villosus, one coypu Myocastor coypus and one capybara Hidrochoerus hidrochaeris) found by citizens in anthropic areas of Monte Mor municipality were captured, restrained and had sera samples collected for Leptospira antibody detection. The samples were titrated by the microagglutination technique (MAT) for different serogroups. A total of 35.56% (16/45) animals were reactive for Leptospira antibodies for 11 different serogroups. The most frequent serovar, among the 12 identified, was Icterohaemorrhagiae (6/16), followed by Gryppotyphosa (4/16) and Pyrogenes (2/16). Didelphis albiventris, the most abundant species in the study, had a prevalence of 35.9% (14/39) for Leptospira antibodies, while S. villosus had 0% (0/4), M. coypus (1/1) and H. hydrochaeris (1/1) 100%. Among the seropositive D. albiventris, 35.71% (5/14) and 28.57% (4/14) seroreacted for Leptospira interrogans species, serogroups Icterohaemorrhagiae and Gryppotyphosa respectively, indicating environmental contamination by these bacteria and the possibility of exposure and infection of humans and domestic animals in the studied area. Programa de Pós-Graduação em Animais Selvagens Faculdade de Medicina Veterinária e Zootecnia FMVZ Universidade Estadual Paulista UNESP Campus de Botucatu Faculdade de Medicina Veterinária do Centro Universitário Sul de Minas UNIS Departamento de Higiene Veterinária e Saúde Pública FMVZ UNESP Campus de Botucatu Departamento de Cirurgia Veterinária e Reprodução Animal FMVZ UNESP Campus de Botucatu Programa de Pós-Graduação em Animais Selvagens Faculdade de Medicina Veterinária e Zootecnia FMVZ Universidade Estadual Paulista UNESP Campus de Botucatu Departamento de Higiene Veterinária e Saúde Pública FMVZ UNESP Campus de Botucatu Departamento de Cirurgia Veterinária e Reprodução Animal FMVZ UNESP Campus de Botucatu

Two young opossums were necropsied and diagnosed with rickets. This study aims to describe the clinical-pathological aspects of rickets in Didelphis albiventris. Macroscopically, the opossums presented kyphosis and scoliosis, lateral deviation of the limbs in varus, locomotion difficulty, and enlargement with softening of costochondral junctions (rickety rosary). Samples of bones and joints were processed for hematoxylin and eosin staining and Masson’s trichrome. Microscopically, we observed thickening of the epiphyseal plate, characterized by irregular and multifocal proliferation of serialized and hypertrophic cartilage zones, which formed circular groups of large, dysplastic chondrocytes towards the spongy zone, often surrounded by non-mineralized osteoid tissue. In the cortical bone, there were pale eosinophilic zones around the Havers channels consistent with non-mineralized osteoid. The staining of Masson’s trichrome evidenced the accumulation of osteoid tissue in cortical and trabecular bones. It is possible that a mixed cause of absorption deficiency of vitamin D3 associated with an unbalanced Ca:P diet based on lactose-free milk and fruits may have triggered the disease. RESUMO: Dois gambás jovens foram necropsiados e diagnosticados com raquitismo. O objetivo do trabalho é descrever os aspectos clínico-patológicos de raquitismo em Didelphis albiventris. Macroscopicamente os gambás apresentaram cifose e escoliose, desvio lateral dos membros em varus, dificuldade de locomoção e alargamento com amolecimento das junções costocondrais (rosário raquítico). Amostras dos ossos e articulações foram processadas para coloração de hematoxilina e eosina e Tricrômico de Masson. Microscopicamente havia espessamento da placa epifisária, caracterizada pela proliferação irregular e multifocal das zonas de cartilagem seriada e hipertrófica, que formavam grupos circulares de condrócitos grandes, displásicos em direção a zona esponjosa frequentemente cercados por tecido osteoide não mineralizado. No osso cortical haviam zonas eosinofílicas pálidas ao redor dos canais de Havers consistentes com osteoide não mineralizado. A coloração de Tricrômico de Masson evidenciou o acúmulo de tecido osteoide no nosso cortical e trabecular. Acredita-se que uma causa mista de déficit de absorção de vitamina D3 associada a uma dieta desbalanceada em Ca:P a base de leite sem lactose e frutas tenha desencadeado a doença.

Adoption by an alloparent of an offspring or a litter occurs in at least eight mammal orders, but is rare in marsupials, and was never confirmed in opossums. Here we report the first unequivocal and documented successful event of alloparental adoption of two distinct litters by a single captive female Southern Black-eared Opossum Didelphis aurita (Didelphimorphia, Didelphidae). The female, still nursing her biological litter, accepted and nursed the two offered litters. All three litters were raised simultaneously, and the female cared for and displayed protective behaviour indistinctively of the biological or adopted pups. She was kept captive until released along with her biological litter, which was weaned and fled independently, and the two adoptive litters clinging on her back. This event sheds additional light on the little known social and maternal behaviour of opossums, suggesting it is possibly more complex than originally thought.

Traumatic injury, including bone fracture, is, to date, one of the leading causes of koala mortality in the South East Queensland region of Australia. Further, the specialist diet of koalas, which is restricted to certain Eucalyptus spp., may impact their normal bone physiology. Considering the dramatic koala population decline and high incidence of trauma, a greater understanding of koala bone physiology may support conservation. We retrieved from GenBank the protein sequences of parathyroid hormone (PTH), osteocalcin (OCN), and tissue-nonspecific alkaline phosphatase (TNALP) in human, dog, cattle, horse, koala, and gray short-tailed opossum. After homology was determined, plasma samples from 13 koalas were analyzed with human PTH, OCN, and bone-specific ALP (BALP) assay kits. Although koala PTH exhibited relatively low sequence homology with placental mammals, high sequence homology between humans and koalas was observed for both OCN and TNALP, and successful cross-reactivity was achieved using human enzyme immunoassay kits for detection of OCN and BALP biomarkers in koala plasma. However, we identified no correlation between OCN and BALP concentrations of healthy and trauma-affected koalas ( p = 0.66 and p = 0.79, respectively). Further analysis of OCN and BALP in healthy and diseased koalas will allow a better understanding of bone physiology in this unique marsupial.

We report the first confirmed occurrence of the Guianan White-eared Opposum Didelphis imperfecta Mondolfi & Pérez-Hernéndez, 1984 (Didelphimorphia: Didelphidae) from Colombia. The individual was captured in a tropical lowland rain forest in the easternmost portion of the Colombian Orinoco Llanos region. The species is endemic of the Guiana Shield and has the smallest distribution area among the species of the genus. Our record shows that the Orinoco river does not constitute a biogeographical barrier for the species. To date, only two species of the genus Didelphis Linnaeus, 1758 have been recorded in Colombia, our results increase the reported number of records for this genus.

Common opossums (Didelphis marsupialis) are found throughout the Caribbean island of Trinidad and Tobago. The present work was conducted on the fresh normal skin of 10 common opossums and aimed to provide morphometric data and a histological description of the skin in different regions of the body. In the examined regions, the skin presented a typical thin skin morphology, with numerous folds on the surface. The dermis-epidermis junction is smooth, without the occurrence of dermal papillae. The average thickness of the opossum epidermis was 19.5 µm. The cranial region of the back showed the greatest epidermal thickness, and together with the other areas of the back presented an epidermis 2-3 times thicker compared with the other areas examined. To further confirm that the skin changes in the opossum are age- or diet-related, additional studies are required.

Wildlife rehabilitation facilities in the Caribbean region are limited, yet they can provide relevant information on wild populations. Didelphis marsupialis insularis is a popularly hunted, under-studied, neo-tropical marsupial species that is increasingly being admitted for rehabilitation. The aim of this study was 1. To record the experiences of rehabilitating D. marsupialis insularis in the neo-tropical island of Trinidad and Tobago and 2. To extract and highlight information on the biology of this opossum sub-species. Using admission records, obtained over a roughly four year period, two breeding periods (February to March and August to October) were illustrated. Litter sizes averaged five individuals, with a range of 1 to 8 young. This species was found to be common in urban areas of the country, with dog attacks reported as the major cause for admission. Thus the information recorded by this wildlife rehabilitation facility has provided great insight on the sparsely studied opossum, D. marsupialis insularis. Resumo As instalações de reabilitação e assistência à vida selvagem na região neotropical do Caribe são limitadas, mas informações relevantes sobre populações selvagens podem ser obtidas nesses locais. Didelphis marsupialis insularis é uma espécie de marsupial neotropical, subestimada e popularmente caçada; no entanto, essa espécie está sendo cada vez mais admitida para a reabilitação. Os objetivos deste estudo foram: 1. Registrar as experiências de reabilitação de D. marsupialis insularis na ilha neotropical de Trinidad e Tobago; e 2. Extrair e destacar informações sobre a biologia dessa subespécie de gambá. Utilizando registros de admissão, obtidos ao longo de um período de aproximadamente quatro anos, foram mostrados dois períodos de reprodução, de fevereiro a março e de agosto a outubro. O tamanho da ninhada foi em média de cinco indivíduos, variando de um a oito jovens. Comumente encontrado em áreas urbanas do país, os ataques de cães foram relatados como a principal causa de internação dessa espécie. Assim, a informação registrada por essa instalação de reabilitação de vida selvagem forneceu uma grande visão sobre o gambá D. marsupialis insularis, que tem sido pouco estudado.

Cities have grown throughout the Andes and we know little about the ecology of those species that tolerate them, limiting our options to do conservation. We applied optimal foraging theory to examine the behavior of the Andean White-eared Opossum (Didelphis pernigra), in a suburban area in Bogotá, Colombia. We used the giving-up density technique, which uses the amount of food left in a feeding patch, to evaluate whether the opossum’s foraging costs were affected by the height of food from the ground, and the quality and quantity of food. We also evaluated whether the spatial heterogeneity of the study site affected the opossum’s foraging. We used an artificial feeding patch to test these ideas. When food was either concentrated and, in less amount, (concentrated food) or diluted and more amount (diluted food), the opossums preferred to forage at 2 m than at 0.5 m, but concentrated food at 0.5 m was not significantly different from diluted food at 2 m. The opossums’ habitat use was affected by the spatial heterogeneity at the study site and animals preferred foraging along metal fences than on live fences made of trees. When a cable allowed connection between the metallic and live fences, the value of food patches at the live fence appeared to increase. Thus, although the opossums need resources associated with natural environments, our results suggest that there are human modifications that can benefit them, such as those that reduce the risk of predation and favor their mobility in suburban environments.

Made available in DSpace on 2020-12-12T02:20:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 The white-eared opossum present a higher roadkill number in Brazil, and the vertebral column is often affected when some type of trauma occurs. Thus, this study describes the osteology and radiology of the vertebral column in white-eared opossum to serve as a basis for support in the veterinary clinical care, since the casuistry of care of this marsupial has increased every year. Radiographs of the cervical (C), thoracic (T), lumbar (L), sacral (S) and caudal (Cd) segments of the vertebral column were taken in thirty-five white-eared opossums (Didelphis albiventris). Furthermore, ten opossums without evident vertebral acquired or congenital abnormalities at the radiographic study were selected for anatomical study. Osteology was correlated with the radiographic images. The use of radiographs allowed the identification of congenital and acquired vertebral changes, as well as the identification of anatomical structures, their distribution and morphology and the number of vertebrae. The vertebral formula varied in the white-eared opossum. In 27 of 35 white-eared opossums (77.2%) with normal vertebral morphology, three vertebral formulas were observed: C7/T13/L6/S2 (62.9%), C7/T13/L5/S2 (5.7%) and C7/T13/L7/S2 (8.6%). Most of the specimens presented 27 caudal vertebrae. The anticlinal vertebra was identified as T10 in 77.2% and T11 in 22.8% of opossums. Cervical block vertebra was observed in two animals and sacrocaudal block vertebra in one animal. The haemal arches could be seen from Cd3–Cd4 in 80% and Cd2–Cd3 in 20% of opossums. The white-eared opossum showed a slender vertebral column with a relatively short thoracic region, a relatively long lumbar region and a highly flexible lumbosacral transition, suggesting that this animal is a fast-running and agile opossum. Therefore, these findings may serve as a basis for further research and support the veterinary clinical care, since the casuistry of care for this marsupial has increased every year. School of Veterinary Medicine and Animal Science Graduate Program in Wild Animals São Paulo State University (UNESP) Department of Anatomy Institute of Biosciences São Paulo State University (UNESP) Department of Animal Reproduction and Veterinary Radiology School of Veterinary Medicine and Animal Science São Paulo State University (UNESP) School of Veterinary Medicine and Animal Science Graduate Program in Wild Animals São Paulo State University (UNESP) Department of Anatomy Institute of Biosciences São Paulo State University (UNESP) Department of Animal Reproduction and Veterinary Radiology School of Veterinary Medicine and Animal Science São Paulo State University (UNESP)

Habitat fragmentation may affect animal movement patterns due to changes in intra- and interspecific interactions as well as in habitat quality and structure. Although the effects of habitat fragmentation on terrestrial movements are relatively well-known, it is unclear whether and how they affect aboveground locomotion of individuals. We compared aboveground locomotion of a Neotropical small mammal, the gray four-eyed opossum, Philander quica, between two forest fragments and two areas of continuous forest in the Brazilian Atlantic Forest. We 1) quantified support availability and tested for active selection of different support diameters and inclinations by individuals; and 2) compared support diameters and inclinations used (observed values) among areas and between males and females. Both males and females selected supports based on diameters and inclinations in forest fragments. In continuous forests sites, females selected supports based on diameters and inclinations, but males selected only support diameters. Frequency of support diameter use differed significantly between forest fragments and continuous forest sites and between males and females. Frequency of support inclination use differed significantly between areas only for females, and between sexes only in continuous forest sites. Sex-related differences in support selection and use are likely related to differences in body size and conflicting energetic and behavioral demands related to use of arboreal space. Site-related differences in aboveground movements likely reflect the effects of forest edges that result in increased use of thinner supports in forest fragments. These results complement our previous findings that habitat fragmentation reduces daily home ranges and increases the total amount of aboveground locomotion of P. quica, and provide a more thorough picture of how forest-dependent species are able to use and persist in small forest fragments.

The present study aimed to investigate if the white-eared opossum under natural conditions is capable of spontaneously solving the parallel string task. The experimental study with this primitive mammal was carried out on fifteen naïve animals of both sexes in northeastern Brazil. The parallel strings task was arranged in apparatuses with a vertical and a horizontal arrangement. A food reward (a slice of banana) was connected at the extremity of one string. A total of 505 videos were recorded using trap cameras. Despite the observed interest in obtaining the bait, the number of attempts to reach it and the use of the strings as support (trying to directly reach the bait in the vertical apparatus), the individuals were unable to pull any of the strings, suggesting that they could not understand the problem. The present study points to the relevance of using the species Didelphis albiventris and other species from this family (e.g., D. virginiana) to broaden our knowledge about the cognitive capacity of mammalian species. In addition, the opossums might represent an advisable path to better understand the evolution of cognition in this group.

Opossums in the clade Didelphini are well known to be resistant to snake venom due to endogenous circulating inhibitors which target metalloproteinases and phospholipases. However, the mechanisms through which these opossums cope with a variety of other damaging venom proteins are unknown. A protein involved in blood clotting (von Willebrand Factor) has been found to have undergone rapid adaptive evolution in venom-resistant opossums. This protein is a known target for a subset of snake venom C-type lectins (CTLs), which bind it and then induce it to bind platelets, causing hemostatic disruption. Several amino acid changes in vWF unique to these opossums could explain their resistance; however, experimental evidence that these changes disrupt venom CTL binding was lacking. We used platelet aggregation assays to quantify resistance to a venom-induced platelet response in two species of venom-resistant opossums (Didelphis virginiana, Didelphis aurita), and one venom-sensitive opossum (Monodelphis domestica). We found that all three species have lost nearly all their aggregation response to the venom CTLs tested. Using washed platelet assays we showed that this loss of aggregation response is not due to inhibitors in the plasma, but rather to the failure of either vWF or platelets (or both) to respond to venom CTLs. These results demonstrate the potential adaptive function of a trait previously shown to be evolving under positive selection. Surprisingly, these findings also expand the list of potentially venom tolerant species to include Monodelphis domestica and suggest that an ecological relationship between opossums and vipers may be a broader driver of adaptive evolution across South American marsupials than previously thought.

Currently, a great proportion of the emerging infectious human diseases are zoonotic, with most of the pathogens originated from wildlife. In this sense, synanthropic animals such as marsupials play important role in the dissemination of pathogens due to their proximity to human dwellings. These hosts are affected by many gastrointestinal parasites, including species with zoonotic potential. The aim of this study was to assess the diversity of gastrointestinal parasites infecting the black-eared opossum D. aurita captured in urban areas of Southeastern, Brazil. In addition, the potential risk for the human population based on the One Health perspective has been discussed. Forty-nine marsupial specimens were captured with Tomahawk live traps and fecal samples were collected. The samples were evaluated by parasitological procedures. Eggs and oocysts were analyzed at different magnifications (400 × and 1000 ×), and their identification, together with adult nematodes, was established on morphological and morphometric data. Forty-three hosts (87.76%) scored positive for at least one gastrointestinal parasite, being 83.67% (41/49) for helminths, and 65.30% (32/49) for protozoa. For Cryptosporidium sp., only 13 samples were evaluated due to insufficient amount of feces obtained of some animals. A prevalence of 23.08% (3/13) was reported for this parasite. PCR analysis revealed Ancylostomatidae eggs to belong to the genus Ancylostoma. Our results demonstrated that multiparasitism is frequently found in these animals and a high percentage of potentially zoonotic parasites are observed, implying that D. aurita may be involved in zoonotic cycles in urban environments.

Trypanosoma cruzi, a zoonotic protozoan parasite, infects a wide range of mammals. The southern United States has endemic sylvatic transmission cycles maintained by several species of wildlife and domestic dogs. We hypothesized that urban-dwelling opossums (Didelphis virginiana) in South Texas are infected with T. cruzi, and that tissue pathology would be associated with infection. In 2017, we collected blood, heart tissue and anal gland secretions from 100 wild opossums across three seasons that were trapped by animal control in South Texas. In addition, anal gland tissue and intercostal muscle were collected from 43 of the 100 opossums for which time allowed the extra tissue collection. All blood, tissue, and secretion samples were screened for T. cruzi DNA using qPCR with confirmation of positive status achieved through one or more additional PCR assays, including a qPCR to determine the parasite discrete typing unit (DTU). T. cruzi DNA was detected in at least one tissue of 15% of the opossums sampled: blood clot (9%), heart tissue (10%), anal gland secretions (12%), intercostal muscle (16.3%), and anal gland tissue (11.6%). Infection was detected in two or more different tissue types in nine of the opossums. The 35 tissues for which parasite DTU was determined were exclusively ‘Tcl’- a DTU previously associated with locally-acquired human disease in the United States. T. cruzi-positive opossums were nearly 14 times more likely to exhibit significant heart lesions on histopathology (lympoplasmacytic inflammation±fibrosis) when compared to negative opossums (OR = 13.56, CI = 1.23–751.28, p-value = 0.03). Three triatomines were opportunistically collected from the study site, of which two were infected (66.7%), and bloodmeal analysis revealed canine, opossum, and human bloodmeals. Given the presence of parasite in opossum blood, unique potential for shedding of parasite in anal glad secretions, and evidence of vectors feeding on opossums, it is likely that opossums serve as wild reservoirs around urban dwellings in South Texas., Graphical abstract Image 1, Highlights • Trypanosoma cruzi type ‘TcI’ DNA was detected in 15% of opossums from South Texas. • Infected tissues included blood, heart, skeletal muscle, and anal glands and secretions. • Heart pathology occurred more frequently in opossums with infected tissues. • Local triatomines were found to feed on opossum, dog, and human. • Urban opossums likely serve as T. cruzi reservoirs in the US.

A fragment of a Dracunculus-like worm was extracted from the hind limb of a 2-year-old dog from Toledo, Spain. Cytochrome oxidase I and rRNA sequences confirmed an autochthonous mammalian Dracunculus worm infection in Europe. Sequence analyses suggest close relation to a parasite obtained from a North American opossum.

One of the major challenges of modern neurobiology concerns the inability of the adult mammalian central nervous system (CNS) to regenerate and repair itself after injury. It is still unclear why the ability to regenerate CNS is lost during evolution and development and why it becomes very limited in adult mammals. A convenient model to study cellular and molecular basis of this loss is neonatal opossum (Monodelphis domestica). Opossums are marsupials that are born very immature with the unique possibility to successfully regenerate postnatal spinal cord after injury in the first two weeks of their life, after which this ability abbruptly stops. Using comparative proteomic approach we identified the proteins that are differentially distributed in opossum spinal tissue that can and cannot regenerate after injury, among which stand out the proteins related to neurodegenerative diseases (NDD), such as Huntington, Parkinson and Alzheimer's disease, previously detected by comparative transcriptomics on the analog tissue. The different distribution of the selected proteins detected by comparative proteomics was further confirmed by Western blot (WB), and the changes in the expression of related genes were analysed by quantitative reverse transcription PCR (qRT-PCR). Furthermore, we explored the cellular localization of the selected proteins using immunofluorescent microscopy. To our knowledge, this is the first report on proteins differentially present in developing, non-injured mammalian spinal cord tissue with different regenerative capacities. The results of this study indicate that the proteins known to have an important role in the pathophysiology of neurodegeneration in aged CNS, could also have an important phyisological role during CNS postnatal development and in neuroregeneration process.

Developing a captive breeding system for the widely hunted Caribbean species of opossum Didelphis marsupialis insularis can greatly aide in the management and conservation of this species in the neo-tropics. Although this species possesses ideal traits for captive breeding in this region (tolerance to high heat and humidity, high reproductive rate, and resistance to disease), challenges due to its aggressive behaviour and limited information on its breeding behaviour have prevented a system from being developed for this species. The present study describes a breeding system, and the reproductive behaviour of this species under captive conditions. Six (1 male; 5 females) adult opossums were maintained and managed for breeding over a ten (10) month period. Pouch litter sizes averaged 5±2.5 with a range of 2 to 8. Gestation length was found to be 13.25±0.96 days and 4 litters (n=23) were successfully weaned at 11-13 weeks. It was found that the male D. m. insularis exhibits behaviours of interest that can serve as indicators for receptivity of the female, and overall, that this species can be successfully reared and bred under captive conditions in the neo-tropics.

Functionalized nanostructured systems can be used for imaging and drug delivery for anti-tumor therapy, including breast tumors. This is a more efficient approach that offers reduced systemic side effects compared to conventional diagnostic and chemotherapy methods. Multifunctional nanoparticles are potential tools in the diagnosis, location tracing and kill tumor cells through a less invasive manner. Functionalized phosphate-based nanoparticles are capable of encapsulating, or may be associated, with fluorescent probes. In this study, we synthesize a nanoparticle phosphate-based composite (NPC) and functionalize it with poly-ethylene glycol (PEG), hyaluronic acid (HA), the fluorescent probe rhodamin 6G (R6G) and the antimitotic doxorubicin (DOX). We focused on targeting human breast cancer cells reporting the biological effects of functionalized NPC on them. NPC and NPC formulations containing PEG, HA, and R6G did not cause cell viability reduction on MCF-7 and MDA-MB-231 cell lines. The cellular internalization of NPC was quantified by real-time in vitro observation, and confirmed by electron microscopy techniques. Intracellular NPC distribution is detected in the cytoplasm and nucleus of tumor cells by confocal fluorescent images. The percent association of doxorubicin to NPC matrix was approximately 18% and NPC formulations associated with doxorubicin led to a significant reduction in cell viability in MDA-MB-231 and MCF-7 cells. This data suggest the potential use of NPC as a non-cytotoxic platform for association with functional ligands to selective targeting breast cancer cells. NPC use can be also explored in drug delivery to cancer cells.

The opossum (Monodelphis domestica), with its sequenced genome, ease of laboratory care and experimental manipulation, and unique biology, is the most used laboratory marsupial. Using the mammalian methylation array, we generated DNA methylation data from n=100 opossum tissues including blood, liver, and tail. We contrast age-related changes in the opossum methylome to those of C57BL/6J mice. We present several epigenetic clocks for opossums that are distinguished by their compatibility with tissue type (pan-tissue and blood clock) and species (opossum and human). Two dual-species human-opossum pan-tissue clocks accurately measure chronological age and relative age, respectively. These human-opossum epigenetic clocks are expected to provide a significant boost to the attractiveness of opossum as a biological model.

Made available in DSpace on 2022-04-29T08:32:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul The order Piroplasmida encompasses tick-borne pathogens of veterinary and medical importance positioned in two main families: Babesiidae and Theileriidae. Even though previous studies carried out in Brazil recorded the occurrence of piroplasmid species circulating in small mammals, 18S RNA gene sequences were only partially sequenced, preventing the assessment of their phylogenetic positioning. The current study aimed to detect and characterize, using morphological, molecular, and bioinformatic approaches, piroplasmids from wild mammals and associated ticks sampled in Central-Western Brazil. Out of 67 Didelphis albiventris sampled, 22 (16.4%) were positive for piroplasmids by PCR. In contrast, none of the 48 small rodents and 14 capybaras (Hydrochoerus hydrochaeris) was PCR-positive. Four Amblyomma dubitatum ticks—one from Rattus rattus, one from H. hydrochaeris, and two from D. albiventris—out of 114 Amblyomma spp. DNA samples were positive for piroplasmids by PCR. The phylogenetic inference performed using the near-complete 18S rRNA gene positioned the putative novel piroplasmid species detected in D. albiventris and associated A. dubitatum ticks near to Babesia sensu lato clade (Western group—cluster III) and distant from the Australian marsupial-associated piroplasms. Phylogenetic inferences based on two additional molecular markers, namely hsp-70 and cox-1, supported the near-complete 18S rRNA gene phylogenetic inference. Finally, the partial 18S rRNA gene sequences detected in ticks from rodents (R. rattus and H. hydrochaeris) showed 97.2–99.4% identity with the Piroplasmida previously detected in a capybara from Brazil, raising evidence that a still uncharacterized piroplasmid species has been identified in the capybara, the largest rodent species from South America. Graduate Program of Agricultural and Livestock Microbiology Faculty of Agrarian and Veterinary Sciences FCAV/UNESP) Department of Pathology Reproduction and One Health - Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista (FCAV – UNESP), Campus de Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane, s/n, Zona Rural Veterinary Clinical Pathology Laboratory College of Agronomy and Veterinary Medicine (FAV) University of Brasília Laboratory of Parasitic Biology Dom Bosco Catholic University Graduate Program of Natural Resources Federal University of Mato Grosso Do Sul Wild Animals Section Veterinary Hospital of the College of Agronomy and Veterinary Medicine (FAV) University of Brasília Graduate Program of Agricultural and Livestock Microbiology Faculty of Agrarian and Veterinary Sciences FCAV/UNESP) Department of Pathology Reproduction and One Health - Faculdade de Ciências Agrárias E Veterinárias Universidade Estadual Paulista (FCAV – UNESP), Campus de Jaboticabal, Via de Acesso Prof. Paulo Donato Castellane, s/n, Zona Rural CAPES: 001 FAPESP: 2018/02753-0 FAPESP: 2020/12037-0 CNPq: 302420 / 2017-7 CNPq: 308768/2017-5 Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul: 59 / 300.187 / 2016

The zinc-activated channel (ZAC, nomenclature as agreed by the NC-IUPHAR Subcommittee for the Zinc Activated Channel) is a member of the Cys-loop family that includes the nicotinic ACh, 5-HT3, GABAA and strychnine-sensitive glycine receptors [2, 3, 4]. The channel is likely to exist as a homopentamer of 4TM subunits that form an intrinsic cation selective channel equipermeable to Na+, K+ and Cs+, but impermeable to Ca2+ and Mg2+ [4]. ZAC displays constitutive activity that can be blocked by tubocurarine and high concentrations of Ca2+ [4]. Although denoted ZAC, the channel is more potently activated by H+ and Cu2+, with greater and lesser efficacy than Zn2+, respectively [4]. ZAC is present in the human, chimpanzee, dog, cow and opossum genomes, but is functionally absent from mouse, or rat, genomes [2, 3].

The state of Acre is in the western part of the Brazilian Amazon region and few studies involving ticks are available. The aim of the present study was to provide the first report of occurrence of Amblyomma latepunctatum and the second record of Ixodes luciae in Acre. Ticks were collected in October 2020 inside an open forested area in the municipality of Rio Branco, the state capital of Acre. Ixodid ticks were identified according to their external morphological characteristics. Three specimens were found on the vegetation by means of a visual search and were identified as Amblyomma scalpturatum (one male and one female) and Amblyomma latepunctatum (one male). Another specimen was found parasitizing a Didelphis marsupialis female that was caught using a Tomahawk trap; this was identified as Ixodes luciae (one male). This first report of A. latepunctatum in the state of Acre increases the number of species recorded here to 22. In addition, presence of I. luciae is confirmed in this state (second record), in the western Brazilian Amazon region. Resumo O estado do Acre está localizado na Amazônia ocidental brasileira e apresenta poucos estudos envolvendo carrapatos. O presente estudo objetivou relatar, pela primeira vez, a ocorrência da espécie Amblyomma latepunctatum e o segundo registro de Ixodes luciae no estado do Acre, Brasil. A coleta de carrapatos foi realizada em outubro de 2020 no interior de uma floresta aberta no município de Rio Branco, capital do estado do Acre. Carrapatos ixodídeos foram identificados de acordo com suas características morfológicas externas. Três espécimes foram encontrados sobre a vegetação pelo método de inspeção visual e identificados como as espécies Amblyomma scalpturatum (um macho e uma fêmea) e Amblyomma latepunctatum (um macho); e outro foi encontrado parasitando uma fêmea de Didelphis marsupialis que foi capturada por uma armadilha Tomahawk, e identificado como Ixodes luciae (um macho). Este primeiro relato de A. latepunctatum no estado do Acre aumenta o número de espécies registradas aqui para 22. Além disso, a presença de I. luciae é confirmada no estado do Acre (segundo registro), na região da Amazônia ocidental brasileira.

Opossums are marsupials from the New World of the genus Didelphis and known as synanthropic animals due to their proximity with human beings. To date, ‘Candidatus Mycoplasma haemodidelphis’ has been solely found infecting the North American opossum (Didelphis virginiana). Accordingly, the aim of this study was to screen eight white-eared opossums (Didelphis albiventris) from a public park in Maringa city, Paraná State, southern Brazil, for hemoplasma infection. Blood samples were taken from caudal venipuncture, and DNA was extracted and further screened by a pan-hemoplasma PCR assay. Seven out of eight (87.50%; CI 95%: 47.35-99.68%) white-eared opossums were positive for Mycoplasma spp. Sequencing of the 16S rRNA fragment showed 98,97% identity with ‘Ca. M. haemodidelphis’ detected in the USA. Three out of eight (37.50%; CI 95%: 8.52-75.51%) white-eared opossums were infested by Amblyomma dubitatum ticks. This is the first report on detection of a potentially novel hemotropic Mycoplasma sp. infecting opossums from South America.

OBJECTIVES Documenting the variety of quadrupedal walking gaits in a variety of marsupials (arboreal vs. terrestrial, with and without grasping hind feet), to aid in developing and refining a general theory of gait evolution in primates. MATERIALS AND METHODS Video records of koalas, ringtail possums, tree kangaroos, sugar gliders, squirrel gliders, wombats, numbats, quolls, a thylacine, and an opossum walking on a variety of substrates were made and analyzed to derive duty factors and diagonalities for symmetrical walking gaits. The resulting distributions of data points were compared with published data and theories. RESULTS Terrestrial marsupials' gaits overwhelmingly plot slightly below the theoretical "horse line" (Cartmill et al., Zoological Journal of the Linnean Society. 2002;136:401-420) typical of terrestrial mammals; arboreal marsupials' gaits overwhelmingly plot more decisively above it. Both distributions are roughly parallel to the horse line, but arboreal animals exhibit increased diagonality, so that their higher-speed walking gaits overlap with those of typical primates on the Hildebrand diagram of diagonality against duty factor. CONCLUSIONS Quadrupeds avoid gaits lying exactly on the (theoretically optimum) horse line, to avoid fore/hind limb interference ("forging"). This can be accomplished by either a slight reduction in diagonality ("downshifting") or a more decisive increase ("upshifting"). Tree-dwellers adopt the second option to eliminate unilateral bipods of support from the gait cycle. The upshifted horse line represents an early phase in the evolution of primate-like diagonal-sequence gaits.

In January 2018, a young male of Didelphis aurita (Wied-Neuwied, 1826), the Brazilian common opossum, was admitted for veterinary evaluation at the Recovery Clinic of Wild Animals of Estácio de Sá University, CRAS, in Rio de Janeiro, Brazil, due to the presence of a partially duplicated right hind limb. After x-ray evaluation, polymelia associated with syndactyly was diagnosed. The images revealed the following alterations on the right limb: single femur with increased diameter, two tibiae, two fibulae and absence of hallux. The observed malformations were restricted to the hind right limb, which remains functional. This is the first report of such anomalies in an individual of Didelphis aurita. Resumo Em janeiro de 2018, um macho jovem de Didelphis aurita (Wied-Neuwied, 1826), o gambá-de-orelha-preta, foi recebido para atendimento veterinário na Clínica de Recuperação de Animais Silvestres (CRAS) da Universidade Estácio de Sá, no Rio de Janeiro, por ser portador de membro posterior direito parcialmente duplicado. Após exame radiográfico, constatou-se a ocorrência de polimelia associada a sindactilia. As imagens radiográficas revelaram as seguintes alterações no membro posterior direito: um fêmur com diâmetro aumentado, duas tíbias, duas fíbulas e ausência de hálux. As malformações observadas restringiram-se apenas ao membro posterior direito, o qual mantém sua funcionalidade. Essas alterações nunca antes foram descritas na espécie Didelphis aurita.

Marsupials have short gestation periods, with altricial neonates completing their development attached to a teat, a condition that induces remarkable structural changes in the inguinal region of reproductive females. In this study, we analyzed the morphological variation in the inguinal region of female museum specimens of Monodelphis domestica in search for external traits reminiscent of their reproductive condition when collected. We examined 427 taxidermied skins of wild females from northeastern Brazil and classified their inguinal region by color, density of fur, shape, and the presence of spots and teats. We determined relative age based on tooth eruption and wear, to infer the chronological order of inguinal changes. These conditions were computed for each age class and for each month over 4 years for samples from two mesoregions in northeastern Brazil, identified from climatic characteristics. Four distinct morphological patterns recognized in the inguinal region of females were associated with the following reproductive conditions: 1) non-lactating: general shape of the pelvic region indistinct from the rest of body (straight), inguinal region lacking teats, same fur density and color (grayish) as the rest of the body; 2) pre-lactating: pelvic and inguinal regions similar to non-lactating, but yellowish fur and presence of small teats; 3) early-lactating: inguinal region with well-developed teats, fur yellowish (rarely whitish) and less dense, and form of the pelvic region rounded; and 4) late or post-lactating: inguinal region with well-developed teats and dark orange and less dense fur, pelvic region rounded. Lactating females were only recorded from age class 4 on. We also found indications that pelage changes in the inguinal region do not revert after reproduction in the wild. Monthly frequencies of the different conditions recorded for lactating females corroborate previous studies that suggested that M. domestica breeds all year long in northeastern Brazil.Marsupiais caracterizam-se por apresentar um curto período de gestação, com neonatos altriciais completando seu desenvolvimento ligados à teta, uma condição que induz mudanças estruturais marcantes na região inguinal de fêmeas reprodutivas. No presente estudo analisamos a variação morfológica da região inguinal de fêmeas taxidermizadas de Monodelphis domestica, buscando traços reminiscentes de suas condições reprodutivas quando coletadas. Examinamos 427 peles taxidermizadas de fêmeas silvestres obtidas no Nordeste do Brasil, e classificamos a região inguinal pela cor, densidade de pelos, presença de manchas e tetas, e forma da região pélvica. Determinamos a idade relativa com base na erupção e no desgaste dentário, para inferir a ordem cronológica das mudanças inguinais. Essas condições foram registradas para cada idade e por cada mês ao longo de 4 anos para amostras de duas mesorregiões no Nordeste do Brasil, identificadas com base em características climáticas. Quatro padrões morfológicos distintos reconhecidos na região inguinal das fêmeas foram associadas às seguintes condições reprodutivas: 1) não-lactante: forma geral da região pélvica indistinta do resto do corpo (retas), região inguinal sem tetas e mesma cor e densidade da pelagem (cinza) que o resto do corpo; 2) pré-lactante: regiões inguinal e pélvica similares às do padrão não-lactante, mas pelagem amarelada e presença de tetas pequenas; 3) lactante inicial: região inguinal com tetas bem desenvolvidas, pelagem inguinal amarelada (raramente branca) e menos densa, forma da região pélvica arredondada; 4) lactante tardia ou pós-lactante: região inguinal com tetas bem desenvolvidas, pelagem laranja escura e menos densa, região pélvica arredondada. Fêmeas lactantes foram observadas apenas da classe de idade 4 em diante. Encontramos evidências de que a mudança da pelagem na região inguinal não é revertida depois da reprodução na natureza. Frequências mensais das diferentes condições reprodutivas das fêmeas observadas corroboram estudos prévios que sugerem que M. domestica pode se reproduzir ao longo de todo o ano no Nordeste do Brasil.

Milk provides mammalian neonates with nutritional support and passive immunity. This is particularly true in marsupials where young are born highly altricial and lacking many components of a fully functional adaptive immune system. Here we investigated the T cell populations in the mammaries of a lactating marsupial, the gray short-tailed opossum Monodelphis domestica. Immunohistochemistry confirmed the presence of T cells within the opossum mammaries throughout lactation. Results of quantifying transcript abundance for lymphocyte markers are consistent with γδ T cells being the most common T cell type within lactating mammaries. Numbers of γδ T cells appear to peak early during the first postnatal week, and then decline throughout lactation until weaning. In contrast, numbers of αβ T cells and γμ T cells appear to be low to non-existent in the lactating mammaries. The results support an ancient and conserved role of immune cells in the evolution and function of mammalian mammary tissue.

Made available in DSpace on 2019-10-06T16:24:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01. Added 1 bitstream(s) on 2019-10-09T18:35:22Z : No. of bitstreams: 1 S1984-29612019000100140.pdf: 1179525 bytes, checksum: ac285496c1fbb19eeb76eedfe6492121 (MD5) Erlichiosis affects humans and animals worldwide. Its distribution and prevalence depends on the presence of tick vectors and hosts in one geographic area. The aim of the present study was to investigate the occurrence of Ehrlichia spp. and Anaplasma spp. in opossums (Didelphis sp.) from the State of Rio de Janeiro, southeast Brazil. Blood samples from 37 animals were tested for these two pathogens using molecular methods. One animal (2.7%) was positive for Ehrlichia sp. by 16S rRNA-based nested PCR. In a phylogenetic analysis based on the 16S rRNA gene using the maximum likelihood method and the GTRGAMMA+I evolutionary model, we detected a novel Ehrlichia sp. genotype closely related to genotypes of E. canis previously reported in dogs from Brazil. To the authors’ knowledge, this is the first molecular detection of Ehrlichia sp. in opossums from this State in the southeastern region of the country. Departamento de Medicina e Cirurgia Veterinária Instituto de Veterinária Universidade Federal Rural do Rio de Janeiro - UFRRJ Centro de Recuperação de Animais Silvestres - CRAS Universidade Estácio de Sá - UNESA Departamento de Patologia Veterinária Faculdade de Ciências Agrárias e Veterinárias - FCAV Universidade Estadual Paulista - UNESP Departamento de Patologia Veterinária Faculdade de Ciências Agrárias e Veterinárias - FCAV Universidade Estadual Paulista - UNESP

Considered ecologically generalist, Didelphis albiventris is reported as reservoir for different species of parasites, especially Trypanosoma cruzi. However, the knowledge about the influence of T. cruzi on hematological parameters of free-living opossum remains scarce. The present study aimed to evaluate the influence of T. cruzi on hematological parameters of white-ear opossums (D. albiventris) from Campo Grande, Mato Grosso do Sul, Brazil. The blood samples and biometric data were collected from 40 opossums captured by Tomahawk and Sherman traps in six urban forest fragments located in the city. The health of these animals was inferred, mainly, by means of blood parameters (PCV, RBC, WBC, MCV and WBC differential). Molecular detection of T. cruzi infection was performed by nested polymerase chain reaction (nPCR), using 18S and 24Sα rDNA region as target. Paired-t-test and simple linear regression were used for statistical analysis. No significant difference was observed between the averages of hematological variables in relation to gender and body condition. The molecular diagnosis showed that 32.5% (13/40) of the opossums were infected by T. cruzi, which presented lymphocytosis (3.4 ± 1.5) and eosinophilia (0.09 ± 0.13). Path analysis showed that T. cruzi infection resulted in increased numbers of lymphocytes and indirectly decreased the body condition of opossums. Moreover T. cruzi infection resulted in a direct effect on decrease of MCV. Overall, our results suggest that T. cruzi infection may represent a risk to health of opossums since the lymphocytosis may cause a secondary damage on body condition of infected animals., Graphical abstract Image 1, Highlights • Trypanosoma cruzi infection may pose a risk to health of opossums. • Lymphocytosis may cause a secondary damage on body condition of infected animals. • D. albiventris is an important host of T. cruzi in the Campo Grande city.

Over the past two centuries, mammalian chewing and related anatomical features have been among the most discussed of all vertebrate evolutionary innovations1-3. Chief among these features are two characters: the dentary-only mandible, and the tribosphenic molar with its triangulated upper cusps and lower talonid basin3-5. The flexible mandibular joint and the unfused symphysis of ancestral mammals-in combination with transformations of the adductor musculature and palate-are thought to have permitted greater mobility of each lower jaw, or hemimandible6,7. Following the appearance of precise dental occlusion near the origin of the mammalian crown8,9, therians evolved a tribosphenic molar with a craggy topography that is presumed to have been used to catch, cut and crush food. Here we describe the ancestral tribosphenic therian chewing stroke, as conserved in the short-tailed opossum Monodelphis domestica: it is a simple symmetrical sequence of lower tooth-row eversion and inversion during jaw opening and closing, respectively, enacted by hemimandibular long-axis rotation. This sequence is coupled with an eversion-inversion rotational grinding stroke. We infer that the ancestral therian chewing stroke relied heavily on long-axis rotation, including symmetrical eversion and inversion (inherited from the first mammaliaforms) as well as a mortar-and-pestle rotational grinding stroke that was inherited from stem therians along with the tribosphenic molar. The yaw-dominated masticatory cycle of primates, ungulates and other bunodont therians is derived; it is necessitated by a secondarily fused jaw symphysis, and permitted by the reduction of high, interlocking cusps10-12. The development of an efficient masticatory system-culminating in the tribosphenic apparatus-allowed early mammals to begin the process of digestion by shearing and crushing food into small boli instead of swallowing larger pieces in the reptilian manner, which necessitates a long, slow and wholly chemical breakdown. The vast diversity of mammalian teeth has emerged from the basic tribosphenic groundplan13.

Short-tailed opossums of the nominotypical subgenus Monodelphis occur throughout most of the cis-Andean lowlands of tropical South America. Among its member species, a monophyletic group that includes M. glirina (Amazonian red-sided opossum), M. sanctaerosae (Santa Rosa short-tailed opossum), and an unnamed taxon, herein referred to as the Monodelphis glirina group, is the focus of this paper. I provide an emended diagnosis for species of the group, information about geographic variation in M. glirina (including M. maraxina [Marajó short-tailed opossum]), and a formal description for the unnamed taxon mentioned above. The new species, known from two savanna localities in northeastern Roraima, is geographically disjunct from its closer relatives, M. glirina and M. sanctaerosae, only known to occur south of the Amazon. The new species differs from other congeneric taxa by a set of morphological characters and by DNA sequences.Cuícas-de-cauda-curta do subgênero nominotípico Monodelphis ocorrem na maior parte das planícies cis-Andinas da América do Sul tropical. Dentre as espécies membro, o grupo monofilético que inclui M. glirina, M. sanctarosae, e um táxon ainda não descrito, referido como grupo Monodelphis glirina, é o foco do presente estudo. Aqui são fornecidas diagnoses emendadas para as espécies do grupo, informações sobre variação geográfica em M. glirina (incluindo M. maraxina), e descrição formal para o novo táxon mencionado acima. A nova espécie, conhecida de duas localidades de savana no nordeste de Roraima, encontra-se geograficamente disjunta das espécies mais proximamente relacionadas, M. glirina e M. sanctaerosae, somente conhecidas para a porção sul da Amazônia. A nova espécie difere das demais espécies congenéricas por um conjunto de características morfológicas e por sequências de DNA.

The aims of this study were to determine the seroprevalence of Sarcocystis neurona antibodies in equines in the Ilhéus-Itabuna microregion (BA), and identify possible factors associated with infection. The presence of sporocysts/oocysts of Sarcocystis spp. was also verified in Didelphis spp. A total of 669 serum samples were collected from equines in 56 properties located in 12 municipalities in the region. Indirect fluorescent antibody test was performed with slides containing merozoites of the S. neurona, using a cut-off titer of 1:80. Occurrence of 7.92% of anti-S. neurona antibodies was observed in the sampled equines. The purposes trade and work were significantly associated with the presence of antibodies (p

The sprawling–parasagittal postural shift was a major transition during synapsid evolution and is considered key to mammalian ecological diversity. Despite a good fossil record, debate remains over when the shift to parasagittal posture occurred, primarily due to limited comparative biomechanical data on extant species. Here, we built forelimb musculoskeletal models of three extant taxa that bracket the sprawling–parasagittal transition: a tegu lizard, an echidna, and an opossum. We measured shoulder joint range of motion (ROM) about all three degrees of rotational freedom and characterized shoulder muscle moment arms (MMAs) across the entire pose space. Our results show that both the opossum and the tegu had high shoulder joint ROM, and both were substantially higher than the echidna. However, the opossum occupied a distinct region of pose space characterized by high humeral retraction angles. There are clear interspecific differences in MMAs related to posture, with the sprawling tegu and echidna emphasizing humeral depression, and the parasagittal opossum emphasizing humeral elevation. There are also notable differences between our sprawling taxa, with the echidna possessing much greater moment arms for humeral pronation than the tegu. We demonstrate clear functional variation between locomotor grades and use these data to hypothesize major shifts in forelimb function and posture along the mammalian stem.

Two new species of Viannaia from the intestine of the North American opossums, Didelphis virginiana (Virginia opossum), and Philander opossum (gray four-eyed opossum), are described based on morphological and molecular data, through an integrative taxonomic approach. Maximum likelihood and Bayesian inference analyses for each dataset and the concatenated dataset were performed using a mitochondrial cytochrome c oxidase subunit 1 (COI) gene, and the nuclear ribosomal internal transcribed spacer region (ITS1-5.8S-ITS2). The phylogenetic analyses revealed 2 new species that occur in Mexico, one from the western state of Colima and another from the southern state of Chiapas. Our phylogenetic trees for both molecular markers and concatenated datasets yielded similar topologies with high bootstrap values and posterior probabilities. Viannaia is recovered as a monophyletic group, but the family Viannaiidae appears as non-monophyletic, due to the position of Travassostrongylus scheibelorum, similar to previous studies. Finally, the morphology of Viannaia and Hoineffia is discussed.

Behavioral strategies that depend on sensory information are not immutable; rather they can be shaped by the specific sensory context in which animals develop. This behavioral plasticity depends on the remarkable capacity of the brain to reorganize in response to alterations in the sensory environment, particularly when changes in sensory input occur at an early age. To study this phenomenon, we utilize the short-tailed opossum, a marsupial that has been a valuable animal model to study developmental plasticity due to the extremely immature state of its nervous system at birth. Previous studies in opossums have demonstrated that removal of retinal inputs early in development results in profound alterations to cortical connectivity and functional organization of visual and somatosensory cortex; however, behavioral consequences of this plasticity are not well understood. We trained early blind and sighted control opossums to perform a two-alternative forced choice texture discrimination task. Whisker trimming caused an acute deficit in discrimination accuracy for both groups, indicating the use of a primarily whisker-based strategy to guide choices based on tactile cues. Mystacial whiskers were important for performance in both groups; however, genal whiskers only contributed to behavioral performance in early blind animals. Early blind opossums significantly outperformed their sighted counterparts in discrimination accuracy, with discrimination thresholds that were lower by ∼75 μm. Our results support behavioral compensation following early blindness using tactile inputs, especially the whisker system., Summary: Whisker-mediated touch guides texture discrimination in short-tailed opossums. Texture discrimination sensitivity and associated tactile strategies in these marsupials show behavioral plasticity, which is dependent on sensory inputs available during development.

Protozoan parasites of the genus Sarcocystis are obligatory heteroxenous cyst-forming coccidia that infect a wide variety of animals and encompass approximately 200 described species. At least four Sarcocystis spp. (S. falcatula, S. neurona, S. lindsayi and S. speeri) use opossums (Didelphis spp.) as definitive hosts, and two of them, S. neurona and S. falcatula, are known to cause disease in horses and birds, respectively. Opossums are restricted to the Americas, but their distribution in the Americas is heterogeneous. Five Didelphis spp. are distributed in South America (D. aurita, D. albiventris, D. marsupialis, D. imperfecta and D. pernigra) whereas just one opossum species (D. virginiana) is found in North America. Studies conducted in the last decades show that Sarcocystis spp., derived from South American Didelphis spp., have biological and genetic differences in relation to Sarcocystis spp. shed by the North American opossum D. virginiana. The aim of this review was to address the peculiar scenario of Sarcocystis species shed by South American opossums, with a special focus on diagnosis, epidemiology, and animal infections, as well as the genetic characteristics of these parasites., Parasitos protozoários do gênero Sarcocystis são coccídios heteroxenos formadores de cistos, que infectam variadas espécies animais e compreendem cerca de 200 espécies descritas. Pelo menos quatro Sarcocystis spp. (S. falcatula, S. neurona, S. lindsayi e S. speeri) utilizam gambás (Didelphis spp.) como hospedeiros definitivos; e duas delas, S. neurona and S. falcatula são conhecidas por causarem doença em equinos e aves, respectivamente. Gambás didelfídeos são restritos ao continente americano, contudo são distribuídos de forma heterogênea nas Américas. Cinco Didelphis spp. são distribuídos na América do Sul (D. aurita, D. albiventris, D. marsupialis, D. imperfecta e D. pernigra), enquanto somente uma espécie (D. virginiana) é encontrada na América do Norte. Trabalhos conduzidos, nas últimas décadas, mostram que Sarcocystis spp. derivados de Didelphis spp. sulamericanos possuem diferenças biológicas e genéticas, quando comparados a Sarcocystis spp. excretados pelo gambá norte-americano D. virginiana. O objetivo desta revisão é discutir a situação peculiar das espécies de Sarcocystis na América do Sul com um foco especial em diagnóstico, epidemiologia e infecções animais, assim como nas características genéticas desses parasitos., Facultad de Ciencias Veterinarias

Males have evolved species-specifical sperm morphology and swimming patterns to adapt to different fertilization environments. In eutherians, only a small fraction of the sperm overcome the diverse obstacles in the female reproductive tract and successfully migrate to the fertilizing site. Sperm arriving at the fertilizing site show hyperactivated motility, a unique motility pattern displaying asymmetric beating of sperm flagella with increased amplitude. This motility change is triggered by Ca2+ influx through the sperm-specific ion channel, CatSper. However, the current understanding of the CatSper function and its molecular regulation is limited in eutherians. Here, we report molecular evolution and conservation of the CatSper channel in the genome throughout eutherians and marsupials. Sequence analyses reveal that CatSper proteins are slowly evolved in marsupials. Using an American marsupial, gray short-tailed opossum (Monodelphis domestica), we demonstrate the expression of CatSper in testes and its function in hyperactivation and unpairing of sperm. We demonstrate that a conserved IQ-like motif in CatSperζ is required for CatSperζ interaction with the pH-tuned Ca2+ sensor, EFCAB9, for regulating CatSper activity. Recombinant opossum EFCAB9 can interact with mouse CatSperζ despite high sequence divergence of CatSperζ among CatSper subunits in therians. Our finding suggests that molecular characteristics and functions of CatSper are evolutionarily conserved in gray short-tailed opossum, unraveling the significance of sperm hyperactivation and fertilization in marsupials for the first time.

Feline Morbillivirus (FeMV) was first detected in 2012 in domestic cats from Hong Kong and was found to be associated with tubulointerstitial nephritis and chronic kidney disease. In subsequent studies in other countries, FeMV was detected in asymptomatic cats. However, it is not clear whether FeMV plays a role as a pathogen in the kidney diseases of cats, and other epidemiological data are still unknown. To date, studies have reported the presence of FeMV exclusively in domestic cats. This study is the first molecular detection of the FeMV RNA associated with pathological and immunohistochemical findings in a synanthropic marsupial, the white-eared opossum (Didelphis albiventris), inhabiting peri-urban areas of north-central Parana, Southern Brazil. Molecular techniques identified the viral RNA in the lungs and kidneys. Histopathologic evaluation of these tissues revealed interstitial pneumonia in the lungs with lymphocytic nephritis and tubular necrosis in the kidneys. Immunohistochemistry assays detected positive intralesional immunoreactivity to N protein of FeMV within the lungs and kidneys. A FeMV opossum strain was isolated in Crandell Rees feline kidney lineage cells, resulting in syncytia formation and cell death. Therefore, these results support the ability of FeMV to infect other mammal species and reinforce the possibility of the opossum to be a disseminator of this virus among domestic and wild animals.