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motor units of the primary ankle extensor muscles of the opossum (didelphis virginiana): functional properties and fiber types.motor units of the medial gastrocnemius (mg) and the single lateral gastrocnemius/soleus (lg/s) muscles of the opossum (didelphis virginiana) were found to have uniformly slow contraction times relative to homologous muscles of the cat. though a broad range of peak tetanic tensions was found among motor units from both muscles, most of the motor units were quite large relative to tension of the whole muscle. comparison of the relative sizes of motor units showed that those of lg/s are significan ...19846481810
a golgi study of the opossum ventral basal complex.the morphology of neurons in the ventral basal complex (vbc) of the adult opossum (didelphis virginiana) is described from thick coronal brain sections, using golgi-, horseradish peroxidase (hrp)-, and nissl-staining methods. soma cross-sectional area, dendritic field shape, and the number of appendages (spines) in a defined major branch zone (mbz) are quantified and statistically analyzed. results indicate that neurons in opossum vbc have relatively large cell bodies, dendrites which branch in ...19836644824
immunohistochemical localization of substance-p, somatostatin, and methionine-enkephalin in the spinal cord and dorsal root ganglia of the north american opossum, didelphis virginiana.the occurrence and distribution of substance-p (sp), somatostatin (som), and enkephalin (enk) were studied in the north american opossum, a generalized marsupial. substance-p immunoreactivity was present in the tract of lissauer as well as within lamina i, the outer part of lamina ii, the lateral portion of laminae iii through vii, and lamina x at all spinal levels. although present, it was very spare in the ventral horn. substance-p was also localized within autonomic areas of the thoracolumbar ...19816165743
life cycle and development of lagochilascaris sprenti (nematoda: ascarididae) from opossums (marsupialia: didelphidae) in louisiana.the life cycle of lagochilascaris sprenti, a species which occurs in the stomach of opossums (didelphis virginiana) in louisiana, was determined. the larva in the egg developed to the infective stage after eggs from the feces of infected animals were in culture about 30 days. when eggs containing infective larvae were fed to mice, the larvae hatched, penetrated the intestinal mucosa, migrated through the liver and lungs, and eventually reached the skeletal muscles where they became encapsulated. ...19836685179
lagochilascaris sprenti sp. n. (nematoda: ascarididae) from the opossum, didelphis virginiana (marsupialia: didelphidae).sixty-eight specimens of lagochilascaris from the stomach of seven naturally-infected opossums from louisiana were described as lagochilascaris sprenti sp. n. observations were also made on adult worms of both sexes recovered from experimentally-infected opossums and mice. the new species differs from the four previously described species of lagochilascaris in the length of the spicules, number of pits on the circumference of the egg, and position of the vulva. the spicules are shorter in l. spr ...19836685180
sarcocystis of passerine birds: sexual stages in the opossum (didelphis virginiana).sexual stages of a sarcocystis of passerine birds were demonstrated by feeding muscle cysts from cowbirds (molothrus ater) and grackles (cassidix mexicanus) to opossums (didelphis virginiana). opossums were examined at necropsy at 36 h, 13.5 days, and 29.5 days post-inoculation (pi). large numbers of macro- and microgamonts were present in the small intestine 36 h pi, while only sporocysts and oocysts were present 13 days or more pi. microgamonts in different stages of development were in the in ...19806776294
organization of projections from the gracile, medial cuneate and lateral nuclei in the north american opossum. horseradish peroxidase study of the cells projecting to the cerebellum, thalamus and spinal cord.using the horseradish peroxidase technique on the north american opossum, we were able to locate the neurons within the dorsal column and lateral cuneate nuclei which innervate the cerebellum and thalamus as well as those within the dorsal column nuclei which project spinalward. the medial and lateral cuneate nuclei supply axons to the anterior lobe, the paramedian lobule and the pyramis of the cerebellum and the lateral nucleus provides an additional projection to the uvula. the cerebellar proj ...19816788345
ixodes dammini (acari: ixodidae) infestation on medium-sized mammals and blue jays in northwestern illinois.high prevalence of infestation of five species of medium-sized mammals and blue jays, cyanocitta cristata (l.), by immature ixodes dammini spielman, clifford, piesman and corwin was found in castle rock state park in northwestern illinois during may-august 1991. raccoons, procyon lotor l., and opossums, didelphis virginiana kerr, were infested with the highest larval densities and were trapped primarily in bottomland forest and ecotone habitats. all species had similar nymphal densities, except ...19938254647
experimental infection of opossums with brucella abortus.thirteen opossums (didelphis virginiana) trapped in east central alabama were fed approximately 1.5 x 10(9) brucella abortus colony forming units. serologic responses to at least 1 of 3 tests developed in 8 of the 13 opossums. brucella abortus was recovered from 18 of 159 blood samples from 4 of the 13 opossums and from 7 of 159 fecal samples from 6 of them. all culture-positive feces had been excreted within 4 days after exposure. sixty-four urine, 123 saliva, and 78 vaginal samples were cultur ...19816799466
sarcocystis spp. in white-tailed deer. i. definitive and intermediate host spectrum with a description of sarcocystis odocoileocanis n. sp.sporocysts containing four sporozoites and measuring (avg.) 15.2 micrometers x 10.7 micrometers (n = 195) were shed in the feces of dogs (canis familiaris) 8 to 16 days (avg. 11.6 days) after the first feeding of venison infected with sarcocystis sp. sporocysts containing four sporozoites and measuring (avg.) 11.5 micrometers x 8.1 micrometers (n = 35) were shed by a cat (felis catus) 14 days after ingesting sarcocystis-infected venison. statistical (pooled t-test) comparison of the mean measure ...19816802990
the distribution of ganglion cells in the retina of the north american opossum (didelphis virginiana).the distribution of ganglion cells in the retina of the opossum was determined from whole-mounted retinae stained with cresyl violet. isodensity lines were approximately circular with a peak density of 2,000 to 2,700 cells/mm2 in superior temporal retina (area centralis). the total number of retinal ganglion cells was estimated to be 72,000 to 135,000 (mean 101,026) in retinae ranging from 125 to 187 mm2 in total area. three groups of ganglion cells were distinguished on the basis of soma size a ...19816168666
the intermediate host spectrum in a sarcocystis species of birds.the life cycle of an avian sarcocystis has been completed in the laboratory, originating with naturally infected icterids and passing alternately between opossums (didelphis virginiana) and experimentally infected birds. to determine the intermediate host range, six avian species, including canaries (serinus canarius), zebra finches (poephila guttata), budgerigars (melopsittacus undulatus), pigeons (columba livia), chickens (gallus gallus), and guinea fowl (numida meleagris), were inoculated ora ...19826811715
an alternative animal model for perinatal carcinogenesis.the differences in developmental biology between marsupials and eutherian animals provide alternative approaches to major problems in perinatal carcinogenesis. the high susceptibility of the neonatal american marsupial, the opossum (didelphis virginiana), during early postnatal development to oral, chemical induction of dysontogenetic tumors with a close morphologic and biologic resemblance to those in the human suggests that the neonatal marsupial may offer unique opportunities for the study of ...19836850030
cerebrospinal fluid-contacting neurons of the central canal and terminal ventricle in various vertebrates.cerebrospinal fluid (csf)-contacting neurons were studied by means of electron microscopy in the spinal cord and/or terminal ventricle of the ray, raja clavata (elasmobranchii), the opossum, didelphis virginiana (marsupialia), the mouse, mus musculus, and the guinea pig, cavia cobaya (rodentia). dendrites of the csf-contacting neurons in the spinal cord of the ray penetrate the ependyma of the central canal and form terminals bearing stereocilia. axons apparently belonging to these neuronal peri ...19836871973
parasitic arthropods of sympatric opossums, cotton rats, and cotton mice from merritt island, florida.six species of parasitic arthropods were collected from 12 opossums (didelphis virginiana), 8 species were obtained from 28 cotton rats (sigmodon hispidus), and 4 species were collected from 10 cotton mice (peromyscus gossypinus) from merritt island, brevard county, florida. the flea polygenis gwyni was the only parasite that infested all 3 host species, and it was present in very high densities (mean intensity = 73.7) on the opossums. the american dog tick, dermacentor variabilis, and the tropi ...19938459341
neocortical projections of the suprageniculate and posterior thalamic nuclei in the marsupial brush-tailed possum, trichosurus vulpecula (phalangeridae), with a comparative commentary on the organization of the posterior thalamus in marsupial and placental mammals.axonal transport methods were used to determine the extent and organisation of neocortical projections from the suprageniculate (sg) and posterior (po) thalamic nuclei in the brush-tailed possum. our findings show that sg projects extensively to the auditory cortex, overlapping the cortical projection field of the medial geniculate nucleus, and to the immediately neighbouring association cortex. though the input relationships of sg appear similar to those reported for other mammals, placental an ...19836886058
an analysis of some thalamic projections to parietofrontal neocortex in the marsupial native cat, dasyurus viverrinus (dasyuridae).thalamocortical projections to parietofrontal neocortex in the marsupial native cat, dasyurus viverrinus, were examined using the retrograde transport of horseradish peroxidase. the results show that the organisation in dasyurus is similar to that reported in another australian marsupial, the brush-tailed possum, trichosurus vulpecula, and is different to that found in the primitive american form, didelphis virginiana. in daysurus, as in trichosurus, the areas of neocortex receiving projections ...19817326576
asynaptic behavior of x and y chromosomes in the virginia oppossum and the southern pygmy mouse.the meiotic behavior of silver-stained x and y chromosomes of the virginia opossum, didelphis virginiana, and the southern pygmy mouse, baiomys musculus, was studied by light microscopy. while the sex chromosomes of these two species differ in both size and morphology, their meiotic behavior is very similar. in both species a typical sex vesicle is formed during pachytene, but unlike most other mammalian species thus far studied, a synaptonemal complex does not form between the x and y chromosom ...19807389409
nucleotide sequence of a marsupial line-1 element and the evolution of placental mammals.l1 (line-1) elements, previously described in several placental species, were shown to exist in several thousands of copies dispersed in the genome of a marsupial (the north american opossum, didelphis virginiana). a restriction fragment containing the partial nucleotide sequence of the reverse transcriptase gene (orf-2) from the marsupial l1 element was cloned and sequenced. the element was shown to evolve in concert within the marsupial when compared to placental mammals. when the marsupial l1 ...19957476141
acute hepatitis in an opossum (didelphis virginiana) infected with salmonella turnidorp.salmonella turnidorp was isolated in pure culture from the liver of an opossum that died of acute hepatitis. microscopically, there were random foci of hepatic coagulation necrosis and gram negative bacteria within hepatocytes. the salmonella turnidorp isolate was aberrant in that it did not utilize citrate and did not agglutinate by a commercial salmonella polyvalent antiserum. additional salmonella serotypes, including salmonella mbandaka, salmonella rubislaw, and salmonella anatum were isolat ...19827078089
husbandry of a small breeding colony of opossums (didelphis virginiana).a small breeding colony of opossums was established in a semi-enclosed structure. minor modifications of pre-existing pens permitted efficient and productive management of the opossums. dry dog food was provided, and large amounts of shredded paper was used for nesting material. vaginal smears were taken from opossums that were restrained only by their tail, a procedure that allowed one person to obtain and interpret vaginal smears from 20 females in less than 2 hours per day. pregnancy resulted ...19827144133
insulin-like growth factor improves renal architecture of fetal kidneys with complete ureteral obstruction.others have previously demonstrated that the administration of insulin-like growth factor-i accelerates recovery from ischemic acute tubular necrosis in the rat kidney. we investigated the effect of insulin-like growth factor-i on the histology of unilaterally obstructed kidneys in the pouch young of the north american opossum, didelphis virginiana. in this model complete unilateral ureteral obstruction reliably induces statistically significant degrees of caliceal dilatation, tubular cystic cha ...19957609156
natural la crosse virus infection in the red fox (vulpes fulva), gray fox (urocyon cinereoargenteus), raccoon (procyon lotor), and opossum (didelphis virginiana).natural infection of sentinel red foxes (vulpes fulva) and free-ranging red foxes, gray foxes (urocyon cinereoargenteus) and raccoons (procyon lotor) with la crosse (lac) virus was demonstrated. one isolate of lac virus was obtained from a sentinel red fox in an enzootic area. the viremia titer of the lac virus-infected red fox was above the threshold of infection for aedes triseriatus mosquitoes. antibody responses were measured by the microneutralization test employing four california group vi ...19817258486
a description of the dorsal thalamus of the marsupial native cat, dasyurus viverrinus (dasyuridae).the nuclear architecture of the dorsal thalamus in the marsupial native cat, dasyurus viverrinus, is described. the nine midline and intralaminar nuclei comprise a large and prominent part of the thalamus. the lateroposterior nucleus is clearly divided into medial and lateral divisions. a ventroanterior nucleus is distinguished from the ventrolateral nucleus, and the ventroposterior complex is divided into cytoarchitecturally distinctive medial and lateral divisions. there is a large posterior n ...19817326574
effect of deer exclusion on the abundance of immature ixodes scapularis (acari: ixodidae) parasitizing small and medium-sized mammals.effects of deer exclusion on abundance of immature ixodes scapularis say parasitizing small and medium-sized mammals, and the role mammals have in introducing ticks to exclosure areas, were examined at two sites in westchester county, new york. in total, 686 mammal captures representing nine species were obtained, with white-footed mice, peromyscus leucopus rafinesque, composing > 80% of all captures, followed by raccoons, procyon lotor (l.); opossums, didelphis virginiana (kerr); and striped sk ...19957869342
projection of visuotopically organized afferents to the dorsal thalamus in the opossum, monodelphis domestica.retrogradely transported dyes, fluorogold and fast blue were injected into both sides of the dorsal thalamus in the monodelphis opossum. projection of the presumed primary visual cortical area, superior colliculus and parabigeminal nucleus to the dorsal lateral geniculate nucleus and the lateral posterior--lateral intermedius nuclear complex were described. they show close similarities to the homologous projections in the north american opossum, insectivores and some rodents. in comparison with ...19947887182
uroguanylin: structure and activity of a second endogenous peptide that stimulates intestinal guanylate cyclase.the intestinal hormone guanylin and bacterial heat-stable enterotoxins (sts) are members of a peptide family that activates intestinal membrane guanylate cyclase. two different peptides that activate the human intestinal t84 cell guanylate cyclase have been purified from urine and intestinal mucosa of opossums (didelphis virginiana). the highly acidic peptide, qedcelcinvactgc, was named uroguanylin because it was isolated from urine and shares 53% identity with guanylin. a second peptide, shtcei ...19937902563
murine typhus: updated roles of multiple urban components and a second typhuslike rickettsia.studies using serologic and polymerase chain reaction-(pcr) facilitated analysis of field samples from southern texas indicate the presence of rickettsia typhi and elb agent infected cat fleas, ctenocephalides felis (bouché), and the first observation of elb infected vertebrates (opossums). the elb agent is a recently described typhus-like rickettsia that is not distinguished from r. typhi or r. prowazekii by currently available serologic reagents. restriction digests of pcr products from 399 fl ...19947966170
experimental ureteral obstruction in the fetal opossum: histologic assessment.in the north american opossum, didelphis virginiana unilateral complete ureteral obstruction (eco) and partial unilateral (epo) ureteral obstruction were created during the early metanephric stage of kidney development in pups attached to the teat (approximately 4.5 cm. long, 20 days old). at 70 days of pouch life (full-term equivalent in the human) some completely obstructed ureters were unobstructed with reanastomosis in the bladder (reco). other pups underwent unilateral complete ureteral lig ...19947966702
site selection by intestinal helminths of the virginia opossum (didelphis virginiana).digestive tract helminths of the virginia opossum (didelphis virginiana) were examined for site specificity and interspecific interactions. thirty opossums were live-trapped at 2 localities in georgia, killed, and their digestive tracts removed and divided into the following sections; esophagus, stomach, small intestine (20 equal sections), cecum, and large intestine (5 equal sections). helminths present in each section were identified and counted. three trematode, 1 cestode, 2 acanthocephala, a ...199910207354
distribution of heat-stable enterotoxin/guanylin receptors in the intestinal tract of man and other mammals.the human intestinal tract, as well as that of several eutherian and metatherian mammals, was examined for the distribution of heat-stable enterotoxin (st)/guanylin receptors. these receptors were confined to the intestinal epithelium lining the lumen and forming the intestinal glands throughout the length of both the small intestine and colon of all species examined. in man and most other mammalian species, there appeared to be a decrease in receptor density distally along the longitudinal axis ...19948014132
the marsupial mitochondrial genome and the evolution of placental mammals.the entire nucleotide sequence of the mitochondrial genome of the american opossum, didelphis virginiana, was determined. two major features distinguish this genome from those of other mammals. first, five trna genes around the origin of light strand replication are rearranged. second, the anticodon of trna(asp) is posttranscriptionally changed by an rna editing process such that its coding capacity is altered. when the complete protein-coding region of the mitochondrial genome is used as an out ...19948056314
intrinsic factor-cobalamin receptor activity in a marsupial, the american opossum (didelphis virginiana).1. significant and specific binding of intrinsic factor-cobalamin occurred in proximal but not in the distal half of the intestine in an adult marsupial, the american opossum. 2. the purified opossum kidney receptor, like rat and canine kidney receptors, revealed a single band of m(r) approximately 230 on sds-page. however, unlike the rat and canine receptors, the opossum receptor was sensitive to both endoglycosidase h and peptide-n-glycosidase f. 3. the opossum intrinsic factor-cobalamin recep ...19938097983
oxidation reactions of human, opossum (didelphis virginiana) and spot (leiostomus xanthurus) hemoglobins: a search for a correlation with some structural-functional properties.1. relative to human hba, opossum (didelphis virginiana) hemoglobin was found to be more susceptible to autoxidation. while the initial rate of autoxidation of spot (leiostomus xanthurus) hemoglobin is close to that of hba, complete oxidation occurs in 50 hr. 2. direct addition of hydrogen peroxide (h2o2) induced oxidation of hemoglobins in a definite order: spot hb > hba > opossum hb. excess h2o2 led to heme degradation and precipitation that occurred much faster for spot hb than the case with ...19938243064
the effect of enzyme replacement on red cell adenine deoxyribonucleotides in adenosine deaminase-deficient erythrocytes of the opossum, didelphis virginiana.1. polyethyleneglycol-modified bovine adenosine deaminase was administered (10-20 u/kg/week) intramuscularly to two opossums for 15 weeks and changes in red cell adenine ribo- and deoxyribonucleotides quantitated by hplc. 2. only a moderate decline of erythrocyte daxp was observed at the end of the study when compared to results of enzyme replacement seen in human adenosine deaminase deficient patients. 3. opossum red cells salvage substantial amounts of deoxyadenosine provided in physiologic (5 ...19938281757
2'-deoxyadenosine metabolism in human and opossum didelphis virginiana erythrocytes in vitro.1. in erythrocytes of both species, deamination and phosphorylation of dado was completely inhibited by 5 microm 2'deoxycoformycin and 10 microm 5-itu respectively. 2. under physiologic conditions, provided with nanomolar concentrations of dado there was complete deamination of dado in human red cells. in opossum erythrocytes deamination and phosphorylation of the deoxynucleoside were nearly; additionally, 1-2% of the substrate was metabolized to axp. 3. with ada inhibited in intact red cells, a ...19938281758
development of the eye in the north american opossum (didelphis virginiana).marsupials are unique models for developmental biology-oriented research because of the immature state of their development at birth. the north american opossum (didelphis virginiana) has several advantages over other marsupials, including large litter size, short prenatal period (12.5 d), an extended postnatal period while accessible in the pouch, and its ability to reproduce reliably in captivity. studies of ocular development in this species have not been reported previously. the aim of the p ...19938300421
characterization of mannose 6-phosphate receptors (mprs) from opossum liver: opossum cation-independent mpr binds insulin-like growth factor-ii.bovine, human, and rat cation-independent mannose 6-phosphate receptors (ci-mprs) are capable of binding both mannose 6-phosphate and insulin-like growth factor-ii (igf-ii). however, the receptor isolated from either chicken or frog lacks the high affinity igf-ii-binding site. to determine whether ci-mprs isolated from a species that is closely related to placental mammals can bind igf-ii, the mprs were purified from a marsupial, the american opossum (didelphis virginiana), by phosphomannan-seph ...19938344189
isolation of sarcocystis speeri dubey and lindsay, 1999 parasite from the south american opossum (didelphis albiventris) from argentina.sarcocystis sporocysts from the intestines of 2 opossums (didelphis albiventris) from argentina were fed to gamma-interferon knockout (ko) and nude mice. protozoal schizonts were seen in brain, liver, spleen, and adrenal glands of mice examined 33-64 days after feeding sporocysts. sarcocysts were seen in skeletal muscles of ko mice 34-71 days after feeding sporocysts. schizonts and sarcocysts were structurally similar to sarcocystis speeri dubey and lindsay, 1999 seen in mice fed sporocysts from ...200010701583
characterization of a marsupial sperm protamine gene and its transcripts from the north american opossum (didelphis marsupialis).a synthetic oligonucleotide primer, designed from marsupial protamine protein-sequence data [balhorn, r., corzett, m., matrimas, j. a., cummins, j. & faden, b. (1989) analysis of protamines isolated from two marsupials, the ring-tailed wallaby and gray short-tailed opossum, j. cell. biol. 107] was used to amplify, via the polymerase chain reaction, protamine sequences from a north american opossum (didelphis marsupialis) cdna. using the amplified sequences as probes, several protamine cdna clone ...19938344286
opossum serum alpha 1-proteinase inhibitor: purification, linear sequence, and resistance to inactivation by rattlesnake venom metalloproteinases.opossum (didelphis virginiana) serum was fractionated with (nh4)2so4 and then chromatographed on deae-sepharose and phenyl-sepharose. affinity chromatography on a protein a-sepharose-antibody column removed traces of opossum serum metalloproteinase inhibitors, and resulted in a homogeneous preparation of opossum alpha 1-proteinase inhibitor (alpha 1-pi). the inhibitor is a single-chain glycoprotein (17.7% carbohydrate) with an estimated m(r) = 54,000. an opossum liver cdna library was immunoscre ...19938422360
man and the chimaera. selective versus neutral oxytocin evolution.the oxytocin/vasopressin superfamily encompasses vertebrate and invertebrate peptides and therefore the ancestral gene encoding the precursor protein antedates the divergence between the two groups, about 700 million years ago. the preserved nonapeptide pattern indicates that both the precursor structures and the processing enzymatic machinery were greatly conserved to ensure the building of a specific conformation. substitutions, which may be neutral or selective, occurred in precise positions. ...19958714026
ticks (acari: ixodidae) in bulloch county, georgia.an 18-mo study was conducted in bulloch county, georgia, to determine tick species composition, seasonal activity of individual tick species, and host-tick associations. the following 7 methods of tick collection were included: (1) live trapping of potential host animals, (2) checking wild game, (3) drag sampling, (4) carbon dioxide attraction, (5) checking livestock, road kills, nests, and burrows, (6) samples submitted from veterinarians, and (7) ticks collected by local residents and submitte ...19968742526
a molecular and evolutionary study of the beta-globin gene family of the australian marsupial sminthopsis crassicaudata.beta-globin gene families in eutherians (placental mammals) consist of a set of four or more developmentally regulated genes which are closely linked and, in general, arranged in the order 5'-embryonic/fetal genes-adult genes-3'. this cluster of genes is proposed to have arisen by tandem duplication of ancestral beta-globin genes, with the first duplication occurring 200 to 155 mybp just prior to a period in mammalian evolution when eutherians and marsupials diverged from a common ancestor. in t ...19968752008
the seroprevalence of antibodies to sarcocystis neurona in michigan equids.a cross-sectional study of serum antibodies to sarcocystis neurona (the etiologic agent of equine protozoal myeloencephalitis, epm) was performed on michigan equids. our objectives were to determine the seroprevalence of antibodies to s. neurona in michigan equids and to identify specific risk factors for seropositivity. a random, weighted sample of michigan horse farms (stratified by the state's opossum (didelphis virginiana) population and the number of equids on each operation) was selected. ...200111154784
evolution of transthyretin gene expression in the liver of didelphis virginiana and other american marsupials.the occurrence of the thyroid hormone-binding plasma protein transthyretin in the bloodstream was investigated for four american marsupial species. serum samples were analyzed by incubation with radioactive t4, followed by electrophoresis, then autoradiography, and western blotting. transthyretin was found in serum from monodelphis domestica, didelphis virginiana, caluromys lanatus, and dromiciops australis. for unambiguous identification, transthyretin from d, virginiana was purified from serum ...19968754780
ontogeny of suckling mechanisms in opossums (didelphis virginiana).although adult mammals have several different mechanisms for drinking liquids, relatively little is known about the variation in mechanisms used by infants for suckling and how the mechanics of suckling change as a function of ontogeny. we examined suckling in infant opossums, animals that as adults use a lapping mechanism to drink. the youngest infants (45 days old) used a suction, pumping mechanism, based on dorsal/ventral tongue movements, similar to what has been documented in infant primate ...19968872320
experimental induction of equine protozoal myeloencephalitis in horses using sarcocystis sp. sporocysts from the opossum (didelphis virginiana).sarcocystis sp. sporocysts isolated from eight feral opossums (didelphis virginiana) were pooled and fed to 18 commercially reared budgerigars (melopsittacus undulatus), 14 wild-caught sparrows (passer domesticus), one wild-caught slate-colored junco (junco hyemalis) and five weanling horses (equus caballus). all budgerigars died within 5 weeks post inoculation (wpi). histologic examination revealed meronts within the pulmonary epithelia and typical sarcocystis falcatula sarcocysts developing in ...19979066066
development of the lymphoid tissues of the tammar wallaby macropus eugenii.a study has been made of the development of four lymphoid tissues from birth to maturity in the tammar wallaby macropus eugenii--the cervical and thoracic thymus, lymph nodes and gut-associated lymphoid tissue (galt). the development of these tissues in the tammar wallaby is similar to that in two other marsupials, the quokka setonix brachyurus and the virginian opossum didelphis virginiana. lymphocytes were first detected in the cervical thymus of the tammar at day 2 post partum and in the thor ...19979208435
mycobacterium bovis in coyotes from michigan.during a survey for tuberculosis in wild carnivores and omnivores, mycobacterium bovis was cultured from pooled lymph nodes of three adult female coyotes (canis latrans) harvested by hunters in michigan (usa). no gross or histologic lesions suggestive of tuberculosis were seen in these animals. one coyote was taken from montmorency county and two coyotes from alcona county located in the north-eastern portion of michigan's lower peninsula where free-ranging white-tailed deer (odocoileus virginia ...19989706576
prevalence of neospora hughesi and sarcocystis neurona antibodies in horses from various geographical locations.parasite-specific antibody responses to neospora antigens were detected using the immunofluorescent antibody test (ifat) and immunoblot analysis in select equine populations. for comparison, a naturally infected neospora hughesi horse and an experimentally inoculated neospora caninum horse were used. in addition, all samples were tested for antibodies to sarcocystis neurona by immunoblot analysis. a total of 208 samples was evaluated. the equine populations were derived from five distinct geogra ...200111223207
prevalence of sarcocystis neurona sporocysts in opossums (didelphis virginiana) from rural mississippi.sarcocystis species sporocysts were found in intestinal scrapings from 24 of 72 opossums (didelphis virginiana) from rural mississippi. the number of sporocysts in each opossum varied from a few ( < 100000) to 187 million. sporocysts from 24 opossums were bioassayed for sarcocystis neurona infections by feeding to gamma-interferon knockout (ko) mice. s. neurona was detected in the brains of ko mice fed sporocysts from 19 opossums by immunohistochemical staining with anti-s. neurona specific poly ...200111223208
the detection of hemorrhagic proteins in snake venoms using monoclonal antibodies against virginia opossum (didelphis virginiana) serum.most snakes and a few warm-blooded animals have a resistance to snake venoms because of naturally occurring antihemorrhagins found in their sera. the antihemorrhagins in serum of virginia opossum (didelphis virginiana) neutralize hemorrhagic activity by binding to hemorrhagins in snake venoms. the binding characteristic of antihemorrhagins in d. virginiana serum was used to develop a five-step western blot. the detection of hemorrhagic proteins were measured indirectly with antihemorrhagins in v ...19989723843
seroprevalence of antibodies against toxoplasma gondii in free-ranging mammals in iowa.serum samples from raccoons (procyon lotor), striped skunks (mephitis mephitis), virginia opossums (didelphis virginiana), and free-ranging house cats trapped in iowa between 1984 and 1988 were tested for antibodies against toxoplasma gondii using the modified direct agglutination test (mat). antibody titers > or = 1:32 were considered indicative of infection. prevalence rates by species were estimated for raccoons at 134/885 (15%), skunks at 38/81 (47%), opossums at 12/53 (23%), and cats at 16/ ...19989813854
isolation of a third species of sarcocystis in immunodeficient mice fed feces from opossums (didelphis virginiana) and its differentiation from sarcocystis falcatula and sarcocystis neurona.opossums (didelphis virginiana) were found to be hosts for 3 species of sarcocystis: sarcocystis falcatula with an avian intermediate host, s. neurona with an undetermined intermediate host, and a third, unnamed, species. sporocysts from the intestines of 2 opossums (nos. 26 and 47) were fed to budgerigars (melopsittacus undulatus), nude mice, and gamma-interferon knockout (ko) mice. sporocysts of s. falcatula were not infective to nude or ko mice. sporocysts of s. neurona induced encephalitis i ...19989920306
isolation in immunodeficient mice of sarcocystis neurona from opossum (didelphis virginiana) faeces, and its differentiation from sarcocystis falcatula.sarcocystis neurona was isolated in nude mice and gamma-interferon knockout mice fed sporocysts from faeces of naturally infected opossums (didelphis virginiana). mice fed sporocysts became lethargic and developed encephalitis. protozoa were first found in the brain starting 21 days post-inoculation. sarcocystis neurona was recovered in cell culture from the homogenate of liver, spleen and brain of a nude mouse 11 days after feeding sporocysts. the protozoa in mouse brain and in cell culture mul ...19989925260
multiple dna markers differentiate sarcocystis neurona and sarcocystis falcatula.studies designed to investigate the causative agent of equine protozoal myeloencephalitis and its life cycle have been hampered by the marked similarity of sarcocystis neurona to other sarcocystis spp. present in the same definitive host. random-amplified polymorphic dna techniques were used to amplify dna from isolates of s. neurona and sarcocystis falcatula. dna sequence analysis of polymerase chain reaction (pcr) products was then used to design pcr primers to amplify specific sarcocystis spp ...199910219299
are sarcocystis neurona and sarcocystis falcatula synonymous? a horse infection challenge.equine protozoal myeloencephalitis (epm) is a debilitating neurologic disease of the horse. the causative agent. sarcocystis neurona, has been suggested to be synonymous with sarcocystis falcatula, implying a role for birds as intermediate hosts. to test this hypothesis, opossums (didelphis virginiana) were fed muscles containing s. falcatula sarcocysts from naturally infected brown-headed cowbirds (molothrus ater). ten horses were tested extensively to ensure no previous exposure to s. neurona ...199910219313
patterns of infestation by adult dermacentor variabilis (acari: ixodidae) in a mark-recapture study of raccoons (mammalia: carnivora) and virginia opossums (mammalia: didelphimorphia) in tennessee.a mark-recapture study of raccoons (procyon lotor l.) and virginia opossums (didelphis virginiana kerr) was conducted from february 1991 through april 1994 to determine host interactions with adult dermacentor variabilis say. we captured 1,293 raccoons and virginia opossums during the 3-yr study (140 individual raccoons and 160 individual virginia opossums) with 1,895 adult d. variabilis collected. raccoons had a significantly higher mean intensity and higher prevalence of adult ticks than virgi ...199910337094
implications of raccoon latrines in the epizootiology of baylisascariasis.raccoons (procyon lotor) frequently establish defecation sites, termed latrines, on large logs, stumps, rocks, and other horizontally oriented structures/surfaces. these latrines are important foci of infective eggs of baylisascaris procyonis, a nematode parasite of raccoons which is pathogenic to numerous species of mammals and birds. to examine the role of raccoon latrines in this animal-parasite interaction, we documented animal visitations to raccoon latrines in two large forested tracts and ...199910479081
subretinal macrophages in the developing eye of eutherian mammals and marsupials.blood-borne mononuclear cells invade the developing retina via the hyaloid vasculature at the optic nerve head. following removal of apoptotic cell debris they give rise to the network of resident microglia. the population of cells recently described in the peripheral subretinal space of developing human eyes may represent a further population of macrophages destined to become microglia. the aim of the present study was to confirm the presence of subretinal macrophages in the developing eye in o ...199910526023
ticks and antibodies to borrelia burgdorferi from mammals at cape hatteras, nc and assateague island, md and va.results of a survey for ixodid ticks and/or serum antibodies to borrelia burgdorferi from 14 species of small to large mammals from eastern coastal areas of the united states are presented. most samples were obtained from july 1987 through june 1989 (excluding december-march) at 3 locales: assateague is. national seashore, worcester co., md., and accomack co., va. (approximately 38 degrees 05' n 75 degrees 10' w), and cape hatteras national seashore, dare co., nc (approximately 35 degrees 30' n ...199910534951
oral rabies vaccine contact by raccoons and nontarget species in a field trial in florida.rabies is enzootic in raccoons (procyon lotor) in the eastern united states. oral vaccination of free-ranging raccoons against rabies has the potential to control the disease in a principal reservoir and reduce the risk of rabies exposure among domestic animals and humans. free-ranging animal contact with baits containing a vaccinia virus recombinant vaccine expressing the rabies glycoprotein gene (v-rg) was monitored in pinellas county (florida, usa) from february through may 1997. bait contact ...199910574527
sarcocystis speeri n. sp. (protozoa: sarcocystidae) from the opossum (didelphis virginiana).the north american opossum (didelphis virginiana) is host to at least 3 species of sarcocystis: sarcocystisfalcatula, sarcocystis neurona, and a recently recognized sarcocystis sp. a new name, sarcocystis speeri, is proposed for the third unnamed sarcocystis. immunodeficient mice are an experimental intermediate host for s. speeri. sarcocystis speeri sporocysts are 12-15 x 8-10 microm in size, and its schizonts are found in many organs of mice. sarcocysts of s. speeri are found in skeletal muscl ...199910577729
streptococcus didelphis sp. nov., a streptococcus with marked catalase activity isolated from opossums (didelphis virginiana) with suppurative dermatitis and liver fibrosis.beta-haemolytic, catalase-positive, gram-positive cocci that formed chains in broth media but did not react with lancefield group antisera were isolated from skin lesions, spleen, liver and lungs of nine opossums, including eight from a research colony and one from a wildlife rehabilitation organization. the isolates had vigorous catalase activity that was retained on initial passage on non-blood-containing media, but this activity was lost in subsequent passages. the use of standard phenotypic ...200010758886
identification of opossums (didelphis virginiana) as the putative definitive host of sarcocystis neurona.sarcocystis neurona is an apicomplexan that causes equine protozoal myeloencephalitis (epm) in north and south america. horses appear to be an aberrant host, because the merozoites continually divide in the central nervous system, without encysting. the natural host species has not previously been identified. the small subunit ribosomal rna (ssurna) gene of s. neurona was compared to those of sarcocystis muris, sarcocystis cruzi, toxoplasma gondii, and cryptosporidium parvum to identify a unique ...19958544064
sarcocystis falcatula from passerine and psittacine birds: synonymy with sarcocystis neurona, agent of equine protozoal myeloencephalitis.equine protozoal myeloencephalitis (epm) is a neurologic disease of horses caused by sarcocystis neurona. the horse is a dead-end host for s. neurona and the definitive and intermediate hosts have not previously been identified. we hypothesized that s. neurona is actually sarcocystis falcatula, a parasite that cycles in nature between virginia opossums (didelphis virginiana) and any of a variety of avian intermediate hosts. we extracted dna from s. falcatula sarcocysts in the muscle of a brown-h ...19958544067
experimental inoculation of north american opossums (didelphis virginiana) with mycobacterium bovis.eight north american opossums (didelphis virginiana) were inoculated with 1 x 10(5) colony forming units of mycobacterium bovis to investigate their potential as reservoir hosts for bovine tuberculosis in michigan. four animals received this dose orally and four were inoculated intramuscularly (i.m.). in each group, two animals were euthanized 1 mo postinoculation (pi) and two at 2 mo pi. four control animals were housed separately and sacrificed in the same manner as those inoculated. one of fo ...200212038125
light and electron microscopic features of eperythrozoon-like parasites in a north american opossum (didelphis virginiana).epierythrocytic parasites associated with a severe anemic episode have not been previously reported in the opossum. a wright-giemsa-stained peripheral blood smear from an anemic north american opossum (didelphis virginiana) revealed numerous organisms attached to red blood cells either singularly or in chains. ring forms of the organism were common and could be found free in the plasma. electron microscopy revealed that these organisms were attached to the intact plasma membrane in depressions o ...200010982141
'candidatus mycoplasma haemodidelphidis' sp. nov., 'candidatus mycoplasma haemolamae' sp. nov. and mycoplasma haemocanis comb. nov., haemotrophic parasites from a naturally infected opossum (didelphis virginiana), alpaca (lama pacos) and dog (canis familiaris): phylogenetic and secondary structural relatedness of their 16s rrna genes to other mycoplasmas.the 16s rrna sequence of newly characterized haemotrophic bacteria in an opossum (didelphis virginiana) and alpaca (lama pacos) was determined. in addition, the 16s rrna sequence of a haemotrophic parasite in the dog (canis familiaris) was determined. sequence alignment and evolutionary analysis as well as secondary structural similarity and signature nucleotide sequence motifs of their 16s rrna genes, positioned these organisms in the genus mycoplasma. the highest scoring sequence similarities ...200212054227
a staging scheme for assessing development in vitro of organogenesis stage embryos of the stripe-faced dunnart, sminthopsis macroura (marsupialia: dasyuridae).the inaccessibility of mammalian organogenesis stage embryos has precluded their widespread use in embryological and teratological studies. as organogenesis occurs during the last 1.5 days of the 10. 7 days of gestation in the stripe-faced dunnart (sminthopsis macroura), the aim of the present study was to investigate whether day 9 and day 10 embryos and fetuses could be grown to term in vitro. high glucose dulbecco's modified eagle's medium with 10% fetal calf serum (fcs) supported embryonic gr ...200011006151
experimental inoculation of domestic cats (felis domesticus) with sarcocystis neurona or s. neurona-like merozoites.sarcocystis neurona is the parasite most commonly associated with equine protozoal myeloencephalitis (epm). recently, cats (felis domesticus) have been demonstrated to be an experimental intermediate host in the life cycle of s. neurona. this study was performed to determine if cats experimentally inoculated with culture-derived s. neurona merozoites develop tissue sarcocysts infectious to opossums (didelphis virginiana), the definitive host of s. neurona. four cats were inoculated with s. neuro ...200212072209
the south american opossum, didelphis marsupialis, from brazil as another definitive host for sarcocystis speeri dubey and lindsay, 1999.the north american opossum, didelphis virginiana, is a definitive host for at least 3 species of sarcocvstis: s. falcatula stiles 1983, s. neurona dubey, davis, speer, bowman, de lahunta, granstrom, topper, hamir, cummings, suter 1991, and s. speeri dubey and lindsay 1999. in order to identify species of sarcocystis in the south american opossum, d. inarsupialis, sarcocystis sporocysts from the intestines of a naturally infected opossum (d. marsupialis) from brazil were fed to 4 gamma-interferon ...200011155929
completion of the life cycle of sarcocystis neurona.sarcocystis neurona is the most important cause of a neurologic disease in horses, equine protozoal myeloencephalitis (epm). the complete life cycle of s. neurona, including the description of sarcocysts and intermediate hosts, has not been completed until now. opossums (didelphis spp.) are definitive hosts, and horses and other mammals are aberrant hosts. in the present study, laboratory-raised domestic cats (felis domesticus) were fed sporocysts from the intestine of a naturally infected oposs ...200011191904
host utilization and seasonal occurrence of dermacentor species (acari:ixodidae) in missouri, usa.a total of 3,235 dermacentor variabilis (say) specimens were collected from birds, mammals, and by dragging vegetation, and 2,683 d. albipictus (packard) ticks were collected from deer from 1993 to 1996. peak seasonal occurrence of adult d. variabilis was from may through july with a precipitous decrease in august. nymphal d. variabilis populations peaked in june. peak activity of larvae was bimodal, with one activity peak during late summer (september) and a second peak in winter or early sprin ...200011201355
a review of sarcocystis neurona and equine protozoal myeloencephalitis (epm).equine protozoal myeloencephalitis (epm) is a serious neurological disease of horses in the americas. the protozoan most commonly associated with epm is sarcocystis neurona. the complete life cycle of s. neurona is unknown, including its natural intermediate host that harbors its sarcocyst. opossums (didelphis virginiana, didelphis albiventris) are its definitive hosts. horses are considered its aberrant hosts because only schizonts and merozoites (no sarcocysts) are found in horses. epm-like di ...200111223193
immunoconversion against sarcocystis neurona in normal and dexamethasone-treated horses challenged with s. neurona sporocysts.equine protozoal myeloencephalitis is a common neurologic disease of horses in the americas usually caused by sarcocystis neurona. to date, the disease has not been induced in horses using characterized sporocysts from didelphis virginiana, the definitive host. s. neurona sporocysts from 15 naturally infected opossums were fed to horses seronegative for antibodies against s. neurona. eight horses were given 5x10(5) sporocysts daily for 7 days. horses were examined for abnormal clinical signs, an ...200111223200
sporocyst size of isolates of sarcocystis shed by the virginia opossum (didelphis virginiana).the virginia opossum (didelphis virginiana) is a definitive host for multiple sarcocystis species including sarcocystis neurona, one of the causative agents of equine protozoal myeloencephalitis (epm), a severe, neuromuscular disease of horses. size and morphologic characteristics of isolates of sarcocystis shed by the opossum were examined to determine if differences were useful in discriminating between the isolates and/or species. collections of sporocysts from 17 opossums were molecularly ch ...200111223210
evaluation of the shedding of sarcocystis falcatula sporocysts in experimentally infected virginia opossums (didelphis virginiana).five virginia opossums (didelphis virginiana) were fed muscles of brown-headed cowbirds (molothrus ater) containing sarcocysts of sarcocystis falcatula. shedding of sporocysts was confirmed in all five opossums by fecal flotation. counts were conducted daily for 2 weeks and then biweekly until the animals were euthanized and necropsied. the average prepatent period was 9.8 (7-16) days. the number of sporocysts shed varied greatly between the opossums with maximum mean shedding occurring at 71.6 ...200111223211
host associations and seasonal occurrence of haemaphysalis leporispalustris, ixodes brunneus, i. cookei, i. dentatus, and i. texanus (acari: ixodidae) in southeastern missouri.hemaphysalis leporispalustris (packard), ixodes brunneus koch, ixodes cookei packard, ixodes dentatus marx, and ixodes texanus banks were collected during a 3-yr study of pathogen-tick-host interactions in southeastern missouri. h. leporispalustris was collected from the eastern cottontail rabbit, northern bobwhite, and carolina wren, and it was active all year. i. brunneus was collected by drag and from passerine birds during december, march, and april. i. cookei was collected from raccoons and ...200312597662
development of sarcocystis falcatula in its intermediate host, the brown-headed cowbird (molothrus ater).sporocysts of sarcocystis falcatula obtained from experimentally infected virginia opossums (didelphis virginiana) were inoculated orally to 60 wild-caught brown-headed cowbirds (molothrus ater). another 30 brown-headed cowbirds were not challenged and served as uninfected controls. two inoculated and one control cowbird were necropsied every 2 weeks and the pectoral and thigh muscles were examined grossly for cyst development. stained histologic sections of pectoral muscle, thigh muscle, and lu ...200111223213
bovine tuberculosis in free-ranging carnivores from michigan.during a survey of carnivores and omnivores for bovine tuberculosis conducted in michigan (usa) since 1996, mycobacterium bovis was cultured from lymph nodes pooled from six coyotes (canis latrans) (four adult female, two adult male), two adult male raccoons (procyon lotor), one adult male red fox (vulpes vulpes), and one 1.5-yr-old male black bear (ursus americanus). one adult, male bobcat (felis rufus) with histologic lesions suggestive of tuberculosis was negative on culture but positive for ...200111272505
the nine-banded armadillo (dasypus novemcinctus) is an intermediate host for sarcocystis neurona.the nine-banded armadillo (dasypus novemcinctus) is an intermediate host of at least three species of sarcocystis, sarcocystis dasypi, sarcocystis diminuta, and an unidentified species; however, life cycles of these species have not been determined. following feeding of armadillo muscles containing sarcocysts to the virginia opossum (didelphis virginiana), the opossums shed sporulated sarcocystis sporocysts in their faeces. mean dimensions for sporocysts were 11.0x7.5 microm and each contained f ...200111306111
spotted fever group rickettsia in dermacentor variabilis (acari: ixodidae) infesting raccoons (carnivora: procyonidae) and opossums (marsupialia: didelphimorphidae) in tennessee.spotted fever group rickettsia were present in 13 of 1,171 (1.1%) of adult dermacentor variabilis say removed from raccoons (procyon lotor l.) and virginia opossums (didelphis virginiana kerr) in western tennessee. spotted fever group rickettsia were detected by amplification of a 617-bp segment of the citrate synthase gene by polymerase chain reaction.200111476343
sarcocystis greineri n. sp. (protozoa: sarcocystidae) in the virginia opossum (didelphis virginiana).sarcocysts were found in the skeletal muscles of road-killed and live-trapped opossums collected in north central florida. sarcocysts were spindle-shaped and macroscopic and had an average measurement of 3.8 mm by 154.6 microm. sarcocysts were only observed in skeletal muscle. sarcocysts have invaginations throughout the sarcocyst wall, which is approximately 1 microm thick. protrusions on the sarcocyst wall are stumpy and digitlike and contain fibrillar elements that extend from the interior po ...200111695370
prevalence of antibodies to neospora caninum, sarcocystis neurona, and toxoplasma gondii in wild horses from central wyoming.sarcocystis neurona, neospora caninum, n. hughesi, and toxoplasma gondii are 4 related coccidians considered to be associated with encephalomyelitis in horses. the source of infection for n. hughesi is unknown, whereas opossums, dogs, and cats are the definitive hosts for s. neurona, n. caninum, and t. gondii, respectively. seroprevalence of these coccidians in 276 wild horses from central wyoming outside the known range of the opossum (didelphis virginiana) was determined. antibodies to t. gond ...200314533680
sarcocystis neurona infections in raccoons (procyon lotor): evidence for natural infection with sarcocysts, transmission of infection to opossums (didelphis virginiana), and experimental induction of neurologic disease in raccoons.equine protozoal myeloencephalitis (epm) is a serious neurologic disease of horses in the americas and sarcocystis neurona is the most common etiologic agent. the distribution of s. neurona infections follows the geographical distributions of its definitive hosts, opossums (didelphis virginiana, didelphis albiventris). recently, cats and skunks were reported as experimental and armadillos as natural intermediate hosts of s. neurona. in the present report, raccoons (procyon lotor) were identified ...200111698157
comparative pathology and pathogenesis of naturally acquired and experimentally induced colonic spirochetosis.research in the past decade has led to the recognition of brachyspira (formerly serpulina) pilosicoli as the primary etiologic agent of colonic spirochetosis (cs), an emerging cause of colitis in humans and animals. attachment of spirochetes to the epithelial surface of the lower intestine is considered to be the hallmark of cs. however, because b. pilosicoli, b. aalborgi and unclassified flagellated bacteria are found singly or together in humans and non-human primates with cs lesions, attachme ...200111708743
neurologic disease in gamma-interferon gene knockout mice caused by sarcocystis neurona sporocysts collected from opossums fed armadillo muscle.fifteen gamma-interferon gene knockout mice were each orally inoculated with 5 x 10(3) sarcocystis sporocysts derived from virginia opossums (didelphis virginiana) fed nine-banded armadillo (dasypus novemcinctus) muscle containing sarcocysts. three mice were inoculated with similarly obtained homogenates, but in which no sporocysts were detected. mouse m8 was pregnant when inoculated and gave birth during the trial. fifteen of 15 (100%) mice inoculated with sporocysts developed neurologic signs ...200211751001
risk factors associated with the presence of sarcocystis neurona sporocysts in opossums (didelphis virginiana).sarcocystis neurona is the most important cause of equine protozoal myeloencephalitis (epm) in horse in the americas. the only known definitive host for this parasite in the united states is the opossum (didelphis virginiana); however, despite the importance of the disease, the epidemiology of the parasite in the definitive host is poorly understood. to begin addressing these data gaps, potential risk factors were evaluated for their association with the presence of sporocysts of s. neurona in o ...200111777597
sarcocystis neurona infections in sea otter (enhydra lutris): evidence for natural infections with sarcocysts and transmission of infection to opossums (didelphis virginiana).although sarcocystis neurona has been identified in an array of terrestrial vertebrates, recent recognition of its capacity to infect marine mammals was unexpected. here, sarcocysts from 2 naturally infected sea otters (enhydra lutris) were characterized biologically, ultrastructurally, and genetically. dna was extracted from frozen muscle of the first of these sea otters and was characterized as s. neurona by polymerase chain reation (pcr) amplification followed by restriction fragment length p ...200111780826
sarcocystis neurona reacting antibodies in missouri feral domestic cats (felis domesticus) and their role as an intermediate host.sarcocystis neurona is the parasite associated with equine protozoal myeloencephalitis (epm). recently, cats (felis domesticus) have been implicated as a potential intermediate host in the life cycle of s. neurona. this study was initiated to determine whether cats have antibodies that react to s. neurona antigens similar to antibodies from horses with epm, and to evaluate the role of cats as intermediate hosts in the parasite's life cycle. nine feral cats were used for analysis. only one had an ...200211826870
seroprevalence of trypanosoma cruzi in raccoons from south carolina and georgia.trypanosoma cruzi, the causative agent of american trypanosomiasis or chagas' disease, is of both medical and veterinary importance as is evidenced by chronic phase myocarditis in humans and dogs. further, t. cruzi has been reported from over 20 species of wildlife reservoir hosts in the usa, with raccoons (procyon lotor) and opossums (didelphis virginiana) being the most common. whereas previous studies on t. cruzi in raccoons have included only culture and direct examination of blood, the indi ...200211838232
experimental transmission of sarcocystis speeri dubey and lindsay, 1999 from the south american opossum (didelphis albiventris) to the north american opossum (didelphis virginiana).sarcocystis speeri dubey and lindsay, 1999 from the south american opossum didelphis albiventris was successfully transmitted to the north american opossum didelphis virginiana. sporocysts from a naturally infected d. albiventris from argentina were fed to 2 gamma-interferon knockout (ko) mice. the mice were killed 64 and 71 days after sporocyst feeding (daf). muscles containing sarcocysts from the ko mouse killed 71 daf were fed to a captive d. virginiana; this opossum shed sporocysts 11 days a ...200010864267
serologic evidence of exposure of wild mammals to flaviviruses in the central and eastern united states.serosurveys were conducted to obtain flavivirus and west nile virus (wnv) seroprevalence data from mammals. sera from 513 small- and medium-sized mammals collected during late summer and fall 2003 from colorado, louisiana, new york, ohio, and pennsylvania were screened for flavivirus-specific antibodies. sera samples containing antibody to flaviviruses were screened for wnv-specific antibodies by epitope-blocking enzyme-linked immunosorbent assays and confirmed with plaque reduction neutralizati ...200515891139
serologic evidence of west nile virus infection in free-ranging mammals, slidell, louisiana, 2002.after an outbreak of west nile virus (wnv) infections in slidell, louisiana, in 2002, we detected neutralizing antibodies to wnv in 13 of 120 mammals, representing five of six species sampled. seroprevalence was measured in opossum, didelphis virginiana (75%, n = 8), raccoons, procyon lotor (60%, n = 5), black rats, rattus rattus (6%, n = 36), hispid cotton rats, sigmodon hispidus (4%, n = 24), and eastern gray squirrels, sciurus carolinensis (2%, n = 43).200516187899
why fuse the mandibular symphysis? a comparative analysis.fused symphyses, which evolved independently in several mammalian taxa, including anthropoids, are stiffer and stronger than unfused symphyses. this paper tests the hypothesis that orientations of tooth movements during occlusion are the primary basis for variations in symphyseal fusion. mammals whose teeth have primarily dorsally oriented occlusal trajectories and/or rotate their mandibles during occlusion will not benefit from symphyseal fusion because it prevents independent mandibular moveme ...200010918127
bartonella and rickettsia in fleas and lice from mammals in south carolina, u.s.a.species in the genera bartonella and rickettsia are vector-borne pathogens of humans and domestic animals. the natural reservoirs and enzootic transmission cycles of these bacteria are poorly known in south carolina. thirteen species of lice and fleas were collected from urban animals and screened for the presence of bartonella and rickettsia by pcr amplification using genus-specific primers. bartonella henselae was present in cat fleas (ctenocephalides felis) from virginia opossums (didelphis v ...200516599169
spontaneous squamous cell carcinoma of the tongue and multiple bronchioloalveolar carcinomas in a virginia opossum (didelphis virginiana).two primary tumours, squamous cell carcinoma of the tongue and multiple bronchioloalveolar carcinomas, were diagnosed in a virginia opossum (didelphis virginiana). two oral masses were located in the right ventrolateral surface of the tongue, near the frenulum, and the lungs contained multiple, widely distributed, nodular masses. microscopically, the oral masses were composed of invasive cords of pleomorphic, polyhedral cells, typical of squamous cells. the multiple pulmonary masses consisted of ...200211945013
porrorchis nickoli n. sp. (acanthocephala:: plagiorhynchidae) from mammals in southeastern mexico, first known occurrence of porrorchis in the western hemisphere.porrorchis nickoli n. sp. is described from the intestine of the gray four-eyed opossum philander opossum (type host), the virginia opossum didelphis virginiana, the common opossum didelphis marsupialis, and the white-nosed coati nasua narica. hosts were collected in southeastern mexico in the los tuxtlas region of the state of veracruz (type locality) and in the states of tabasco and chiapas. this new species is distinguished from other porrorchis species by its small proboscis (0.286-0.428 mm ...200212058721
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