| fleas and lice parasitizing mammals in missouri. | three species of chewing lice, 11 species of sucking lice, and 28 species of fleas are recorded from mammals in missouri. of these, seven species of sucking lice (hoplopleura acanthopus, hoplopleura hesperomydis, hoplopleura sciuricola, neohaematopinus sciuri, neohaematopinus sciurinus, neohaematopinus sciuropteri, and solenopotes ferrisi) and one species of flea (doratopsylla blarinae) represent new state records. from 1993 to 1995, 773 individual mammals were examined for ectoparasites in sout ... | 1997 | 9491363 |
| serologic evidence of infection with ehrlichia spp. in wild rodents (muridae: sigmodontinae) in the united states. | rodent (muridae: sigmodontinae) blood and sera collected from 14 states were tested for seroreactivity to a cultured isolate of the human granulocytic ehrlichiosis (hge) agent by using an indirect immunofluorescence assay. of the 1,240 samples tested, 136 (11%) were found to be reactive at titers of > or = 32. rodents with hge agent-specific antibodies were found in new york (23% of 491 samples; geometric mean endpoint titer [gmt] = 441), connecticut (11% of 100 samples; gmt = 481), california ( ... | 1998 | 9508298 |
| comparison of the lateral diffusion constant of hepatocyte membrane proteins in two wild mouse strains of considerably different longevity: frap studies on liver smears. | the liver cells of male and female wild mice (peromyscus leucopus and mus musculus) have been studied in young, adult, and old age groups. because p. leucopus displays a life expectancy of 7-8 years, the age groups of this strain were from 5.5 to 68 months. m. musculus survives only to about 2.5 years; therefore, the age groups of this strain ranged from 6 to 27 months. protein lateral diffusion in hepatocyte membranes was measured by means of fluorescence recovery after photobleaching (frap) in ... | 1993 | 8482810 |
| age- and gender-related variations in the activities of drug-metabolizing and antioxidant enzymes in the white-footed mouse (peromyscus leucopus). | the effects of aging on the activities of drug-metabolizing enzymes and antioxidant enzymes were studied in male and female white-footed mice (peromyscus leucopus) at ages of 6, 8, 12, 18, 24, 30, 36, and 48 months. male mice had significantly higher liver microsomal cytochrome p450 (p450) content and nadph:cytochrome p450 oxidoreductase (p450 reductase) activities than females at all age groups. many of the p450-dependent enzyme activities were also generally higher in males. female mice showed ... | 1993 | 8495997 |
| regional analysis of 5-ht1a receptors in two species of peromyscus. | two species of deer-mice, peromyscus maniculatus (p. man) and peromyscus leucopus (p. leu), were compared for differences in 5-hydroxytryptamine1a (5-ht1a) receptor number and affinity. both species enter into torpor; however, p. man enters spontaneous torpor with a higher frequency and for a longer duration than p. leu. further, compared to p. leu a higher percentage of p. man exhibit daily torpor. deer mice can be induced to enter torpor by a reduction in food supply, shortened photoperiods, a ... | 1993 | 8516353 |
| coccidian parasites (apicomplexa) from snakes in the southcentral and southwestern united states: new host and geographic records. | four hundred thirty-five leptotyphlopid, colubrid, elapid, and viperid snakes were collected from various localities in arkansas, new mexico, oklahoma, and texas, and their feces were examined for coccidian parasites. of these, 131 (30%) were passing oocysts or sporocysts of at least 1 coccidian; 88 (67%) of the infected snakes had only 1 species of coccidian when they were examined. aquatic and semiaquatic snakes accounted for 48% of the infections, whereas strictly terrestrial snakes comprised ... | 1995 | 7876980 |
| genetic, phenotypic, and behavioral variation in north american sylvatic isolates of trichinella. | two restriction endonucleases (cla i and hpa ii) produced polymorphic repetitive dna profiles which were used in a clustering analysis to quantify the level of genetic variation among 14 north american sylvatic isolates of t5 trichinella. differences in genetic profiles reflected phenotypic differences in parasite reproductive success as measured by an isolate's reproductive capacity index in natural hosts. two genetically distinct isolates of the t5 genotype and t. spiralis were used to infect ... | 1994 | 7931904 |
| an experimental study of inbreeding depression in a natural habitat. | inbreeding is known to lead to decreased survival and reproduction in captive populations of animals. it is also important to know whether inbreeding has deleterious effects in natural habitats. an estimate was made of the effects of inbreeding in white-footed mice, peromyscus leucopus noveboracensis, derived from a wild population. this study demonstrates that inbreeding had a significant detrimental effect on the survivorship of mice reintroduced into a natural habitat. this effect was more se ... | 1994 | 7939661 |
| parasitic arthropods of white-footed mice at mcclintic wildlife station, west virginia. | seven species of parasitic arthropods (one sucking louse, one bot, 2 fleas, one tick, and 2 mites) were recovered from 81 white-footed mice, peromyscus leucopus, live-trapped on the grounds of the mcclintic wildlife station, mason county, wv, from march through november 1990. the most commonly collected arthropods were the fleas orchopeas leucopus (89 specimens) and epitedia wenmanni (23), and the tick dermacentor variabilis (38). sex ratios for both flea species were female biased; 1.8:1.0 for ... | 1994 | 8014620 |
| reservoir competence of the meadow vole (rodentia: cricetidae) for the lyme disease spirochete borrelia burgdorferi. | the reservoir competence of the meadow vole, microtus pennsylvanicus ord, for the lyme disease spirochete borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner was established on patience island, ri. meadow voles were collected from 5 locations throughout rhode island. at 4 of the field sites, m. pennsylvanicus represented only 4.0% (n = 141) of the animals captured. however, on patience island, m. pennsylvanicus was the sole small mammal collected (n = 48). of the larval ixodes scap ... | 1998 | 9775612 |
| new york 1 and sin nombre viruses are serotypically distinct viruses associated with hantavirus pulmonary syndrome. | new york 1 virus (ny-1) and sin nombre virus (sn) are associated with hantavirus pulmonary syndrome (hps). ny-1 and sn are derived from unique mammalian hosts and geographic locations but have similar g1 and g2 surface proteins (93 and 97% identical, respectively). focus reduction neutralization assays were used to define the serotypic relationship between ny-1 and sn. sera from ny-1-positive peromyscus leucopus neutralized ny-1 and sn at titers of >/=1/3,200 and </=1/400, respectively (n = 12). ... | 1999 | 9854075 |
| comparison of chromosomal distribution of a retroposon (line) and a retrovirus-like element mys in peromyscus maniculatus and p. leucopus. | chromosomal distribution for two interspersed elements (lines and mys) that are thought to have established their chromosomal position primarily by transposition was compared between two species of deer mice (peromyscus leucopus and p. maniculatus). both lines and mys generally produced an autosomal banding pattern reflective of g-bands and both hybridized preferentially to the sex chromosomes. the pattern on the long arm of the x was unique for each, with mys reflecting the g-bands (four bands ... | 1994 | 8069462 |
| notes on responses of blacklegged ticks (acari: ixodidae) to host urine. | in laboratory bioassays under conditions of high humidity, host-seeking female black-legged ticks, ixodes scapularis say, avoided urine of reproductively active male and nonestrous female white-tailed deer, odocoileus virginianus (zimmermann), the principal host species of the adult stage. at 50% rh, female i. scapularis did not avoid urine from male and female deer. larval and nymphal i. scapularis did not exhibit an arrestment response to urine from male and female white-footed mice, peromyscu ... | 1999 | 10083760 |
| failure of cryptorchidism to suppress fertility in a tropical rodent. | the cane mouse (zygodontomys brevicauda) breeds year-round on the hot llanos of venezuela, only 8 degrees above the equator. the reproductive responses of the males of this species to heat were compared with those of a temperature zone rodent, the white-footed mouse (peromyscus leucopus). when tested at different ambient temperatures, the movement of the testis in relation to the scrotum was similar in the two species, but the cane mouse's testis proved to be much more resistant to maintenance a ... | 1993 | 8100454 |
| immunological, hematological, and biochemical responses in immature white-footed mice following maternal aroclor 1254 exposure: a possible bioindicator. | a number of hematological, immunological, and biochemical parameters were measured in peromyscus leucopus pups born from dams exposed to a single dose (300 mg/kg body weight) of aroclor 1254. to increase the chances of uncovering even modest consequences of the exposure, in one protocol the pups were weaned at 3 weeks and examined at 6 weeks of age, while in a second protocol the pups were kept with their mother for 4 weeks, at which time they were examined. the older pups showed significant dec ... | 1999 | 10227867 |
| antibodies to granulocytic ehrlichiae in white-footed and cotton mice in eastern united states. | serum samples, collected from peromyscus leucopus (white-footed mouse) or peromyscus gossypinus (cotton mouse) during 1987 through 1990 in florida, georgia, maryland, mississippi, and north carolina (usa), and in 1997 in southern connecticut were analyzed by indirect fluorescent antibody (ifa) staining methods or western blot procedures for antibodies to granulocytic ehrlichiae. of the 82 sera from white-footed mice in connecticut tested by ifa methods with either the bds or nch-1 strain of the ... | 1999 | 10231752 |
| correlative analysis of heavy metal bioconcentration and genetic damage in white-footed mice (peromyscus leucopus) from a hazardous waste site. | | 1994 | 8186636 |
| biochemical correlates of longevity in two closely related rodent species. | the objective of this study was to explore the basis of variations in the life span and metabolic potential, i.e., total amount of energy consumed during life, between different species, in context of the free radical hypothesis of aging. a comparison was made between the house mouse (mus musculus) and the white-footed mouse (peromyscus leucopus): the latter has > 2-fold greater life span and metabolic potential than the former. longer life span and higher metabolic potential of peromyscus were ... | 1993 | 8216337 |
| longitudinal study of infection with borrelia burgdorferi in a population of peromyscus leucopus at a lyme disease-enzootic site in maryland. | the maintenance of borrelia burgdorferi in a population of peromyscus leucopus was investigated from 202 mark and recapture mice and 61 mice that were removed from a site in baltimore county, maryland. borrelia burgdorferi infection was detected by culture and polymerase chain reaction (pcr) of ear tissue, and exposure to the spirochete was quantified by serology. overall prevalence of b. burgdorferi, as determined by culture and pcr of ear tissue at first capture, was 25% in the longitudinal sa ... | 1999 | 10348235 |
| age and temperature related changes in behavioral and physiological performance in the peromyscus leucopus mouse. | age-related and ambient temperature-related changes in motor activity, body temperature, body weight (b.w.), and food consumption were studied in the long-lived peromyscus leucopus mouse at environmental temperatures of 29 and 21 degrees c. major changes in physiological performance were observed between the young (6 months) and old (60-72 month) age groups. the number of daily activity episodes, and total activity output was significantly lower in old mice. maximum, average and minimum daily bo ... | 1997 | 9152960 |
| natural infection of small mammal species in minnesota with the agent of human granulocytic ehrlichiosis. | the natural reservoirs for the agent of human granulocytic ehrlichiosis (hge) are suspected to be the small mammals that host immature stages of ixodes scapularis ticks. to determine if such small mammals are naturally infected, we collected blood and serum samples from small mammal species in rural and suburban areas of minneapolis and st. paul, minn. samples were collected from white-footed mice (peromyscus leucopus), eastern chipmunks (tamias striatus), southern red-backed voles (clethrionomy ... | 1997 | 9157141 |
| susceptibility of peromyscus leucopus and mus musculus to infection with baylisascaris procyonis. | in this study, we compared the susceptibility of peromyscus leucopus (white-footed mouse), a common natural intermediate host, and mus musculus, a commonly used experimental model, to infection with larvae of the raccoon ascarid, baylisascaris procyonis. three groups of 10 mice of each species were given 50, 250, or 500 infective b. procyonis eggs by gavage. the mice were observed daily for clinical signs of central nervous system (cns) disease and at necropsy the distribution of larvae in 10 bo ... | 1997 | 9406787 |
| retrospective serosurvey for human granulocytic ehrlichiosis agent in urban white-footed mice from maryland. | archived serum samples from 111 peromyscus leucopus, collected 1984-88 in baltimore city (maryland, usa), were analyzed by indirect immunofluorescence assay. sera from two (2%) individuals contained antibodies reactive to ehrlichia equi and the human granulocytic ehrlichiosis (hge) agent. this suggests that the hge agent or an antigenically related organism has been present in rodent populations in this locality for more than a decade, and was present in the region at least 12 yr before a case o ... | 1998 | 9476244 |
| density-dependent factors regulating feeding success of ixodes scapularis larvae (acari: ixodidae). | we studied the effects of different parasite and host densities on the feeding success of larval ixodes scapularis ticks upon white-footed mice peromyscus leucopus. mice were infested daily with 10, 25, 50, or 100 larvae and kept individually or in groups of 2 and 3 to simulate co-nesting in the field. engorgement weight and molting success of replete larvae did not change during more than 3 wk of continuous infestation, but overall larval feeding success decreased from 24% to 12% with increased ... | 1998 | 9488335 |
| infection with agents of human granulocytic ehrlichiosis, lyme disease, and babesiosis in wild white-footed mice (peromyscus leucopus) in connecticut. | white-footed mice, peromyscus leucopus, were captured in southern connecticut during 1997 and 1998 to determine the prevalence of infections caused by granulocytic ehrlichia sp., borrelia burgdorferi, and babesia microti. of the 50 mice captured and recaptured, 25 of 47 (53.2%) and 23 of 48 (47.9%) contained antibodies to the bds or nch-1 ehrlichia strains, respectively, as determined by indirect fluorescent antibody (ifa) staining methods. the majority (83.3%) of 48 mice also contained antibodi ... | 1999 | 10449470 |
| transgenic mice expressing a truncated peromyscus leucopus tnf-alpha gene manifest an arthritis resembling ankylosing spondylitis. | several studies have implicated tumor necrosis factor-alpha (tnf-alpha) in autoimmune diseases, such as rheumatoid arthritis (ra). to elucidate further the role of tnf-alpha in inflammatory arthritis, we generated transgenic mice harboring a truncated peromyscus leucopus tnf-alpha (pe-tnf) gene. an arthritic phenotype closely resembling human ankylosing spondylitis was observed only in transgenic lines expressing the pe-tnf transgene at the mrna level. we characterized the arthritic phenotype in ... | 1998 | 9568723 |
| isolation of bartonella spp. from embryos and neonates of naturally infected rodents. | embryos and neonatal offspring of wild-captured cotton rats (sigmodon hispidus) and white-footed mice (peromyscus leucopus) were tested for the presence of bartonella spp. isolates of bartonella spp. were obtained from 18 of 31 embryos and 7 of 19 neonates from bacteremic dams of the two species; no isolates were obtained from material from non-bacteremic dams. sequence analysis demonstrated that the isolates from embryos and neonates matched the phylogenetic group of bartonella spp. isolates ob ... | 1998 | 9577777 |
| evaluation of two oral baiting systems for wild rodents. | tetracycline hydrochloride (tc)-treated peanut butter or rodent chow baits were distributed during march 1990, on separate 0.53 ha sites in oglethorpe county, georgia (usa). rodents were trapped on a control site prior to bait distribution and on two baited sites 6 days post-distribution. cleaned skulls from euthanized mammals were grossly examined for tc fluorescence using an ultraviolet (uv) light. mandibles were sectioned and examined for tc fluorescence using an ultraviolet light microscope. ... | 1998 | 9577787 |
| a mathematical model of the ecology of lyme disease. | a mathematical model of enzootic lyme-disease transmission in a natural focus is presented. this model is based on the life history of the vector tick ixodes scapularis say and the primary reservoir host peromyscus leucopus. using this model, the threshold condition for the disease to be able to invade a nonenzootic region is determined as a function of the various possible transmission chains operating throughout the year. these expressions show that the transmission chain in which ticks acquir ... | 1999 | 10520492 |
| population dynamics of a naturally occurring heterogeneous mixture of borrelia burgdorferi clones. | two unique isolates of borrelia burgdorferi, differing in plasmid content and outer surface protein c expression, were cultured on sequential captures of a single free-living peromyscus leucopus mouse and were examined for differences in transmissibility. both isolates were transmissible from inoculated c.b-17 mice to larval ixodes scapularis ticks and, subsequently, from infected nymphal ticks to c3h/hej mice. plasmid and protein analyses suggested that the original isolates were a mixed popula ... | 1999 | 10531219 |
| 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 ... | 1999 | 10534951 |
| lack of seroreactivity to ehrlichia chaffeensis among rodent populations. | a retrospective serosurvey for antibodies to ehrlichia chaffeensis was conducted on eight species of wild rodents (mus musculus, oryzomys palustris, peromyscus leucopus, rattus norvegicus, reithrodontomys humulis, sciurus carolinensis, sciurus niger, and sigmodon hispidus) from the southeastern united states. serum samples (n = 281) collected between 1973 and 1993 were evaluated using an indirect fluorescent antibody test. all samples, screened at a dilution of 1:32, were negative for antibodies ... | 1998 | 9577793 |
| infestation of peromyscus leucopus and tamias striatus by ixodes scapularis (acari: ixodidae) in relation to the abundance of hosts and parasites. | the risk of humans acquiring lyme disease is a function of the local density of nymphal and adult ticks that are infected with lyme disease spirochetes. this in turn, will be related to host-use patterns of ticks and to the densities of both juvenile ticks and their hosts. at a forested site in dutchess county, ny, we quantified host-use patterns of larval and nymphal ixodes scapularis say infesting the 2 dominant vertebrate hosts, white-footed mice and eastern chipmunks, during a 3-yr period. l ... | 1999 | 10593076 |
| a polymorphic multigene family encoding an immunodominant protein from babesia microti. | human babesiosis in the united states is caused predominantly by babesia microti, a tick-transmitted blood parasite. improved testing methods for the detection of infection with this parasite are needed, since asymptomatic b. microti infection represents a potential threat to the blood supply in areas where b. microti is endemic. we performed immunoscreening of an expression library of genomic dna from a human isolate of b. microti (strain mn1). among 17 unique immunoreactive clones, we identifi ... | 2000 | 10618117 |
| water-deprived white-footed mice express c-fos on a day/night cycle graded according to the duration of deprivation. | mammals respond to electrolyte and water imbalance by a variety of neural and endocrine mechanisms that regulate water and salt intake and loss. we used the expression of c-fos and fos-related antigens to indicate neuronal activation in hypothalamic neurons of members of an outbred laboratory population of white-footed mice (peromyscus leucopus) deprived of water for biologically reasonable periods of time (6-18 h). we examined fos-like immunoreactivity (fos-lir) in the supraoptic nucleus (son) ... | 1998 | 9593799 |
| immunity reduces reservoir host competence of peromyscus leucopus for ehrlichia phagocytophila. | infection with ehrlichia phagocytophila in white-footed mice is transient and followed by a strong immune response. we investigated whether the presence of acquired immunity against e. phagocytophila precludes white-footed mice from further maintenance of this agent in nature. mice were infected with e. phagocytophila via tick bite and challenged either 12 or 16 weeks later by ixodes scapularis nymphs infected with the same agent. xenodiagnostic larvae fed upon each mouse simultaneously with cha ... | 2000 | 10678968 |
| focal epidemic of sarcoptid (acarina: sarcoptidae) mite infestation in an insular population of white-footed mice. | the abrupt and focal emergence of an infestation of sarcoptid mites was documented during long-term studies of populations of the white-footed mouse, peromyscus leucopus (rafinesque), on nantucket island, ma. from 1985 to 1996, > 1,000 trap nights were recorded each year in 2 permanently situated sampling grids that were sampled monthly from april through november. in april 1995, prominent excrescences were first noted on the pinnae of mice trapped solely from 1 of the 2 sites. histopathology of ... | 1998 | 9701941 |
| immunohistochemical demonstration of serotonin-containing axons in the hypothalamus of the white-footed mouse, peromyscus leucopus. | the wild white-footed mouse, peromyscus leucopus, is commonly used for photoperiod studies utilizing physiological, behavioral, and other biological measures indicative of hypothalamic functions. indoleamines, like melatonin and serotonin, are implicated in regulating these hypothalamic functions. although neurochemical analyses of hypothalamic serotonin and its receptors have been reported for this species, the relevant neuroanatomy of the serotonin system within mouse hypothalamus has not been ... | 1998 | 9767166 |
| comparative vector competence of dermacentor variabilis and ixodes scapularis (acari: ixodidae) for the agent of human granulocytic ehrlichiosis. | vector competence of ixodes scapularis say and dermacentor variabilis say for the agent of human granulocytic ehrlichiosis (hge) was compared. five white-footed mice, peromyscus leucopus rafinesque, were inoculated intra-peritoneally with blood from a mouse infected with the agent of hge. approximately 100 i. scapularis and d. variabilis larvae were placed on each mouse and allowed to feed to repletion. fed larvae were collected, separated according to species and allowed to molt to nymphs. twen ... | 1999 | 10083755 |
| hantavirus pulmonary syndrome associated with monongahela virus, pennsylvania. | the first two recognized cases of rapidly fatal hantavirus pulmonary syndrome in pennsylvania occurred within an 8-month period in 1997. illness in the two patients was confirmed by immunohistochemical techniques on autopsy material. reverse transcription-polymerase chain reaction analysis of tissue from one patient and environmentally associated peromyscus leucopus (white-footed mouse) identified the monongahela virus variant. physicians should be vigilant for such monongahela virus-associated ... | 2000 | 11076720 |
| nitroaromatic munition compounds: environmental effects and screening values. | available data on the occurrence, transport, transformation, and toxicity of eight nitroaromatic munition compounds and their degradation products, tnt, tnb, dnb, dna, 2-adnt, rdx, hmx, and tetryl were used to identify potential fate in the environment and to calculate screening benchmarks or safe environmental levels for aquatic and terrestrial organisms. results of monitoring studies revealed that some of these compounds persist at sites where they were produced or processed. most of the compo ... | 1999 | 10218448 |
| isolation of the etiologic agent of human granulocytic ehrlichiosis from the white-footed mouse (peromyscus leucopus). | we examined white-footed mice (peromyscus leucopus) from minnesota for infection with the etiologic agent of human granulocytic ehrlichiosis (hge). from april to september 1997, we collected p. leucopus from washington county, minnesota, an area enzootic for hge. blood was cultivated in hl60 cells for isolation of the hge agent. of 59 mice examined, only a single mouse was culture positive for the hge agent. the 16s ribosomal dna sequence of the isolate was determined to be identical to that of ... | 2001 | 11136794 |
| retrotransposon mys was active during evolution of the peromyscus leucopus-maniculatus complex. | mys is a retrovirus-like transposable element found throughout the genus peromyscus. several mys subfamilies identified on the basis of restriction site variation occur in more than one species. the distribution of these subfamilies is consistent with the accepted species phylogeny, suggesting that mys was present in the ancestor of peromyscus and has been active through much of the evolution of this genus. quantitative southern blot analysis was used to examine the variability of subfamilies in ... | 1996 | 8576963 |
| the uptake and effects of lead in small mammals and frogs at a trap and skeet range. | this study was performed to evaluate the bioavailability and effects of lead in wildlife at a trap and skeet range. the total lead concentration in a composite soil sample (pellets removed) was 75,000 micrograms/g dry weight. elevated tissue lead concentrations and depressed alad activities in small mammals and frogs indicate that some of the lead deposited at the site is bioavailable. mean tissue lead concentrations (micrograms/g dry wt.) in white-footed mice (peromyscus leucopus) at the range ... | 1996 | 8593083 |
| entomological correlates of babesia microti prevalence in an area where ixodes scapularis (acari:ixodidae) is endemic. | zoonotic prevalence of babesia microti franca piroplasms infecting white-footed mice, peromyscus leucopus rafinesque, was determined at 34 sites in rhode island where nymphal blacklegged tick, ixodes scapularis say, densities ranged from low to hyperabundant (1.7-525.3 nymphs per hour of flagging). babesia was only detected at sites where tick abundance was moderate to high (> 20 nymphs per hour of flagging) and appeared to exhibit a clumped distribution. where b. microti was detected, the mean ... | 1996 | 8840700 |
| enzootic transmission of deer tick virus in new england and wisconsin sites. | to determine whether rodents that are intensely exposed to the deer tick-transmitted agents of lyme disease, human granulocytic ehrlichiosis, and human babesiosis are also exposed to deer tick virus (dtv), we assayed serum samples from white-footed mice (peromyscus leucopus) and meadow voles (microtus pennsylvanicus) in sites densely infested by deer ticks. to conduct serosurveys, we developed an enzyme-linked immunosorbent assay (elisa) and western blot assay by cloning, expressing, and purifyi ... | 2000 | 11357992 |
| interspecific differences between small mammals as hosts of immature dermacentor variabilis (acari: ixodidae) and a model for detection of high risk areas of rocky mountain spotted fever. | fourteen species of small mammals were captured from july 1990 through august 1991 in tennessee, from which 1,217 immature dermacentor variabilis and 1 ixodes dentatus were collected. mammal species were given scores of importance (ts) as hosts to immature d. variabilis based on mean intensity and prevalence. the rice rat ranked the highest, with a ts = 5, followed by the golden mouse ts = 4, white-footed mouse ts = 3, pine vole ts = 2, cotton rat ts = 1, with the norway rat, house mouse, and sh ... | 1996 | 8885876 |
| analysis of orthologous retrovirus-like elements in the white-footed mouse, peromyscus leucopus. | three loci in the genome of the white-footed mouse, peromyscus leucopus, were examined for the presence or absence of orthologous copies of the retrovirus-like element mys using polymerase chain reaction. we examined these loci in 28 mice collected throughout the p. leucopus species range. mys insertions were present in only one of the individuals examined at the mys-1 and mys-7 loci. conversely, the mys-6 element was found in several individuals, but the presence of this element was limited to ... | 1997 | 9010138 |
| spatial distribution of larval ixodes scapularis (acari:ixodidae) on peromyscus leucopus and microtus pennsylvanicus at two island sites. | larval blacklegged ticks, ixodes scapularis, were collected from white-footed mice. peromyscus leucopus, on prudence island (where microtus pennsylvanicus were not captured) and from meadow voles. m. pennsylvanicus, on patience island (where p. leucopus was absent) in narragansett bay, rhode island from june to october 1992. ixodes scapularis larvae were also collected by flagging in the vicinity of host captures. on both islands, the relative density of larvae changed from july to september in ... | 1997 | 9105297 |
| host associations of ticks parasitizing rodents at borrelia burgdorferi enzootic sites in south carolina. | a total of 237 rodents was collected in 4 regions of south carolina from july 1994 through december 1995. eight species were collected, including cotton mouse, hispid cotton rat, eastern woodrat, marsh rice rat, white-footed mouse, eastern harvest mouse, golden mouse, and black rat. of the 1,514 ticks recovered from these hosts, ixodes minor neumann, including larvae, nymphs, and adults, was the most abundant species, representing 54% of the total. only immature stages of other tick species were ... | 2001 | 11780825 |
| the efficacy of co-feeding as a means of maintaining borrelia burgdorferi: a north american model system. | although research on co-feeding as a means of maintaining tick-borne pathogens has focused chiefly on viruses, recent interest has been directed toward the importance of this phenomenon in maintaining the lyme disease spirochete, borrelia burgdorferi. in the current study, an experimental model was developed to determine under what conditions immature co-feeding ticks exchange b. burgdorferi using the principal north american vector (ixodes scapularis) and reservoir (peromyscus leucopus) species ... | 2001 | 11813659 |
| dna sequence of the peromyscus leucopus mhc class ii gene aa (mhcpeleaa). | | 1996 | 9110938 |
| parasites of mammals on the sevilleta national wildlife refuge, socorro, new mexico: cuterebra austeni and c. neomexicana (diptera:oestridae) from neotoma and peromyscus (rodentia:muridae), 1991-1994. | in total, 6,486 rodents representing 3 families (muridae, heteromyidae, and sciuridae) and 24 species were trapped may through august of 1991 through 1994. of these, only the white-throated woodrat. neotoma albigula hartley; piñon mouse, peromyscus truei shufeldt; and white-footed mouse, p. leucopus rafinesque, were infested with cuterebra clark larvae. of the 594 n. albigula that were captured 103 (17.3%) were infested with 139 cuterebra larvae with all infestations occurring in the throat regi ... | 1997 | 9151503 |
| development and distribution of pathologic lesions are related to immune status and tissue deposition of human granulocytic ehrlichiosis agent-infected cells in a murine model system. | to evaluate pathology and the role of immune status in a murine model system of human granulocytic ehrlichiosis (hge), c3h/hej, c3h-scid, and peromyscus leucopus mice were infected with an hge agent. all mice remained healthy. ehrlichemia was not detected after day 14 in p. leucopus and c3h/hej mice but increased between days 14 and 90 in c3h-scid mice. in tissues examined at day 21 and later, infection was rarely detected in immunocompetent mice but was present in all c3h-scid mice and included ... | 1999 | 10395880 |
| the ecology of infectious disease: effects of host diversity and community composition on lyme disease risk. | the extent to which the biodiversity and community composition of ecosystems affect their functions is an issue that grows ever more compelling as human impacts on ecosystems increase. we present evidence that supports a novel function of vertebrate biodiversity, the buffering of human risk of exposure to lyme-disease-bearing ticks. we tested the dilution effect model, which predicts that high species diversity in the community of tick hosts reduces vector infection prevalence by diluting the ef ... | 2003 | 12525705 |
| comparison of pcr assays for detection of the agent of human granulocytic ehrlichiosis, anaplasma phagocytophilum. | human granulocytic ehrlichiosis is an emerging infectious disease in the united states and europe, and pcr methods have been shown to be effective for the diagnosis of acute infections. numerous pcr assays and primer sets have been reported in the literature. the analytical sensitivities (limits of detection) of 13 published pcr primer sets were compared using dna extracted from serial dilutions of anaplasma phagocytophilum-infected hl-60 cells. the specificity of the assays that were able to de ... | 2003 | 12574272 |
| lyme disease spirochete, borrelia burgdorferi endemic at epicenter in rondeau provincial park, ontario. | the lyme disease spirochete, borrelia burgdorferi johnson, schmidt, hyde, steigerwalt, and brenner was discovered in blacklegged ticks, ixodes scapularis say at rondeau provincial park, ontario, canada during this 2-yr study, spirochetes were found in b. burgdorferi-positive i. scapularis larvae attached to b. burgdorferi-infected white-footed mice, peromyscus leucopus rafinesque. isolates of b. burgdorferi were cultured from blacklegged tick adults, and confirmed positive with polymerase chain ... | 2003 | 12597659 |
| effects of climate on variability in lyme disease incidence in the northeastern united states. | numbers of reported lyme disease cases have increased dramatically over the past decade in the northeastern united states, but the year-to-year variability is sizable (average standard deviation approximately 30% of the mean). an improved understanding of the causes of such variability would aid in prevention and control of the disease, which is transmitted by a spirochete carried in the "black-legged" tick, ixodes scapularis. in this study, the variability in reported lyme disease incidence bet ... | 2003 | 12631543 |
| a relapsing fever group spirochete transmitted by ixodes scapularis ticks. | a species of borrelia spirochetes previously unknown from north america has been found to be transmitted by ixodes scapularis ticks. infected ticks are positive for borrelia spp. by dfa test but negative for borrelia burgdorferi by polymerase chain reaction (pcr) using species-specific primers for 16s rdna, outer surface protein a, outer surface protein c, and flagellin genes. a 1,347-bp portion of 16s rdna was amplified from a pool of infected nymphs, sequenced, and compared with the homologous ... | 2001 | 12653133 |
| ospa immunization decreases transmission of borrelia burgdorferi spirochetes from infected peromyscus leucopus mice to larval ixodes scapularis ticks. | recombinant outer surface protein a (ospa) vaccination of wild animal reservoirs has potential application for reducing borrelia burgdorferi transmission in nature and subsequent risk of human infection. as a major reservoir host, the white-footed mouse (peromyscus leucopus) is a candidate for a vaccination program designed to reduce infection prevalence in vector ticks. in this study we characterized the effect of various levels of immunization with recombinant ospa-glutathione transferase fusi ... | 2001 | 12653137 |
| spatiotemporal variation in a lyme disease host and vector: black-legged ticks on white-footed mice. | we monitored population density of white-footed mice (peromyscus leucopus), burdens of immature black-legged ticks (ixodes scapularis) on mice, and infection prevalence of host-seeking ticks on six forest plots in southeastern new york state from 1995 through 1999. despite densities of mice that fluctuated two orders of magnitude, average larval and nymphal tick burdens per mouse remained remarkably constant. spatial variability in mouse density and tick burdens was modest. the total number of l ... | 2001 | 12653143 |
| interference between the agents of lyme disease and human granulocytic ehrlichiosis in a natural reservoir host. | agents of lyme disease (borrelia burgdorferi) and human granulocytic ehrlichiosis (ehrlichia phagocytophila) are perpetuated in a natural cycle involving the black-legged tick (ixodes scapularis) and its vertebrate hosts. using i. scapularis nymphs as the mode of infectious challenge, we studied how infection with one pathogen in white-footed mice (peromyscus leucopus) affects their ability to acquire the other agent and subsequently to infect larvae, which these agents would do in nature. two g ... | 2001 | 12653144 |
| species differences in paternal behavior and aggression in peromyscus and their associations with vasopressin immunoreactivity and receptors. | previous comparative studies have suggested that the distribution of arginine vasopressin (avp) pathways within the brain is associated with species-typical patterns of social behavior. in the current study, male parental behavior and aggression were compared in two species of peromyscus. as predicted based on other studies, male mice from a monogamous species, the california mouse peromyscus californicus, spent more time providing parental care to offspring than males from a polygamous species, ... | 1999 | 10433884 |
| genetic detection of sex-biased dispersal. | we investigated the application of a recently developed genetic test for sex bias in dispersal. this test determines an animal's 'assignment index' or the expected frequency of its genotype in the population in which it is captured. low assignment indices indicate a low probability of being born locally. we investigated the use of this test with the white-footed mouse, peromyscus leucopus, in which dispersal is predominantly male-biased, but not extreme. we found that male p. leucopus had signif ... | 1999 | 10434424 |
| allelic diversity at the mhc-dqa locus in cotton rats (sigmodon hispidus) and a comparison of dqa sequences within the family muridae (mammalia: rodentia). | the cotton rat (sigmodon hispidus) is a common murid rodent of the southern united states, mexico, and central america. using single-stranded conformation polymorphism analysis and dna sequencing techniques, 11 dqa exon 2 alleles were detected among 180 s. hispidus from caddo county, oklahoma, usa. the alleles represent a single locus exhibiting a high level of polymorphism. nucleotide and amino acid distance values among dqa alleles of s. hispidus were higher than those within mus musculus and ... | 1999 | 10436183 |
| transmission efficiency of the ap-variant 1 strain of anaplasma phagocytophila. | nymphal ixodes scapularis ticks were collected from several sites in rhode island. dna was extracted from a subset of these ticks, and pcr and dna sequencing of the 16s rrna gene were used to determine the ratio of anaplasma phagocytophila-human agent (ap-ha) to a genetic variant not associated with human disease (ap-variant 1). the remaining ticks were allowed to feed to repletion on either white-footed (peromyscus leucopus) or dba/2 (mus musculus) mice. the engorged ticks, and blood samples dr ... | 2003 | 12860603 |
| resistance of the white-footed field mouse (peromyscus leucopus noveboracensis) to the carcinogenic action of urethane. | | 1953 | 13106842 |
| 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 ... | 1999 | 10479081 |
| illumination and the perception of remote habitat patches by white-footed mice. | perceptual range, or the distance at which habitat 'patches' can be perceived, constrains an animal's informational window on a given landscape. if such constraints are great, they may limit successful dispersal between distant habitat patches. on dark nights, nocturnal white-footed mice, peromyscus leucopus, have surprisingly limited perceptual abilities regarding distant forested habitat. in fact, their ability to orient towards such habitat while travelling in a bare agricultural field indica ... | 1999 | 10479364 |
| differences in hypothalamic 2-[125i]iodomelatonin binding in photoresponsive and non-photoresponsive white-footed mice, peromyscus leucopus. | photoperiod is an environmental cue used by many temperate-zone species to regulate their reproductive timing. within species, the degree of reproductive photoresponsiveness can vary widely both among and within populations. the neuroendocrine mechanisms causing this individual variation in photoresponsiveness are unknown. using selected lines from a population of white-footed mice known to vary genetically in reproductive photoresponsiveness, we tested the hypothesis that variation in the numbe ... | 1999 | 10517952 |
| cross-transmission studies with eimeria arizonensis, e. arizonensis-like oocysts and eimeria langebarteli: host specificity at the genus and species level within the muridae. | cross-transmission experiments were done using sporulated oocysts of eimeria arizonensis from peromyscus truei and peromyscus maniculatus, and oocysts of 2 putative species that resemble e. arizonensis, i.e., eimeria albigulae from neotoma albigula, and eimeria onychomysis from onychomys leucogaster. oocysts of each species were inoculated into representatives of p. maniculatus and the latter 2 rodent species. other experiments were conducted wherein oocysts of eimeria langebarteli from peromysc ... | 1999 | 10577723 |
| detection of antibody for the serodiagnosis of hantavirus infection in different rodent species. | peroxidase-labeled staphylococcal protein a, streptococcal protein g, and antibodies directed against mus musculus (mouse), rattus norvegicus (rat), mesocretus auratus (hamster), and peromyscus leucopus were examined for their reactivity with immunoglobulin g (igg) from various rodent species. the purpose of this study was to identify the optimal secondary antibodies or reagents for specific serodiagnosis of hantavirus infection in various rodent species. using elisa, a total of 65 sera from 29 ... | 2003 | 14551813 |
| analysis of weather effects on variability in lyme disease incidence in the northeastern united states. | in this study, variability in reported lyme disease incidence between 1993 and 2001 was analyzed in seven states in the northeastern part of the usa. positive significant correlations at p < 0.05 were found in all states between early summer disease incidence and the june moisture index in the region two years prior. these correlations may reflect an enhanced nymphal ixodes scapularis survival under wetter conditions. in some states, significant correlations were observed related to warmer winte ... | 2002 | 14570138 |
| inability of a variant strain of anaplasma phagocytophilum to infect mice. | nymphal ixodes scapularis ticks were collected from several sites in rhode island. polymerase chain reaction and dna sequencing were used to determine the presence and prevalence of anaplasma phagocytophilum human agent (ap-ha) and a genetic variant not associated with human disease (ap-variant 1). the remaining ticks from each cohort were allowed to feed to repletion on either white-footed (peromyscus leucopus) or dba/2 (mus musculus) mice. the engorged ticks and murine blood samples were evalu ... | 2003 | 14639548 |
| testicular regression in response to food restriction and short photoperiod in white-footed mice (peromyscus leucopus) is mediated by apoptosis. | short day lengths or reduced food availability are salient cues for small mammals that breed seasonally. photoperiod-mediated gonadal regression in white-footed mice (peromyscus leucopus) is a slow, orderly process that involves testicular apoptosis. testicular regression in response to restricted caloric intake is relatively rapid, and it is generally reversed quickly by ad libitum (ad lib) feeding. to determine the contribution of apoptotic cell death during food restriction, and to examine po ... | 2000 | 10642572 |
| hematology values from clinically healthy peromyscus leucopus. | reported herein are hematocrit and total and differential wbcs obtained from 132 clinically healthy male and female white-footed mice (peromyscus leucopus) of four different age groups: 4, 5-8, 9-20, and >32 wk old. minimal differences were identified between the age groups. the number and percentage of neutrophils in the 4-wk-old mice were significantly higher than those in the other groups; the relative percentage of lymphocytes in the 4-wk-old mice was significantly lower than in the 9-20-wk- ... | 1999 | 10749452 |
| bacteriolytic activity of selected vertebrate sera for borrelia burgdorferi sensu stricto and borrelia bissettii. | an in vitro assay to evaluate the bacteriolytic activity of the complement pathway was applied to 2 strains of borrelia bissettii, co501 and dn127, and compared with that of b. burgdorferi sensu stricto b31. sera from mule deer (odocoileus hemionus) and the western fence lizard (sceloporus occidentalis) were completely borreliacidal for b. burgdorferi and for both strains of b. bissettii. serum from bobwhite quail (colinus virginianus) was nonlytic for b. burgdorferi and partially lytic for b. b ... | 2003 | 14740924 |
| short photoperiods reduce vascular endothelial growth factor in the testes of peromyscus leucopus. | testicular regression in rodents occurs after short-day exposure. vascular support is withdrawn during regression, and, presumably, new angiogenesis is inhibited. blood vessel growth and maintenance are regulated by paracrine factors, including vascular endothelial growth factor (vegf). reduced angiogenesis may contribute to the onset of photoperiod-induced regression; i.e., reduction of vegf protein would be detected early during gonadal atrophy. alternatively, loss of blood vessel maintenance ... | 2000 | 10956275 |
| experimental evidence of host specificity of bartonella infection in rodents. | a large number of bartonella species and genetic variants were compared for their ability to cause bacteremia in different rodent species: the cotton rat (sigmodon hispidus), white-footed mouse (peromyscus leucopus), balb/c mouse and wistar rat. experimental data supported field observations that host specificity can occur among certain bartonella species and rodent species. bacteremia could only be readily produced in cotton rats or white-footed mice if the strains used for inoculation were ori ... | 2000 | 11038125 |
| tau differences between short-day responsive and short-day nonresponsive white-footed mice (peromyscus leucopus) do not affect reproductive photoresponsiveness. | in laboratory-bred rodent populations, intraspecific variation in circadian system organization is a known cause of individual variation in reproductive photoresponsiveness. the authors sought to determine whether circadian system variation accounted for individual variation in reproductive photoresponsiveness in a single, highly genetically variable population of peromyscus leucopus recently derived from the wild. running-wheel activity patterns of male and female mice, aged 70 to 90 days, from ... | 2000 | 11106067 |
| lyme disease spirochete, borrelia burgdorferi, endemic in epicenter at turkey point, ontario. | the lyme disease spirochete, borrelia burgdorferi johnson, schmidt, hyde, steigerwalt, and brenner, was discovered in blacklegged ticks, ixodes scapularis say at turkey point, ontario, canada. we report the first isolation of b. burgdorferi from a vertebrate animal collected on mainland ontario. during this 2-yr study, spirochetes were isolated from the white-footed mouse, peromyscus leucopus rafinesque, and attached i. scapularis larvae. similarly, isolates of b. burgdorferi were cultured from ... | 2004 | 15061282 |
| borrelia burgdorferi infection in a natural population of peromyscus leucopus mice: a longitudinal study in an area where lyme borreliosis is highly endemic. | blood samples from peromyscus leucopus mice captured at an enzootic site in connecticut were examined for antibodies to and dna of borrelia burgdorferi, to characterize the dynamics of infection in this reservoir population. from trappings conducted over the course of 2 transmission seasons, 598 (75%) of 801 serum samples from 514 mice were found to be positive by enzyme immunoassay. seropositivity correlated with date of capture and mouse age, was similar among locations within the site, increa ... | 2004 | 15073690 |
| babesia microti and borrelia bissettii transmission by ixodes spinipalpis ticks among prairie voles, microtus ochrogaster, in colorado. | an endemic transmission cycle of babesia microti was discovered in colorado in the foothills of the rocky mountains. b. microti were found by pcr in 4 of 25 ixodes spinipalpis tick pools tested (a 3.2 % minimum infection rate) and in 87% (13 of 15) of microtus ochrogaster (the prairie vole) spleen and blood samples. using naturally infected i. spinipalpis collected from wild-caught m. ochrogaster as vectors, b. microti and borrelia bissettii were successfully transmitted to laboratory-born m. oc ... | 2000 | 11155930 |
| 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 ... | 2000 | 11201355 |
| interaction and transmission of two borrelia burgdorferi sensu stricto strains in a tick-rodent maintenance system. | in the northeastern united states, the lyme disease agent, borrelia burgdorferi sensu stricto, is maintained by enzoonotic transmission, cycling between white-footed mice (peromyscus leucopus) and black-legged ticks (ixodes scapularis). b. burgdorferi sensu stricto is genetically variable and has been divided into three major genotypes based on 16s-23s ribosomal dna spacer (rst) analysis. to better understand how genetic differences in b. burgdorferi sensu stricto may influence transmission dyna ... | 2004 | 15528545 |
| populations of ixodes scapularis (acari: ixodidae) are modulated by drought at a lyme disease focus in illinois. | from 1990 through 1997, ixodes scapularis say larvae and nymphs were sampled between may and october along a 400-m segment of a nature trail in a lyme disease endemic site in northern illinois. ticks were removed from peromyscus leucopus mice and collected via tick drags at approximately 3-wk intervals. mouse population estimates along the trail varied from 2, in the spring of 1996 following a year of drought, to > 200 in 1993, the wettest year on record. during the 8-yr period, there were major ... | 2000 | 15535585 |
| a dispersal model for the range expansion of blacklegged tick (acari: ixodidae). | the blacklegged tick, ixodes scapularis say, a vector for the agents of lyme borreliosis and other diseases, has expanded its range dramatically over the past 20 yr. however, the relative contributions of different vertebrate host species to this expansion have remained largely unexplored. to address this issue, we simulated the expansion of a theoretical tick population across a simple landscape by using a deterministic, spatially explicit, cellular automata model. the model incorporates the ec ... | 2004 | 15535611 |
| feasibility of micronucleus methods for monitoring genetic damage in two feral species of small mammals. | peromyscus leucopus (white-footed mouse) and cryptotis parva (least shrew) possess desirable attributes for biomonitoring contamination of terrestrial ecosystems, but few studies have examined the potential use of these species for monitoring exposure to genotoxic contaminants. the susceptibility of laboratory-reared c. parva, p. leucopus, and mus musculus (house mouse, strain cd-1) to micronucleus (mn) induction by known clastogens was evaluated. animals were exposed for 24 hr to methyl methane ... | 1999 | 10334624 |
| lyme disease--a hazard of an appointment to the united states. | lyme disease is just one of the many tick borne diseases to be encountered within the united states that can affect humans. to the visitor who confines their time to major conurbations the risk of contracting lyme disease is minimal. however, anyone planning a hiking trip during tick season must take precautions to prevent being bitten and possibly infected. for those of us who live within an endemic area the shower after a days gardening is not just to remove sweat and dirt but also an opportun ... | 2004 | 15580952 |
| abundance of ixodes scapularis (acari: ixodidae) larvae and nymphs in relation to host density and habitat on long point, ontario. | ixodes scapularis say populations were evaluated within 4 habitats on long point, ontario, from 1990 to 1992 to ascertain whether differences in density of mouse populations within and among habitats were correlated with that of immature i. scapularis populations. i. scapularis immatures were rarely collected by dragging within the cottonwood dune habitat. significantly more larvae (p < or = 0.05) were collected by drag sampling within the maple forest habitat than in the oak savannah or white p ... | 1999 | 10337092 |
| control of immature ixodes scapularis (acari: ixodidae) on rodent reservoirs of borrelia burgdorferi in a residential community of southeastern connecticut. | a 3-yr community-based study was conducted on residential properties on mason's island, mystic, ct, to determine the efficacy of a rodent-targeted acaricide (fipronil) to control immature ixodes scapularis (say) on peromyscus leucopus. results indicated that modified commercial bait boxes were effective as an acaricide delivery method for reducing nymphal and larval tick infestations on white-footed mice by 68 and 84%, respectively. passive application of fipronil significantly reduced the infec ... | 2004 | 15605643 |
| an ecological approach to preventing human infection: vaccinating wild mouse reservoirs intervenes in the lyme disease cycle. | many pathogens, such as the agents of west nile encephalitis and plague, are maintained in nature by animal reservoirs and transmitted to humans by arthropod vectors. efforts to reduce disease incidence usually rely on vector control or immunization of humans. lyme disease, for which no human vaccine is currently available, is a commonly reported vector-borne disease in north america and europe. in a recently developed, ecological approach to disease prevention, we intervened in the natural cycl ... | 2004 | 15608069 |
| short photoperiods evoke testicular apoptosis in white-footed mice (peromyscus leucopus). | many small, nontropical mammals stop breeding during winter. chronic exposure of males to short days (<12.5 h light/day) causes the testes to atrophy and both steroidogenesis and gametogenesis to decrease. male white-footed mice (peromyscus leucopus) exposed to inhibitory short day lengths provide a natural animal model to study the cellular mechanisms regulating testicular regression. in the present study, the possible role of apoptosis was assessed during naturally occurring, short day-induced ... | 1999 | 10385406 |
| cryptosporidium parvum infection involving novel genotypes in wildlife from lower new york state. | cryptosporidium, an enteric parasite of humans and a wide range of other mammals, presents numerous challenges to the supply of safe drinking water. we performed a wildlife survey, focusing on white-tailed deer and small mammals, to assess whether they may serve as environmental sources of cryptosporidium. a pcr-based approach that permitted genetic characterization via sequence analysis was applied to wildlife fecal samples (n = 111) collected from september 1996 to july 1998 from three areas i ... | 2001 | 11229905 |
| transmission route efficacy and kinetics of anaplasma phagocytophilum infection in white-footed mouse, peromyscus leucopus. | anaplasma phagocytophilum was used to infect peromyscus leucopus mice by three routes of inoculation: infected tick infestation and intraperitoneal (ip) and subcutaneous (sq) injection of infected tissue culture cells. a set of 12 mice were infected (four tick, four ip, and four sq), and blood was drawn at 1, 3, 6, 9, 12, 15, 21, 28, 35, and 60 days post-infection and analyzed by use of a quantitative pcr assay to assess the level of infection. an additional set of 108 mice were infected (36 tic ... | 2004 | 15682514 |
| vasopressin and aggression in cross-fostered california mice (peromyscus californicus) and white-footed mice (peromyscus leucopus). | to examine how developmental experiences alter neural pathways associated with adult social behavior, we cross-fostered pups between the more aggressive and monogamous california mouse (peromyscus californicus) and the less aggressive and polygamous white-footed mouse (p. leucopus). cross-fostered males became more like their foster parents when tested as adults. male white-footed mice became more aggressive only in an aggression test in a neutral arena, whereas the territorial california mice b ... | 2001 | 11467884 |
| effects of pre- and postnatal polychlorinated biphenyl exposure on metabolic rate and thyroid hormones of white-footed mice. | energy budgets have proven to be a valuable tool for predicting life history from physiological data in terrestrial vertebrates, yet these concepts have not been applied to the physiological effects of contaminants. contaminants might affect energy budgets by imposing an additional metabolic cost or by reducing the overall amount of energy taken in; either process will reduce the energy available for production (i.e., growth or reproduction). this study examined whole animal energetic effects of ... | 2001 | 11491552 |
| testicular apoptosis is down-regulated during spontaneous recrudescence in white-footed mice (peromyscus leucopus). | among individuals of many nontropical species, seasonal breeding is timed by tracking changes in the daily photoperiod. transfer of rodents to short (< 12 h of light/day) day lengths for 6 to 14 weeks can induce regression of the testes mediated by apoptosis. after 16 to 20 weeks of short day exposure, reproductive function is "spontaneously" initiated, and testicular recrudescence is observed. the gonadal mechanisms that underlie testicular recrudescence are not fully understood. if the onset o ... | 2001 | 11669421 |
| immunological and physiological effects of chronic exposure of peromyscus leucopus to aroclor 1254 at a concentration similar to that found at contaminated sites. | polychlorinated biphenyls (pcbs) are environmental contaminants known to cause adverse health effects to biological systems. limited data are available on their effects on the immune system of wildlife species. previously, we found that 4 and 6-week-old white-footed mice (peromyscus leucopus) born from dams injected with a single dose (300 mg/kg) of aroclor 1254, had altered immunological, hematological, and biochemical responses. here, we examined the effect of transplacental, lactational and p ... | 2002 | 12007856 |
| presence of borrelia burgdorferi (spirochaetales: spirochaetaceae) in southern kettle moraine state forest, wisconsin, and characterization of strain w97f51. | lyme disease, caused by borrelia burgdorferi johnson, schmidt, hyde, steigerwalt & brenner; babesiosis, caused by babesia microti franca; and human granulocytic ehrlichiosis, caused by anaplasma phagocytophilum bakken & dumler have been reported in wisconsin, mainly in the endemic areas of the northwestern part of the state. people exposed to blacklegged ticks, ixodes scapularis say, from this region can potentially contract one or all of these diseases concurrently. within the past several year ... | 2005 | 15962800 |