Publications

could parasites destabilize mouse populations? the potential role of pterygodermatites peromysci in the population dynamics of free-living mice, peromyscus leucopus.	peromyscus leucopus populations exhibit unstable population dynamics. mathematical models predict instability with chronic parasite infections that reduce host fecundity when the parasite distribution within the host population is close to random. we examined the role the nematode pterygodermatites peromysci may play in influencing the dynamics of these mice. there were seven gastrointestinal worms infecting mice. pterygodermatites peromysci was the most prevalent and varied seasonally from 12.3 ...	2009	19409901
testing hypotheses of aging in long-lived mice of the genus peromyscus: association between longevity and mitochondrial stress resistance, ros detoxification pathways, and dna repair efficiency.	in the present review we discuss the potential use of two long-lived mice of the genus peromyscus--the white-footed mouse (p. leucopus) and the deer mouse (p. maniculatus) maximum lifespan potential approximately 8 years for both--to test predictions of theories about aging from the oxidative stress theory, mitochondrial theory and inflammatory theory. previous studies have shown that p. leucopus cells exhibit superior antioxidant defense mechanisms and lower cellular production of reactive oxyg ...	2008	19424862
rapid morphological and genetic change in chicago-area peromyscus.	we report rapid change of morphology and mitochondrial genes in white-footed mice (peromyscus leucopus) in the chicago (illinois, usa) region. we sequenced mitochondrial dna cox2 from 55 museum skins of white-footed mice caught in the chicago area since 1855 and from 44 mice recently trapped in the same locations. we found consistent directional genotype replacement at five separate collection locations. we later focused on a single one of these locations (volo bog state natural area) and sequen ...	2008	17892465
heavy metal exposure, reproductive activity, and demographic patterns in white-footed mice (peromyscus leucopus) inhabiting a contaminated floodplain wetland.	we examined the concentrations of selected metals and selenium (se) in the tissues of white-footed mice (peromyscus leucopus) collected at a constructed wetland originally created as a retention basin for sediments dredged from lake depue, illinois. these sediments were contaminated with high concentrations of cadmium (cd), zinc (zn), and other elements as a result of nearby smelting operations. white-footed mice inhabiting the former retention basin experienced greater exposure to cd, pb, and s ...	2008	17900661
population dynamics of a generalist rodent in relation to variability in pulsed food resources in a fragmented landscape.	1. pulsed food resources are often considered equivalent in their potential impact on the reproduction and population dynamics of consumers, but differences in the attributes of food pulses and their distribution in the landscape may cause differences in their effects. 2. we tested whether a perishable pulsed resource (periodical cicadas, magicicada spp.) had similar effects on the population dynamics of a generalist forest rodent, peromyscus leucopus, as have been reported for a cacheable pulse ...	2008	17976166
the interaction of parasites and resources cause crashes in a wild mouse population.	1. populations of white-footed mice peromyscus leucopus and deer mice peromyscus maniculatus increase dramatically in response to food availability from oak acorn masts. these populations subsequently decline following this resource pulse, but these crashes cannot be explained solely by resource depletion, as food resources are still available as population crashes begin. 2. we hypothesized that intestinal parasites contribute to these post-mast crashes; peromyscus are infected by many intestina ...	2008	18028357
6-mboa affects testis size, but not delayed-type hypersensitivity, in white-footed mice (peromyscus leucopus).	many rodents use day length to time reproduction to occur when resources are abundant, but some species also use supplementary environmental cues. one supplementary cue is the plant-derived compound, 6-methoxy-2-benzoxazolinone (6-mboa). most rodents grow their gonads in response to 6-mboa in their diets, but it is presently unknown whether they also use 6-mboa to adjust other aspects of physiology, specifically their immune systems. 6-mboa is structurally similar to melatonin, and seasonal chan ...	2008	18160321
presence of multiple variants of borrelia burgdorferi in the natural reservoir peromyscus leucopus throughout a transmission season.	white-footed mice (peromyscus leucopus) serve as the principal reservoir for borrelia burgdorferi and have been shown to remain infected for life. complex infections with multiple genetic variants of b. burgdorferi occur in mice through multiple exposures to infected ticks or through exposure to ticks infected with multiple variants of b. burgdorferi. using a combination of cloning and single strand conformation polymorphism (sscp), b. burgdorferi ospc variation was assessed in serial samples co ...	2008	18399776
a genome-wide proteome array reveals a limited set of immunogens in natural infections of humans and white-footed mice with borrelia burgdorferi.	humans and other animals with lyme borreliosis produce antibodies to a number of components of the agent borrelia burgdorferi, but a full accounting of the immunogens during natural infections has not been achieved. employing a protein array produced in vitro from 1,292 dna fragments representing approximately 80% of the genome, we compared the antibody reactivities of sera from patients with early or later lyme borreliosis to the antibody reactivities of sera from controls. overall, approximate ...	2008	18474646
oxidative stress in vascular senescence: lessons from successfully aging species.	cardiovascular disease is a main cause of morbidity and a leading cause of death of elderly americans. studies identifying the pathophysiological mechanisms underlying cardiovascular aging hold promise to develop treatments to delay/prevent coronary artery disease and stroke in the elderly. evidence supporting the roles of oxidative stress and inflammation in the cardiovascular aging process is presented in detail in this review. mammalian lifespan ranges hundred-fold and we propose that long-li ...	2008	18508570
projected effects of climate change on tick phenology and fitness of pathogens transmitted by the north american tick ixodes scapularis.	ixodes scapularis is the principal tick vector of the lyme borreliosis agent borrelia burgdorferi and other tick-borne zoonoses in northeastern north america. the degree of seasonal synchrony of nymphal and larval ticks may be important in influencing the basic reproductive number of the pathogens transmitted by i. scapularis. because the seasonal phenology of tick vectors is partly controlled by ambient temperature, climate and climate change could shape the population biology of tick-borne pat ...	2008	18634803
parasites prevent summer breeding in white-footed mice, peromyscus leucopus.	food and parasites can independently play a role in destabilizing population fluctuations of animals, and yet, more than 50 years ago, david lack proposed that these two factors should act in concert. we examined the role of these factors on the vital rates of free-living white-footed mice (peromyscus leucopus) over the summer and autumn months. we used a replicated factorial experiment in which deer exclosures doubled acorn availability and anthelmintic application reduced gastrointestinal helm ...	2008	18724735
multiple causes of variable tick burdens on small-mammal hosts.	blood meals by blacklegged ticks (ixodes scapularis) on vertebrate hosts serve to transmit the agents of several zoonotic diseases, including lyme disease, human babesiosis, and human granulocytic anaplasmosis, between host and tick. if ticks are aggregated on hosts, a small proportion of hosts may be responsible for most transmission events. therefore, a key element in understanding and controlling the transmission of these pathogens is identifying the group(s) or individuals feeding a dispropo ...	2008	18724736
acorn mast drives long-term dynamics of rodent and songbird populations.	resource pulses can have cascading effects on the dynamics of multiple trophic levels. acorn mast is a pulsed resource in oak-dominated forests that has significant direct effects on acorn predators and indirect effects on their predators, prey, and pathogens. we evaluated changes in acorn mast, rodent abundance, raptor abundance, and reproductive success of a ground-nesting songbird over a 24-year period (1980-2004) in the southern appalachian mountains in an effort to determine the relationshi ...	2007	17924149
vascular superoxide and hydrogen peroxide production and oxidative stress resistance in two closely related rodent species with disparate longevity.	vascular aging is characterized by increased oxidative stress, impaired nitric oxide (no) bioavailability and enhanced apoptotic cell death. the oxidative stress hypothesis of aging predicts that vascular cells of long-lived species exhibit lower production of reactive oxygen species (ros) and/or superior resistance to oxidative stress. we tested this hypothesis using two taxonomically related rodents, the white-footed mouse (peromyscus leucopus) and the house mouse (mus musculus), that show a m ...	2007	17925005
field survey of rodents for hepatozoon infections in an endemic focus of american canine hepatozoonosis.	eighteen of 31 (58%) cotton rats (sigmodon hispidus) and 8 of 24 (33.3%) white-footed mice (peromyscus leucopus) that were wild-trapped from 4 american canine hepatozoonosis endemic sites in oklahoma were infected with hepatozoon species. the predilection organ for merogony of the hepatozoon species in cotton rats was the liver. meronts were not detected in any of the white-footed mice. a 488 bp dna fragment that includes a variable region of the 18s rrna hepatozoon gene amplified from blood or ...	2007	17942230
short days increase hypothalamic-pituitary-adrenal axis responsiveness.	individuals dramatically alter physiology and behavior to adapt to seasonal changes in their environment. to cope with winter stressors such as reduced food availability and low temperatures, central stress responses are presumably modulated at the level of the hypothalamic-pituitary-adrenal (hpa) axis, but the details remain unspecified. we examined the effects of long or short photoperiods (day lengths) on corticosterone responses to restraint, hpa negative feedback sensitivity, glucocorticoid ...	2007	17395702
giving-updensity and dietary shifts in the white-footed mouse, peromyscus leucopus.	dietary shifts are commonly exhibited by omnivorous consumers when foraging from variable food resources. one advantage of dietary shifts for a consumer is the ability to gain complementary resources from different foods. in addition, dietary shifts often affect food-web dynamics. despite the importance of dietary shifts to organismal, community, and ecosystem ecology, empirical studies of the ecological mechanisms that control dietary shifts are limited in scope. in this study, we tested the ef ...	2007	17489457
low rates of hydrogen peroxide production by isolated heart mitochondria associate with long maximum lifespan in vertebrate homeotherms.	an inverse correlation between free radical production by isolated mitochondria and longevity in homeotherms has been reported, but previous comparative studies ignored possible confounding effects of body mass and phylogeny. we investigated this correlation by comparing rates of hydrogen peroxide (h(2)o(2)) production by heart mitochondria isolated from groups or pairs of species selected to have very different maximum lifespans but similar body masses (small mammals, medium-sized mammals, bird ...	2007	17596208
number of immunoreactive gnrh-containing neurons is heritable in a wild-derived population of white-footed mice (peromyscus leucopus).	the evolution of mammalian brain function depends in part on levels of natural, heritable variation in numbers, location, and function of neurons. however, the nature and amount of natural genetic variation in neural traits and their physiological link to variation in function or evolutionary change are unknown. we estimated the level of within-population heritable variation in the number of gonadotropin-releasing hormone (gnrh) neurons, which play a major role in reproductive regulation, in an ...	2007	17717816
vector seasonality, host infection dynamics and fitness of pathogens transmitted by the tick ixodes scapularis.	fitness of tick-borne pathogens may be determined by the degree to which their infection dynamics in vertebrate hosts permits transmission cycles if infective and uninfected tick stages are active at different times of the year. to investigate this hypothesis we developed a simulation model that integrates the transmission pattern imposed by seasonally asynchronous nymphal and larval ixodes scapularis ticks in northeastern north america, with a model of infection in white-footed mice (peromyscus ...	2007	17032476
effects of dietary pcb exposure on reproduction in the white-footed mouse (peromyscus leucopus).	studies of the impact of environmental contaminants on reproduction have typically focused on effects on fertility and subsequent reproductive failure. contaminants may also impact reproductive output or other aspects of life history through effects on resource acquisition or allocation. we fed successfully breeding female white-footed mice (peromyscus leucopus) diets containing polychlorinated biphenyls (2:1 aroclor 1242:1254) at levels of 0 (n = 10), 10 (n = 12), and 25 (n = 10) ppm (mg polych ...	2007	17160489
linking behavior, life history and food supply with the population dynamics of white-footed mice (peromyscus leucopus).	in this paper we review and integrate key aspects of behavioral and life history traits, food supply and population dynamics of the white-footed mouse (peromyscus leucopus), a species that is abundant and widely distributed across much of eastern north america. results are based largely on a 33-year mark-and-recapture study in a forest fragment in northwest ohio, usa. behavioral plasticity in such reproductive traits as mating system and parental care allows this species to adjust quickly to cha ...	2007	21396027
deer browse resistant exotic-invasive understory: an indicator of elevated human risk of exposure to ixodes scapularis (acari: ixodidae) in southern coastal maine woodlands.	we evaluated the relationships between forest understory structure and the abundance of questing adult and nymphal blacklegged ticks, ixodes scapularis say (acari: ixodidae), in three maine towns endemic for lyme disease, 2001-2003. in fragmented new england woodlands, over-abundant white-tailed deer, odocoileus virginianus zimmerman, overbrowse palatable species, allowing browse-resistant exotic-invasive species to replace native forest understory structures. we predicted there would be more ti ...	2006	17162946
mammal diversity and infection prevalence in the maintenance of enzootic borrelia burgdorferi along the western coastal plains of maryland.	the primary vector of borrelia burgdorferi in north america, ixodes scapularis, feeds on various mammalian, avian, and reptilian hosts. several small mammal hosts; peromyscus leucopus, tamias striatus, microtus pennsylvanicus, and blarina spp. can serve as reservoirs in an enzootic cycle of lyme disease. the primary reservoir in the northeast united states is the white-footed mouse, p. leucopus. the infection prevalence of this reservoir as well as the roles of potential secondary reservoirs has ...	2006	17187577
antibodies to whole-cell or recombinant antigens of borrelia burgdorferi, anaplasma phagocytophilum, and babesia microti in white-footed mice.	serum samples were obtained from white-footed mice (peromyscus leucopus) in tick-infested areas of connecticut during the period 2001 through 2003 and analyzed for antibodies to borrelia burgdorferi, anaplasma phagocytophilum, and babesia microti. emphasis was placed on the evaluations of highly specific recombinant vlse or protein (p) 44 antigens of b. burgdorferi and a. phagocytophilum, respectively, in a newly developed enzyme-linked immunosorbent assay (elisa) as well as testing sera with wh ...	2006	17255439
comparative phylogeography of eastern chipmunks and white-footed mice in relation to the individualistic nature of species.	palaeoecological studies have demonstrated that ecological communities as a whole did not remain stable throughout the climatic fluctuations of the quaternary. the result is that long-term associations of species cannot be inferred by contemporary associations in ecological communities. therefore, the evolutionary significance of any contemporary ecological interactions among species and of the biotic community within which species have evolved also cannot be assumed from contemporary conditions ...	2006	17054499
a reverse transcriptase-polymerase chain reaction assay of borrelia burgdorferi 16s rrna for highly sensitive quantification of pathogen load in a vector.	we developed a real-time quantitative detection assay for the pathogen borrelia burgdorferi, a lyme borreliosis (lb) agent, using reverse transcription-polymerase chain reaction (rt-pcr) with primers and probe for a borrelia genus-specific region of 16s ribosomal rna. the standard curve of the assay was linear by semi-log plot over more than five orders of magnitude, and the detection limit of the assay was one thousandth of a single cell of b. burgdorferi. the minimum target level for detection ...	2006	16584333
spatial heterogeneity in predator activity, nest survivorship, and nest-site selection in two forest thrushes.	the ability of prey to find and use predator-free space has far-reaching consequences for their persistence and interactions with their predators. we tested whether nest survivorship of the ground-nesting veery (catharus fuscescens) and shrub-nesting wood thrush (hylocichla mustelina) was related to the local absence of a major nest predator, the white-footed mouse (peromyscus leucopus). mouse-free space was defined by trap stations that failed to trap a mouse during the avian breeding season (a ...	2006	16425046
climate, deer, rodents, and acorns as determinants of variation in lyme-disease risk.	risk of human exposure to vector-borne zoonotic pathogens is a function of the abundance and infection prevalence of vectors. we assessed the determinants of lyme-disease risk (density and borrelia burgdorferi-infection prevalence of nymphal ixodes scapularis ticks) over 13 y on several field plots within eastern deciduous forests in the epicenter of us lyme disease (dutchess county, new york). we used a model comparison approach to simultaneously test the importance of ambient growing-season te ...	2006	16669698
babesia microti primarily invades mature erythrocytes in mice.	babesia microti is a tick-borne red blood cell parasite that causes babesiosis in people. its most common vertebrate reservoir is the white-footed mouse. to determine whether b. microti invades reticulocytes, as does the canine pathogen b. gibsoni, we infected the susceptible inbred mouse strains c.b-17.scid and dba/2 with a clinical isolate of b. microti. staining of fixed permeabilized red blood cells with 4',6'-diamidino-2-phenylindole or yoyo-1, a sensitive nucleic acid stain, revealed paras ...	2006	16714547
testosterone and photoperiod interact to affect spatial learning and memory in adult male white-footed mice (peromyscus leucopus).	gonadal hormones affect spatial learning and memory in mammals and circulating gonadal hormone concentrations fluctuate by season. most nontropical rodents are spring/summer breeders and males display higher testosterone concentrations during the breeding season compared with the nonbreeding season (fall/winter). seasonal patterns of testosterone concentration (as well as many other seasonal modifications of physiology, morphology, and behaviour) are induced by manipulation of photoperiod (day l ...	2006	16819995
weak winner effect in a less aggressive mammal: correlations with corticosterone but not testosterone.	we investigated the existence of the "winner effect" (winning an aggressive encounter following previous victories) and an associated rise in testosterone (t) in the white-footed mouse (peromyscus leucopus) which generally display low levels of aggression and territoriality. we compared the effect of previously winning three, two, one, or zero resident-intruder encounters on the likelihood of winning a subsequent aggressive encounter. although 50% of males were removed during training because of ...	2006	16859719
genetic diversity of borrelia burgdorferi sensu stricto in peromyscus leucopus, the primary reservoir of lyme disease in a region of endemicity in southern maryland.	in the north central and northeastern united states, borrelia burgdorferi sensu stricto, the etiologic agent of lyme disease (ld), is maintained in an enzootic cycle between the vector, ixodes scapularis, and the primary reservoir host, peromyscus leucopus. genetic diversity of the pathogen based on sequencing of two plasmid-located genes, those for outer surface protein a (ospa) and outer surface protein c (ospc), has been examined in both tick and human specimens at local, regional, and worldw ...	2006	16885284
phenotypic plasticity of reproductive traits in response to food availability and photoperiod in white-footed mice (peromyscus leucopus).	although most temperate-zone mammals are seasonal breeders, many populations display variation in winter reproductive phenotype. for most mammals, the primary environmental cues regulating reproductive status are food availability and photoperiod, and these two factors can interact in their effect. low food availability is primarily thought to suppress reproduction by reducing body mass and thereby forcing energy allocations to survival alone. however, because most small mammals rely on an incre ...	2006	16955287
prevalence of borrelia burgdorferi in small mammals in new york state.	intensive small mammal trapping was conducted in 12 counties in new york state during 1998-2000 to investigate the prevalence and site specificity of the lyme disease spirochete, borrelia burgdorferi in, and presence of the blacklegged tick, ixodes scapularis say on, the wild mice peromyscus leucopus rafinesque and peromyscus maniculatus wagner and other small mammal species. previously captured mice (1992-1997) from throughout new york state also were recruited into the study, providing a total ...	2006	17017230
host associations of ixodes scapularis (acari: ixodidae) in residential and natural settings in a lyme disease-endemic area in new jersey.	we live-trapped small mammals and flagged vegetation within wooded natural and residential landscapes to examine how any observed differences in small mammal species composition may influence ixodes scapularis say burdens and the abundance of host-seeking ticks. two years of live trapping showed that eastern chipmunks, tamias striatus, were captured with significantly greater frequency in some residential areas than white-footed mice, peromyscus leucopus, whereas the proportion of white-footed m ...	2005	16465736
response to selection for photoperiod responsiveness on the density and location of mature gnrh-releasing neurons.	natural variation in neuroendocrine traits is poorly understood, despite the importance of variation in brain function and evolution. most rodents in the temperate zones inhibit reproduction and other nonessential functions in short winter photoperiods, but some have little or no reproductive response. we tested whether genetic variability in reproductive seasonality is related to individual differences in the neuronal function of the gonadotropin-releasing hormone network, as assessed by the nu ...	2005	15650126
estrogen receptor alpha and vasopressin in the paraventricular nucleus of the hypothalamus in peromyscus.	the purpose of this study was to determine the presence of estrogen receptor alpha (eralpha) and the relationship between neurons that express eralpha and produce vasopressin (avp) in the paraventricular nucleus of the hypothalamus (pvn) in new world mice of the genus peromyscus. brains were collected from male and female peromyscus californicus, peromyscus leucopus, peromyscus maniculatus, and peromyscus polionotus, and double labeled for the expression of eralpha and avp immunoreactivity (ir). ...	2005	15680954
tick infestations of the eastern cottontail rabbit (sylvilagus floridanus) and small rodentia in northwest alabama and implications for disease transmission.	studies were conducted over a four-county area of northwest alabama to determine the association of eastern cottontail rabbits with dermacentor variabilis, the eastern united states vector of rocky mountain spotted fever. a secondary objective was to compare infestations of this tick on rabbits with infestations on commonly encountered rodent species as a means of determining the relative importance of each in the disease transmission cycle. these epidemiologic surveys were conducted in response ...	2005	16599149
social environment modulates photoperiodic immune and reproductive responses in adult male white-footed mice (peromyscus leucopus).	social cues may interact with photoperiod to regulate seasonal adaptations in photoperiod-responsive rodents. specifically, photoperiod-induced adjustments (e.g., reproduction and immune function) may differ among individuals in heterosexual pairs, same-sex pairs, or isolation. heterosexual cues may be more influential, based on their potential fitness value, than same-sex cues or no social cues. the present study examined the effects of pair (with a male or female) or individual housing on repr ...	2005	15550612
social structure influences effects of pair-housing on wound healing.	chronic stress or noxious stimuli delay wound healing in humans and rodents. the effects of stress on wound healing appear to be mediated by the hypothalamic-pituitary-adrenal (hpa) axis and, in particular, increases in corticosteroids. as previously shown, positive social interaction faciltiates wound healing through suppression of corticosteroids. in the present study, we investigated the effects of pair-housing on wound healing and corticosteroid concentrations in three mouse species, the mon ...	2005	15581739
photoperiod-induced differential expression of angiogenesis genes in testes of adult peromyscus leucopus.	non-pathological angiogenesis in adults is rare and is largely thought to be restricted to wound healing and female reproductive cycles. adult male rodents, however, display seasonal angiogenesis to support seasonal changes in reproductive tissue morphology. non-tropical rodents use photoperiod (day length) to determine the time of year. during short days, the reproductive system undergoes involution and mating behaviours stop, adaptations which presumably allow energy resources to be shifted to ...	2005	15695614
hepatic porphyria induced by the herbicide tralkoxydim in small mammals is species-specific.	tralkoxydim is the active ingredient in a postemergent herbicide used in cereal crops. during preregistration trials, tralkoxydim was observed to cause hepatic porphyria and cholestasis in laboratory mice. porphyria was not seen in similarly exposed rats or hamsters, but data were not collected regarding the susceptibility of any wild small mammal species to the tralkoxydim-induced porphyria. to address this data gap, we exposed small mammals to tralkoxydim, to 3,5-diethoxycarbonyl-1,4-dihydroco ...	2005	15720007
short photoperiods impair spatial learning and alter hippocampal dendritic morphology in adult male white-footed mice (peromyscus leucopus).	although seasonal changes in brain morphology and function are well established in songbirds, seasonal plasticity of brain structure and function remain less well documented in mammals. nontropical animals display many adaptations to reduce energy use to survive winter, including cessation of reproductive activities. because of the high energetic costs of brain tissue, we hypothesized that male white-footed mice (peromyscus leucopus) would reduce brain size in response to short days as well as r ...	2005	15872099
reproduction, foraging and the negative density-area relationship of a generalist rodent.	while many species show positive relationships between population density and habitat patch area, some species consistently show higher densities in smaller patches. few studies have examined mechanisms that may cause species to have negative density-area relationships. we tested the hypothesis that greater reproduction in edge versus interior habitats and small versus large fragments contributes to higher densities of white-footed mice (peromyscus leucopus) in small versus large forest fragment ...	2005	15891823
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
effectiveness of metarhizium anisopliae (deuteromycetes) against ixodes scapularis (acari: ixodidae) engorging on peromnyscus leucopus.	with the incidence of lyme disease increasing throughout the united states, reducing risk of exposure to the disease is of the utmost concern. in the northeastern u.s., the blacklegged tick, ixodes scapularis, is the primary vector and the white-footed mouse, (peromyscus leucopus), the primary reservoir for borrelia burgdorteri, the bacterium causing lyme disease. targeting i. scapularis engorging on white-footed mice with an effective biological control agent, such as the fungus metarhizium ani ...	2005	16007961
positive effects of testosterone and immunochallenge on energy allocation to reproductive organs.	a number of studies have suggested the incompatibility of simultaneous increases in immune and reproductive functions. other research has indicated that immune responses may be modulated depending on the relative benefits of increased survival and prospects for current and future reproduction. we tested the hypothesis that energy allocation to reproductive and other organ systems is not affected by testosterone level and energy expenditure on immune functions. adult male white-footed mice (perom ...	2005	16133494
peromyscus populations and their cuterebra parasites display congruent phylogeographical structure.	the relationships between populations of the deer mouse (peromyscus maniculatus) and the white-footed mouse (p. leucopus) and their respective cuterebra parasites were examined. population genetic structure of hosts and parasites was inferred using cytochrome oxidase mitochondrial sequences of specimens from 7 populations. genetic analyses revealed that isolation-by-distance applies for p. maniculatus and its associated parasite (c. grisea). a significant correlation was also observed between th ...	2005	16145940
frequent harderian gland adenocarcinomas in inbred white-footed mice (peromyscus leucopus).	in 1997, three lines of inbred peromyscus leucopus--gs109a, gs16a1, and gs16b--were acquired by the peromyscus genetic stock center. since then, records have been kept on tumors detected by visible inspection of live animals. the inbred lines gs109a and gs16a1 presented tumors with frequencies substantially higher than that of the other inbred line or of random-bred p. leucopus stock. the average age of detection was 456 +/- 75 days (n = 24) for gs109a and 568 +/- 168 days (n = 12) for gs16a1 re ...	2005	16158914
a longitudinal study of bayou virus, hosts, and habitat.	what is currently known about the ecology of north american hantaviruses has come largely from studies on sin nombre virus (snv). we conducted a longitudinal study of bayou virus (bayv), the second-leading agent of hantavirus pulmonary syndrome in the united states. antibodies to hantavirus were detected from oryzomys palustris (most commonly infected species), sigmodon hispidus, peromyscus leucopus, reithrodontomys fulvescens, and baiomys taylori. however, only o. palustris had viral rna in tis ...	2005	16354810
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
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
top-down approaches to the study of natural variation in complex physiological pathways using the white-footed mouse (peromyscus leucopus) as a model.	variation in complex physiological pathways has important effects on human function and medical treatment. complex pathways involve cells at multiple locations, which serve different functions regulated by many genes and include complex neuroendocrine pathways that regulate physiological function. one of two competing hypotheses regarding the effects of selection on complex pathways predicts that variability should be common within complex pathways. if this hypothesis is correct, then we should ...	2004	14752203
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
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
reduced free-radical production and extreme longevity in the little brown bat (myotis lucifugus) versus two non-flying mammals.	the extended longevity of bats, despite their high metabolic rate, may provide insight to patterns and mechanisms of aging. here i test predictions of the free radical or oxidative stress theory of aging as an explanation for differences in lifespan between the little brown bat, myotis lucifugus (maximum lifespan potential mlsp=34 years), the short-tailed shrew, blarina brevicauda (mlsp=2 years), and the white-footed mouse, peromyscus leucopus (mlsp=8 years) by comparing whole-organism oxygen co ...	2004	14706233
movement and spatial organization of small mammals following vertebrate predator exclusion.	predation directly changes the demographics of prey, generally through a numerical decrease. an indirect effect of predators is alteration of movements and spatial patterns of prey. the relationship between these direct and indirect effects can be tested by excluding predators. home range size of white-footed mice (peromyscus leucopus) decreased and home range overlaps increased in the absence of predators. home range size and overlaps of meadow voles (microtus pennsylvanicus) did not change des ...	2004	15042459
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
effects of heavy metals on immunocompetence of white-footed mice (peromyscus leucopus).	continued human population growth and industrialization result in increased contamination of wildlife habitats. effects of such habitat deterioration on the well-being of natural populations are unclear. exposure to contaminants may impair immunocompetence, thereby increasing disease susceptibility. the mammalian immune system is important in maintaining health and in its sensitivity to toxins. in our study conducted from may 1999 through may 2001, we examined assays of immnnoompetence in the wh ...	2004	15362816
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
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
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
immune response, not immune maintenance, is energetically costly in wild white-footed mice (peromyscus leucopus).	understanding the cost of immune function is essential for more accurate characterization of energy budgets of animals and better understanding of the role of immunity in the evolution of life-history strategies. we examined the energetic cost of maintaining a normally functioning immune system and mounting a mild immune response in wild male white-footed mice (peromyscus leucopus). to evaluate the cost of maintaining immunocompetence, we compared resting and daily metabolic rates (rmr; dmr) and ...	2003	14671721
vasopressin and the transmission of paternal behavior across generations in mated, cross-fostered peromyscus mice.	the role of arginine vasopressin (avp) in the nongenomic transfer of paternal behavior from fathers to offspring was examined in peromyscus. male california mice (p. californicus) exposed to fewer retrievals by white-footed mouse (p. leucopus) foster parents displayed fewer retrievals of biological offspring. in contrast, white-footed mice were retrieved equally rarely by california mouse foster parents and by biological parents and displayed no changes in pup retrieval behavior. avp-immunoreact ...	2003	12802874
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
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
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
sequence, expression, and polymorphism of the peromyscus leucopus mhc class ib gene, m4.	the h2 m region harbors about 20 class i genes or gene fragments the function of which are largely obscure. the rat mhc ( rt1) appears to contain several orthologs of h2 m region genes although orthologs in more distantly related species have yet to be clearly identified. in this report, the sequence of a genomic clone containing a peromyscus leucopus mhc ( pele) class i gene is presented and based on sequence similarity was found to be the pele ortholog of h2-m4. unlike h2-m4, which is a pseudo ...	2003	12700875
comparison of the reservoir competence of medium-sized mammals and peromyscus leucopus for anaplasma phagocytophilum in connecticut.	in the northeastern united states, anaplasma phagocytophilum, the agent of human granulocytic ehrlichiosis (hge), is transmitted by the tick vector ixodes scapularis. the white-footed mouse peromyscus leucopus is a competent reservoir for this agent, but the reservoir competence of non-peromyscus hosts of i. scapularis has not been studied. here, we report data confirming reservoir competence of medium-sized mammals for a. phagocytophilum. raccoons, virginia opossums, gray squirrels, and striped ...	2002	12737542
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
influences of inbreeding and genetics on telomere length in mice.	we measured telomere lengths of blood leukocytes in several inbred and outbred mammalian species, using a telomere-specific fluorescent probe and flow cytometry. humans, non-human primates, and three outbred populations of peromyscus mice ( peromyscus leucopus, peromyscus maniculatus, and peromyscus polionotus) have short telomeres. two common strains of laboratory mice, c57bl/6j and dba/2j, have telomeres several times longer than most other mammals surveyed. moreover, the two inbred laboratory ...	2002	12016510
comparison of white-footed mice and rice rats as biomonitors of polychlorinated biphenyl and metal contamination.	a study was conducted to assess differences in contaminant assimilation among co-occurring white-footed mice (peromyscus leucopus) and rice rats (oryomys palustris) captured at a contaminated site. rodents were collected from five areas at the paducah gaseous diffusion plant (pgdp), a uranium enrichment facility. relatively few white-footed mice (8.7%) had quantifiable concentrations of pcbs compared to 42% of rice rats (chi2 = 6.49, d.f. = 1, p < 0.025), and seven of the 11 rice rats (64%) over ...	2002	12152833
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
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
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
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
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
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
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
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
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
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
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
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
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