pneumonic plague--arizona, 1992.on august 26, 1992, a 31-year-old male resident of tucson, arizona, died of an illness subsequently diagnosed as primary pneumonic plague. this is the 10th case of plague reported in the united states in 1992, the first pneumonic plague case this year, and the first plague fatality reported since 1987 (cdc, unpublished data). this report summarizes the investigation of this case by county, state, and federal public health officials in arizona and colorado.19921406565
susceptibility to yersinia pestis in the northern grasshopper mouse (onychomys leucogaster).the laboratory-born progeny from two geographically distant populations of northern grasshopper mice (onychomys leucogaster) were challenged with yersinia pestis to determine their relative susceptibilities to plague. one of the o. leucogaster populations was associated with a known epizootic focus of the disease and was found to be nearly 2,000 times more resistant to mortality than were members of another population from an area historically free of plague. the ecology and omnivorous behavior ...19883373638
serological and bacteriological investigations of an outbreak of plague in an urban tree squirrel population. 19714928594
cat-transmitted fatal pneumonic plague in a person who traveled from colorado to arizona.plague, primarily a disease of rodents and their infected fleas, is fatal in 50% of infected humans if untreated. in the united states, human cases have been concentrated in the southwest. the most common modes of plague transmission are through flea bites or through contact with infected blood or tissues; however, primary pneumonic plague acquired from cats has become increasingly recognized. we report on the case investigation of a patient, presumably exposed to a plague-infected cat in colora ...19948059908
fatal human plague--arizona and colorado, 1996, five cases of human plague, of which two were fatal, were reported in the united states; both decedents had septicemic plague that was not diagnosed until after they died. this report summarizes the investigation of the two fatal cases and underscores the need for health-care providers in areas with endemic plague to maintain a high level of awareness about the risk for plague in their patients.19979218646
from the centers for disease control and prevention. fatal human plague--arizona and colorado, 1996. 19979244319
a cryptic 19-kilobase plasmid associated with u.s. isolates of yersinia pestis: a dimer of the 9.5-kilobase plasmid.yersinia pestis, the etiologic agent of plague, carries three prototypic plasmids with sizes of 110 kb (pfra, ptox), 70 kb (plcr, pvw, pcad), and 9.5 kb (ppla, ppst). studies suggest that geographic isolates of y. pestis may be differentiated by plasmid profiles. yersinia pestis isolated from the western united states harbor an additional plasmid, estimated to be approximately 19 kb in size. this cryptic plasmid was characterized by restriction endonuclease digestion, amplification and sequencin ...19989840581
pcr detection of yersinia pestis in fleas: comparison with mouse inoculation.the "gold standard" for identifying yersinia pestis-infected fleas has been inoculation of mice with pooled flea material. inoculated mice are monitored for 21 days, and those that die are further analyzed for y. pestis infection by fluorescent-antibody assay and/or culture. pcr may provide a more rapid and sensitive alternative for identifying y. pestis in fleas. to compare these assays, samples were prepared from 381 field-collected fleas. each flea was analyzed individually by both pcr and mo ...199910325359
serologic survey for selected infectious disease agents in swift and kit foxes from the western united states.a serologic survey of swift fox (vulpes velox) and kit fox (v. macrotis) from the western usa was conducted for 12 infectious diseases. samples from swift fox were collected between 1987 and 1992 from colorado (n = 44), kansas (n = 10), and wyoming (n = 9). samples from kit fox were collected in california (n = 86), new mexico (n = 18), utah (n = 9), and arizona (n = 6). overall antibody prevalence rates were 33 of 110 (30%) for canine parvovirus (cpv), 9 of 72 (13%) for canine distemper virus ( ...200011085448
detection of novel bartonella strains and yersinia pestis in prairie dogs and their fleas (siphonaptera: ceratophyllidae and pulicidae) using multiplex polymerase chain reaction.we developed a multiplex polymerase chain reaction (pcr) assay that simultaneously detects three types of flea-associated microorganisms. targets for the assay were sequences encoding portions of the glta, a 17-kda antigen, and pla genes of bartonella spp. strong et al., rickettsia spp. da rocha-lima, and yersinia pestis yersin, respectively. a total of 260 flea samples containing bloodmeal remnants were analyzed from fleas collected from abandoned prairie dog (cynomys ludovicianus) burrows at t ...200312943112
quantities of yersinia pestis in fleas (siphonaptera: pulicidae, ceratophyllidae, and hystrichopsyllidae) collected from areas of known or suspected plague activity.we used a quantitative competitive polymerase chain reaction (pcr) (qc-pcr) to determine bacterial loads in 669 fleas collected in areas of confirmed and suspected plague epizootics. fleas were collected out of rodent burrows (67.9%) and off of captured animals (24.1%) and rodent carcasses (8.1%). an initial pcr screening assay indicated that 12.1% (81/669) of all fleas were positive for yersinia pestis. fleas collected from burrows had significantly lower (chi2 = 264.9, p < 0.0001) infection ra ...200015535587
serologic survey for canine infectious diseases among sympatric swift foxes (vulpes velox) and coyotes (canis latrans) in southeastern colorado.swift foxes (vulpes velox) and coyotes (canis latrans) are sympatric canids distributed throughout many regions of the great plains of north america. the prevalence of canid diseases among these two species where they occur sympatrically is presently unknown. from january 1997 to january 2001, we collected blood samples from 89 swift foxes and 122 coyotes on the us army piñon canyon maneuver site, las animas county, se colorado (usa). seroprevalence of antibodies against canine parvovirus (cpv) ...200415650093
human plague--four states, 2006.plague is a zoonotic disease caused by the bacterium yersinia pestis. in 2006, a total of 13 human plague cases have been reported among residents of four states: new mexico (seven cases), colorado (three cases), california (two cases), and texas (one case). this is the largest number of cases reported in a single year in the united states since 1994. dates of illness onset ranged from february 16 to august 14; two (15%) cases were fatal. the median age of patients was 43 years (range: 13-79 yea ...200616943764
plague as a mortality factor in canada lynx (lynx canadensis) reintroduced to part of a species recovery program, 129 canada lynx (lynx canadensis) originating from british columbia, the yukon, manitoba, and quebec, canada, and alaska, usa, were reintroduced to southwestern colorado, usa, from 1999 to 2003. of 52 lynx mortalities documented by october 2003, six lynx, including a female and her 5-mo-old kitten, had evidence of yersinia pestis infection as determined by fluorescent antibody test and/or culture. postmortem findings in these lynx were characterized by pneu ...200617092896
multiple antimicrobial resistance in plague: an emerging public health risk.antimicrobial resistance in yersinia pestis is rare, yet constitutes a significant international public health and biodefense threat. in 1995, the first multidrug resistant (mdr) isolate of y. pestis (strain ip275) was identified, and was shown to contain a self-transmissible plasmid (pip1202) that conferred resistance to many of the antimicrobials recommended for plague treatment and prophylaxis. comparative analysis of the dna sequence of y. pestis plasmid pip1202 revealed a near identical inc ...200717375195
human plague in the southwestern united states, 1957-2004: spatial models of elevated risk of human exposure to yersinia pestis.plague is a rare but highly virulent flea-borne zoonotic disease caused by the gram-negative bacterium yersinia pestis yersin. identifying areas at high risk of human exposure to the etiological agent of plague could provide a useful tool for targeting limited public health resources and reduce the likelihood of misdiagnosis by raising awareness of the disease. we created logistic regression models to identify landscape features associated with areas where humans have acquired plague from 1957 t ...200717547242
the potential role of swift foxes (vulpes velox) and their fleas in plague outbreaks in prairie dogs.swift foxes (vulpes velox) have been proposed as potential carriers of fleas infected with the bacterium yersinia pestis between areas of epizootics in black-tailed prairie dogs (cynomys ludovicianus). we examined antibody prevalence rates of a population of swift foxes in colorado, usa, and used polymerase chain reaction (pcr) assays to examine their flea biota for evidence of y. pestis. fifteen of 61 (24%) captured foxes were seropositive, and antibody prevalence was spatially correlated with ...200717699080
prevalence and abundance of fleas in black-tailed prairie dog burrows: implications for the transmission of plague (yersinia pestis).plague, the disease caused by the bacterium yersinia pestis, can have devastating impacts on north american wildlife. epizootics, or die-offs, in prairie dogs (cynomys ludovicianus) occur sporadically and fleas (siphonaptera) are probably important in the disease's transmission and possibly as maintenance hosts of y. pestis between epizootics. we monitored changes in flea abundance in prairie dog burrows in response to precipitation, temperature, and plague activity in shortgrass steppe in north ...200818605787
exposure of small rodents to plague during epizootics in black-tailed prairie dogs.plague, caused by the bacterium yersinia pestis, causes die-offs of colonies of prairie dogs (cynomys ludovicianus). it has been argued that other small rodents are reservoirs for plague, spreading disease during epizootics and maintaining the pathogen in the absence of prairie dogs; yet there is little empirical support for distinct enzootic and epizootic cycles. between 2004 and 2006, we collected blood from small rodents captured in colonies in northern colorado before, during, and for up to ...200818689662
scavenging by mammalian carnivores on prairie dog colonies: implications for the spread of plague.plague causes mass mortality of prairie dogs (cynomys ludovicianus) in shortgrass steppe. although the pathogen, the bacterium yersinia pestis, is spread within colonies by flea bites or contact between infected hosts, it is unclear how y. pestis is transported over long distances between isolated colonies. one possibility is that wideranging, plague-resistant mammalian carnivores pick up fleas when scavenging prairie dog carcasses. using guinea pigs as surrogates for prairie dogs, we compared h ...200918945188
are carnivores universally good sentinels of plague?sylvatic plague, caused by the bacterium yersinia pestis, is a flea-borne disease that primarily affects rodents but has been detected in over 200 mammal species worldwide. mammalian carnivores are routinely surveyed as sentinels of local plague activity, since they can present antibodies to y. pestis infection but show few clinical signs. in boulder county, colorado, usa, plague epizootic events are episodic and occur in black-tailed prairie dogs. enzootic hosts are unidentified as are plague f ...200918973449
evidence for the involvement of an alternate rodent host in the dynamics of introduced plague in prairie dogs.1. the introduction of plague to north america is a significant threat to colonies of prairie dogs (cynomys ludovicianus), a species of conservation concern in the great plains. other small rodents are exposed to the causative agent, yersinia pestis, during or after epizootics; yet, its effect on these rodents is not known, and their role in transmitting and maintaining plague in the absence of prairie dogs remains unclear. 2. we live-trapped small rodents and collected their fleas on 11 colonie ...200919302321
flea abundance on black-tailed prairie dogs (cynomys ludovicianus) increases during plague prairie dogs (cynomys ludovicianus) on the great plains of the united states are highly susceptible to plague, caused by the bacterium yersinia pestis, with mortality on towns during plague epizootics often approaching 100%. the ability of flea-borne transmission to sustain disease spread has been questioned because of inefficiency of flea vectors. however, even with low individual efficiency, overall transmission can be increased if flea abundance (the number of fleas on hosts) inc ...200919492944
effects of weather and plague-induced die-offs of prairie dogs on the fleas of northern grasshopper mice.plague, the disease caused by the bacterium yersinia pestis, can have devastating impacts on black-tailed prairie dogs (cynomys ludovicianus ord). other mammal hosts living on prairie dog colonies may be important in the transmission and maintenance of plague. we examined the flea populations of northern grasshopper mice (onychomys leucogaster wied) before, during, and after plague epizootics in northern colorado and studied the influence of host and environmental factors on flea abundance patte ...200919496431
wild felids as hosts for human plague, western united states.plague seroprevalence was estimated in populations of pumas and bobcats in the western united states. high levels of exposure in plague-endemic regions indicate the need to consider the ecology and pathobiology of plague in nondomestic felid hosts to better understand the role of these species in disease persistence and transmission.200919961691
inferring host-parasite relationships using stable isotopes: implications for disease transmission and host specificity.identifying the roles of different hosts and vectors is a major challenge in the study of the ecology of diseases caused by multi-host pathogens. intensive field studies suggested that grasshopper mice (onychomys leucogaster) help spread the bacterium that causes plague (yersinia pestis) in prairie dog colonies by sharing fleas with prairie dogs (cynomys ludovicianus); yet conclusive evidence that prairie dog fleas (oropsylla hirsuta) feed on grasshopper mice is lacking. using stable nitrogen is ...200919967881
detection of yersinia pestis dna in prairie dog-associated fleas by polymerase chain reaction assay of purified dna.we evaluated, refined, and applied well-established polymerase chain reaction (pcr) techniques for detecting yersinia pestis dna in fleas (mainly oropsylla spp.) collected from prairie dog (cynomys spp.) burrows. based on results from pcr of avirulent y. pestis strain a1122 dna, we used dna purification and primers for the plasminogen activator gene to screen field-collected fleas. we detected y. pestis dna in flea pools from two black-tailed prairie dog (cynomys ludovicianus) colonies with evid ...201020688665
population genetic structure of the prairie dog flea and plague vector, oropsylla hirsuta.oropsylla hirsuta is the primary flea of the black-tailed prairie dog and is a vector of the plague bacterium, yersinia pestis. we examined the population genetic structure of o. hirsuta fleas collected from 11 prairie dog colonies, 7 of which had experienced a plague-associated die-off in 1994. in a sample of 332 o. hirsuta collected from 226 host individuals, we detected 24 unique haplotype sequences in a 480 nucleotide segment of the cytochrome oxidase ii gene. we found significant overall po ...201120696095
colorado animal-based plague surveillance systems: relationships between targeted animal species and prediction efficacy of areas at risk for humans.human plague risks (yersinia pestis infection) are greatest when epizootics cause high mortality among this bacterium's natural rodent hosts. therefore, health departments in plague-endemic areas commonly establish animal-based surveillance programs to monitor y. pestis infection among plague hosts and vectors. the primary objectives of our study were to determine whether passive animal-based plague surveillance samples collected in colorado from 1991 to 2005 were sampled from high human plague ...200920836802
resistance to plague among black-tailed prairie dog populations.abstract in some rodent species frequently exposed to plague outbreaks caused by yersinia pestis, resistance to the disease has evolved as a population trait. as a first step in determining if plague resistance has developed in black-tailed prairie dogs (cynomys ludovicianus), animals captured from colonies in a plague-free region (south dakota) and two plague-endemic regions (colorado and texas) were challenged with y. pestis at one of three doses (2.5, 250, or 2500 mouse ld50s). south dakota p ...201121923261
serologic survey for cross-species pathogens in urban coyotes (canis latrans), colorado, usa.abstract as coyotes (canis latrans) adapt to living in urban environments, the opportunity for cross-species transmission of pathogens may increase. we investigated the prevalence of antibodies to pathogens that are either zoonotic or affect multiple animal species in urban coyotes in the denver metropolitan area, colorado, usa, in 2012. we assayed for antibodies to canine parvovirus-2, canine distemper virus, rabies virus, toxoplasma gondii, yersinia pestis, and serotypes of leptospira interrog ...201425121408
outbreak of human pneumonic plague with dog-to-human and possible human-to-human transmission--colorado, june-july 2014.on july 8, 2014, the colorado department of public health and environment (cdphe) laboratory identified yersinia pestis, the bacterium that causes plague, in a blood specimen collected from a man (patient a) hospitalized with pneumonia. the organism had been previously misidentified as pseudomonas luteola by an automated system in the hospital laboratory. an investigation led by tri-county health department (tchd) revealed that patient a's dog had died recently with hemoptysis. three other perso ...201525928467
burrowing owls, pulex irritans, and plague.western burrowing owls (athene cunicularia hypugaea) are small, ground-dwelling owls of western north america that frequent prairie dog (cynomys spp.) towns and other grasslands. because they rely on rodent prey and occupy burrows once or concurrently inhabited by fossorial mammals, the owls often harbor fleas. we examined the potential role of fleas found on burrowing owls in plague dynamics by evaluating prevalence of yersinia pestis in fleas collected from burrowing owls and in owl blood. dur ...201526367482
single-nucleotide polymorphisms reveal spatial diversity among clones of yersinia pestis during plague outbreaks in colorado and the western united western north america, plague epizootics caused by yersinia pestis appear to sweep across landscapes, primarily infecting and killing rodents, especially ground squirrels and prairie dogs. during these epizootics, the risk of y. pestis transmission to humans is highest. while empirical models that include climatic conditions and densities of rodent hosts and fleas can predict when epizootics are triggered, bacterial transmission patterns across landscapes, and the scale at which y. pestis is ...201525988438
season and application rates affect vaccine bait consumption by prairie dogs in colorado and utah, usa.plague, a zoonotic disease caused by the bacterium yersinia pestis, causes high rates of mortality in prairie dogs (cynomys spp.). an oral vaccine against plague has been developed for prairie dogs along with a palatable bait to deliver vaccine and a biomarker to track bait consumption. we conducted field trials between september 2009 and september 2012 to develop recommendations for bait distribution to deliver plague vaccine to prairie dogs. the objectives were to evaluate the use of the bioma ...201424484490
duration of plague (yersinia pestis) outbreaks in black-tailed prairie dog (cynomys ludovicianus) colonies of northern colorado.plague, caused by the bacterium yersinia pestis, triggers die-offs in colonies of black-tailed prairie dogs (cynomys ludovicianus), but the time-frame of plague activity is not well understood. we document plague activity in fleas from prairie dogs and their burrows on three prairie dog colonies that suffered die-offs. we demonstrate that y. pestis transmission occurs over periods from several months to over a year in prairie dog populations before observed die-offs.201324057801
persistence of black-tailed prairie-dog populations affected by plague in northern colorado, usa.the spatial distribution of prairie dog (cynomys ludovicianus) colonies in north america has changed from large, contiguous populations to small, isolated colonies in metapopulations. one factor responsible for this drastic change in prairie-dog population structure is plague (caused by the bacterium yersinia pestis). we fit stochastic patch occupancy models to 20 years of prairie-dog colony occupancy data from two discrete metapopulations (west and east) in the pawnee national grassland in colo ...201323951717
rodent and flea abundance fail to predict a plague epizootic in black-tailed prairie dogs.small rodents are purported to be enzootic hosts of yersinia pestis and may serve as sources of infection to prairie dogs or other epizootic hosts by direct or flea-mediated transmission. recent research has shown that small rodent species composition and small rodent flea assemblages are influenced by the presence of prairie dogs, with higher relative abundance of both small rodents and fleas at prairie dog colony sites compared to grasslands without prairie dogs. however, it is unclear if incr ...201020158331
transmission efficiency of two flea species (oropsylla tuberculata cynomuris and oropsylla hirsuta) involved in plague epizootics among prairie dogs.plague, caused by yersinia pestis, is an exotic disease in north america circulating predominantly in wild populations of rodents and their fleas. black-tailed prairie dogs (cynomys ludovicianus) are highly susceptible to infection, often experiencing mortality of nearly all individuals in a town as a result of plague. the fleas of black-tailed prairie dogs are oropsylla tuberculata cynomuris and oropsylla hirsuta. we tested the efficiency of o. tuberculata cynomuris to transmit y. pestis daily ...200818787922
season of deltamethrin application affects flea and plague control in white-tailed prairie dog (cynomys leucurus) colonies, colorado, 2008 and 2009, we evaluated the duration of prophylactic deltamethrin treatments in white-tailed prairie dog ( cynomys leucurus ) colonies and compared effects of autumn or spring dust application in suppressing flea numbers and plague. plague occurred before and during our experiment. overall, flea abundance tended to increase from may or june to september, but it was affected by deltamethrin treatment and plague dynamics. success in trapping prairie dogs (animals caught/trap days) declined ...201627195680
use of a public telephone hotline to detect urban plague cases.current methods for vector-borne disease surveillance are limited by time and cost. to avoid human infections from emerging zoonotic diseases, it is important that the united states develop cost-effective surveillance systems for these diseases. this study examines the methodology used in the surveillance of a plague epizootic involving tree squirrels (sciurus niger) in denver colorado, during the summer of 2007. a call-in centre for the public to report dead squirrels was used to direct animal ...201222429398
flea and small mammal species composition in mixed-grass prairies: implications for the maintenance of yersinia pestis.maintenance of sylvatic plague in prairie dogs (cynomis spp.) was once thought unlikely due to high mortality rates; yet more recent findings indicate that low-level enzootic plague may be maintained in susceptible prairie dog populations. another hypothesis for the maintenance of sylvatic plague involves small mammals, other than prairie dogs, as an alternative reservoir in the sylvatic plague system. these hypotheses, however, are not mutually exclusive, as both prairie dogs and small mammals ...201728520514
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