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occurrence of ixodes pacificus (parasitiformes: ixodidae) in arizona.adults and immatures of ixodes pacificus cooley & kohls were collected by flagging vegetation and from lizards during a 3-mo period in the hualapai mountain park, mohave county, az, in 1991. collections were made at altitudes > or = 2,134 m. two of 48 gut-salivary gland extracts of adult ticks were positive by ifa using a monoclonal antibody (h5332) specific to borrelia burgdorferi. these are the first records of i. pacificus and of spirochetes tentatively identified as b. burgdorferi in arizona ...19921460624
the western fence lizard sceloporus occidentalis: evidence of field exposure to borrelia burgdorferi in relation to infestation by ixodes pacificus (acari: ixodidae).the role of the western fence lizard sceloporus occidentalis in the enzootiology of the lyme disease spirochete borrelia burgdorferi was evaluated in the hopland and ukiah areas of mendocino county, california. in 1989, half of 74 lizards collected monthly from april to october at hopland were infested by the immature western black-legged tick ixodes pacificus at a mean intensity of 6.0 ticks per lizard. the prevalence of infestation of lizards by immature i. pacificus (36 of 73) at ukiah was si ...19921524146
lyme disease in california: a novel enzootic transmission cycle of borrelia burgdorferi.knowledge of zoonotic transmission cycles is essential for the development of effective strategies for disease prevention. the enzootiology of lyme disease in california differs fundamentally from that reported from the eastern united states. woodrats, not mice, serve as reservoir hosts, and ixodes neotomae, a nonhuman-biting tick, maintains the agent of lyme disease, borrelia burgdorferi, in enzootic cycles. the western black-legged tick, ixodes pacificus, is the primary vector to humans, but i ...19921604318
wood rats and kangaroo rats: potential reservoirs of the lyme disease spirochete in california.the etiologic agent of lyme disease, borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner, was isolated repeatedly from dusky-footed wood rats, neotoma fuscipes baird, and california kangaroo rats, dipodomys californicus merriam, in northern california. all animals were collected in a region endemic for lyme disease but for which the natural reservoir of b. burgdorferi was unknown. similar attempts to isolate spirochetes from lizards, other species of rodents, jack rabbits, and deer ...19911875357
lyme borreliosis: ten years after discovery of the etiologic agent, borrelia burgdorferi.since the recovery of its causative agent, borrelia burgdorferi, in 1981, lyme borreliosis has become the most prevalent tick-borne disease in the united states as well as in europe. its steadily increasing clinical spectrum now includes erythema migrans, acrodermatitis chronica atrophicans, lymphadenosis beniga cutis, arthritis, myocarditis, progressive meningoencephalitis, myositis, and various ocular and skin disorders. the true incidence of lyme borreliosis in the world is unknown. in the un ...19911917043
lyme disease in california: interrelationship of ixodid ticks (acari), rodents, and borrelia burgdorferi.the association of immature ixodid ticks, several species of rodents, and the lyme disease spirochete, borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner, was studied in two habitats in northern california in spring and summer 1985 and year-round in 1986. a total of 428 rodents were collected from ecotonal chaparral and a woodland-grass-rock outcrop; the former habitat yielded six species, the latter three species. the deer mouse, peromyscus maniculatus (wagner), and the piñon mou ...19911941942
lyme disease: a clinical review.lyme disease is caused by the spirochete borrelia burgdorferi, which is transmitted primarily by ixodes dammini ticks in the northeast and upper midwest, by ixodes pacificus in western states, and by ixodes ricinus in europe. lyme disease can affect the skin, nervous system, heart, eyes, and joints, and is diagnosed in patients with these characteristic clinical features: exposure to an endemic area and usually a positive serologic test for b. burgdorferi six or more weeks after infection. full ...19911944020
characterization of a tick isolate of borrelia burgdorferi that possesses a major low-molecular-weight surface protein.an unusual strain of borrelia burgdorferi (dn 127 cl 9-2) that was isolated from an ixodes pacificus tick did not react with monoclonal antibodies (mabs) to ospa and ospb surface proteins, which are found in most u.s. strains. the strain exhibited an abundant protein with an apparent molecular weight of 25,000 (25k protein). a mab, 86 dn-1, that was prepared to the 25k protein was used in studies on the effect of proteases on the intact spirochetes, immune electron microscopy, and western blot ( ...19902199499
survey of birds and lizards for ixodid ticks (acari) and spirochetal infection in northern california.a total of 138 birds (24 species) was captured in an oak woodland between december 1988 and june 1989 at the university of california, sierra foothill range field station, yuba county, calif. ticks were not found on 71 birds captured between december 1988 and march 1989. five subadult ixodes pacificus cooley & kohls were removed from 3 of 67 birds caught between april and june 1989. these three birds, an orange-crowned warbler (vermivora celata (say], a lazuli bunting (passerina amoena (say], an ...19902280384
susceptibility of the western fence lizard (sceloporus occidentalis) to the lyme borreliosis spirochete (borrelia burgdorferi).attempts to infect juvenile and adult western fence lizards (sceloporus occidentalis) with the lyme borreliosis spirochete (borrelia burgdorferi) were largely unsuccessful. spirochetes could not be isolated from the blood and various tissues of 14 lizards 21-32 days after they had been inoculated ip (n = 8) or sc (n = 6) with 10(6) or 10(8) b. burgdorferi representing 3 tick isolates, although 1 lizard apparently developed a transitory spirochetemia lasting 2 days. similarly, spirochetes could n ...19902301709
dna and protein analyses of tick-derived isolates of borrelia burgdorferi from california.nine isolates of borrelia burgdorferi from ixodid ticks collected in northern california were characterized. restriction endonuclease analysis, pulsed-field gel electrophoresis, and western blot (immunoblot) analysis were used in this study. four isolates were very similar to each other. the others shared some similarities but were classified as having unique genotypes. a strain from an ixodes neotomae tick displayed the greatest genetic and antigenic diversity when compared to the isolates coll ...19902332468
host-seeking behavior of adult ixodes pacificus (acari: ixodidae) as determined by flagging vegetation.diurnal host-seeking by adults of the western black-legged tick, ixodes pacificus cooley & kohls in relation to vegetative habitat type and meterological factors was investigated at a coastal and an inland site in northern california. host-seeking behavior and relative tick abundance were determined with a tick drag method from late fall to midwinter 1987-1988. at the inland site, tick abundance usually was significantly greater in chaparral-grassland ecotones than in adjoining dense chaparral o ...19902332872
epizootiology of borrelia in ixodes tick vectors and reservoir hosts.four north american and two european species of ixodes ticks harbor borreliae. three of the north american species--ixodes dammini, ixodes scapularis, and ixodes pacificus--and two old world species--ixodes ricinus and ixodes persulcatus--feed on a wide range of hosts, including humans; the north american ixodes dentatus has a predilection for cottontail rabbits and rarely parasitizes humans. in lyme disease foci in north america where i. dammini is common, borrelia burgdorferi or similar types ...19892682957
antigenic characteristics of borrelia burgdorferi isolates from ixodid ticks in california.twenty (1.4%) of 1,421 adult ixodes pacificus ticks and 2 (20%) of 10 adult ixodes neotomae ticks collected in five counties of northern california were found to contain spirochetes by direct immunofluorescence examination of their tissues with a polyvalent conjugate. borreliae isolated from the tissues of nine of these ticks (i. pacificus, 8; i. neotomae, 1) were identified as borrelia burgdorferi with specific monoclonal antibodies and characterized further by polyacrylamide gel electrophoresi ...19892685030
treatment of clothing with a permethrin spray for personal protection against the western black-legged tick, ixodes pacificus (acari: ixodidae).the synthetic pyrethroid, permethrin, when applied to clothing with a pressurized spray at an application rate estimated previously to be 4 micrograms a.i./cm2, was found to be 100% effective for personal protection against all three parasitic stages of the western black-legged tick, ixodes pacificus cooley and kohls. this tick has been implicated as the primary vector of the lyme disease spirochete (borrelia burgdorferi) to humans in the far-western united states. periods of exposure to permeth ...19892743839
lyme disease in california: interrelationship of ixodes pacificus (acari: ixodidae), the western fence lizard (sceloporus occidentalis), and borrelia burgdorferi.the relationship of immature western black-legged ticks, ixodes pacificus cooley and kohls, to the western fence lizard, sceloporus occidentalis baird and girard, and to the lyme disease spirochete, borrelia burgdorferi, was investigated in chaparral and woodland-grass habitats in northern california from 1984 to 1986. immature ticks were found on lizards in spring and summer, but the prevalence and abundance of ticks on this host were considerably greater in spring. the peak of larval abundance ...19892769705
complete heart block in a dog seropositive for borrelia burgdorferi. similarity to human lyme carditis.lyme disease has been recognized in humans since 1975 when it was associated with an outbreak of oligoarthritis in children in lyme, connecticut. erythema chronicum migrans (ecm) is a clinical marker for the human disease, which usually appears within 3 to 32 days after an infected tick bite. lyme disease is caused by spirochete, borrelia burgdorferi, which is vectored by the hard ticks ixodes dammini or ixodes pacificus in the united states. in humans, lyme disease has been found to cause a var ...19883225808
lyme borreliosis in california. acarological, clinical, and epidemiological studies.the relative abundance of, and spirochetal-infection rates in, adult ixodid ticks from eight lyme borreliosis clinical-case areas and two comparison areas were investigated in northern california from late fall to early spring, 1984-87. the western black-legged tick (ixodes pacificus) was the most abundant species at seven of nine sites yielding specimens as determined with a tick drag method. the pacific coast tick (dermacentor occidentalis) was the most abundant species at two sites, and lesse ...19883263826
characterization of borrelia burgdorferi strains isolated from ixodes pacificus ticks in california.in a survey of 1,714 adult ixodes pacificus ticks collected in northern california, 24 (1.4%) were found to be infected with spirochetes that reacted with an anti-borrelia burgdorferi polyvalent conjugate in direct immunofluorescence tests. eleven isolates of b. burgdorferi from these ticks were characterized by monoclonal antibody, polyacrylamide gel electrophoresis, and western blot (immunoblot) analyses. ten of the isolates had molecular and antigenic characteristics similar to those of other ...19873323225
potential role of native and exotic deer and their associated ticks (acari: ixodidae) in the ecology of lyme disease in california, usa.the relationship of native columbian black-tailed deer, two species of exotic deer (axis and fallow), and their ticks to the lyme disease spirochete, borrelia burgdorferi, was studied in coastal and inland areas of northern california, usa. spirochetemias were detected in 27% of black-tailed deer, 50% of axis deer, and 56% of fallow deer collected in late fall and winter. antibody prevalence was 38% in black-tailed deer, 24% in fallow deer, and 6% in axis deer. one to 3 tick species were collect ...19863554845
transovarial and transstadial passage of borrelia burgdorferi in the western black-legged tick, ixodes pacificus (acari: ixodidae).transovarial and transstadial passage of borrelia burgdorferi was demonstrated for the first time in the western black-legged tick, ixodes pacificus. one of three field-collected females with spirochetes in ovarial tissues produced 100% infected progeny that maintained the spirochetes transstadially and in 4 of 5 cases passed them via eggs to as many as 97% of f2 filial ticks. the progeny infected ovarially and by subsequent transstadial passage had generalized tissue infections that exhibited r ...19873605502
the western black-legged tick, ixodes pacificus: a vector of borrelia burgdorferi.to determine the significance of the western black-legged tick, ixodes pacificus, as a vector of the lyme disease spirochete, borrelia burgdorferi, a tick/spirochete survey was conducted in northern california and southwestern oregon from 1982 to 1984. of 1,687 adult ticks collected off vegetation, 25 (1.48%) contained spirochetes. of 715 ticks from oregon, 14 (1.96%) were infected whereas 11 (1.13%) of 972 ticks from california harbored spirochetes. an isolate of 1 of the spirochetes reacted sp ...19853898886
discovery of the lyme disease spirochete and its relation to tick vectors.the various hypotheses concerning the etiologic agent of erythema chronicum migrans of europe and of lyme disease in the united states are reviewed, and an account of events that led to the discovery of the causative spirochetal agent in ixodes dammini is presented. spirochetes morphologically and antigenically similar, if not identical to, the organism detected in i. dammini were also found for the first time in ixodes pacificus and ixodes ricinus, the vectors hitherto incriminated, respectivel ...19846516454
evidence implicating nymphal ixodes pacificus (acari: ixodidae) in the epidemiology of lyme disease in california.to clarify the role of nymphal versus adult western black-legged ticks (ixodes pacificus) in the epidemiology of lyme disease, the seasonal distribution, abundance, and spirochetal infection rates in these stages, and the seasonal occurrence of ticks biting humans and of incident cases of lyme disease were determined in northern california. although their seasonal activity periods overlapped for about one-third of the year, nymphs and adults predominated in different seasons, the former from lat ...19957573703
species of borrelia distinguished by restriction site polymorphisms in 16s rrna genes.three phyletic groups of borrelia associated with lyme disease, b. burgdorferi, b. garinii and group vs461 can be distinguished from each other and other species of borrelia by bfai restriction site polymorphisms in pcr amplified 16s rrna genes. one strain isolated from an ixodes pacificus tick in california that was previously unclassifiable was distinguishable from b. burgdorferi by an mn/i restriction site polymorphism.19937691681
transmission of borrelia burgdorferi by ixodes pacificus nymphs and reservoir competence of deer mice (peromyscus maniculatus) infected by tick-bite.the transmission of borrelia burgdorferi to deer mice (peromyscus maniculatus) by ixodes pacificus nymphs was investigated experimentally. deer mice were exposed to infected nymphs for 24, 48, or 72 hr, or until ticks had fed to repletion (> or = 96 hr). infection status of hosts was assessed 4 wk later by culture of ear-punch biopsies in bsk ii medium and by indirect immunofluorescence. eight mice exposed to ticks for 24 hr did not become infected. in contrast, infection was acquired by 1 of 9 ...19957707191
vector competence of ixodes pacificus and dermacentor occidentalis (acari: ixodidae) for various isolates of lyme disease spirochetes.the vector competence of the western black-legged tick, ixodes pacificus cooley & kohls, and the pacific coast tick, dermacentor occidentalis marx, for the lyme disease spirochete (borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner) was compared. rabbits, hamsters, and the deer mouse, peromyscus maniculatus (wagner), were injected with cultured spirochetes or infected tick-suspensions, or were fed upon by spirochete-infected ticks. five of seven isolates used as inocula were reiso ...19948057316
distribution and molecular analysis of lyme disease spirochetes, borrelia burgdorferi, isolated from ticks throughout california.previous studies describing the occurrence and molecular characteristics of lyme disease spirochetes, borrelia burgdorferi, from california have been restricted primarily to isolates obtained from the north coastal region of this large and ecologically diverse state. our objective was to look for and examine b. burdorferi organisms isolated from ixodes pacificus ticks collected from numerous regions spanning most parts of california where this tick is found. thirty-one isolates of b. burgdorferi ...19938308101
an ospa antigen-capture enzyme-linked immunosorbent assay for detecting north american isolates of borrelia burgdorferi in larval and nymphal ixodes dammini.an antigen-capture enzyme-linked immunosorbent assay (elisa) was developed for detecting north american isolates of borrelia burgdorferi in larval, nymphal, and adult ticks. the assay uses an anti-ospa monoclonal antibody (h5332) for antigen capture and biotin-labelled polyclonal sera with streptavidinhorseradish peroxidase for signal generation. the assay recognized 15 of 15 north american b. burgdorferi isolates and did not cross-react with spirochete antigens of borrelia hermsii, borrelia tur ...19938432812
efficiency of transovarial transmission of the lyme disease spirochete, borrelia burgdorferi, in the western blacklegged tick, ixodes pacificus (acari: ixodidae).the efficiency of transovarial transmission of borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner was evaluated in ixodes pacificus cooley & kohls collected from two areas of northern california where lyme disease is endemic. in total, 132 (8.8%) of 1,499 replete females examined by direct immunofluorescence were demonstrated to be infected with b. burgdorferi. larvae or eggs from 119 of these females were examined for the presence of spirochetes by direct immunofluorescence, plac ...19938433348
temporal and spatial distribution of ixodes pacificus and dermacentor occidentalis (acari: ixodidae) and prevalence of borrelia burgdorferi in contra costa county, california.the seasonal activity and spatial distribution of adult and immature ixodes pacificus cooley & kohls and dermacentor occidentalis marx were determined along trails and on hillsides in two parks in contra costa county, ca. i. pacificus and d. occidentalis adults were most numerous in january and may, respectively. adult ticks were significantly more abundant along heavily vegetated trails than on open grassy hillsides, and on the uphill versus the downhill side of trails. five species of rodents ...19938510115
reservoir competence of four chaparral-dwelling rodents for borrelia burgdorferi in california.aspects of the reservoir competence of four rodents for the lyme disease spirochete, borrelia burgdorferi, were evaluated in california. rodents were live-trapped and ear-punch biopsies were cultured during each season. a second set of biopsies was cultured from representative individuals after 2-3 weeks of captivity and the results of culturing biopsies taken on both dates were compared with the results of feeding ixodes pacificus larvae on hosts xenodiagnostically. the prevalence of infections ...19968651378
evaluation of permethrin-impregnated cotton balls as potential nesting material to control ectoparasites of woodrats in california.the dusky-footed woodrat, neotoma fuscipes baird is a natural reservoir of the lyme disease spirochete, borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner, in california. to investigate the potential of host-targeted insecticide to control the tick vectors of b. burgdorferi, permethrin-impregnated or untreated cotton balls were distributed in metal cylinders as potential nesting material adjacent to 95 woodrat houses in chaparral-covered rangeland. laboratory experiments demonstra ...19968667381
comparison of infectivities of six tick-derived isolates of borrelia burgdorferi for rodents and ticks.the infectivity and dissemination to the skin of six isolates of borrelia burgdorferi were evaluated by inoculating them into groups of deer mice (peromyscus maniculatus), hamsters, and swiss webster mice. rodent infection was assayed by culture of ear punch biopsy specimens taken at 4, 8, and 12 weeks postinoculation (p.i.). spirochetes were detected in biopsy specimens from individuals of all three host species that had been inoculated with four isolates (ca3, ca4, ca7, and ca8). ear punch bio ...19968748276
risk of human exposure to vector ticks (acari: ixodidae) in a heavily used recreational area in northern california.the risk of humans encountering vector ticks along hiking trails or in picnic grounds in a lyme disease-endemic area was evaluated in a multipurpose recreational area (tilden regional park) in the populous san francisco bay region of california. four hillside hiking trails (two high-use, two low-use) were sampled by dragging and walking through low vegetation biweekly for one year; four heavily used picnic areas were sampled concurrently by dragging. adults of three human-biting ticks were enume ...19968780455
lyme borreliosis in the southern united states: a review.lyme borreliosis (lyme disease) is the most often reported arthropod transmitted disease in humans in the u.s.a. although it has been reported from 43 states, cases are especially abundant in the mid-atlantic and northeastern regions. borrelia burgdorferi, the etiologic agent, is transmitted primarily by the western blacklegged tick (ixodes pacificus) in far western north america, and by the blacklegged tick (ixodes scapularis) in eastern north america. although lyme disease cases have been repo ...19968973401
population genetic structure of ixodes pacificus (acari:ixodidae) using allozymes.genetic analysis of the population structure of the western blacklegged tick, ixodes pacificus cooley & kohls, was conducted using allozymes. this vector tick transmits the lyme disease spirochete, borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner, in the far-western united states. it ranges from british columbia to baja california and disjunct populations are present in oregon, nevada, utah, and arizona. host-seeking adult ticks were collected from vegetation across the range of ...19979220679
role of small mammals in the ecology of borrelia burgdorferi in a peri-urban park in north coastal california.the role of small mammals other than woodrats in the enzootiology of the lyme disease spirochete, borrelia burgorferi, was assessed in the peri-urban park. mammals were collected monthly from september through to april. following tick removal, the animals were tested for b. burgdorferi by culture of ear-punch biopsies. larvae and nymphs that were intermediate in morphology between ixodes spinipalpis and ixodes neotomae occurred on several species of rodents (peromyscus truei, peromyscus californ ...19979291589
taxonomic status of ixodes neotomae and i. spinipalpis (acari: ixodidae) based on mitochondrial dna evidence.ixodes spinipalpis hadwen & nuttall and i. neotomae cooley are enzootic vectors of borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner in western north america. the taxa overlap in host preference, habitat, and morphology. mitochondrial dna was compared between the taxa to test for reproductive isolation. a 300-bp region of the mitochondrial 16s ribosomal dna gene was amplified in 28 specimens of i. neotomae and 149 specimens of i. spinipalpis. these products were screened for sequ ...19979439125
borreliacidal factor in the blood of the western fence lizard (sceloporus occidentalis).in some populations of the western black-legged tick, ixodes pacificus, the prevalence of infection with lyme disease spirochetes (borrelia burgdorferi) in nymphal ticks exceeds those in adult ticks by 3-4-fold. experiments were conducted to determine if the reduced spirochetal prevalence in adult ticks is due to the presence of anti-borrelial antibodies or to another borreliacidal factor in the blood of the western fence lizard, sceloporus occidentalis, a primary host of subadult i. pacificus, ...19989488334
distribution of ixodes pacificus and ixodes scapularis re concurrent babesiosis and lyme disease. 19989704540
reported distribution of ixodes scapularis and ixodes pacificus (acari: ixodidae) in the united states.lyme disease, caused by infection with borrelia burgdorferi, is the most frequently reported arthropod-borne disease in the united states. to develop a national map of the distribution of the vectors of b. burgdorferi to humans (ixodes scapularis say and ixodes pacificus cooley & kohls ticks), we sent questionnaires to acarologists, health officials, and lyme disease researchers; surveyed the 1966-1996 medline data base; and reviewed 1907-1995 national tick collection data. tick collection metho ...19989775584
infestation of the southern alligator lizard (squamata: anguidae) by ixodes pacificus (acari: ixodidae) and its susceptibility to borrelia burgdorferi.to investigate the reservoir potential of the southern alligator lizard, elgaria multicarinata (blainville), for the lyme disease spirochete, borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner, 14 lizards were collected from 1 county on each side of the northern central valley of california. seven animals were collected from a placer county site (drivers flat) and a yolo county site (cache creek) where b. burgdorferi had been isolated previously from ixodes pacificus cooley & kohl ...19989835700
life history of ixodes (ixodes) jellisoni (acari: ixodidae) and its vector competence for borrelia burgdorferi sensu lato.ixodes (ixodes) jellisoni cooley & kohls, a nonhuman biting and little known tick, is one of 4 members of the i. ricinus complex in the united states. a localized population of i. jellisoni inhabiting a grassland biotope in mendocino county, ca, was studied from 1993 to 1997. rodent trapping in all seasons revealed that the only host of both immature and adult i. jellisoni was the heteromyid rodent dipodomys californicus merriam. field investigations suggested that i. jellisoni is nidicolous in ...199910337104
geographic survey of vector ticks (ixodes scapularis and ixodes pacificus) for infection with the lyme disease spirochete, borrelia burgdorferi.populations of adult ixodes scapularis and ixodes pacificus, the two principal vectors of lyme disease spirochetes in the united states, were collected from 17 sites in 12 states. female ticks were fed on experimental rabbits; ticks and rabbits were subsequently examined for infection with borrelia burgdorferi. fourteen rabbits were exposed to i. scapularis ticks from the northeastern states of connecticut, new york, new jersey, and maryland; all 14 rabbits became infected with b. burgdorferi. a ...199910436883
isolation of borrelia burgdorferi from neotoma fuscipes, peromyscus maniculatus, peromyscus boylii, and ixodes pacificus in oregon.the number of lyme disease cases in oregon has increased in recent years despite the fact that the pathogen, borrelia burgdorferi, has never been isolated in the state. rodent and tick surveys were undertaken in 1997 to isolate and characterize strains of b. burgdorferi from oregon and to identify potential reservoirs and vectors of lyme disease. borrelia burgdorferi was isolated from neotoma fuscipes, peromyscus maniculatus, p. boylii, and ixodes pacificus. both n. fuscipes and p. maniculatus w ...199910466976
variation in the density of questing ixodes pacificus (acari:ixodidae) nymphs infected with borrelia burgdorferi at different spatial scales in california.the density of, and prevalence of infection with borrelia burgdorferi in, ixodes pacificus nymphs as well as the density of infected nymphs were compared at 12 properties at a small rural community at high risk for lyme disease (chr) and at 12 areas at the university of california hopland research and extension center (hrec), mendocino county, california. the mean infection prevalence and density of infected nymphs were 1.7% (range, 0-4.2%) and 0.10 infected nymphs per 100 m2 (range, 0-0.23 per ...199910577716
abundance of ticks (acari: ixodidae) infesting the western fence lizard, sceloporus occidentalis, in relation to environmental factors.we examined the impact of environmental characteristics, such as habitat type, topographic exposure and presence of leaf litter, on the abundance of ixodes pacificus ticks infesting the western fence lizard (sceloporus occidentalis) at the university of california hopland research and extension center (hrec), mendocino county, california. a total of 383 adult lizards were slip-noosed and examined for tick infestation in april and may 1998. at least 94% of the lizards were infested by ticks and a ...199910581712
mitochondrial dna sequence variation in ixodes pacificus (acari: ixodidae).the western black-legged tick, ixodes pacificus, is a primary vector of the spirochaete, borrelia burgdorferi, that causes lyme disease. we used variation in a 355-bp dna portion of the mitochondrial cytochrome oxidase iii gene to assess the population structure of the tick across its range from british columbia to southern california and east to utah. ixodes pacificus showed considerable haplotype diversity despite low nucleotide diversity. maximum parsimony and isolation-by-distance analyses r ...199910583539
anti-arthropod saliva antibodies among residents of a community at high risk for lyme disease in california.the role of the western black-legged tick (ixodes pacificus) versus that of other potential arthropod vectors in the epidemiology of lyme disease was evaluated by determining the prevalence of anti-arthropod saliva antibodies (aasa) among residents (n = 104) of a community at high-risk (chr). salivary gland extracts prepared from i. pacificus, the pacific coast tick (dermacentor occidentalis), the western cone-nose bug (triatoma protracta), and the western tree-hole mosquito (aedes sierrensis) w ...199910586924
cytokine responses of c3h/hen mice infested with ixodes scapularis or ixodes pacificus nymphs.lyme borreliosis, caused by borrelia burgdorferi, is transmitted by ixodes scapularis in the eastern and midwestern united states and by ixodes pacificus in the far-western united states. studies have shown that infestation with i. scapularis nymphs modulates host cytokine production; however, the influence of i. pacificus infestation on host cytokines remains uninvestigated. this study demonstrated how repeated infestations with pathogen-free i. scapularis or i. pacificus nymphs affects the pro ...200010607289
density and spatial distribution of ixodes pacificus (acari: ixodidae) in two recreational areas in north coastal california.the density and distribution of ixodes pacificus was assessed at 2 parks in north coastal california. the density of i. pacificus adults and nymphs varied significantly between years, trails, and sides of trails. adult ticks occurred on vegetation along sun-exposed trails in january through march, their density (0-1.93 per 20 m) correlated with brush density, trail width, and presence of an uphill slope. nymphs (0.06-5.10 per 20 m) occurred in leaf litter along shaded trails in may-july. adult i ...200011037789
ecology of borrelia burgdorferi in ticks (acari: ixodidae), rodents, and birds in the sierra nevada foothills, placer county, california.this study examined the prevalence of borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner in host-seeking adult and nymphal ixodes pacificus cooley & kohls and estimated the i. pacificus infestation and b. burgdorferi infection of rodent and avian hosts in the western sierra nevada foothills of northern california. additionally, we identified species likely to participate in an enzootic cycle for b. burgdorferi in this yellow pine transition habitat. evidence of infection with b. b ...200011126549
complement-mediated killing of borrelia burgdorferi by nonimmune sera from sika deer.various species of cervid deer are the preferred hosts for adult, black-legged ticks (ixodes scapularis and ixodes pacificus) in the united states. although frequently exposed to the agent of lyme disease (borrelia burgdorferi), these animals, for the most part, are incompetent as transmission reservoirs. we examined the borreliacidal activity of normal and b. burgdorferi-immune sera from sika deer (cervus nippon) maintained in a laboratory setting and compared it to that of similar sera from re ...200011191897
birds and their ticks in northwestern california: minimal contribution to borrelia burgdorferi enzootiology.birds and their attendant ticks were surveyed for infection with the lyme disease spirochete borrelia burgdorferi, in chaparral and woodland-grass habitats in northwestern california from march to july, 1998 to 1999. in total, 234 birds were captured and recaptured (15%); nearly 2.5 times more birds were captured in chaparral than in woodland-grass. overall, 34 species representing 15 families were collected during this study; of these, 24 species were caught in chaparral, 19 in woodland-grass, ...200111534638
persistent infection in neotoma fuscipes (muridae: sigmodontinae) with ehrlichia phagocytophila sensu lato.dusky-footed wood rats (neotoma fuscipes baird) and two species of peromyscus mice (p. maniculatus wagner and p. truei shufeldt) were collected over a 16-month period from three sites in sonoma county, california. blood was collected from 93 wood rats and 177 mice and serum or plasma was tested for seroreactivity with ehrlichia phagocytophila sensu lato (also known as the human granulocytic ehrlichiosis agent). thirty-five (37.6%) wood rats and 15 (8.5%) mice were seropositive. positive neotoma ...200111693866
prevalence and abundance of ixodes pacificus immatures (acari: ixodidae) infesting western fence lizards (sceloporus occidentalis) in northern california: temporal trends and environmental correlates.the prevalence and abundance of immature ixodes pacificus ticks on western fence lizards (sceloporus occidentalis) were examined in relation to time of year, host attributes (i.e., age, gender, and presence or absence of blood parasites), and 5 environmental characteristics, including topographic exposure and ground cover substrate, over a 2-year period in northern california. lizards were infested with subadult ticks from early march until late july or early august, with peak median numbers of ...200111780813
seasonal activity patterns of ixodes pacificus nymphs in relation to climatic conditions.in western north america, the tick ixodes pacificus cooley & kohls (acari: ixodidae) is the primary vector to humans and domestic animals of the disease agents causing lyme disease and granulocytic ehrlichiosis. we examined the seasonal activity patterns of i. pacificus nymphs over a 4-year period, including the wet and cold el niño winter/spring of 1998, in a dry oak/madrone woodland, and for one year in a cooler and moister redwood/tanoak woodland in mendocino county, california. linear regres ...200212243224
relative importance of lizards and mammals as hosts for ixodid ticks in northern california.abstract lizards and mammals were trapped and examined for ticks from august 1992 to june 1993 in two habitat types, chaparral and woodland-grass, in northern california. five tick species were collected from mammals (dermacentor occidentalis, haemaphysalis leporispalustris, ixodes pacificus, i. spinipalpis, i. woodi), but only i. pacificus was found on lizards. dermacentor occidentalis, i. pacificus, and i. woodi occurred in both habitats, whereas h. leporispalustris and i. spinipalpis were fou ...200212475082
geographical and seasonal correlation of multiple sclerosis to sporadic schizophrenia.background: clusters by season and locality reveal a striking epidemiological overlap between sporadic schizophrenia and multiple sclerosis (ms). as the birth excesses of those individuals who later in life develop schizophrenia mirror the seasonal distribution of ixodid ticks, a meta analysis has been performed between all neuropsychiatric birth excesses including ms and the epidemiology of spirochaetal infectious diseases. results: the prevalence of ms and schizophrenic birth excesses entirely ...200212537588
acarologic risk of exposure to emerging tick-borne bacterial pathogens in a semirural community in northern california.an acarologic study was conducted in a semirural community in northern california to determine the relative abundance of, and the prevalence of infection with, three emerging bacterial pathogens in the western black-legged tick (ixodes pacificus). these included the agents causing lyme disease (borrelia burgdorferi), human granulocytic ehrlichiosis [ehrlichia phagocytophila (formerly ehrlichia equi)], and human monocytic ehrlichiosis (ehrlichia chaffeensis). the study area in sonoma county consi ...200112653148
vector competence of ixodes pacificus and i. spinipalpis (acari: ixodidae), and reservoir competence of the dusky-footed woodrat (neotoma fuscipes) and the deer mouse (peromyscus maniculatus), for borrelia bissettii.we investigated the experimental vector competence of ixodes pacificus cooley and kohls and ixodes spinipalpis hadwen and nuttall, and the reservoir competence of the dusky-footed woodrat (neotoma fuscipes baird) and the deer mouse (peromyscus maniculatus [wagner]), for borrelia bissettii postic, marti ras, lane, hendson, and baranton. both rodent species are capable reservoirs for b. bissettii; infection rates for i. pacificus or i. spinipalpis nymphs fed as larvae on infected animals ranged fr ...200312943110
detection of borrelia burgdorferi, ehrlichia chaffeensis, and anaplasma phagocytophilum in ticks (acari: ixodidae) from a coastal region of california.a study was conducted in santa cruz county to estimate the prevalence and distribution of the agents of lyme disease, human granulocytic (hge), and human monocytic (hme) ehrlichiosis in 1,187 adult ixodid ticks collected from eight public-use recreation areas over a 2-yr period. borrelia burgdorferi, the causative agent of lyme disease, was detected by a polymerase chain reaction (pcr) in 44 of 776 (5.67%) ixodes pacificus ticks and in 3 of 58 (5.17%) dermacentor variabilis ticks. anaplasma phag ...200314680123
the western black-legged tick, ixodes pacificus, in the sutter buttes.the western black-legged tick, ixodes pacificus, was collected from huff canyon in the sutter buttes in north central california, sutter county. the sutter buttes are within the sacramento valley and outside the normal distribution of i. pacificus in california. adult i. pacificus were collected via flagging as they quested along deer trails; subadult life stages were collected from three species of lizard, elgaria multicarinata, sceloporus occidentalis, and s. graciosus. adult ticks were tested ...200314714665
acarologic risk of exposure to borrelia burgdorferi spirochaetes: long-term evaluations in north-western california, with implications for lyme borreliosis risk-assessment models.over a 5-year period (1997-2001) the population densities of ixodes pacificus cooley & kohls (acari: ixodidae) nymphs infected with spirochaetes of borrelia burgdorferi sensu lato (s.l.) were evaluated in areas of 2000 ha at two localities (chr, nine sites; hrec, seven sites) 25 km apart in mendocino county, north-western california. the 5-year median density of infected nymphs was significantly higher at chr than at hrec (0.51 vs. 0.09 per 100 m(2) and site-specific yearly densities exceeding o ...200415009444
human behaviors elevating exposure to ixodes pacificus (acari: ixodidae) nymphs and their associated bacterial zoonotic agents in a hardwood forest.epidemiological evidence suggests that the nymph of the western black-legged tick, ixodes pacificus cooley and kohls, is the primary vector of the lyme disease spirochete, borrelia burgdorferi johnson, schmid, hyde, steigerwalt, and brenner, to humans in northwestern california. in spring 2002, six different human behaviors were evaluated as potential risk factors for acquiring i. pacificus nymphs in a deciduous woodland in mendocino county, california. also, the prevalence of b. burgdorferi sen ...200415061284
life stage-related differences in density of questing ticks and infection with borrelia burgdorferi sensu lato within a single cohort of ixodes pacificus (acari: ixodidae).the primary aims of this study were to quantify the density of ixodes pacificus cooley and kohls nymphs and adults of the same generational cohort collected within a single year in six oak or madrone leaf litter habitats and to compare the prevalence of infection with borrelia burgdorferi sensu lato (s.l.) in adults originating from nymphal cohorts with a low (<1%) versus high (>10%) infection prevalence. because adult densities were very low both in and adjacent to several sites, direct compari ...200415311473
habitat-related variation in infestation of lizards and rodents with ixodes ticks in dense woodlands in mendocino county, california.during the spring and early summer of 2002, we examined the relative importance of borrelia-refractory lizards (sceloporus occidentalis, elgaria spp.) versus potential borrelia burgdorferi sensu lato (s.l.)-reservoirs (rodents) as hosts for ixodes pacificus immatures in 14 woodland areas (six oak, five mixed oak/douglas fir, and three redwood/tanoak areas) distributed throughout mendocino county, california. lizards were estimated to serve as hosts for 93-98% of all larvae and > or =99.6% of all ...200415347025
remote sensing (normalized difference vegetation index) classification of risk versus minimal risk habitats for human exposure to ixodes pacificus (acari: ixodidae) nymphs in mendocino county, california.in california, ixodes pacificus cooley & kohls nymphs have been implicated as the primary bridging vectors to humans of the spirochetal bacterium causing lyme disease (borrelia burgdorferi). because the nymphs typically do not ascend emergent vegetation, risk of human exposure is minimal in grasslands, chaparral, and woodland-grass. instead, woodlands with a ground cover dominated by leaf litter (hereinafter referred to as woodland-leaf) have emerged as a primary risk habitat for exposure to b. ...200515691012
the roles of birds, lizards, and rodents as hosts for the western black-legged tick ixodes pacificus.we compared the infestation by ixodid ticks of lizards, rodents, and birds collected simultaneously within areas representing common habitat types in mendocino county, ca. lizards were infested only by ixodes pacificus cooley and kohls, birds by i. pacificus and haemaphysalis leporispalustris (packard), and rodents by i. pacificus, i. spinipalpis hadwen and nuttall, i. woodi bishopp, dermacentor occidentalis marx, and d. variabilis (say). infestation by i. pacificus larvae and nymphs of lizards ...200415709249
gis-facilitated spatial epidemiology of tick-borne diseases in coyotes (canis latrans) in northern and coastal california.ixodes pacificus is the main tick vector for transmission of anaplasma phagocytophilum and borrelia burgdorferi to large vertebrates in california. the present study was undertaken in i. pacificus-infested counties in california to examine spatial and temporal relationships among a. phagocytophilum and b. burgdorferi-exposed coyotes with vegetation type and climate. the overall a. phagocytophilum and b. burgdorferi seroprevalences were 39.5% (n=215) and 18.9% (n=148), respectively, with no assoc ...200515857659
western gray squirrel (rodentia: sciuridae): a primary reservoir host of borrelia burgdorferi in californian oak woodlands?in california, dense woodlands have been recognized as important biotopes where humans are exposed to the nymphal stage of the western blacklegged tick, ixodes pacificus cooley & kohls, the primary vector of the lyme disease spirochete borrelia burgdorferi sensu stricto (s.s.), in the far-western united states. to identify the principal reservoir host(s) of this spirochete, and of closely related spirochetes in the b. burgdorferi sensu lato (s.l.) complex, in dense woodlands in mendocino county, ...200515962792
co-detection of bartonella henselae, borrelia burgdorferi, and anaplasma phagocytophilum in ixodes pacificus ticks from california, usa.presence of bartonella dna was explored in 168 questing adult ixodes pacificus ticks from santa cruz county, california. bartonella henselae type i dna was amplified from 11 ticks (6.55%); previously, two (1.19%) were found to be infected with borrelia burgdorferi and five (2.98%) with anaplasma phagocytophilum. detection of b. henselae was not dependent on co-infection. the present study offers additional evidence that ixodes spp. ticks may act as hosts and possibly vectors for b. henselae.200616584332
predicting density of ixodes pacificus nymphs in dense woodlands in mendocino county, california, based on geographic information systems and remote sensing versus field-derived data.ixodes pacificus nymphs are the primary vectors to humans of borrelia burgdorferi, the etiologic agent of lyme disease, in california. we used a supervised classification model, based on remote sensing (rs) data from multi-seasonal landsat tm 5 images, to identify the key habitat in mendocino county where humans are exposed to i. pacificus nymphs (woodlands carpeted with leaf litter). the model, based on the normalized difference vegetation index (ndvi), brightness, and wetness, separated the ny ...200616606998
an avian contribution to the presence of ixodes pacificus (acari: ixodidae) and borrelia burgdorferi on the sutter buttes of california.birds from 45 species were sampled during three spring seasons from an isolated canyon on the sutter buttes in california for the presence of subadult stages of ixodes pacificus cooley & kohls, and for infection with borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner. these birds were found to have an infestation prevalence of 45%, a density of 1.7 ticks per bird, and an intensity of 3.8 ticks per infested bird. there was a significant difference in the i. pacificus infestations b ...200616619623
geographical distribution patterns and habitat suitability models for presence of host-seeking ixodid ticks in dense woodlands of mendocino county, california.we used drag sampling to examine the geographical distribution patterns of ixodid ticks engaging in open (non-nidicolous) host-seeking behavior in dense woodland habitats of the climatically and ecologically diverse mendocino county in north coastal california. the findings based on this sampling methodology reflect risk of human exposure to host-seeking ticks rather than the true distribution of the ticks. drag sampling in 78 sites yielded 7,860 nymphal or adult ixodes pacificus cooley & kohls, ...200616619628
sylvatic maintenance of borrelia burgdorferi (spirochaetales) in northern california: untangling the web of transmission.lyme borreliosis is associated with several genospecies of borrelia burgdorferi sensu lato (s.l.) (spirochaetales), but human disease has been associated only with borrelia burgdorferi sensu stricto (s.s.) johnson, schmid, hyde, steigerwalt & brenner in the western united states. restriction fragment length polymorphism (rflp) analysis of rrf-rrl amplicons from 124 tick and mammalian isolates from various habitats yielded 13 rflp patterns. of these patterns, six were patterns previously associat ...200616892634
refractoriness of the western fence lizard (sceloporus occidentalis) to the lyme disease group spirochete borrelia bissettii.the western fence lizard, sceloporus occidentalis, is refractory to experimental infection with borrelia burgdorferi sensu stricto, one of several lyme disease spirochetes pathogenic for humans. another member of the lyme disease spirochete complex, borrelia bissettii, is distributed widely throughout north america and a similar, if not identical, spirochete has been implicated as a human pathogen in southern europe. to determine the susceptibility of s. occidentalis to b. bissettii, 6 naïve liz ...200616995383
spatial patterns of lyme disease risk in california based on disease incidence data and modeling of vector-tick exposure.ixodes pacificus, particularly the nymphal life stage, is the primary vector to humans of the lyme disease agent borrelia burgdorferi in california. during 2004, we collected i. pacificus nymphs from 78 woodland sites in ecologically diverse mendocino county, which has a moderately high incidence of lyme disease. within this county, nymphal density was elevated in forested areas with a growing degree day range of 2,600-3,000 (10 degrees c base). using a geographic information systems approach, w ...200617038692
ectoparasite diversity and exposure to vector-borne disease agents in wild rodents in central coastal california.a survey of wild rodents was performed in the morro bay area of central coastal california to determine serological and polymerase chain reaction (pcr) prevalence of anaplasma phagocytophilum dumler, barbet, bekker, dasch, palmer, ray, rikihisa, and rurangirwa, borrelia burgdorferi johnson, schmidt, hyde, steigerwalt, and brenner, francisella tularensis mccoy, and yersinia pestis yersin; to describe the ectoparasitic fauna on important vector-borne disease hosts; and to determine whether pathoge ...200717427705
lyme disease in oregon.the incidence of lyme disease in oregon is calculated from cases reported to the oregon state health division. we reviewed the exposure history of reported cases of lyme disease and performed field surveys for infected ixodes pacificus ticks. the incidence of lyme disease correlated with the distribution of infected i. pacificus ticks.200818448697
effect of prescribed fire for tick control in california chaparral.prescribed fire was investigated as a method for controlling ixodid and argasid ticks in chaparral habitats in northern california. two experimental and two adjacent control plots within a wildlife preserve were monitored for 1 yr postburn. ticks were collected by flagging vegetation, by co2-baited pitfall trap, and by live-trapping rodents. twice as many rodents were caught at control sites compared with burn sites and no dusky-footed woodrats, neotoma fuscipes baird, were found in the treatmen ...200919769046
molecular identification of salp15, a key salivary gland protein in the transmission of lyme disease spirochetes, from ixodes persulcatus and ixodes pacificus (acari: ixodidae).salp15 is a multifunctional protein, vital to the tick in its need to obtain vertebrate host blood without stimulating a host inflammatory and immune response. the salpl5 protein from both ixodes scapularis say and ixodes ricinus (l.), the principal vectors of the lyme disease spirochete in eastern north america and europe, respectively, have been well characterized and found to bind the murine cd4 receptor, dc-sign, and the ospc protein of borrelia burgdorferi. in the current study, we characte ...200919960697
ecological niche modeling of lyme disease in british columbia, canada.the purpose of this study was to describe the geographic distribution and model the ecological niche for borrelia burgdorferi (johnson, schmidt, hyde, steigerwaldt & brenner), ixodes pacificus (cooley & kohls), and ixodes angustus (neumann), the bacterium and primary tick vectors for lyme disease, in british columbia (bc), canada. we employed a landscape epidemiology approach using geographic information systems mapping and ecological niche modeling (genetic algorithm for rule-set prediction) to ...201020180315
community ecology and disease risk: lizards, squirrels, and the lyme disease spirochete in california, usa.vector-borne zoonotic diseases are often maintained in complex transmission cycles involving multiple vertebrate hosts and their arthropod vectors. in the state of california, u.s.a., the spirochete borrelia burgdorferi, which causes lyme disease, is transmitted between vertebrate hosts by the western black-legged tick, ixodes pacificus. several mammalian species serve as reservoir hosts of the spirochete, but levels of tick infestation, reservoir competence, and borrelia-infection prevalence va ...201020380218
transmission cycles of borrelia burgdorferi and b. bissettii in relation to habitat type in northwestern california.this study was undertaken to determine which rodent species serve as primary reservoirs for the lyme disease spirochete borrelia burgdorferi in commonly occurring woodland types in inland areas of northwestern california, and to examine whether chaparral or grassland serve as source habitats for dispersal of b. burgdorferi- or b. bissettii-infected rodents into adjacent woodlands. the western gray squirrel (sciurus griseus) was commonly infected with b. burgdorferi in oak woodlands, whereas exam ...200920514140
effects of an invasive forest pathogen on abundance of ticks and their vertebrate hosts in a california lyme disease focus.invasive species, including pathogens, can have important effects on local ecosystems, including indirect consequences on native species. this study focuses on the effects of an invasive plant pathogen on a vertebrate community and ixodes pacificus, the vector of the lyme disease pathogen (borrelia burgdorferi) in california. phytophthora ramorum, the causative agent of sudden oak death, is a non-native pathogen killing trees in california and oregon. we conducted a multi-year study using a grad ...201020941513
impact of the experimental removal of lizards on lyme disease risk.the distribution of vector meals in the host community is an important element of understanding and predicting vector-borne disease risk. lizards (such as the western fence lizard; sceloporus occidentalis) play a unique role in lyme disease ecology in the far-western united states. lizards rather than mammals serve as the blood meal hosts for a large fraction of larval and nymphal western black-legged ticks (ixodes pacificus-the vector for lyme disease in that region) but are not competent reser ...201121325326
differences in prevalence of borrelia burgdorferi and anaplasma spp. infection among host-seeking dermacentor occidentalis, ixodes pacificus, and ornithodoros coriaceus ticks in northwestern california.previous studies revealed that the pacific coast tick (dermacentor occidentalis) is infected occasionally with the agents of lyme disease (borrelia burgdorferi) or human granulocytic anaplasmosis (anaplasma phagocytophilum) and that it is an inefficient experimental vector of b. burgdorferi. the relationship of the pajahuello tick (ornithodoros coriaceus) to each of these bacterial zoonotic agents has not been reported. the primary bridging vector of both bacterial zoonotic agents to humans is t ...201021359090
influence of abiotic and environmental factors on the density and infection prevalence of ixodes pacificus (acari:ixodidae) with borrelia burgdorferi.the abiotic and biotic factors that govern the spatial distribution of lyme disease vectors are poorly understood. this study addressed the influence of abiotic and biotic environmental variables on ixodes pacificus cooley & kohls (acari:ixodidae) nymphs, because it is the primary vector of borrelia burgdorferi johnson, schmidt, hyde, steigerwaldt & brenner in the far-western united states. three metrics of lyme disease risk were evaluated: the density of nymphs, the density of infected nymphs, ...201121337944
coinfection of western gray squirrel (sciurus griseus) and other sciurid rodents with borrelia burgdorferi sensu stricto and anaplasma phagocytophilum in california.overlapping geographic distributions of tick-borne disease agents utilizing the same tick vectors are common, and coinfection of humans, domestic animals, wildlife, and ticks with both borrelia burgdorferi and anaplasma phagocytophilum has been frequently reported. this study was undertaken in order to evaluate the prevalence of both b. burgdorferi sensu stricto (hereinafter referred to as b. burgdorferi) and a. phagocytophilum in several species of sciurid rodents from northern california, usa. ...201020090047
distribution of the lyme disease spirochete borrelia burgdorferi in naturally and experimentally infected western gray squirrels (sciurus griseus).the dynamics of borrelia burgdorferi infections within its natural hosts are poorly understood. we necropsied four wild-caught western gray squirrels (sciurus griseus) that were acquired during a previous study that evaluated the reservoir competence of this rodent for the lyme disease spirochete. one animal was infected experimentally, whereas the others were infected in the wild before capture. to investigate dissemination of b. burgdorferi and concurrent histopathologic lesions in different t ...201020017717
delineation of a new species of the borrelia burgdorferi sensu lato complex, borrelia americana sp. nov.analysis of borrelia isolates collected from ticks, birds, and rodents from the southeastern united states revealed the presence of well-established populations of borrelia burgdorferi sensu stricto, borrelia bissettii, borrelia carolinensis, and borrelia sp. nov. multilocus sequence analysis of five genomic loci from seven samples representing borrelia sp. nov. isolated from nymphal ixodes minor collected in south carolina showed their close relatedness to california strains known as genomospec ...200919846628
population structure of the lyme borreliosis spirochete borrelia burgdorferi in the western black-legged tick (ixodes pacificus) in northern california.factors potentially contributing to the lower incidence of lyme borreliosis (lb) in the far-western than in the northeastern united states include tick host-seeking behavior resulting in fewer human tick encounters, lower densities of borrelia burgdorferi-infected vector ticks in peridomestic environments, and genetic variation among b. burgdorferi spirochetes to which humans are exposed. we determined the population structure of b. burgdorferi in over 200 infected nymphs of the primary bridging ...200919783741
identifying the reservoir hosts of the lyme disease spirochete borrelia burgdorferi in california: the role of the western gray squirrel (sciurus griseus).we investigated the role of the western gray squirrel (sciurus griseus) as a reservoir host of the lyme disease spirochete borrelia burgdorferi. a survey of 222 western gray squirrels in california showed an overall prevalence of b. burgdorferi infection of 30%, although at a county level, prevalence of infection ranged from 0% to 50% by polymerase chain reaction. laboratory trials with wild-caught western gray squirrels indicated that squirrels were competent reservoir hosts of the lyme disease ...200818840740
spatial dynamics of lyme disease: a review.lyme disease (ld), the most frequently reported vector-borne disease in the united states, requires that humans, infected vector ticks, and infected hosts all occur in close spatial proximity. understanding the spatial dynamics of ld requires an understanding of the spatial determinants of each of these organisms. we review the literature on spatial patterns and environmental correlates of human cases of ld and the vector ticks, ixodes scapularis in the northeastern and midwestern united states ...200818787920
diagnosis and treatment of lyme disease.lyme disease is the most common tick-borne disease in the united states. this review details the risk factors, clinical presentation, treatment, and prophylaxis for the disease. information was obtained from a search of the pubmed and medline databases (keyword: lyme disease) for articles published from august 31, 1997, through september 1, 2007. approximately 20,000 cases of lyme disease are reported annually. residents of the coastal northeast, northwest california, and the great lakes region ...200818452688
host-seeking behavior of ixodes pacificus (acari: ixodidae) nymphs in relation to environmental parameters in dense-woodland and woodland-grass habitats.in the far-western united states, the bacteria that cause lyme disease (borrelia burgdorferi, bb) and human granulocytic anaplasmosis (anaplasma phagocytophilum, ap) are transmitted by the western black-legged tick (ixodes pacificus). in a dense woodland, human behaviors involving contact with wood were recently found to pose greater risk for encountering i. pacificus nymphs than behaviors entailing exclusive exposure to leaf litter. a four-year follow-up study was undertaken in the same woodlan ...200718260527
wild turkey (meleagris gallopavo) as a host of ixodid ticks, lice, and lyme disease spirochetes (borrelia burgdorferi sensu lato) in california state parks.rio grande wild turkeys (meleagris gallopavo intermedia) were evaluated as potential hosts of ixodid ticks, lice, and lyme disease spirochetes (borrelia burgdorferi sensu lato [s.l.]) in three state parks in sonoma county, california, usa, during 2003 and 2004. in total, 113 birds were collected, 50 (44.2%) of which were found to be infested by 361 ixodid ticks representing three species: the western black-legged tick (ixodes pacificus, n=248), the rabbit tick (haemaphysalis leporispalustris, n= ...200617255442
migratory songbirds disperse ticks across canada, and first isolation of the lyme disease spirochete, borrelia burgdorferi, from the avian tick, ixodes auritulus.during a 3-yr comprehensive study, 196 ixodid ticks (9 species) were collected from 89 passerine birds (32 species) from 25 localities across canada to determine the distribution of avian-associated tick species and endogenous lyme disease spirochetes, borrelia burgdorferi johnson, schmid, hyde, steigerwalt, and brenner. we report the following first records of tick parasitism on avian hosts: the rabbit-associated tick, ixodes dentatus marx, from manitoba and ontario; the mouse tick, ixodes muri ...200517089744
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