| 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 ... | 1991 | 1941942 |
| 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 ... | 1989 | 2769705 |
| 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 ... | 1995 | 7573703 |
| 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 ... | 1996 | 8748276 |
| 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 ... | 1997 | 9291589 |
| 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 ... | 1996 | 8780455 |
| 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 ... | 1996 | 8667381 |
| 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 ... | 2003 | 14680123 |
| 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 ... | 1996 | 8651378 |
| 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 ... | 1993 | 8510115 |
| 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 ... | 1993 | 8308101 |
| 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 ... | 2004 | 15311473 |
| 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 ... | 1985 | 3898886 |
| 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 ... | 1986 | 3554845 |
| 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 ... | 1987 | 3323225 |
| 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 ... | 2005 | 15857659 |
| 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, ... | 2005 | 15962792 |
| 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. | 2006 | 16584332 |
| 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 ... | 1988 | 3263826 |
| 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 ... | 1989 | 2685030 |
| 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 ... | 1990 | 2332468 |
| 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 ... | 1990 | 2280384 |
| 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 ... | 1991 | 1875357 |
| 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 ... | 1992 | 1604318 |
| 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 ... | 2007 | 17427705 |
| 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 ... | 1992 | 1524146 |
| 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 ... | 2001 | 11780813 |
| 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 ... | 2001 | 11693866 |
| 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 ... | 2009 | 19846628 |
| 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, ... | 2001 | 11534638 |
| 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 ... | 2000 | 11126549 |
| 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 ... | 2010 | 20380218 |
| 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 ... | 2000 | 11037789 |
| 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 ... | 1999 | 10586924 |
| 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 ... | 1999 | 10583539 |
| 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, ... | 2011 | 21337944 |
| 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 ... | 1999 | 10581712 |
| 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 ... | 1999 | 10577716 |
| 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 ... | 1997 | 9220679 |
| 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 ... | 2001 | 12653148 |
| 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 ... | 2003 | 14714665 |
| 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 ... | 2004 | 15009444 |
| 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 ... | 2004 | 15061284 |
| 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 ... | 2004 | 15347025 |
| 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. ... | 2005 | 15691012 |
| 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 ... | 2004 | 15709249 |
| 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 ... | 2006 | 16606998 |
| 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 ... | 2006 | 16619623 |
| 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, ... | 2006 | 16619628 |
| 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 ... | 2006 | 16892634 |
| 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 ... | 2006 | 17038692 |
| 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 ... | 2009 | 19783741 |
| 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. ... | 2010 | 20090047 |
| horizontal and vertical movements of host-seeking ixodes pacificus (acari: ixodidae) nymphs in a hardwood forest. | the nymph of the western black-legged tick (ixodes pacificus) is an important bridging vector of the lyme disease spirochete (borrelia burgdorferi) to humans in the far-western united states. the previously unknown dispersal capabilities of this life stage were studied in relation to logs, tree trunks, and adjacent leaf-litter areas in a mixed hardwood forest using mark-release-recapture methods. in two spatially and temporally well-spaced trials involving logs, the estimated mean distances that ... | 2009 | 20352083 |
| 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 ... | 2009 | 20514140 |
| a spatially-explicit model of acarological risk of exposure to borrelia burgdorferi-infected ixodes pacificus nymphs in northwestern california based on woodland type, temperature, and water vapor. | in the far-western united states, the nymphal stage of the western black-legged tick, ixodes pacificus, has been implicated as the primary vector to humans of borrelia burgdorferi sensu stricto (hereinafter referred to as b. burgdorferi), the causative agent of lyme borreliosis in north america. in the present study, we sought to determine if infection prevalence with b. burgdorferi in i. pacificus nymphs and the density of infected nymphs differ between dense-woodland types within mendocino cou ... | 2010 | 20532183 |
| 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 ... | 2010 | 20941513 |
| 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 ... | 2010 | 21359090 |
| 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= ... | 2006 | 17255442 |
| 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 ... | 2008 | 18452688 |
| 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 ... | 2009 | 19769046 |