| isolation of spotted fever group and wolbachia-like agents from field-collected materials by means of plaque formation in mammalian and mosquito cells. | three isolations from ticks (dermacentor occidentalis) of a rickettsia of the spotted fever group and 5 isolations from chipmunk (eutamias rugicaudus) blood of a wolbachia-like agent were obtained from plaques formed in singh's aedes albopictus (mosquito) and vero (african green monkey kidney) cell cultures. these organisms could not be isolated by injection of the infected ticks or blood into embryonated chicken eggs, guinea pigs, or voles (microtus pennsylvanicus), but fluid cultures of grace' ... | 1975 | 241251 |
| the distribution in oregon of ixodes pacificus, dermacentor andersoni, and dermacentor occidentalis with a note on dermacentor variabilis (acarina: ixodidae). | | 1977 | 845890 |
| distribution of suspected tick vectors and reported cases of rocky mountain spotted fever in california. | evidence is presented for an area of human risk to rocky mountain spotted fever (rmsf) in california extending beyond the range of its classic tick vector, dermacentor andersoni. geographic, seasonal, and host distributions of dermacentor variabilis and dermacentor occidentalis suggest these species as potential vectors of rmsf in california outside the range of dermacentor andersoni. | 1976 | 961695 |
| 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 |
| parasitic and phoretic arthropods of the elephant-eared and the santa cruz kangaroo rats. | the parasitic and phoretic arthropods of the elephant-eared kangaroo rat (dipodomys elephantinus) and santa cruz kangaroo rat (d. venustus) are reported; most of these represent new host records. thirteen of 14 (93%) of d. elephantinus and 11 of 12 (92%) of d. venustus had 11 and nine arthropod species, respectively. larval and nymphal stages of the tick dermacentor occidentalis were the most prevalent parasite (77%) on d. elephantinus whereas the mesostigmatid mite androlaelaps fahrenholzi was ... | 1991 | 2067062 |
| 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 |
| spirochetes in mammals and ticks (acari: ixodidae) from a focus of lyme borreliosis in california. | in northern california, antibodies to borrelia burgdorferi were detected in 58 of 73 (79%), and spirochetemias in one of 26 (4%) black-tailed jackrabbits (lepus californicus californicus), by indirect and direct immunofluorescence, respectively. five species of ticks (dermacentor occidentalis, d. parumapertus, ixodes neotomae, i. pacificus, and haemaphysalis leporispalustris) were collected from rabbits. two of these species of ticks were found to contain spirochetes; two of 10 (20%) i. neotomae ... | 1988 | 3280837 |
| diurnal host seeking of adult pacific coast ticks, dermacentor occidentalis (acari: ixodidae), in relation to vegetational type, meteorological factors, and rickettsial infection rates in california, usa. | | 1985 | 3930742 |
| cytogenetics of ticks (acari: ixodoidea). 7. spermatogenesis in the pacific coast tick, dermacentor occidentalis marx (ixodidae). | | 1972 | 4553961 |
| studies of the role of dermacentor occidentalis in the transmission of bovine chlamydial abortion. | dermacentor occidentalis nymphal ticks were successfully infected with the agent of bovine chlamydial abortion. multiplication of the agent was shown to occur during nymphal engorgement, but chlamydial isolations were not made from nymphal ticks after detachment or during subsequent metamorphosis. primary tissue cultures of nymphal viscera infected in vitro or in vivo failed to demonstrate chlamydial replication. | 1973 | 4735374 |
| reproduction in ticks (acari: ixodoidea). 3. copulation in dermacentor occidentalis marx and haemaphysalis leporispalustris (packard) (ixodidae). | | 1974 | 4833860 |
| serotypes of tick-borne spotted fever group rickettsiae from western california. | a rickettsial survey of ixodid ticks known to bite man was conducted in 1979 in four coastal counties of california to obtain isolates from tick species that might be involved in the transmission of spotted fever-like illnesses, and to examine serologic characteristics of the rickettsiae relative to defined members of the spotted fever group (sfg). one hundred and seventy (19.4%) of 877 ticks comprising three species were shown by hemolymph test to harbor rickettsia-like organisms. a total of 85 ... | 1981 | 6789691 |
| diel activity of nymphal dermacentor occidentalis and ixodes pacificus (acari: ixodidae) in relation to meteorological factors and host activity periods. | relation of diel activity and questing behavior of nymphal dermacentor occidentalis marx and ixodes pacificus cooley & kohls to meteorological factors was investigated in a shaded versus a sun-exposed outdoor arena. oak-woodland soil covered partially with leaf litter and small rocks, and 24 vertically oriented grass stems 2.5, 5.0, 10.0, and 20.0 cm tall were provided as substrate and potential questing sites. tick activity and weather conditions were monitored bihourly during 15 diel (24-h) ex ... | 1995 | 7616519 |
| 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 ... | 1994 | 8057316 |
| 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 |
| 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 |
| 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 |
| ehrlichia phagocytophila genogroup rickettsiae in ixodid ticks from california collected in 1995 and 1996. | a total of 1,246 ixodid ticks collected in 1995 and 1996 from seven california counties were examined for the presence of ehrlichia phagocytophila genogroup rickettsiae by using a nested pcr technique. of 1,112 adult ixodes pacificus cooley and kohls ticks tested, nine pools, each containing five ticks, were positive (minimum percentage of ticks harboring detectable ehrlichiae, 0.8%). positive ticks were limited to four of the seven counties (sonoma, el dorado, santa cruz, and orange). in santa ... | 1997 | 9230373 |
| optimal sampling and spatial distribution of ixodes pacificus, dermacentor occidentalis and dermacentor variabilis ticks (acari: ixodidae). | a common method for sampling tick populations is flagging, which is a method of dragging a white cloth over a plant substrate for a fixed distance along a transect. flagging over rough physical surfaces or using long subtransect lengths could lead to the underestimation of tick densities. using estimates of the drop-off rates of adult ixodes pacificus in flag sampling, optimal sampling schemes (the length and number of subtransects) were examined using the relationships between the tick drop-off ... | 1998 | 9588010 |
| lethal effect of rickettsia rickettsii on its tick vector (dermacentor andersoni). | rickettsia rickettsii, the causative agent of rocky mountain spotted fever, was lethal for the majority of experimentally and transovarially infected rocky mountain wood ticks (dermacentor andersoni). overall, 94.1% of nymphs infected as larvae by feeding on rickettsemic guinea pigs died during the molt into adults and 88. 3% of adult female ticks infected as nymphs died prior to feeding. in contrast, only 2.8% of uninfected larvae failed to develop into adults over two generations. infected fem ... | 1999 | 9925615 |
| ixodid ticks (acari, ixodidae) found in san diego county, california. | in san diego county, california, 11 species of ixodid ticks were collected from vegetation and/or from small and large mammals, and/or found parasitizing humans. adults of the pacific coast tick, dermacentor occidentalis, were the most abundant tick collected from vegetation, with peak numbers occurring during march and april. adults of the western black-legged tick, ixodes pacificus, were the second most abundant, with peaks occurring during february and march. eight species of ticks were found ... | 1999 | 10436879 |
| dusky-footed wood rats (neotoma fuscipes) as reservoirs of granulocytic ehrlichiae (rickettsiales: ehrlichieae) in northern california. | dusky-footed wood rats (neotoma fuscipes) and peromyscus sp. mice (p. maniculatus and p. truei) were collected from one site in placer county, one site in santa cruz county, and two sites in sonoma county in northern california. serum or plasma samples from 260 rodents were tested for antibodies to the agent of human granulocytic ehrlichiosis. of these, samples from 25 wood rats (34% of those tested) and 10 (8%) peromyscus sp. mice were found to be seropositive, but only those from one site. pcr ... | 1999 | 10488199 |
| q fever. | q fever is a zoonosis with a worldwide distribution with the exception of new zealand. the disease is caused by coxiella burnetii, a strictly intracellular, gram-negative bacterium. many species of mammals, birds, and ticks are reservoirs of c. burnetii in nature. c. burnetii infection is most often latent in animals, with persistent shedding of bacteria into the environment. however, in females intermittent high-level shedding occurs at the time of parturition, with millions of bacteria being r ... | 1999 | 10515901 |
| 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 |
| molecular evidence of bartonella spp. in questing adult ixodes pacificus ticks in california. | ticks are the vectors of many zoonotic diseases in the united states, including lyme disease, human monocytic and granulocytic ehrlichioses, and rocky mountain spotted fever. most known bartonella species are arthropod borne. therefore, it is important to determine if some bartonella species, which are emerging pathogens, could be carried or transmitted by ticks. in this study, adult ixodes pacificus ticks were collected by flagging vegetation in three sites in santa clara county, calif. pcr-res ... | 2001 | 11283031 |
| description and epidemiology of theileria youngi n. sp. from a northern californian dusky-footed woodrat (neotoma fuscipes) population. | an epidemiologic study designed to identify the small mammal reservoir for the zoonotic wa1-type babesial parasite resulted in the discovery of a small, intraerythrocytic piroplasm in smeared blood from dusky-footed woodrats (neotoma fuscipes) in northern california. the woodrat parasites were isolated and compared to other piroplasm parasites based on their morphology, antigenicity, and genetic characteristics. these studies indicated that the woodrat parasites were not the wa1-type babesial ag ... | 2001 | 11318567 |
| investigation of bartonella infection in ixodid ticks from california. | a total of 1253 ixodid ticks (254 tick pools) collected between the end of 1995 and the spring of 1997 from six california counties (el dorado, los angeles, orange, santa cruz, shasta and sonoma) were examined for the presence of bartonella dna by pcr of the citrate synthase gene. of 1,119 adult ixodes pacificus ticks tested, 26 (11.6%) of 224 pools, each containing five ticks, were positive (minimum percentage of ticks harboring detectable bartonella dna, 2.3%). bartonella pcr-positive ticks we ... | 2002 | 12135237 |
| 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 ... | 2002 | 12475082 |
| 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 |
| 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 |
| columbian black-tailed deer (odocoileus hemionus columbianus) as hosts for borrelia spp. in northern california. | the prevalence of infection of columbian black-tailed deer (odocoileus hemionus columbianus) with borrelia spp. was evaluated in an area of northwestern california (usa) where lyme disease is endemic and the relapsing-fever group spirochete borrelia coriaceae is enzootic, and in a far-removed comparison area having a disparate climate and lower density of vector ticks. blood samples collected from both deer herds in 1987, 1988, and from 2000-02 were assayed for borrelial infection with microscop ... | 2005 | 15827217 |
| 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 |
| tick-borne rickettsioses around the world: emerging diseases challenging old concepts. | during most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. an element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. in this context, it was considered that relatively few tick-borne rickettsiae caused human disease. this concept was modified extensively from 1984 through 2005 by the identif ... | 2005 | 16223955 |
| 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 |
| isolation and identification of rickettsia massiliae from rhipicephalus sanguineus ticks collected in arizona. | twenty rhipicephalus sanguineus ticks collected in eastern arizona were tested by pcr assay to establish their infection rate with spotted fever group rickettsiae. with a nested pcr assay which detects a fragment of the rickettsia genus-specific 17-kda antigen gene (htra), five ticks (25%) were found to contain rickettsial dna. one rickettsial isolate was obtained from these ticks by inoculating a suspension of a triturated tick into monolayers of vero e6 monkey kidney cells and xtc-2 clawed toa ... | 2006 | 16885311 |
| isolation of rickettsia rhipicephali and rickettsia bellii from haemaphysalis juxtakochi ticks in the state of são paulo, brazil. | in the present study, attempts to isolate rickettsia in cell culture were performed individually in seven specimens of haemaphysalis juxtakochi ticks collected in the state of são paulo (southeastern brazil). rickettsia was successfully isolated by the shell vial technique and established in vero cell culture from six ticks (six isolates). dna extracted from infected cells of these isolates was tested by pcr and dna sequencing, using genus-specific rickettsia primers targeting the genes glta, ht ... | 2007 | 17142361 |
| 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 |
| molecular typing of isolates of rickettsia rickettsii by use of dna sequencing of variable intergenic regions. | rickettsia rickettsii, the causative agent of rocky mountain spotted fever, is found throughout the americas, where it is associated with different animal reservoirs and tick vectors. no molecular typing system currently exists to allow for the robust differentiation of isolates of r. rickettsii. analysis of eight completed genome sequences of rickettsial species revealed a high degree of sequence conservation within the coding regions of chromosomes in the genus. intergenic regions between codi ... | 2007 | 17553977 |
| life cycles of seven ixodid tick species (acari: ixodidae) under standardized laboratory conditions. | studies of transmission, maintenance, infectivity, virulence, and pathogenicity of tick-borne agents require the use of large numbers of live laboratory-raised ticks. colonies of ixodes scapularis say, ixodes pacificus cooley & kohls, amblyomma americanum (l.), dermacentor occidentalis marx, dermacentor variabilis (say), hemaphysalis leporispalustris (packard), and rhipicephalus sanguineus (latrielle) have been maintained in our laboratory at the centers for disease control and prevention for fi ... | 2007 | 17915502 |
| experimental transmission of bovine anaplasmosis (caused by anaplasma marginale) by means of dermacentor variabilis and d. andersoni (ixodidae) collected in western canada. | canadian cattle are free of bovine anaplasmosis, with the exception of 4 isolated incursions since 1968, which were eradicated. it is not known why the disease has not become established in regions of canada adjacent to the united states where it is endemic. to assess the vector competence of wild-caught ticks in cattle-rearing regions, dermacentor variabilis and d. andersoni were collected in western canada and fed on calves experimentally infected with anaplasma marginale (st. maries strain). ... | 2007 | 17955901 |
| detection and identification of spotted fever group rickettsiae in dermacentor species from southern california. | dermacentor occidentalis marx and dermacentor variabilis (say) commonly bite humans in california. these dermacentor species may play a role in transmitting spotted fever group (sfg) rickettsiae to humans in many parts of the state where dermacentor andersoni stiles, a known vector for the etiologic agent of rocky mountain spotted fever, rickettsia rickettsii, is absent. however, the specific rickettsial agents present in these ticks and their current prevalence are poorly understood. in total, ... | 2008 | 18533446 |
| prevalence of rickettsia species in canadian populations of dermacentor andersoni and d. variabilis. | we determined the prevalence of rickettsiae in dermacentor adults at 15 localities in canada. rickettsia rickettsii was not detected in any tick, whereas rickettsia peacockii was present in 76% of dermacentor andersoni adults and rickettsia montanensis in 8% of dermacentor variabilis adults. this host specificity was maintained in localities where both tick species occurred in sympatry. | 2009 | 19151178 |
| feeding preferences of the immature stages of three western north american ixodid ticks (acari) for avian, reptilian, or rodent hosts. | larval and nymphal ixodes pacificus cooley and kohls, i. (ixodes) jellisoni cooley and kohls, and dermacentor occidentalis marx were tested for host preference when simultaneously presented with a deer mouse (peromyscus maniculatus wagner), california kangaroo rat (dipodomys californicus merriam), western fence lizard (sceloporus occidentalis baird and girard), and california towhee (pipilo crissalis vigors) in an experimental apparatus. differences were observed in the preferences among the thr ... | 2009 | 19198525 |
| ecology of anaplasma phagocytophilum infection in gray foxes (urocyon cinereoargenteus) in northwestern california. | although granulocytic anaplasmosis, caused by infection of anaplasma phagocytophilum, is an emerging human and domestic animal disease, the ecology and natural history of the parasite is not well understood. gray foxes (urocyon cinereoargenteus) are relatively common, occasionally peri-urban mesocarnivores whose geographic distribution overlaps the reported distribution of granulocytic anaplasmosis in humans and domestic animals in north america. we evaluated the potential of foxes as hosts and ... | 2009 | 19395744 |
| transovarial transmission of francisella-like endosymbionts and anaplasma phagocytophilum variants in dermacentor albipictus (acari: ixodidae). | dermacentor albipictus (packard) is a north american tick that feeds on cervids and livestock. it is a suspected vector of anaplasmosis in cattle, but its microbial flora and vector potential remain underevaluated. we screened d. albipictus ticks collected from minnesota white-tailed deer (odocoileus virginianus) for bacteria of the genera anaplasma, ehrlichia, francisella, and rickettsia using polymerase chain reaction (pcr) gene amplification and sequence analyses. we detected anaplasma phagoc ... | 2009 | 19496436 |
| 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 |
| rickettsia 364d: a newly recognized cause of eschar-associated illness in california. | four spotted fever group rickettsiae (sfgr) are known to infect humans in the united states. a member of the sfgr designated 364d and detected in dermacentor occidentalis ticks has not previously been identified as a human pathogen. | 2010 | 20073993 |
| potential for tick-borne bartonelloses. | as worldwide vectors of human infectious diseases, ticks are considered to be second only to mosquitoes. each tick species has preferred environmental conditions and biotopes that determine its geographic distribution, the pathogens it vectors, and the areas that pose risk for tick-borne diseases. researchers have identified an increasing number of bacterial pathogens that are transmitted by ticks, including anaplasma, borrelia, ehrlichia, and rickettsia spp. recent reports involving humans and ... | 2010 | 20202411 |
| 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 |
| absence of rickettsia rickettsii and occurrence of other spotted fever group rickettsiae in ticks from tennessee. | rocky mountain spotted fever (rmsf) is the most common tick-borne illness in tennessee. little is known about the occurrence of r. rickettsii, the causative agent, in ticks in tennessee. to better understand the prevalence and distribution of rickettsial agents in ticks, we tested 1,265 amblyomma, dermacentor, and ixodes adult and nymphal ticks. additionally, we tested 231 amblyomma americanum larvae. ticks were collected from 49 counties from humans, wild animals, domestic canines, and flannel ... | 2010 | 20810834 |
| 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 |
| tick paralysis in australia caused by ixodes holocyclus neumann. | ticks are obligate haematophagous ectoparasites of various animals, including humans, and are abundant in temperate and tropical zones around the world. they are the most important vectors for the pathogens causing disease in livestock and second only to mosquitoes as vectors of pathogens causing human disease. ticks are formidable arachnids, capable of not only transmitting the pathogens involved in some infectious diseases but also of inducing allergies and causing toxicoses and paralysis, wit ... | 2011 | 21396246 |
| association of different genetic types of francisella-like organisms with the rocky mountain wood tick (dermacentor andersoni) and the american dog tick (dermacentor variabilis) from localities near their northern distributional limits. | dermacentor andersoni and dermacentor variabilis from allopatric and sympatric populations near their northern distributional limits were examined for the presence of francisella species using molecular techniques that targeted 373 bp of the 16s ribosomal rna gene. although there was no evidence for the presence of francisella tularensis in any tick, francisella-like endosymbionts (fles) were common in d. andersoni and d. variabilis adults and immatures. a significantly greater proportion of fem ... | 2011 | 22179251 |
| larval keys to the genera of ixodidae (acari) and species of ixodes (latreille) ticks established in california. | in california, hard (ixodidae) ticks transmit at least 8 zoonotic disease agents (1 virus, 6 bacteria, 1 protozoan) to humans or other animals. the correct taxonomic identification of all 3 parasitic stages (larvae, nymphs, adults) of ticks is integral to understanding host-tick associations and disease dynamics, but immature ticks, especially the larvae, can be difficult to identify. here, we present larval keys to the 4 genera of ixodidae (dermacentorkoch, 1844; haemaphysaliskoch, 1844; ixodes ... | 2008 | 20027236 |
| what is the risk for exposure to vector-borne pathogens in united states national parks? | united states national parks attract > 275 million visitors annually and collectively present risk of exposure for staff and visitors to a wide range of arthropod vector species (most notably fleas, mosquitoes, and ticks) and their associated bacterial, protozoan, or viral pathogens. we assessed the current state of knowledge for risk of exposure to vector-borne pathogens in national parks through a review of relevant literature, including internal national park service documents and organismal ... | 2013 | 23540107 |
| lyme disease risk in southern california: abiotic and environmental drivers of ixodes pacificus (acari: ixodidae) density and infection prevalence with borrelia burgdorferi. | tick-borne diseases, particularly lyme disease, are emerging across the northern hemisphere. in order to manage emerging diseases and predict where emergence will likely occur, it is necessary to understand the factors influencing the distribution, abundance and infection prevalence of vector species. in north america, lyme disease is the most common vector-borne disease and is transmitted by blacklegged ticks. this study aimed to explore the abiotic and environmental drivers of density and infe ... | 2017 | 28057067 |
| identification of endosymbionts in ticks by broad-range polymerase chain reaction and electrospray ionization mass spectrometry. | many organisms, such as insects, filarial nematodes, and ticks, contain heritable bacterial endosymbionts that are often closely related to transmissible tickborne pathogens. these intracellular bacteria are sometimes unique to the host species, presumably due to isolation and genetic drift. we used a polymerase chain reaction/electrospray ionization-mass spectrometry assay designed to detect a wide range of vectorborne microorganisms to characterize endosymbiont genetic signatures from amblyomm ... | 2012 | 22897044 |
| the eco-epidemiology of pacific coast tick fever in california. | rickettsia philipii (type strain "rickettsia 364d"), the etiologic agent of pacific coast tick fever (pctf), is transmitted to people by the pacific coast tick, dermacentor occidentalis. following the first confirmed human case of pctf in 2008, 13 additional human cases have been reported in california, more than half of which were pediatric cases. the most common features of pctf are the presence of at least one necrotic lesion known as an eschar (100%), fever (85%), and headache (79%); four ca ... | 2016 | 27706171 |
| the recent evolution of a maternally-inherited endosymbiont of ticks led to the emergence of the q fever pathogen, coxiella burnetii. | q fever is a highly infectious disease with a worldwide distribution. its causative agent, the intracellular bacterium coxiella burnetii, infects a variety of vertebrate species, including humans. its evolutionary origin remains almost entirely unknown and uncertainty persists regarding the identity and lifestyle of its ancestors. a few tick species were recently found to harbor maternally-inherited coxiella-like organisms engaged in symbiotic interactions, but their relationships to the q fever ... | 2015 | 25978383 |
| virus discovery using tick cell lines. | while ticks have been known to harbor and transmit pathogenic arboviruses for over 80 years, the application of high-throughput sequencing technologies has revealed that ticks also appear to harbor a diverse range of endogenous tick-only viruses belonging to many different families. almost nothing is known about these viruses; indeed, it is unclear in most cases whether the identified viral sequences are derived from actual replication-competent viruses or from endogenous virus elements incorpor ... | 2016 | 27679414 |
| update on tick-borne rickettsioses around the world: a geographic approach. | tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus rickettsia. these zoonoses are among the oldest known vector-borne diseases. however, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. several species of tick-borne rickettsiae that wer ... | 0 | 24092850 |
| expanding range of amblyomma americanum and simultaneous changes in the epidemiology of spotted fever group rickettsiosis in the united states. | spotted fever group (sfg) rickettsia species are etiologic agents of a wide range of human infections from asymptomatic or mild infections to severe, life-threatening disease. in the united states, recent passive surveillance for sfg rickettsiosis shows an increased incidence and decreased severity of reported cases. the reasons for this are not well understood; however, we hypothesize that less pathogenic rickettsiae are causing more human infections, while the incidence of disease caused by mo ... | 2015 | 26503270 |
| seroepidemiologic study of human infections with spotted fever group rickettsiae in north carolina. | increasing entomologic and epidemiologic evidence suggests that spotted fever group rickettsiae (sfgr) other than rickettsia rickettsii are responsible for spotted fever rickettsioses in the united states. a retrospective seroepidemiologic study was conducted on stored acute- and convalescent-phase sera that had been submitted for rocky mountain spotted fever testing to the north carolina state laboratory of public health. we evaluated the serologic reactivity of the paired sera to r. rickettsii ... | 2014 | 25187639 |
| an insight into the microbiome of the amblyomma maculatum (acari: ixodidae). | the aim of this study was to survey the bacterial diversity of amblyomma maculatum koch, 1844, and characterize its infection with rickettsia parkeri. pyrosequencing of the bacterial 16s rrna was used to determine the total bacterial population in a. maculatum. pyrosequencing analysis identified rickettsia in a. maculatum midguts, salivary glands, and saliva, which indicates successful trafficking in the arthropod vector. the identity of rickettsia spp. was determined based on sequencing the ric ... | 0 | 24605461 |
| investigation of anaplasma marginale seroprevalence in a traditionally managed large california beef herd. | recent observations by stakeholders suggested that ecosystem changes may be driving an increased incidence of bovine erythrocytic anaplasmosis, resulting in a reemerging cattle disease in california. the objective of this prospective cohort study was to estimate the incidence of anaplasma marginale infection using seroconversion in a northern california beef cattle herd. a total of 143 black angus cattle (106 prebreeding heifers and 37 cows) were enrolled in the study. serum samples were collect ... | 2016 | 27656312 |
| diversity of rickettsial pathogens in columbian black-tailed deer and their associated keds (diptera: hippoboscidae) and ticks (acari: ixodidae). | cervids host multiple species of ixodid ticks, other ectoparasites, and a variety of rickettsiae. however, diagnostic test cross-reactivity has precluded understanding the specific role of deer in rickettsial ecology. in our survey of 128 columbian black-tailed deer (odocoileus hemionus columbianus (richardson)) and their arthropod parasites from two northern californian herds, combined with reports from the literature, we identified four distinct anaplasma spp. and one ehrlichia species. two ke ... | 2016 | 27232123 |
| eco-epidemiological factors contributing to the low risk of human exposure to ixodid tick-borne borreliae in southern california, usa. | little is known about the eco-epidemiology of lyme disease in southern california, a region where the incidence is much lower than it is in northern california. here, we sought to discover the previously unknown microhabitats of nymphs of the primary vector, the western black-legged tick (ixodes pacificus), in 3 moderately to heavily-utilized state parks in the santa monica mountains in los angeles county; to elucidate the seasonal distribution and abundance of adults of i. pacificus and another ... | 2013 | 23643357 |
| manual for maintenance of multi-host ixodid ticks in the laboratory. | use of laboratory animals as hosts for blood-sucking arthropods remains a time-proven and the most efficient method for establishment and propagation of slowly feeding ixodid ticks, despite introduction of techniques involving artificial feeding on either animal skins or synthetic membranes. new zealand white rabbits are usually the most accessible and most suitable hosts routinely used for establishment and maintenance of a large variety of multi-host tick species. here we describe standard pro ... | 2016 | 27651325 |
| metagenomic-based surveillance of pacific coast tick dermacentor occidentalis identifies two novel bunyaviruses and an emerging human ricksettsial pathogen. | an increasing number of emerging tick-borne diseases has been reported in the united states since the 1970s. using metagenomic next generation sequencing, we detected nucleic acid sequences from 2 novel viruses in the family bunyaviridae and an emerging human rickettsial pathogen, rickettsia philipii, in a population of the pacific coast tick, dermacentor occidentalis in mendocino county sampled annually from 2011 to 2014. a total of 250 adults of this human-biting, generalist tick were collecte ... | 2017 | 28947798 |
| endosymbiont interference and microbial diversity of the pacific coast tick, dermacentor occidentalis, in san diego county, california. | the pacific coast tick, dermacentor occidentalis marx, is found throughout california and can harbor agents that cause human diseases such as anaplasmosis, ehrlichiosis, tularemia, rocky mountain spotted fever and rickettsiosis 364d. previous studies have demonstrated that nonpathogenic endosymbiotic bacteria can interfere with rickettsia co-infections in other tick species. we hypothesized that within d. occidentalis ticks, interference may exist between different nonpathogenic endosymbiotic or ... | 2017 | 28503372 |