| seroepidemiologic survey of antibodies to ehrlichia equi in horses of northern california. | the prevalence of antibodies to ehrlichia equi in horses from the foothill regions of northern california and from the sacramento valley (non-foothill area) was determined, using an indirect fluorescent antibody test. horses from foothill regions had a higher prevalence of seropositivity (10.4%) and higher titer (1:10 to 1:80) than did those from non-foothill regions (3.1%; titer less than or equal to 1:10). fifty percent of healthy horses on a foothill farm enzootic for e equi had titer to e eq ... | 1990 | 2195000 |
| equine ehrlichiosis in northern california: 49 cases (1968-1981). | case records of horses with equine ehrlichiosis (ehrlichia equi) at the university of california veterinary medical teaching hospital and ackerman creek large animal clinic were analyzed for evaluation of clinical signs, time of onset, hematologic values, response to treatment, and recovery. equine ehrlichiosis was found to be seasonal in horses in the foothills of northern california, with higher incidence than reported previously. the horses developed fever, anorexia, depression, limb edema, i ... | 1987 | 3558086 |
| infection in two dogs with an agent resembling ehrlichia equi. | | 1982 | 7061334 |
| evidence for a high rate of false-positive results with the indirect fluorescent antibody test for ehrlichia risticii antibody in horses. | the original objective was to determine seroprevalence of ehrlichia risticii antibody among horses in california. on the basis of the unexpected results of the survey, an investigation into the accuracy and reproducibility of results of the indirect fluorescent antibody (ifa) test for e risticii was carried out. | 1995 | 7493874 |
| human granulocytic ehrlichiosis: report of a case in northern california. | | 1996 | 8879806 |
| seroepidemiology of emerging tickborne infectious diseases in a northern california community. | a seroprevalence and risk factor study of emerging tickborne infectious diseases (lyme disease, ehrlichiosis, and babesiosis) was conducted among 230 residents of a semirural community in sonoma county, california. over 50% of residents reported finding a tick on themselves in the preceding 12 months. samples from 51(23%) residents were seroreactive to antigens from one or more tickborne disease agents: 1.4% to borrelia burgdorferi, 0.4% to ehrlichia equi, 4.6% to ehrlichia chaffeensis, and 17.8 ... | 1997 | 9180183 |
| 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 |
| serologic evidence of infection with ehrlichia spp. in wild rodents (muridae: sigmodontinae) in the united states. | rodent (muridae: sigmodontinae) blood and sera collected from 14 states were tested for seroreactivity to a cultured isolate of the human granulocytic ehrlichiosis (hge) agent by using an indirect immunofluorescence assay. of the 1,240 samples tested, 136 (11%) were found to be reactive at titers of > or = 32. rodents with hge agent-specific antibodies were found in new york (23% of 491 samples; geometric mean endpoint titer [gmt] = 441), connecticut (11% of 100 samples; gmt = 481), california ( ... | 1998 | 9508298 |
| experimental transmission of ehrlichia equi to horses through naturally infected ticks (ixodes pacificus) from northern california. | we report the experimental transmission of ehrlichia equi from naturally infected ixodes pacificus ticks to horses. three weeks after exposure to ticks, two of three horses developed clinical signs compatible with e. equi infection, while one horse remained asymptomatic. 16s rrna gene pcr of blood leukocyte lysates was positive for all horses at various time points; two horses seroconverted. the 16s rrna gene sequences amplified from tick-exposed horses showed more than 99% homology to correspon ... | 1998 | 9650983 |
| detection of ehrlichia risticii, the agent of potomac horse fever, in freshwater stream snails (pleuroceridae: juga spp.) from northern california. | ehrlichia dna was identified by nested pcr in operculate snails (pleuroceridae: juga spp.) collected from stream water in a northern california pasture in which potomac horse fever (phf) is enzootic. sequencing of pcr-amplified dna from a suite of genes (the 16s rrna, groesl heat shock operon, 51-kda major antigen genes) indicated that the source organism closely resembled ehrlichia risticii, the causative agent of phf. the minimum percentage of juga spp. harboring the organism in the population ... | 1998 | 9687446 |
| ehrlichia spp. in cervids from california. | blood samples from six mule deer (odocoileus hemionus hemionus), 15 black-tailed deer (o. hemionus columbianus), and 29 elk (cervus elaphus nannodes) were assayed for human monocytic and human granulocytic ehrlichiosis (hge) by polymerase chain reaction (pcr), dna sequencing, and serology to determine whether or not cervids are involved in the maintenance of these potential human pathogens in california (usa). the deer were sampled in august to october 1992-95. the 29 tule elk from point reyes n ... | 1998 | 9813842 |
| reactivity of human sera to different strains of granulocytic ehrlichiae in immunodiagnostic assays. | sera from 35 patients diagnosed with human granulocytic ehrlichiosis in connecticut were tested by indirect ifa staining methods with 5 strains of ehrlichia equi or the human granulocytic ehrlichiosis agent to assess the suitability of different strains in laboratory analyses. antigens included horse-derived infected neutrophils (mrk and bds strains) and human isolates cultured in human promyelocytic leukemia cells (nch-1, rch, and webster). of 35 sera, 23 (65.7%) reacted to all 5 strains. serop ... | 1998 | 9815246 |
| detection of the agents of human ehrlichioses in ixodid ticks from california. | a study was conducted in northern california to estimate the prevalence and distribution in ixodid ticks of the rickettsial agents of human monocytic (hme) and human granulocytic (hge) ehrlichioses. more than 650 ixodid ticks were collected from 17 sites in six california counties over a 15-month period. ehrlichia chaffeensis, the causative agent of hme, was detected by a nested polymerase chain reaction (pcr) in ixodes pacificus (minimum infection rate [mir] = 13.3%) and dermacentor variabilis ... | 1999 | 9988324 |
| human granulocytic ehrlichiosis in northern california: two case descriptions with genetic analysis of the ehrlichiae. | we report two cases of human granulocytic ehrlichiosis (hge) that occurred in northern california in summer 1998. patients had fever, malaise, and myalgia, reported tick bites, had moderate thrombocytopenia, and had normal or slightly elevated liver enzyme activities. ehrlichial inclusions were observed in the blood of one patient, and hge-agent dna was amplified by pcr from both patients. genetically, the strains resembled horse isolates from northern california. the close spatial and temporal ... | 1999 | 10476747 |
| 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 |
| association of ixodes pacificus (acari: ixodidae) with the spatial and temporal distribution of equine granulocytic ehrlichiosis in california. | this study was conducted to determine if the biology of certain ticks associated with horses regulates the spatial and temporal distribution of equine granulocytic ehrlichiosis (ege) in california north of monterey county. we compared the spatial and temporal distribution of ege cases with the seasons of activity and life histories of ticks that infest horses. spatially, cases collected from equine veterinarians clustered around each other in a manner different from the way in which control citi ... | 1999 | 10534948 |
| granulocytic ehrlichiosis and tick infestation in mountain lions in california. | forty-seven mountain lions (puma concolor) collected year-round in 1996 to 1998 from the sierra nevada foothills, the northern coast ranges, and in monterey county (california, usa) were examined for infestation with ixodes pacificus and dermacentor variabilis ticks. ticks were found predominantly in winter and spring. the seroprevalence of granulocytic ehrlichiae (ge) antibodies (ehrlichia equi or the agent of human granulocytic ehrlichiosis) was 17% and the pcr-prevalence of dna characteristic ... | 1999 | 10574529 |
| comparison of the nucleotide sequences of 16s rrna, 444 ep-ank, and groesl heat shock operon genes in naturally occurring ehrlichia equi and human granulocytic ehrlichiosis agent isolates from northern california. | we examined 11 naturally occurring isolates of ehrlichia equi in horses and two human granulocytic ehrlichiosis agent isolates in california for sequence diversity in three genes. ehrlichia equi isolates were from sierra (n = 6), mendocino (n = 3), sonoma (n = 1), and marin (n = 1) counties, and human granulocytic ehrlichiosis (hge) agent isolates were obtained from humboldt county. pcr with specific primers for 16s rrna, 444 ep-ank and groesl heat shock operon genes successfully produced amplic ... | 2000 | 10747108 |
| ehrlichia equi infection of horses from minnesota and wisconsin: detection of seroconversion and acute disease investigation. | equine granulocytic ehrlichiosis (ege) is caused by infection with ehrlichia equi. ege has been reported primarily in northern california, where e equi is transmitted by the tick ixodes pacificus. reports of ege and the emergence of human granulocytic ehrlichia in minnesota prompted a seroprevalence study of e equi in horses of minnesota and wisconsin. tick (ixodes scapularis) endemic areas of minnesota and wisconsin were compared to nonendemic regions of minnesota. indirect fluorescent antibody ... | 2000 | 10830537 |
| serologic and molecular evidence of ehrlichia spp. in coyotes in california. | in order to determine the role of coyotes in the epidemiology of granulocytic and monocytic ehrlichial agents in california (usa), we tested 149 serum samples for antibodies against ehrlichia equi, e. risticii, and e. canis, using an indirect immunofluorescent antibody test. polymerase chain reaction (pcr) assay was used to survey for the presence of members of the e. phagocytophila genogroup, e. risticii and e. canis in blood samples of 95 coyotes. sixty-eight (46%) samples were seropositive fo ... | 2000 | 10941735 |
| infection rate of ehrlichia risticii, the agent of potomac horse fever, in freshwater stream snails (juga yrekaensis) from northern california. | juga yrekaensis freshwater snails were tested for trematode stages and for ehrlichia risticii dna using a nested pcr assay. snails were collected monthly from two potomac horse fever (phf) endemic locations in northern california (montague and weed). the trematode infection rate varied between 40 and 93.3% in large snails (shell size >15mm) and between 0 and 13.3% in small snails (<15mm). the highest trematode infection rate for large and small snails was recorded in september and the lowest inf ... | 2000 | 10946138 |
| molecular detection of an ehrlichia-like agent in rainbow trout (oncorhynchus mykiss) from northern california. | ehrlichia dna was identified by nested pcr in rainbow trout (oncorhynchus mykiss) collected from a creek in northern california where potomac horse fever is endemic. ehrlichia dna was found in tissues from several organs including the gills, heart, spleen, liver, kidneys and intestine of trout and from three different adult digenetic trematodes (deropegus sp., crepidostomum sp., creptotrema sp.) parasitizing the gallbladder and/or the intestine of the trout. sequencing of pcr-amplified dna from ... | 2000 | 10962157 |
| spatial distribution of seropositivity to the causative agent of granulocytic ehrlichiosis in dogs in california. | to assess spatial and temporal patterns of seroprevalence among dogs in california to the causative agent of granulocytic ehrlichiosis (ge). | 2001 | 11592326 |
| 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 |
| 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 |
| detection of neorickettsia (ehrlichia) risticii in tissues of mice experimentally infected with cercariae of trematodes by in situ hybridization. | neorickettsia (ehrlichia) risticii was demonstrated to occur in cercariae developing in juga yrekaensis snails by experimental transmission, genetic detection and histopathology. cercariae were isolated from the digestive glands of snails collected in a fresh stream water area of siskiyou county, ca, and inoculated into cf1 mice. mice developed clinical signs, splenomegaly and histopathologic abnormalities. the agent was maintained by serial passages of whole blood in cf1 mice. a 527-bp product ... | 2002 | 12151198 |
| antibiotic susceptibilities of anaplasma (ehrlichia) phagocytophilum strains from various geographic areas in the united states. | we tested the antibiotic susceptibilities of eight strains of anaplasma phagocytophilum (the agent of human granulocytic ehrlichiosis) collected in various geographic areas of the united states, including minnesota, wisconsin, california, and new york. the results are homogeneous and show that doxycycline, rifampin, and levofloxacin are the most active antibiotics against these strains in vitro. | 2003 | 12499227 |
| 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 |
| 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 |
| 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 |
| clinical, epidemiologic, and environmental surveillance for ehrlichiosis and anaplasmosis in an endemic area of northern california. | two forms of tick-borne leukocytotropic rickettsioses have been recognized in california since the mid-1990s: human monocytic ehrlichiosis (hme) caused by ehrlichia chaffeensis and human granulocytic anaplasmosis (hga) caused by anaplasma phagocytophilum. between 1997 and 1999, two cases of hme and four cases of hga were diagnosed in residents of southern humboldt county, california. environmental followup at case-patients' residences revealed dense populations of ixodes pacificus ticks, particu ... | 2005 | 16007950 |
| evidence of tick-borne organisms in mule deer (odocoileus hemionus) from the western united states. | free-ranging mule deer (md; odocoileus hemionus) from arizona and california were tested for evidence of infection with several tick-borne pathogens, including species of ehrlichia, anaplasma, babesia, and borrelia. of 125 mule deer tested from arizona, 29 (23%) and 11 (9%) had antibodies reactive to e. chaffeensis and a. phagocytophilum by indirect immunofluorescent antibody testing, respectively; none of the six md tested from california were seropositive. using a commercial competitive elisa ... | 2005 | 16417431 |
| detection of rickettsia rickettsii and bartonella henselae in rhipicephalus sanguineus ticks from california. | sixty-two questing adult rhipicephalus sanguineus (latreille) ticks were collected by direct removal from blades of turfgrass and adjacent concrete walkways at a suburban home in riverside county, ca, and tested for the presence of rickettsia, bartonella, and ehrlichia dna. polymerase chain reaction (pcr) was used to amplify fragments of the 17-kda antigen gene and the rompa gene of the spotted fever group rickettsiae. one male tick contained r. rickettsii dna; its genotype differed from r. rick ... | 2007 | 17294935 |
| spatial distribution of seroprevalence for anaplasma phagocytophilum, borrelia burgdorferi, ehrlichia canis, and dirofilaria immitis in dogs in washington, oregon, and california. | background: in the us little spatially defined information regarding exposure to most vector-borne pathogens in dogs is available for the states of california (ca), oregon (or), and washington (wa). objectives: the purpose of the present study was to evaluate the spatial distribution of seroprevalence for 4 vector-borne pathogens, anaplasma phagocytophilum, borrelia burgdorferi, ehrlichia canis, and dirofilaria immitis, across the 3 western coastal states of the contiguous united states that ext ... | 2011 | 21827514 |