| ultrastructural and antigenic characterization of a granulocytic ehrlichiosis agent directly isolated and stably cultivated from a patient in new york state. | a human granulocytic ehrlichiosis (hge) agent with 16s rdna sequence identical to the published sequence of hge agents was isolated from a patient from new york state by inoculation of the blood leukocyte fraction directly into a human promyelocytic leukemia cell line hl-60. the hge agent was also isolated from the leukocyte fraction of the blood and bone marrow of a mouse inoculated with the leukocyte fraction of the patient's blood. the isolate has been passaged in tissue culture 30 times over ... | 1997 | 8985223 |
| antibodies to multiple tick-borne pathogens of babesiosis, ehrlichiosis, and lyme borreliosis in white-footed mice. | serum samples from peromyscus leucopus (white-footed mouse), collected in connecticut (usa) in 1983, 1985, and during 1990 to 1993, were analyzed by an enzyme-linked immunosorbent assay (elisa) or indirect fluorescent antibody (ifa) staining methods for antibodies to borrelia burgdorferi (strain 2591), babesia microti, ehrlichia chaffeensis (arkansas strain), and ehrlichia equi (mrk strain). of the 294 serum samples tested, 160 (54%) contained immunoglobulins to one or more of these pathogens. t ... | 1997 | 9249691 |
| granulocytic ehrlichiosis in the laboratory mouse. | c3h mice that were inoculated with ehrlichiae isolated from a patient with human granulocytic ehrlichiosis (hge) developed anemia and leukopenia, but by day 24, they returned to normal values. granulocytic morulae were present in peripheral blood and spleen smears on days 5 and 10, and there was a reduction in morulae on day 17. ehrlichiae were present in hl-60 cell cultures of blood and spleen from all mice at all intervals. pathogenicity, but not infectivity, waned with mouse passage but could ... | 1998 | 9498456 |
| infection of laboratory mice with the human granulocytic ehrlichiosis agent does not induce antibodies to diagnostically significant borrelia burgdorferi antigens. | laboratory diagnosis of borrelia burgdorferi is routinely made by an enzyme-linked immunosorbent assay, with positive results confirmed by western blot analysis. concern has been raised that false-positive diagnoses may be made on the basis of serologic cross-reactivity with antibodies directed against other bacterial pathogens, in particular the agent of human granulocytic ehrlichiosis (hge). the present study made use of a mouse model to ascertain the validity of these concerns. two different ... | 1999 | 10325386 |
| pathology, immunohistology, and cytokine responses in early phases of human granulocytic ehrlichiosis in a murine model. | human granulocytic ehrlichiosis (hge) results in fever, pancytopenia, and mild liver injury. we used a mouse model to examine immunity in the pathogenesis of hge. hge agent-infected c3h/hej mice were necropsied over 21 days. histologic, immunohistologic, and serologic analyses, blood culture, tissue and blood polymerase chain reaction (pcr), cell counts, serum chemistries, and plasma cytokine elisas were performed. no clinical signs were detected. ehrlichiae were identified in neutrophils in hem ... | 2000 | 10608792 |
| superoxide anion production during anaplasma phagocytophila infection. | anaplasma phagocytophila persists within neutrophils and prevents the respiratory burst by inhibiting gp91(phox). mutations in gp91(phox) result in chronic granulomatous disease (cgd), which is diagnosed by use of the nitroblue tetrazolium (nbt) and fc-oxyburst assays that examine whether cells produce o2-. this study assessed whether the nbt and fc-oxyburst assays could detect a respiratory burst during a. phagocytophila infection. o2- production was inhibited in hl-60 cells and neutrophils inf ... | 2002 | 12134266 |
| urban zoonoses caused by bartonella, coxiella, ehrlichia, and rickettsia species. | the last half of the 20th century witnessed an increase in the occurrence and recognition of urban zoonoses caused by members of the genera bartonella, coxiella, ehrlichia, and rickettsia, all traditionally considered to be members of the family rickettsiaceae. in recent years, new human pathogens (bartonella elizabethae, bartonella henselae, and rickettsia felis) have been recognized in urban environments. other newly recognized pathogens (ehrlichia chaffeensis and ehrlichia phagocytophila in t ... | 2001 | 12653141 |
| comparison of the reservoir competence of medium-sized mammals and peromyscus leucopus for anaplasma phagocytophilum in connecticut. | in the northeastern united states, anaplasma phagocytophilum, the agent of human granulocytic ehrlichiosis (hge), is transmitted by the tick vector ixodes scapularis. the white-footed mouse peromyscus leucopus is a competent reservoir for this agent, but the reservoir competence of non-peromyscus hosts of i. scapularis has not been studied. here, we report data confirming reservoir competence of medium-sized mammals for a. phagocytophilum. raccoons, virginia opossums, gray squirrels, and striped ... | 2002 | 12737542 |
| transmission efficiency of the ap-variant 1 strain of anaplasma phagocytophila. | nymphal ixodes scapularis ticks were collected from several sites in rhode island. dna was extracted from a subset of these ticks, and pcr and dna sequencing of the 16s rrna gene were used to determine the ratio of anaplasma phagocytophila-human agent (ap-ha) to a genetic variant not associated with human disease (ap-variant 1). the remaining ticks were allowed to feed to repletion on either white-footed (peromyscus leucopus) or dba/2 (mus musculus) mice. the engorged ticks, and blood samples dr ... | 2003 | 12860603 |
| inability of a variant strain of anaplasma phagocytophilum to infect mice. | nymphal ixodes scapularis ticks were collected from several sites in rhode island. polymerase chain reaction and dna sequencing were used to determine the presence and prevalence of anaplasma phagocytophilum human agent (ap-ha) and a genetic variant not associated with human disease (ap-variant 1). the remaining ticks from each cohort were allowed to feed to repletion on either white-footed (peromyscus leucopus) or dba/2 (mus musculus) mice. the engorged ticks and murine blood samples were evalu ... | 2003 | 14639548 |
| cxcr2 blockade influences anaplasma phagocytophilum propagation but not histopathology in the mouse model of human granulocytic anaplasmosis. | anaplasma phagocytophilum is an obligate intracellular bacterium that infects neutrophils and causes human granulocytic anaplasmosis. infection induces neutrophil secretion of interleukin-8 or murine homologs and perpetuates infection by recruiting susceptible neutrophils. we hypothesized that antibody blockade of cxcr2 would decrease a. phagocytophilum tissue load by interrupting neutrophil recruitment but would not influence murine hepatic pathology. c3h-scid mice were treated with cxcr2 antis ... | 2004 | 15358660 |
| interferon-gamma deficiency reveals that 129sv mice are inherently more susceptible to anaplasma phagocytophilum than c57bl/6 mice. | immunocompetent mice 129sv (129) and c57bl/6 (b6) mice are similarly susceptible to anaplasma phagocytophilum. we now show that 129 mice lacking interferon-gamma (ifn-gamma) develop more severe infection with a. phagocytophilum than ifn-gamma deficient b6 mice. these data demonstrate that there is an inherent increased susceptibility of 129 mice, compared with b6 mice, to a. phagocytophilum that can only be discerned in the absence of ifn-gamma. | 2004 | 15477043 |
| transmission route efficacy and kinetics of anaplasma phagocytophilum infection in white-footed mouse, peromyscus leucopus. | anaplasma phagocytophilum was used to infect peromyscus leucopus mice by three routes of inoculation: infected tick infestation and intraperitoneal (ip) and subcutaneous (sq) injection of infected tissue culture cells. a set of 12 mice were infected (four tick, four ip, and four sq), and blood was drawn at 1, 3, 6, 9, 12, 15, 21, 28, 35, and 60 days post-infection and analyzed by use of a quantitative pcr assay to assess the level of infection. an additional set of 108 mice were infected (36 tic ... | 2004 | 15682514 |
| role of reactive nitrogen species in development of hepatic injury in a c57bl/6 mouse model of human granulocytic anaplasmosis. | human granulocytic anaplasmosis (hga), caused by the granulocytic rickettsia-like organism anaplasma phagocytophilum, is the 3rd most frequent vector-borne infection in north america. to understand the disease mechanisms of hga, we developed a murine model that lacks clinical disease yet exhibits characteristic histopathologic and immunologic changes. because the degree of hepatic histopathology is unrelated to high bacterial numbers, tissue injury in hga is thought to occur due to products of i ... | 2006 | 16521860 |
| 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 |
| il-12/23p40-dependent clearance of anaplasma phagocytophilum in the murine model of human anaplasmosis. | human anaplasmosis is an emerging infectious disease transmitted by ticks that can be potentially fatal in the immunocompromised and the elderly. the mechanisms of defense against the causative agent, anaplasma phagocytophilum, are not completely understood; however, interferon (ifn)-gamma plays an important role in pathogen clearance. here, we show that ifn-gamma is regulated through an early il-12/23p40-dependent mechanism. interleukin (il)-12/23p40 is regulated in macrophages and dendritic ce ... | 2007 | 17521390 |
| tick-borne zoonotic bacteria in wild and domestic small mammals in northern spain. | the prevalence and diversity of tick-borne zoonotic bacteria (borrelia spp., anaplasma phagocytophilum, coxiella burnetii, and spotted fever group rickettsiae) infecting 253 small mammals captured in the basque country (spain) were assessed using pcr and reverse line blot hybridization. trapping sites were selected around sheep farms (study 1, 2000 to 2002) and recreational parks (study 2, 2003 to 2005). the majority of the studied mammals (162) were wood mice (apodemus sylvaticus), but six othe ... | 2007 | 17693556 |
| microbial pathogens in ticks, rodents and a shrew in northern gyeonggi-do near the dmz, korea. | a total of 1,618 ticks [420 individual (adults) and pooled (larvae and nymphs) samples], 369 rodents (apodemus agrarius, rattus norvegicus, tscherskia triton, mus musculus, and myodes regulus), and 34 shrews (crocidura lasiura) that were collected in northern gyeonggi-do near the demilitarized zone (dmz) of korea during 2004-2005, were assayed by pcr for selected zoonotic pathogens. from a total of 420 individual and pooled tick dna samples, anaplasma (a.) phagocytophilum (16), a. platys (16), e ... | 2008 | 18716449 |
| detection of antibodies against anaplasma phagocytophilum in algerian mice (mus spretus), portugal. | the recent detection of anaplasma phagocytophilum in portugal stimulated further research on the agent's enzootic cycle, which usually involves rodents. thus a total 322 rodents belonging to five species, including 30 apodemus sylvaticus (wood mouse), 65 mus musculus (house mouse), 194 m. spretus (algerian mouse), 5 rattus norvegicus (brown rat) and 28 r. rattus (black rat), were studied by indirect immunofluorescent assay (ifa) and/or polymerase chain reaction (pcr) for a. phagocytophilum expos ... | 2009 | 18973448 |
| [ehrlichiosis/anaplasmosis]. | ehrlichiosis and anaplasmosis are zoonoses caused by bacteria from the family anaplasmataceae, including human and animal pathogens. the human pathogens are ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis (hme), anaplasma phagocytophilum, the pathogen causing human granulocytic anaplasmosis (hga), e. ewingii and neorickettsia sennetsu, granulocytotropic and monocytotropic ehrlichia species, respectively. ehrlichia spp. are small, gram-negative, obligate intracellular b ... | 2009 | 20077398 |
| the ifn-+¦-inducible gtpase, irga6, protects mice against toxoplasma gondii but not against plasmodium berghei and some other intracellular pathogens. | clearance of infection with intracellular pathogens in mice involves interferon-regulated gtpases of the irg protein family. experiments with mice genetically deficient in members of this family such as irgm1(lrg-47), irgm3(igtp), and irgd(irg-47) has revealed a critical role in microbial clearance, especially for toxoplasma gondii. the in vivo role of another member of this family, irga6 (iigp, iigp1) has been studied in less detail. we investigated the susceptibility of two independently gener ... | 2011 | 21698150 |
| Evolution of Antigen Variation in the Tick-Borne Pathogen Anaplasma phagocytophilum. | Anaplasma phagocytophilum is an obligately intracellular tick-transmitted bacterial pathogen of humans and other animals. During the course of infection, A. phagocytophilum utilizes gene conversion to shuffle ~100 functional pseudogenes into a single expression cassette of the msp2(p44) gene, which codes for the major surface antigen and major surface protein 2 (MSP2). The role and extent of msp2(p44) recombination, particularly in hosts that only experience acute infections, is not clear. In th ... | 2011 | 21965342 |
| candidatus neoehrlichia mikurensis and anaplasma phagocytophilum in natural rodent and tick communities in southern hungary. | the aim of this study was to investigate the natural cycle of the new human pathogenic bacteria candidatus neoehrlichia mikurensis and anaplasma phagocytophilum in southern hungary. we collected rodents with live-traps (2010-2013) and questing ticks with flagging in 2012. small mammals were euthanized, tissue samples were collected and all the ectoparasites were removed and stored in 70% alcohol. we found relatively low overall prevalence of tick infestation (8%). samples were analysed for a. ph ... | 2015 | 25468763 |