| intrastadial and interstadial transmission of anaplasma marginale by boophilus annulatus ticks in cattle. | the 1-host tick boophilus annulatus was found to transmit anaplasmosis in cattle transstadially. anaplasma marginale was invariably transmitted when ticks that had been pulled off anaplasma-infected calves either after 7 days (as fully engorged larvae) or after 14 to 15 days (as fully engorged nymphs) were transferred within 4 days to susceptible calves. three morphologically different a marginale isolates, 1 round (tailless) and 2 with different types of appendages (tailed) were transmitted by ... | 1993 | 8498744 |
| anaplasma marginale: effect of the treatment of cattle with an interferon gamma-neutralizing monoclonal antibody or the nitric oxide synthetase inhibitor aminoguanidine on the course of infection. | cattle undergoing initial infection with the rickettsia anaplasma marginale were treated with either a monoclonal antibody (moab) with neutralizing activity for bovine interferon gamma (ifn-gamma) or aminoguanidine (ag), a specific inhibitor of the inducible form of nitric oxide synthetase (inos). plasma levels of moab and ag were measured over the time of administration. the course of a. marginale infection was not altered in the moab-treated cattle relative to untreated controls. in cattle tre ... | 1997 | 9347517 |
| carbohydrate moiety of plasmodium falciparum glycoproteins: the nature of the carbohydrate-peptide linkage in the msp-2 glycoprotein. | metabolic labelling of plasmodium falciparum parasites with [3h]glcn, [3h]man, [3h]gal and [3h]ethanolamine, and subsequent purification by sds-page of the labelled material provided effective labelling of the msp-1, 195 kda, and msp-2, 42-53 kda, glycoproteins. reductive beta-elimination of the msp-2 released from the gel consisted of glycopeptides containing labelled sugars. processing of the eliminated components and identification of the sugar residues demonstrated the presence of n-acetylgl ... | 1997 | 9352084 |
| immunodominant major outer membrane proteins of ehrlichia chaffeensis are encoded by a polymorphic multigene family. | several immunodominant major proteins ranging from 23 to 30 kda were identified in the outer membrane fractions of ehrlichia chaffeensis and ehrlichia canis. the n-terminal amino acid sequence of a 28-kda protein of e. chaffeensis (one of the major proteins) was determined. the gene (p28), almost full length, encoding the 28-kda protein was cloned by pcr with primers designed based on the n-terminal sequence of the e. chaffeensis 28-kda protein and the consensus sequence between the c termini of ... | 1998 | 9423849 |
| seasonal prevalence of ticks and tick-transmitted haemoparasites in traditionally managed n'dama cattle with reference to strategic tick control in the gambia. | a survey of tick spatial and seasonal distribution in traditional managed n'dama cattle over 1 year old was carried out in the gambia over 16 months. presence of anaplasma marginale and babesia spp. in the blood smears and their antibodies in the serum of same animals were also examined. tick species, in decreasing order of abundance, were: boophilus geigy, rhipicephalus senegalensis, b.decoloratus, hyalaomma truncatum, h.marginatum rufipes and amblyomma variegatum. all tick species peaked durin ... | 1997 | 9430113 |
| bovine anaplasmosis prevalence in northern veracruz state, mexico. | in order to learn more about the presence of bovine anaplasmosis in northern veracruz state, méxico, paired blood and serum samples from 368 cattle were subjected to polymerase chain reaction (pcr) and complement-fixation test (cft). the overall prevalence of anaplasma marginale by pcr was 69.2% and seroprevalence by cft 54.6%. age-specific prevalence was calculated for each test. sixty-eight percent of animals from 0 to 3 months of age already were infected (pcr-positive), compared to only 42.4 ... | 1997 | 9443325 |
| in vitro cultivation of anaplasma marginale in bovine erythrocytes co-cultured with endothelial cells. | primary cultures of anaplasma marginale infected erythrocytes were used to determine conditions for in vitro cultivation of the rickettsia. the infected erythrocytes that were maintained by regular addition of glasgow's mem with fetal calf serum and uninfected erythrocytes showed a 1-5% increase in percent infected erythrocytes on the evaluation of giemsa stained smears. this increase in parasitemia resulted in up to 70% change in the number of infected erythrocytes. co-culture of the infected e ... | 1997 | 9477491 |
| expression of anaplasma marginale major surface protein 2 variants during persistent cyclic rickettsemia. | anaplasma marginale is an intraerythrocytic rickettsial pathogen of cattle in which infection persists for the life of the animal. persistent a. marginale infection is characterized by repetitive rickettsemic cycles which we hypothesize reflect emergence of a. marginale antigenic variants. in this study, we determined whether variants of major surface protein 2 (msp-2), a target of protective immunity encoded by a polymorphic multigene family, arise during persistent rickettsemia. by using a qua ... | 1998 | 9488414 |
| detection of cattle naturally infected with anaplasma marginale in a region of endemicity by nested pcr and a competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5. | a competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5 (rmsp5-celisa) of anaplasma marginale was validated in a naturally infected cattle herd in an area of eastern oregon where a. marginale is endemic. the true positive and negative a. marginale infection status of 235 randomly selected cattle was determined by using a nested pcr (npcr) coupled with msp5 sequence analysis and hybridization. judgment of the reliability of the npcr and hybridization for detectio ... | 1998 | 9508311 |
| observations on the treatment of natural haemosporidia infections by total alkaloid of peganum harmala l. in cattle. | eighty two cattle naturally infected with haemosporidians were treated with total alkaloid hydrochloride of peganum harmale l. (0.5 mg/kg/day). fifty eight cases with theileria sergenti showed a cure rate of 86%; thirteen cases with theileria annulata showed a cure rate of 85%; eight cattle infected with babesia bigemina showed a cure rate of 88% and three cases of anaplasma marginale were completely cured. the results suggested that the curative effect of total alkaloid of p. harmale was better ... | 1997 | 9512749 |
| evaluation of an enzyme-linked immunosorbent assay using recombinant major surface protein 5 for serological diagnosis of bovine anaplasmosis in venezuela. | an indirect enzyme-linked immunosorbent assay (elisa) was developed for the serological diagnosis of bovine anaplasmosis with purified recombinant major surface protein 5 (msp5) of anaplasma marginale produced in escherichia coli. serum antibody responses against msp5 were detected in calves experimentally infected with a. marginale as early as 21 days postinfection and reached maximum titers at 28 days postinfection. the msp5 elisa performed with serum samples taken from field cattle from diffe ... | 1998 | 9521155 |
| subunit vaccines for the control of tick-borne diseases: implications for the future. | tick-borne parasites are a major constraint to the improvement of livestock productivity in the developing world. these parasites include theileria parva, t. annulata, babesia bigemina, b. bovis, anaplasma marginale and cowdria ruminantium. the impact of these diseases is currently limited by the use of acaricides to decrease transmission by the tick vectors and immunization of the host animals using live vaccines. the use of acaricide is hampered by the development of acaricide resistance and l ... | 1997 | 9530697 |
| characterization of anaplasma isolates from eland (taurotragus oryx). pathogenicity in cattle and sheep and dna profiles analysis. | two eland anaplasma isolates, anape1, from kenya, and anape2, from south africa were characterised. their characterization was based on their pathogenicity to intact and splenectomized cattle and sheep and also their dna profiles. their dna profiles were analysed and compared to anaplasma marginale, a. ovis and a. centrale after endonuclease restrictions and probing with anaplasma dna probes, ac5-12 and ac-1. the results of the pathogenicity trials showed anape1 to be similar to a. ovis and anap ... | 1998 | 9561699 |
| conformational dependence of anaplasma marginale major surface protein 5 surface-exposed b-cell epitopes. | the anaplasma marginale outer membrane is composed of immunogenic major surface proteins (msps) linked both covalently and noncovalently in multimeric complexes (m. c. vidotto, t. c. mcguire, t. f. mcelwain, g. h. palmer, and d. p. knowles, infect. immun. 62:2940-2946). consequently, effective induction of antibody against surface-exposed msp epitopes has been postulated to require maintenance of msp secondary through quatenary structures. using msp5 as a model and the approach of epitope mappin ... | 1998 | 9596725 |
| cloning of the gene encoding the 44-kilodalton antigen of the agent of human granulocytic ehrlichiosis and characterization of the humoral response. | antibodies in the sera of patients with human granulocytic ehrlichiosis (hge) commonly recognize a 44-kda antigen. we cloned the gene encoding the 44-kda protein of the agent of hge (aohge) by probing an aohge lambda zap ii genomic dna expression library with sera from aohge-infected mice. the gene, hge-44, is part of a multigene family, with sequence similarity to the anaplasma marginale msp-2 genes. rna-pcr studies confirmed that hge-44 is expressed by aohge cultured in hl-60 cells and by aohg ... | 1998 | 9632594 |
| the safety and efficacy of australian tick-borne disease vaccine strains in cattle in paraguay. | glycerol preserved, frozen tick-borne disease vaccine strains developed in australia were imported into paraguay to test their safety in pregnant holando heifers and their efficacy against challenge from inoculated local field strains of babesia bigemina, b. bovis and anaplasma marginale in hereford x criolla heifers. the two babesia strains proved to be safe and the b. bovis k strain was very effective in providing immunity to a local field strain of b. bovis. the b. bigemina efficacy trial was ... | 1998 | 9653988 |
| bovine babesiosis and anaplasmosis follow-up on cattle relocated in an endemic area for hemoparasitic diseases. | a multiplex pcr/dna probe assay was used to monitor babesia bovis, b. bigemina and anaplasma marginale infection in cattle introduced to a boophilus microplus-infested area in veracruz, mexico. eight intact, 18-month-old, cross-bred beef cattle (four naive, group a; four babesia species--premunized, group b) were immediately exposed to ticks after arrival and were clinically monitored from day 6 to day 98 post-exposure (pe) to ticks. blood sample analysis for dna detection by the mpcr/dna probe ... | 1998 | 9668444 |
| development of a non-radioactive dna probe and in situ hybridization for detection of anaplasma marginale in ticks and cattle. | a non-radioactive dna probe was developed for detection of anaplasma marginale in ticks and cattle. the probe was labeled with digoxigenin 11-dutp by polymerase chain reaction. the probe was tested on bovine blood and was found to be a sensitive and specific detection method for a. marginale in cattle. the dna probe was then adapted for in situ hybridization (ish) of a. marginale in dermacentor andersoni and d. variabilis ticks infected either as nymphs or adults. one-half of each tick was studi ... | 1998 | 9668458 |
| prospective study for the detection of anaplasma marginale theiler, 1911 (rickettsiales: anaplasmataceae) in costa rica. | a prospective study was conducted to assess the dynamics of the infection and host response to anaplasma marginale in one closed herd in the dry tropical forest of costa rica. the study subjects were the dams and their calves born during 1 breeding season (1995-1996). all cows were sampled at 3 month intervals for antibody detection using a competitive elisa (celisa) and for antigen detection using pcr/nonradioactive probe assay. all 24 calves born during the study were individually identified a ... | 1998 | 9668469 |
| evaluation of anaplasma marginale from tick cell culture as an immunogen for cattle. | anaplasma marginale has been propagated and continuously passaged in an ixodes scapularis cell line. anaplasma development was characterized and cultures with a high density of rickettsiae were harvested at a predictable rate. culture-derived a. marginale (cam) remained infective for cattle and was used effectively as antigen in diagnostic tests with the sensitivity to identify bovine carriers of a. marginale. this study presents results of an initial trial using the cam as an immunogen for catt ... | 1998 | 9668472 |
| use of tick cell culture-derived anaplasma marginale antigen in a competitive elisa for serodiagnosis of anaplasmosis. | anaplasma marginale was propagated in a continuous tick cell line and detergent-solubilized infected cells were used as antigen in a competitive elisa (c-elisa) for detection of anaplasma-specific antibody in bovine sera. positive control sera competed well (> or = 35% inhibition) with an a. marginale-specific monoclonal antibody for binding to this antigen, while negative sera failed to compete (< 35% inhibition). the c-elisa was compared to the standard complement-fixation test (cft) using 2,2 ... | 1998 | 9668475 |
| the development of a semi-automated latex agglutination test for the detection of antibodies to anaplasma marginale using a cell culture-derived antigen. | serologic diagnosis of anaplasmosis is currently done by the complement-fixation, elisa, and card agglutination tests. these tests have utilized a. marginale harvested from bovine erythrocytes as antigen which is often contaminated with erythrocyte stroma. we are currently testing a. marginale propagated in a ixodes scapularis cell line as antigen for serologic tests. in this study, we report the use of the cell culture-derived a. marginale as antigen for development of a rapid, semi-automated l ... | 1998 | 9668476 |
| characterization of an immunogen of anaplasma marginale. | | 1998 | 9668501 |
| seroprevalence of anaplasma marginale in cattle in parana state, brazil, by msp-5 competitive elisa. | | 1998 | 9668503 |
| major antigenic proteins of the agent of human granulocytic ehrlichiosis are encoded by members of a multigene family. | western blot analysis of proteins from a cell culture isolate (usg3) of the human granulocytic ehrlichiosis (hge) agent has identified a number of immunoreactive proteins, including major antigenic proteins of 43 and 45 kda. peptides derived from the 43- and 45-kda proteins were sequenced, and degenerate pcr primers based on these sequences were used to amplify dna from usg3. sequencing of a 550-bp pcr product revealed that it encodes a protein homologous to the msp-2 proteins of anaplasma margi ... | 1998 | 9673253 |
| cloning and characterization of multigenes encoding the immunodominant 30-kilodalton major outer membrane proteins of ehrlichia canis and application of the recombinant protein for serodiagnosis. | a 30-kda major outer membrane protein of ehrlichia canis, the agent of canine ehrlichiosis, is the major antigen recognized by both naturally and experimentally infected dog sera. the protein cross-reacts with a serum against a recombinant 28-kda protein (rp28), one of the outer membrane proteins of a gene (omp-1) family of ehrlichia chaffeensis. two dna fragments of e. canis were amplified by pcr with two primer pairs based on the sequences of e. chaffeensis omp-1 genes, cloned, and sequenced. ... | 1998 | 9705412 |
| observations on the use of anaplasma centrale for immunization of cattle against anaplasmosis in zimbabwe. | a total of 93 bos taurus cattle was used in pen trials to compare vaccine stocks of anaplasma centrale from south africa and australia (which stock came from south africa in 1934) in protecting against three virulent field isolates from clinical anaplasma marginale infections. in addition, field observations were made on the use of a vaccine, prepared from the australian stock, in over 9553 cattle of mixed age and breeds on 16 co-operator farms and at one communal dip. the results of the pen tri ... | 1998 | 9741051 |
| development of an enzyme-linked immunosorbent assay for detection of antibodies to babesia bigemina in cattle. | monoclonal antibodies, directed against a 58-kda babesia bigemina merozoite antigen that reacted strongly with immune sera from experimentally and naturally infected cattle in western blots, were used to develop a competitive-inhibition enzyme-linked immunosorbent assay (elisa). as based on the testing of 70 antibody-positive sera from experimentally infected cattle and 166 antibody-negative sera collected in non-endemic areas of australia, the sensitivity and specificity of the elisa were 95.7% ... | 1998 | 9747938 |
| morphology and development of anaplasma marginale (rickettsiales: anaplasmataceae) in cultured ixodes scapularis (acari: ixodidae) cells. | anaplasma marginale theiler, a tick-borne rickettsial pathogen of cattle, was recently propagated in a continuous tick cell line, ide8, derived from embryonic ixodes scapularis say. cell monolayers were infected briefly with a high multiplicity of infection to synchronize rickettsial development and allow for description of the invasion, development, and release of a. marginale from the cultured cells. sequential samples were collected, fixed, and processed for examination with light and electro ... | 1998 | 9775610 |
| cd4(+) t-lymphocyte and immunoglobulin g2 responses in calves immunized with anaplasma marginale outer membranes and protected against homologous challenge. | protective immunity against the ehrlichial pathogen anaplasma marginale has been hypothesized to require induction of immunoglobulin g2 (igg2) antibody against outer membrane protein epitopes and coordinated activation of macrophages for phagocytosis and killing. in the present study, cell-mediated immune responses, including induction of igg isotype switching, were characterized in calves immunized with purified outer membranes of the florida strain of a. marginale. importantly, these calves we ... | 1998 | 9784551 |
| the repertoire of anaplasma marginale antigens recognized by cd4(+) t-lymphocyte clones from protectively immunized cattle is diverse and includes major surface protein 2 (msp-2) and msp-3. | major surface proteins of anaplasma marginale are vaccine candidates. we recently demonstrated that immunization of calves with outer membranes of the florida strain of a. marginale resulted in protective immunity that correlated with a memory cd4(+) t-lymphocyte response specific for major surface protein 1 (msp-1), msp-2, and msp-3 (w. c. brown, v. shkap, d. zhu, t. c. mcguire, w. tuo, t. f. mcelwain, and g. h. palmer, infect. immun. 66:5406-5413, 1998). as immunogens, these proteins have been ... | 1998 | 9784552 |
| the absence of clinical disease in cattle in communal grazing areas where farmers are changing from an intensive dipping programme to one of endemic stability to tick-borne diseases. | a two-year field study was conducted in four communal grazing areas in south africa. sera were collected from young cattle (6-18 months old) in these areas during the winters of 1991 to 1993. the sera were tested for antibodies to babesia bovis, babesia bigemina, anaplasma marginale and cowdria ruminantium. in two of the four areas, treatment with acaricide was erratic and dependent on the discretion of individual owners. in these areas the drought of 1992 had a major impact on tick burdens and ... | 1998 | 9809321 |
| persistence of anaplasma ovis infection and conservation of the msp-2 and msp-3 multigene families within the genus anaplasma. | goats which have recovered from acute anaplasma ovis infection remain seropositive, although infected erythrocytes cannot be detected by microscopic examination. persistence of a. ovis 17 to 21 months following experimental infection was demonstrated by pcr detection of the msp-5 gene. quantitative analysis of persistent rickettsemia over time showed that all levels were below the limit of microscopic detection and ranged from a low of 10(2) organisms/ml to peaks of 10(6) organisms/ml. two patte ... | 1998 | 9826393 |
| comparative sensitivity of two tests for the diagnosis of multiple hemoparasite infection of cattle. | the purpose of this study was to evaluate the efficacy of light microscopy (lm) examination of blood smears and a multiplex polymerase chain reaction (mpcr) assay, in terms of their ability to detect cattle experimentally infected with babesia bovis, babesia bigemina, and anaplasma marginale. blood samples were collected from 32 intact, 1-2 year old, holstein bulls, previous to and after simultaneous inoculation of culture-derived or field isolates of b. bovis- and b. bigemina-infected erythrocy ... | 1996 | 8784493 |
| prevalence of granulocytic ehrlichia infection among white-tailed deer in wisconsin. | human granulocytic ehrlichiosis (hge) is caused by an agent that is nearly indistinguishable from the veterinary pathogens ehrlichia equi and ehrlichia phagocytophila. the deer tick, ixodes scapularis, is a vector of the hge agent, and the white-tailed deer is the primary host for adult ixodes ticks. we assessed the distribution of granulocytic ehrlichia infection among deer living within (wisconsin) and outside (western and southern iowa) the geographic range of l. scapularis. whole-blood sampl ... | 1997 | 9163463 |
| [clinical and hematological changes in calves infected with anaplasma marginale]. | clinical and hematological changes of six anaplasma marginale (isolated zulia) inoculated calves (experimental group) and four healthy calves (control group) were studied during twenty and eighty days before and after infection, respectively. the behavior of the four calves used as control group was stable and no significant changes in the parameters analyzed was observed. the experimental group developed the three typical phases of illness. during the prepatent phase, which lasted a mean of 21. ... | 1996 | 9334450 |
| comparison of surface proteins of anaplasma marginale grown in tick cell culture, tick salivary glands, and cattle. | anaplasma marginale, a tick-borne rickettsial pathogen of cattle, infects bovine erythrocytes, resulting in mild to severe hemolytic disease that causes economic losses in domestic livestock worldwide. recently, the virginia isolate of a. marginale was propagated in a continuous tick cell line, ide8, derived from embryonic ixodes scapularis. development of a. marginale in cell culture was morphologically similar to that described previously in ticks. in order to evaluate the potential of the cel ... | 1999 | 9864202 |
| restriction of major surface protein 2 (msp2) variants during tick transmission of the ehrlichia anaplasma marginale. | anaplasma marginale is an ehrlichial pathogen of cattle that establishes lifelong persistent infection. persistence is characterized by rickettsemic cycles in which new a. marginale variant types, defined by the sequence of the expressed msp2 transcripts, emerge. the polymorphic msp2 transcripts encode structurally distinct msp2 proteins and result in an antigenically diverse and continually changing a. marginale population within the blood. in this manuscript, we used sequence analysis of msp2 ... | 1999 | 10077656 |
| upregulation of interleukin-4 and ifn-gamma expression by ifn-tau, a member of the type i ifn family. | trophoblast interferon-tau (ifn-tau) is a new member of the type i ifn family that is produced in large quantities by the ruminant conceptus. like other type i ifn, ifn-tau inhibits viral replication and activates natural killer (nk)-mediated cytotoxicity. in mice and humans, type i ifn enhances type 1 t helper (th) cell responses, but the effects of type i ifn, including ifn-tau, on cytokine expression by bovine th cells have not been described. the present study determined the effects of ifn-t ... | 1999 | 10090403 |
| the efficacy of used engine oil against ticks on cattle. | the study was conducted in a peri-urban agricultural system at botshabelo, a city in the south-eastern free state. a questionnaire survey revealed that 88.5% of cattle farmers in the area experienced problems related to ticks and tick-borne diseases. because of the cost of commercial acaricides the botshabelo farmers use alternative, cheaper methods of tick control, including the application of used engine oil. the specific aim of the study was to determine whether used engine oil can effectivel ... | 1998 | 10192839 |
| epidemiology of tick-borne diseases of cattle in botshabelo and thaba nchu in the free state province. | a seroepidemiological study was conducted on 151 cattle from the botshabelo and thaba nchu areas in the central free state province of south africa, two areas where small scale, peri-urban cattle farming is practised. an indirect fluorescent antibody test was used to test for babesia bigemina and b. bovis antibodies. to test for anaplasma marginale antibodies a competitive inhibition enzyme-linked immunosorbent assay method was used. there were no significant differences in serological test resu ... | 1998 | 10192841 |
| infections of granulocytic ehrlichiae and borrelia burgdorferi in white-tailed deer in connecticut. | serum or whole blood samples, obtained from 141 white-tailed deer (odocoileus virginianus) in connecticut (usa) during 1980, 1991, and 1996, were analyzed to detect past or current infections of ehrlichia phagocytophila genogroup organisms and borrelia burgdorferi. when the bds or nch-1 strains of granulocytic ehrlichiae were used separately in indirect fluorescent antibody (ifa) staining methods, antibody positivity rates varied from 25 to 64% in 1991 and 1996, respectively. all 50 sera tested ... | 1999 | 10231753 |
| simultaneous detection of bovine theileria and babesia species by reverse line blot hybridization. | a reverse line blot (rlb) assay was developed for the identification of cattle carrying different species of theileria and babesia simultaneously. we included theileria annulata, t. parva, t. mutans, t. taurotragi, and t. velifera in the assay, as well as parasites belonging to the t. sergenti-t. buffeli-t. orientalis group. the babesia species included were babesia bovis, b. bigemina, and b. divergens. the assay employs one set of primers for specific amplification of the rrna gene v4 hypervari ... | 1999 | 10325324 |
| comparison of a competitive inhibition elisa and the card agglutination test for detection of antibodies to anaplasma marginale and anaplasma centrale in cattle. | to compare a recently developed recombinant msp-5 competitive inhibition elisa with a card agglutination test for detection of antibodies to anaplasma marginale and anaplasma centrale in australian cattle. | 1999 | 10330556 |
| dermacentor hunteri (acari: ixodidae): an experimental vector of anaplasma marginale and a. ovis (rickettsiales: anaplasmataceae) to calves and sheep. | the experimental vector competence of laboratory-reared dermacentor hunteri bishopp for anaplasma marginale theiler and anaplasma ovis lestoquard was evaluated by delayed transfer of male ticks from infected to susceptible holstein calves and from infected to susceptible domestic sheep, respectively. after feeding for 4 or 5 d on rickettsemic acquisition hosts, the ticks were held off the host at 26 degrees c, approximately 93% rh, and a photoperiod of 14:10 (l:d) h for 7 or 8 d, then test fed f ... | 1999 | 10337102 |
| biased immunoglobulin g1 isotype responses induced in cattle with dna expressing msp1a of anaplasma marginale. | immunization with the native major surface protein 1 (msp1) (a heterodimer containing disulfide and noncovalently bonded polypeptides designated msp1a and msp1b) of the erythrocytic stage of anaplasma marginale conferred protection against homologous challenge (g. h. palmer, a. f. barbet, w. c. davis, and t. c. mcguire, science 231:1299-1302, 1986). the msp1a polypeptide possesses a conserved neutralization-sensitive epitope. in the present study, the immune response to dna-mediated immunization ... | 1999 | 10377129 |
| molecular basis for vaccine development against the ehrlichial pathogen anaplasma marginale. | anaplasma marginale is a tick-transmitted ehrlichial pathogen causing severe morbidity and mortality in livestock on six continents. development of safe effective vaccines would be greatly facilitated by identification of the protective immune mechanisms and by understanding how the pathogen evades immune effectors to establish persistent infection. in this article, guy palmer and colleagues review recent progress in identifying how defined epitopes induce protective immunity and the role of ant ... | 1999 | 10377531 |
| vaccine strategies for cowdria ruminantium infections and their application to other ehrlichial infections. | suman mahan and co-authors review the strategies applied to develop improved vaccines for cowdria ruminantium infections (heartwater). inactivated vaccines using cell-cultured c. ruminantium organisms combined with an adjuvant are capable of protecting goats, sheep and cattle against lethal c. ruminantium challenge. immune responses induced with this vaccine, or after recovery from infection, target outer membrane proteins of c. ruminantium, in particular the major antigenic protein 1 (map-1). g ... | 1999 | 10377533 |
| pyruvate metabolism by anaplasma marginale in cell-free culture. | partially purified anaplasma marginale initial bodies were cultivated in a cell-free system in the presence of [3-14c]pyruvate for 24 or 48 h. experiments showed that a significant portion of the pyruvate supplied to the cultures was incorporated into initial body components. label incorporation was reduced by 72% in the presence of oxytetracycline. fractionation and chromatography of the organisms revealed radioactive incorporation as alanine. this is the first report of de novo amino acid synt ... | 1999 | 10380651 |
| emergence of anaplasma marginale antigenic variants during persistent rickettsemia. | anaplasma marginale is an ehrlichial pathogen of cattle, in the order rickettsiales, that establishes persistent cyclic rickettsemia in the infected host. within each rickettsemic cycle, a. marginale expressing antigenically variant major surface protein 2 (msp2) emerge. by cloning 17 full-length msp2 transcripts expressed during cyclic rickettsemia, we determined that emergent variants have a single, central hypervariable region encoding variant b-cell epitopes. the n- and c-terminal regions ar ... | 1999 | 10531237 |
| serosurvey for selected disease agents in white-tailed deer from mexico. | serum samples from 350 white-tailed deer (odocoileus virginianus texanus) collected in march 1994 from northeastern mexico were tested for the prevalence of antibody activity against five infectious diseases of ruminants. the prevalence rate was 81% for bluetongue virus (btv) of all serotypes, 72% for epizootic hemorrhagic disease virus (ehdv), 3% for borrelia burgdorferi, 69% for anaplasma marginale, and 0% for brucella abortus, b. melitensis, and b. ovis. these are diseases that affect domesti ... | 1999 | 10574545 |
| interleukin-12 as an adjuvant promotes immunoglobulin g and type 1 cytokine recall responses to major surface protein 2 of the ehrlichial pathogen anaplasma marginale. | anaplasma marginale is a tick-transmitted pathogen of cattle closely related to the human ehrlichiae, ehrlichia chaffeensis and the agent of human granulocytic ehrlichiosis (hge). these pathogens have in common a structurally conserved outer membrane protein (omp) designated the major surface protein 2 (msp-2) in a. marginale and hge and omp-1 in e. chaffeensis. protective immunity against ehrlichial pathogens is believed to require induction of gamma interferon (ifn-gamma) and opsonizing immuno ... | 2000 | 10603398 |
| prevalence of blood parasites among cattle at the central area of saudi arabia. | the present study aimed to investigate the parasites infecting cattle blood at al-qassim region. examination of 307 blood samples revealed that 235 (76.5%) and 3 (0.98%) of cattle were infected with theileria annulata and anaplasma marginale, respectively. t. annulata was the prevalent blood parasite among cattle while a. marginale was scarcely encountered. the monthly incidence of t. annulata ranged from 38.5% in march to 94.7% in october. also, the infection rate reached a maximum (84.3%) in b ... | 2000 | 10622615 |
| establishment and characterization of an oklahoma isolate of anaplasma marginale in cultured ixodes scapularis cells. | anaplasma marginale is a tick-borne hemoparasite of cattle worldwide. the virginia isolate of a. marginale was propagated previously in a cell line derived from embryos of the tick, ixodes scapularis. the cultured anaplasma (va-tc) was passaged continuously for over 4 years and retained its infectivity for cattle and antigenic stability. we report herein the continuous in vitro cultivation of a second isolate of a. marginale derived from a naturally infected cow in oklahoma (ok-tc). blood from t ... | 2000 | 10669100 |
| effect of breed of cattle on innate resistance to infection with anaplasma marginale transmitted by boophilus microplus. | to assess the innate resistance of and transmission in naive bos taurus cross bos indicus and purebred bos indicus cattle when placed in a paddock with cattle infected with anaplasma marginale and carrying boophilus microplus ticks. | 1999 | 10685172 |
| expression of polymorphic msp1beta genes during acute anaplasma marginale rickettsemia. | immunization of cattle with native msp1 induces protection against anaplasma marginale. the native immunogen is composed of a single msp1a protein and multiple, undefined msp1b polypeptides. in addition to the originally sequenced gene, designated msp1beta(f1), we identified three complete msp1beta genes in the florida strain: msp1beta(f2), msp1beta(f3), and msp1beta(f4). each of these polymorphic genes encodes a structurally unique msp1b protein, and unique transcripts can be identified during ... | 2000 | 10722587 |
| antigenic variation in the persistence and transmission of the ehrlichia anaplasma marginale. | tick-borne transmission of ehrlichial pathogens requires rickettsemic reservoir hosts to maintain a population of infected vectors. persistence in their respective mammalian hosts appears to be a common feature of the tick-transmitted ehrlichiae. how infection persists in immunocompetent hosts is unknown. in this review, we describe studies on anaplasma marginale, an ehrlichial pathogen of cattle, that support antigenic variation as a primary mechanism of persistence. | 2000 | 10742689 |
| strain diversity in major surface protein 2 expression during tick transmission of anaplasma marginale. | specific major surface protein 2 (msp2) variants are expressed by anaplasma marginale within the tick salivary gland and, following transmission, are expressed during acute rickettsemia. in previous work, we have shown that a restricted pattern of msp2 variants is expressed in the salivary glands of dermacentor andersoni ticks infected with the south idaho strain of a. marginale. now we demonstrate that the identical restriction does not apply to two other strains of a. marginale, and that diffe ... | 2000 | 10769008 |
| development of an elisa system for detection of anti-anaplasma marginale antibodies in cattle in brazil. | an elisa test was developed for detecting antibodies against anaplasma marginale in bovine sera. four antigenic preparations were produced from infected red blood cells. some aliquots of this preparation were stored at -70 degrees c with 30% dmso in phosphate-buffered saline (pbs) and others were lysed with 0.9% nh4cl and stored at -20 degrees c. typical anaplasmal structures were seen by electron microscopy in the antigenic preparations containing the erythrocytes that had been stored with dmso ... | 2000 | 10861192 |
| sequence and expression analysis of a surface antigen gene family of the rickettsia anaplasma marginale. | the tick-borne rickettsial organism, anaplasma marginale, causes a disease in cattle of world-wide economic significance. this disease, anaplasmosis, is characterized by severe hemolytic anemia, high levels of rickettsemia and, often, death in animals over 3years of age. animals that survive acute infection remain carriers, with continuous sub-microscopic cycles of rickettsemia that can persist for the lifetime of the animal. in the search for potential recombinant immunogens, it was discovered ... | 2000 | 10925201 |
| antigenic variation in vector-borne pathogens. | several pathogens of humans and domestic animals depend on hematophagous arthropods to transmit them from one vertebrate reservoir host to another and maintain them in an environment. these pathogens use antigenic variation to prolong their circulation in the blood and thus increase the likelihood of transmission. by convergent evolution, bacterial and protozoal vector-borne pathogens have acquired similar genetic mechanisms for successful antigenic variation. borrelia spp. and anaplasma margina ... | 2000 | 10998374 |
| risk of babesiosis and anaplasmosis in different ecological zones of santa cruz department, bolivia. | a cross-sectional study was done of seroprevalence of babesia bigemina, b.bovis, and anaplasma marginale in cattle from eastern bolivia, to characterise the risk of tick-borne disease in three ecological zones. nineteen farms were sampled in the subtropical humid zone, 13 in the dry subtropical zone and nine in the lower western valleys of the andean massif. the enzyme-linked immunosorbent assay was used. all three pathogens were widespread. for b. bovis, seroprevalences were high (75-78%) in th ... | 2000 | 11027858 |
| evaluation of a commercially available elisa kit for detection of antibodies to anaplasma marginale and anaplasma centrale in cattle in australia and zimbabwe. | a newly available competitive inhibition elisa kit for the serological diagnosis of anaplasmosis was evaluated in australia and zimbabwe. in australia the performance of the test was compared with the card agglutination test (cat). the assay was evaluated using negative sera collected from anaplasma-free herds, positive sera from experimentally infected cattle and sera from anaplasma marginale-endemic herds. the sensitivity and specificity of the elisa in australia were 100 % and 83,3 %, respect ... | 2000 | 11028743 |
| antigenic variation of anaplasma marginale by expression of msp2 mosaics. | anaplasma marginale is a tick-borne pathogen, one of several closely related ehrlichial organisms that cause disease in animals and humans. these ehrlichia species have complex life cycles that require, in addition to replication and development within the tick vector, evasion of the immune system in order to persist in the mammalian reservoir host. this complexity requires efficient use of the small ehrlichial genome. a. marginale and related ehrlichiae express immunoprotective, variable outer ... | 2000 | 11035716 |
| anaplasma marginale inactivated vaccine: dose titration against a homologous challenge. | the present study was performed to dose-titrate an anaplasma marginale experimental immunogen derived from partially purified initial bodies from three geographically different mexican strains. three five-bovine groups were inoculated twice on days zero and 21 with a. marginale initial bodies equivalent to 1.5 x 10(10) (group i), 3 x 10(10) (group ii) or 6 x 10(10) (group iii) infected erythrocytes mixed with stdcm adjuvant. a similar group served as non-vaccinated controls. all four groups were ... | 2000 | 11038126 |
| general review of tick species present in portugal. | at present, 24 species are known to occur in portugal: argas vespertilionis, ornithodoros maritimus and ornithodoros erraticus in argasidae; ixodes acuminatus, ixodes bivari, ixodes canisuga, ixodes frontalis, ixodes hexagonus, ixodes ricinus, ixodes simplex simplex, ixodes ventalloi, ixodes vespertilionis, dermacentor marginatus, dermacentor pictus', haemaphysalis hispanica, haemaphysalis inermis, haemaphysalis punctata, rhipicephalus bursa, rhipicephalus pusillus, rhipicephalus sanguineus, rhi ... | 1999 | 11071535 |
| tick-borne diseases of livestock in italy: general review and results of recent studies carried out in the apulia region. | this paper reviews basic information on the knowledge of tick-borne diseases, babesiosis, anaplasmosis and theileriosis, in horses, cattle, sheep and goats in italy with particular reference to the southern part of the country. it is stressed that there is limited knowledge about the parasite species present, their vectors, distribution, prevalence and impact on livestock production and there is the need to assess their epidemiology. a study carried out in the apulia region to assess the prevale ... | 1999 | 11071537 |
| identification of theileria buffeli/orientalis and babesia bigemina in apulian cattle using molecular techniques and study of changes in blood parameters. | recently several cases of theileriosis due to the haemoprotozoan theileria buffeli/orientalis have been recorded in the apulian region, italy. in this area other tick-borne pathogens were usually identified such as anaplasma marginale and babesia bigemina. outbreaks were recorded showing that these pathogens can be observed separately or in mixed infections. sub-clinical cases and carrier animals were also previously identified. a lack of specific techniques could not rule out the presence of ot ... | 1999 | 11071538 |
| development of sero-diagnostic and molecular tools for the control of important tick-borne pathogens of cattle in africa. | tick-borne diseases (tbds) are a major economic constraint to livestock production in sub-saharan africa. ilri is focussing on developing a range of products, such as vaccines, diagnostics and decision support services to underpin improved control programmes against these diseases. we have developed three highly sensitive and specific enzyme linked immuno-assays (elisas), which allow precise diagnosis of theileria parva, babesia bigemina and anaplasma marginale. these tests have been standardise ... | 1999 | 11071549 |
| identification and characterization of corpuscular, soluble and secreted antigens of a venezuelan isolate of anaplasma marginale. | anaplasma marginale is the etiological agent of anaplasmosis, a tick-transmitted disease with an important economic impact that affects cattle throughout the world. although, north american isolates of a. marginale and their antigens have been extensively studied, relatively little information is available on the antigenic composition of south american isolates. the characterization of diverse geographical isolates of a. marginale will result in a thorough antigenic profile and may lead to the i ... | 2000 | 11078939 |
| antigenic analysis of anaplasma marginale grown in bovine erythrocytes co-cultured with bovine endothelial cells. | two monoclonal antibodies (mabs) for a. marginale were used to test the antigenic integrity of a. marginale grown in vitro in bovine erythrocytes co-cultured with endothelial cells. both the mabs reacted in the indirect immunofluorescent antibody test with a. marginale grown in vitro and also detected the antigens in western immunoblots of sds-page separated antigens made from a. marginale infected erythrocytes from the cultures. furthermore, active replication was evident as [35s]-methionine is ... | 2000 | 11078951 |
| highly conserved regions of the immunodominant major surface protein 2 of the genogroup ii ehrlichial pathogen anaplasma marginale are rich in naturally derived cd4+ t lymphocyte epitopes that elicit strong recall responses. | genogroup ii ehrlichia, including the agent of human granulocytic ehrlichiosis, ehrlichia phagocytophila, and the bovine pathogen anaplasma marginale, express a markedly immunodominant outer membrane protein designated major surface protein 2 (msp2). msp2 is encoded by a multigene family, resulting in the expression of variant b cell epitopes. msp2 variants are sequentially expressed in the repeated cycles of rickettsemia that characterize persistent a. marginale infection and control of each ri ... | 2001 | 11145692 |
| strain composition of the ehrlichia anaplasma marginale within persistently infected cattle, a mammalian reservoir for tick transmission. | tick-borne ehrlichial pathogens of animals and humans require a mammalian reservoir of infection from which ticks acquire the organism for subsequent transmission. in the present study, we examined the strain structure of anaplasma marginale, a genogroup ii ehrlichial pathogen, in both an acute outbreak and in persistently infected cattle that serve as a reservoir for tick transmission. using the msp1alpha genotype as a stable strain marker, only a single genotype was detected in a disease outbr ... | 2001 | 11158120 |
| culture-derived parasites in vaccination of cattle against tick-borne diseases. | the major economically important tick-borne diseases of cattle are theileriosis, babesiosis, anaplasmosis, and cowdriosis. culture-derived attenuated schizonts of theileria annulata have proved to be safe for all types of cattle and they protect against tick-borne theileriosis. t. parva was also successfully grown in vitro; however, inoculation of cattle with allogeneic schizont-infected cells resulted in rejection and destruction of the parasites together with the host cells. the number of schi ... | 2000 | 11193616 |
| anaplasmosis control and diagnosis in south africa. | anaplasmosis is widespread in south africa with more than 99% of the total cattle population at risk. five tick species have been experimentally shown to be capable of transmitting anaplasma in south africa. mechanical transmission through blood contaminated instruments and biting flies also occurs. vaccination against anaplasma marginale by administration of an anaplasma centrale live-blood vaccine has been practiced in this country since 1912. although generally a mild pathogen, anaplasma cent ... | 2000 | 11193662 |
| integrated molecular diagnosis of theileria and babesia species of cattle in italy. | a reverse line blot hybridization (rlb) test was developed to specifically identify six theileria spp. (t. annulata, t. parva, t. mutans, t. velifera, t. taurotragi, and t. buffeli/orientalis) and three babesia spp. (b. bovis, b. bigemina, and b. divergens). no cross reaction was observed with other livestock pathogens (such as anaplasma marginale, a. centrale, a. ovis, cowdria ruminantium, trypanosoma brucei, t. congolense, and t. vivax). this method was used to test bovine blood samples collec ... | 2000 | 11193668 |
| homologous and heterologous immune reactions between venezuelan geographic isolates of anaplasma marginale. | | 2000 | 11193694 |
| analysis of the 16s rrna gene sequence of anaplasma centrale and its phylogenetic relatedness to other ehrlichiae. | the nucleotide sequence of the anaplasma centrale 16s rrna gene was determined and compared with the sequences of ehrlichial bacteria. the sequence of a. centrale was closely related to anaplasma marginale by both level-of-similarity (98.08% identical) and distance analysis. a species-specific pcr was developed based upon the alignment data. the pcr can detect a. centrale dna extracted from 10 infected bovine red blood cells in a reaction mixture. a. centrale dna was amplified in the reaction, b ... | 2001 | 11238202 |
| differential adhesion of major surface proteins 1a and 1b of the ehrlichial cattle pathogen anaplasma marginale to bovine erythrocytes and tick cells. | anaplasma marginale is a tick-borne ehrlichial pathogen of cattle for which six major surface proteins (msps) have been described. the msp1 complex, a heterodimer composed of msp1a and msp1b, was shown to induce a protective immune response in cattle and both proteins have been identified as putative adhesins for bovine erythrocytes. in this study the role of msp1a and msp1b as adhesins for bovine erythrocytes and tick cells was defined. msp1alpha and msp1beta1 genes from the oklahoma isolate of ... | 2001 | 11239934 |
| identification of antigenic differences that discriminate between cattle vaccinated with anaplasma centrale and cattle naturally infected with anaplasma marginale. | monoclonal antibodies were raised against the vaccine strain of anaplasma centrale used in australia. a monoclonal antibody that reacted with an 80 kda antigen was used to develop an a. centrale-specific fluorescent antibody test that will be useful for confirming species identity in patent infections. another monoclonal antibody that reacted with a 116 kda antigen was used to develop an a. centrale-specific competitive inhibition enzyme-linked immunosorbent assay (elisa) for the serological ide ... | 2001 | 11239938 |
| sensitivity and specificity of the complement fixation test for detection of cattle persistently infected with anaplasma marginale. | the complement fixation (cf) test commonly is used to identify cattle infected with anaplasma marginale prior to interstate or international movement. estimates of the accuracy of the cf test in detecting animals persistently infected with a. marginale vary widely. in this study, the sensitivity and specificity of the cf test for detection of carrier animals was determined using serum from 232 cattle previously defined as a. marginale positive or negative by nested polymerase chain reaction meth ... | 2001 | 11243370 |
| efficient use of a small genome to generate antigenic diversity in tick-borne ehrlichial pathogens. | ehrlichiae are responsible for important tick-transmitted diseases, including anaplasmosis, the most prevalent tick-borne infection of livestock worldwide, and the emerging human diseases monocytic and granulocytic ehrlichiosis. antigenic variation of major surface proteins is a key feature of these pathogens that allows persistence in the mammalian host, a requisite for subsequent tick transmission. in anaplasma marginale pseudogenes for two antigenically variable gene families, msp2 and msp3, ... | 2001 | 11274438 |
| [molecular tools in the epidemiology of tick-borne bacterial diseases]. | molecular tools have been used to detect rickettsiae in ticks. in ixodes ricinus ticks collected in france, we detected for the first time there an emerging pathogen, rickettsia helvetica, and an ehrlichia sp, closely related to the agent of human granulocytic ehrlichiosis. in guadeloupe (french west indies), we described the occurrence of african tick-bite fever due to rickettsia africae, which had been previously reported in sub-saharan africa only. in africa, we completed our knowledge about ... | 2001 | 11282521 |
| antigenic variation of anaplasma marginale: major surface protein 2 diversity during cyclic transmission between ticks and cattle. | the rickettsial pathogen anaplasma marginale expresses a variable immunodominant outer membrane protein, major surface protein 2 (msp2), involved in antigenic variation and long-term persistence of the organism in carrier animals. msp2 contains a central hypervariable region of about 100 amino acids that encodes immunogenic b-cell epitopes that induce variant-specific antibodies during infection. previously, we have shown that msp2 is encoded on a polycistronic mrna transcript in erythrocyte sta ... | 2001 | 11292724 |
| use of repetitive dna elements to define genetic relationships among anaplasma marginale isolates. | anaplasma marginale genomic dna was tested for the presence of repetitive extragenic palindromic (rep) and enterobacterial repetitive intergenic consensus (eric)-like sequences in order to evaluate the genetic diversity of multiple a. marginale isolates. a. marginale isolates were obtained from cattle of six different states of brazil, from the us and an anaplasma centrale strain was obtained from uruguay. patterns obtained from a. marginale isolates varied from 14 to 17 fragments by rep-polymer ... | 2001 | 11313126 |
| molecular phylogeny and biogeography of north american isolates of anaplasma marginale (rickettsiaceae: ehrlichieae). | anaplasma marginale (a. marginale) is a tick-borne ehrlichial pathogen of cattle that causes the disease anaplasmosis. six major surface proteins (msps) have been identified on a. marginale from cattle and ticks of which three, msp1a, msp4 and msp5, are from single genes and do not vary within isolates. the other three, msp1b, msp2 and msp3, are from multigene families and may vary antigenically in persistently infected cattle. several geographic isolates have been identified in the united state ... | 2001 | 11337128 |
| phylogenetic relationships of anaplasma marginale and 'ehrlichia platys' to other ehrlichia species determined by groel amino acid sequences. | the heat-shock protein (groel) genes of anaplasma marginale, ehrlichia muris and 'ehrlichia platys' were sequenced and compared with the groel of other species of ehrlichia. the groel amino acid sequences of a. marginale and 'e. platys' were most similar to the groel sequence of ehrlichia phagocytophila, with which they formed one group with 6-10% divergence. the e. muris groel was most closely related to the groel of two unclassified strains (hf-565 and anan), then to ehrlichia chaffeensis, ehr ... | 2001 | 11414267 |
| expression of anaplasma marginale major surface protein 2 variants in persistently infected ticks. | anaplasma marginale, an intraerythrocytic ehrlichial pathogen of cattle, establishes persistent infections in both vertebrate (cattle) and invertebrate (tick) hosts. the ability of a. marginale to persist in cattle has been shown to be due, in part, to major surface protein 2 (msp2) variants which are hypothesized to emerge in response to the bovine immune response. msp2 antigenic variation has not been studied in persistently infected ticks. in this study we analyzed msp2 in a. marginale popula ... | 2001 | 11447197 |
| health protocol for translocation of free-ranging elk. | when considering an elk (cervus elaphus) restoration program, wildlife managers must evaluate the positive and negative elements of translocation. we prepared this protocol to give an overview of health considerations associated with translocation of elk, with an emphasis on movement of free-ranging elk from western north america to the southeastern usa. we evaluated infectious agents and ectoparasites reported in elk from two perspectives. first, we made a qualitative estimate of the ability of ... | 2001 | 11504216 |
| detection of haemoparasites in cattle by reverse line blot hybridisation with a note on the distribution of ticks in sicily. | a reverse line blot hybridisation (rlb) of 21 oligonucleotides with polymerase chain reaction (pcr) amplified regions of 16s rrna (ehrlichia/anaplasma group) or 18s rrna (babesia/theileria group) genes of haemoparasites detected theileria annulata, t. buffeli/orientalis, babesia bovis, b. bigemina, b. divergens, ehrlichia bovis, anaplasma marginale, a. centrale and unknown species within the rickettsia tribe.a very high prevalence of mixed infections was detected, which indicated that animals in ... | 2001 | 11511414 |
| ingenious gene generation. | | 2001 | 11514195 |
| citrate synthase gene sequence: a new tool for phylogenetic analysis and identification of ehrlichia. | the sequence of the citrate synthase gene (glta) of 13 ehrlichial species (ehrlichia chaffeensis, ehrlichia canis, ehrlichia muris, an ehrlichia species recently detected from ixodes ovatus, cowdria ruminantium, ehrlichia phagocytophila, ehrlichia equi, the human granulocytic ehrlichiosis [hge] agent, anaplasma marginale, anaplasma centrale, ehrlichia sennetsu, ehrlichia risticii, and neorickettsia helminthoeca) have been determined by degenerate pcr and the genome walker method. the ehrlichial ... | 2001 | 11526124 |
| seroprevalences of vector-transmitted infections of small-holder dairy cattle in coastal kenya. | a cross-sectional study was carried out from july to september 1989 in kaloleni division, coast province, kenya to estimate the prevalence of vector-transmitted diseases in small-holder dairy cattle and to identify the risk factors associated with different management systems. one hundred and thirty of the 157 herds with dairy cattle in kaloleni division were surveyed. these were from three agro-ecological zones (coconut-cassava, cashew nut-cassava and livestock-millet), comprised two management ... | 2001 | 11566374 |
| cd4(+) t lymphocytes from calves immunized with anaplasma marginale major surface protein 1 (msp1), a heteromeric complex of msp1a and msp1b, preferentially recognize the msp1a carboxyl terminus that is conserved among strains. | native major surface protein 1 (msp1) of the ehrlichial pathogen anaplasma marginale induces protective immunity in calves challenged with homologous and heterologous strains. msp1 is a heteromeric complex of a single msp1a protein covalently associated with msp1b polypeptides, of which at least two (designated msp1f1 and msp1f3) in the florida strain are expressed. immunization with recombinant msp1a and msp1b alone or in combination fails to provide protection. the protective immunity in calve ... | 2001 | 11598059 |
| population structure of plasmodium falciparum isolates during an epidemic in southern mauritania. | while the population structure of plasmodium falciparum is well analysed in selected areas with high malaria endemicity in east and west africa, only limited data are available for low endemicity regions bordering the saharan desert. this is one of the first studies for the sahel, where atypically strong rainfalls in 1998 and 1999 led to a severe outbreak of falciparum malaria in south-east mauritania. during a study on in vivo-drug resistance against chloroquine we collected blood samples of pa ... | 2001 | 11679123 |
| immunization of cattle with anaplasma marginale derived from tick cell culture. | anaplasmosis is a hemolytic disease of cattle caused by the ehrlichial tick-borne pathogen anaplasma marginale. killed vaccines used for control of anaplasmosis in the us used antigen harvested from infected bovine erythrocytes which was often contaminated with bovine cells and other pathogens. in this study, we performed an initial cattle trial to test a. marginale harvested from tick cell culture as an immunogen for cattle. eleven yearling holstein cattle were immunized with the cell culture-d ... | 2001 | 11705661 |
| major surface protein 1a effects tick infection and transmission of anaplasma marginale. | anaplasma marginale, an ehrlichial pathogen of cattle and wild ruminants, is transmitted biologically by ticks. a developmental cycle of a. marginale occurs in a tick that begins in gut cells followed by infection of salivary glands, which are the site of transmission to cattle. geographic isolates of a. marginale vary in their ability to be transmitted by ticks. in these experiments we studied transmission of two recent field isolates of a. marginale, an oklahoma isolate from wetumka, ok, and a ... | 2001 | 11730800 |
| specific expression of anaplasma marginale major surface protein 2 salivary gland variants occurs in the midgut and is an early event during tick transmission. | infectivity of anaplasma spp. develops when infected ticks feed on a mammalian host (transmission feed). specific anaplasma marginale major surface protein 2 (msp2) variants are selected for within the tick and are expressed within the salivary glands. the aims of this study were to determine when and where msp2 variant selection occurs in the tick, how msp2 expression is regulated in salivary glands of transmission-feeding ticks, and whether the number of a. marginale organisms per salivary gla ... | 2002 | 11748171 |
| mapping antigenic sites of an immunodominant surface lipoprotein of mycoplasma agalactiae, avgc, with the use of synthetic peptides. | as a first step toward the design of an epitope vaccine to prevent contagious agalactia, the strongly immunogenic 55-kda protein of mycoplasma agalactiae was studied and found to correspond to the avgc protein encoded by the avgc gene. the avg genes of m. agalactiae, which encode four variable surface lipoproteins, display a significant homology to the vsp (variable membrane surface lipoproteins) genes of the bovine pathogen mycoplasma bovis at their promoter region as well as their n-terminus-e ... | 2002 | 11748179 |
| expression of major surface protein 2 variants with conserved t-cell epitopes in anaplasma centrale vaccinates. | major surface protein 2 (msp-2), identified as a protection-inducing immunogen against anaplasma marginale challenge, is an immunodominant outer membrane protein with orthologues in all examined anaplasma species. although immunization with live anaplasma centrale has long been used to induce protection against acute disease upon challenge with virulent a. marginale, its msp-2 structure and whether msp-2 variants are generated during persistence of the vaccine strain was unknown. in this study, ... | 2002 | 11796593 |