Publications

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the immunisation of cattle against east coast fever (theileria parva infection) using tetracyclines: a review of the literature and a reappraisal of the method. 196514344196
application of the indirect fluorescent antibody test in experimental east coast fever (theileria parva infection of cattle). 19714934252
east coast fever: field challenge of cattle immunised against theileria parva (muguga). 19724210445
east coast fever: quantitative studies of theileria parva in cattle. 19744213046
the specific immunoglobulin response in cattle immunized with isolated theileria parva antigens. 19744213482
the effect of leucocytes from cattle immunized against east coast fever on the migration of bovine lymphoblasts infected with theileria parva. 1975812298
[electron microscope studies on developmental stages of theileria parva (theiler, 1904) in the intestine of the tick hyalomma anatolicum excavatum (koch, 1844) (author's transl)].the developmental stages of theileria parva within the intestine of ticks were studied by electron microscopy. on the 2nd-4th day post repletionem (p.r.) the intestine of the ticks contained numerous stages, which were very similar to microgamonts and microgametes of haemosporidia. from these results it seemed likely that gamogony of theileria parva takes place in the intestine of ticks, too. the microgamont-like stages were spear-head-like; they measured about 10.5 mum in length with a maximum ...1976821188
the effect of calf lymph and bovine red blood cells on in vitro cultivation of theileria parva-infected lymphoid cells.calf lymph introduced to cultures of theileria parva-infected lymphoid cells caused a stimulation of both cells and parasites resulting in the formation of rapidly dividing cells and the developmental stages of the parasite. the presence of piroplasms was confirmed when washed bovine red blood corpuscles were added to the culture1976968954
an ultrastructural study of heterokaryons derived from theileria parva-infected bovine lymphoblasts and ehrlich ascites tumour cells.an ultrastructural study was made of sendai virus induced heterokaryons derived from theileria parva-infected lymphoblasts and ehrlich ascites tumour cells. when fusion occurred, parasites were successfully integrated into the cytoplasm of the resulting heterokaryons where they appeared as morphologically normal macroschizonts. homokaryon formation was also noted. this occurred frequently between ehrlich ascites tumour cells and rarely with lymphoblasts. a small proportion of heterokaryons conta ...1976987607
immunization against east coast fever (theileria parva infection of cattle) by infection and treatment: chemoprophylaxis with n-pyrrolidinomethyl tetracycline.cattle were immunized against east coast fever by the inoculation of a tick-derived stabilate of theileria parva infective particles and the intramuscular injection, at daily intervals, of n-pyrrolidinomethyl tetracycline at a dose level of 5 mg/kg. four doses of the tetracycline, starting on the day of inoculation of the infective stabilate, minimised the ecf reactions in the cattle during immunization. immunity to homologous t. parva stabilate challenge was demonstrated in 27 out of 27 cattle ...1977910283
antibody-dependent cell-mediated cytotoxicity in cattle: activity against 51cr-labeled chicken erythrocytes coated with protozoal antigens.bovine mononuclear cells in the presence of bovine anti-chicken erythrocyte sera at high dilutions induce release of chromium-51 from labeled chicken erythrocytes. bovine effector cells are capable of recognizing both bovine immunoglobulin g(1) and bovine immunoglobulin g(2); in contrast, human effector cells only recognize immunoglobulin g(1). effector cell activity of bovine mononuclear cells is equally distributed between peripheral blood and spleen. as in other species, thymus and lymph node ...1978103832
induction of infective stages of theileria parva by exposure of host ticks to high temperature.it was demonstrated that theileria parva parasites infective to cattle could be induced by exposure of infected adult rhipicephalus appendiculatus ticks to 37 degrees c. the production of the sporozoites of t parva was not as efficient as by feeding ticks on rabbits.1979119344
experimental therapy of theileriosis.a tissue culture method was used to screen compounds for activity against theileria parva, and demonstrated that the hydroxy-alkylated naphthoquinones, 'menoctone' and 993c were highly active, with ed50 values around 0,005 mg/l. when injected into cattle artificially infected the t. parva, menoctone cured all of 7 cattle at a total dosage of 10 mg/kg injected intravenously (i.v.). a further trial showed that injection of menoctone, 10 mg/kg, as a single dose gby the intramuscular (i.m.) route wa ...1979553970
organ culture of rhipicephalus appendiculatus with maturation of theileria parva in tick salivary glands in vitro.a technique is described for the organ culture of rhipicephalus appendiculatus ticks. whole, unfed adult ticks with the dorsal integument removed, known as backless tick explants, were cultured in enriched leibovitz' l-15 medium in which they remained active for at least 32 days at 28 degrees c and 9 days at 36 degrees c. development of theileria parva, as demonstrated by methyl green-pyronin staining, occurred in the salivary glands of infected backless tick explants held for 8 days at 28 degre ...19806110322
generation of autologous mixed leucocyte reactions during the course of infection with theileria parva (east coast fever) in cattle.during the course of east coast fever (ecf) in cattle, an examination was made of the evolution of autologous mixed leucocyte reactions (mlr) between normal responder lymphocytes collected prior to infection and stimulators cells prepared from infected lymphoid organs at intervals after challenge. proliferative responses were induced by spleen cells, peripheral blood leucocytes (pbl) and cells (lnc) from both regional and distant lymph nodes. the proliferation by normal pbl in response to lnc oc ...19806447668
bovine lymphocyte antigens (bola) of bovine lymphocytes and derived lymphoblastoid lines transformed by theileria parva and theileria annulata.the bola phenotypes of lymphocytes from seven cattle have been compared with those of 19 lymphoblastoid cell lines derived from them by infection in vitro with either theileria parva or t. annulata. two long-established lines were also studied. in all cases except one, the bola phenotypes of the lymphoblastoid lines were identical with those of the original animal from whose lymphocytes they were derived. the one exception was a chimeric twin where a minor population appeared to have been transf ...19806774305
theileriosis: cell-mediated and humoral immunity.the protozoan parasite of cattle theileria parva transforms lymphoid cells into permanently proliferating cell lines. antibodies reacting with parasite antigens can be detected by several methods, but there is no evidence that they are protective. two cellular responses to infection have been found. in immune animals powerful cytotoxicity restricted to syngeneic infected cells rapidly appears; this is thought to be mediated by t-lymphocytes and to play a major role in resistance to reinfection. ...19816781356
the effect of irradiation on the susceptibility of rhipicephalus appendiculatus ticks to theileria parva infection.irradiation doses of 800 rad. or less had no detectable effect on the subsequent development of unfed nymphal rhipicephalus appendiculatus ticks. doses of 1600 rad. or above impaired feeding and moulting and delayed the subsequent development of unfed nymphs. at 6400 rad. no ticks completed their moult. unfed nymphal r. appendiculatus irradiated at 0, 400, 800 and 1600 rad. were applied to 3 cattle infected with t. parva (kiambu 4). the theileria infections in the salivary glands of the resultan ...19816787541
isoenzyme studies on theileria (protozoa, sporozoa). enzyme activity associated with the erythrocytic stage.bovine blood containing piroplasms of theileria parva, as well as non-infected blood, was lysed and subjected to iso-electric focussing. staining for 13 different enzymes revealed parasite-associated bands of glucose phosphate isomerase (gpi) activity, not of any of the other enzymes. there were no variations between individual donor animals in the host cell gpi bands and these bands did not interfere with the recognition of the parasite-associated bands, so that purification of the piroplasms w ...19816787731
the fine structural relationship between theileria schizonts and infected bovine lymphoblasts from cultures.the fine structure of theileria-lymphoblast relationship was studied using cultured bovine lymphoblastoid cells infected with theileria parva, t lawrencei, or t. annulata. the major findings of this study were: (1) the presence of a very active golgi complex with the associated annulate lamelae; (b) the presence of cytoplasmic microtubules which joined the parasites and host cell centriole during lymphoblast mitosis; and (c) the absence of morphological evidence to suggest that the host cell dev ...19816787815
adoptive transfer of immunity to infection with theileria parva (east coast fever) between cattle twins.resistance to a lethal challenge with theileria parva (muguga) was transferred between two pairs of chimeric bovine co-twins with 5 to 9 x 10(10) syngeneic thoracic duct leucocytes from the immunised partner. in one recipient, the infection became established and was eliminated. in the second recipient, the disease did not become patent. both recipients were immune to a second challenge of t parva (muguga). the results confirm both that chimeric twin calves are suitable as a model for the adopti ...19816789424
theileriosis in uganda. parasitological and serological responses in cattle continually exposed to natural infection.cattle living in a circumscribed area in uganda, where both theileria parva and t. mutans occurred naturally, were monitored for periods of up to 1 year by examination of blood and lymph node smears for parasites and the indirect fluorescent antibody test for antibodies to theileria. uninfected control cattle were added at intervals to ensure continuous challenge and to monitor the challenge. although all 29 control animals became infected with t. parva, challenge was light at first as mortality ...19816789516
in vitro activity of 2-alkyl-3-hydroxy-1,4-naphthoquinones against theileria parva.a variety of naphthoquinones have veen prepared and evaluated in vitro against the causative agent of the cattle disease east coast fever-theileria parva infection. it is concluded from structure-activity studies that a 2-hydroxyl moiety es essential for high activity. the most active compounds tested were 2-hydroxy-3-alkyl-1,4-naphthoquinones in which the alkyl moiety was cyclohexyl, cyclohexylcyclohexyl, tridecyl, or tetradecyl.19816790703
the initial stages of infection of cattle cells with theileria parva sporozoites in vitro.large numbers of theileria parva sporozoites were separated from rhipicephalus appendiculatus adult ticks by filtration and were then concentrated by centrifugation. the sporozoites were incubated at 37 degrees c with leucocytes from 6 cattle of bos indicus and b. taurus types. giemsa-stained smears and living preparations under interference contrast microscopy were used to follow the course of the infection of the leucocytes with sporozoites. sporozoites were seen to attach rapidly to about 25% ...19816791118
epidemiology of east coast fever: some effects of temperature on the development of theileria parva in the tick vector, rhipicephalus appendiculatus.the moulting behaviour of nymphal rhipicephalus appendiculatus from the laboratory colony and 3 field strains from kenya was greatly influenced by constant temperatures between 18 and 37 degrees c but was not significantly different for the 4 tick strains. six batches of r. appendiculatus (muguga laboratory) nymphs which had engorged on cattle parasitaemic with 4 stocks of theileria parva (kiambu 4, kiambu 5, muguga and mbita 4) isolated in kenya were incubated at constant temperatures between 1 ...19816791119
theileria parva: kinetics of infection in the lymphoid system of cattle. 19816791953
chemotherapy of sarcosporidiosis and theileriosis in domestic animals.in goats infected with sarcocystis capracanis and sheep infected with s. ovicanis prophylactical application of halofuginone prevented clinical symptoms but also prevented the development of immunity to homologous challenge. halofuginone was most effective in the treatment of acute sarcosporidiosis at a dose of 0.67 mg/kg b. w. on two successive days in both goats and sheep. in acute bovine theileriosis (theileria parva and t. annulata) halofuginone was effective at a single dose about of 1.2 to ...19816797156
theileria parva: isolation of macroschizonts from in vitro propagated lymphoblastoid cells of cattle. 19816797837
treatment of stabilate-induced east coast fever with menoctone.groups of cattle were infected with theileria parva by the injection of stabilate material prepared from infected rhipicephalus appendiculatus ticks. the cattle were treated with the hydroxy alkylated naphthoquinone, menoctone, which was administered intravenously (i/v), intramuscularly (i/m), or orally (p/o) up to 4 days after the disease became apparent. the disease was rapidly controlled and all the treated cattle (15) recovered following (i/v) or i/m injection of a single dose of menoctone a ...19816806956
kinetics of infection with theileria parva (east coast fever) in the central lymph of cattle.during the course of a lethal infection with theileria parva in susceptible cattle, the dissemination of the parasite was examined in central lymph efferent from superficial lymph nodes in the thoracic duct. from the regional node, lymphocytes containing macroschizonts of t. parva were detected in efferent lymph 8 days after challenge where their appearance coincided with a dramatic increase in the output of lymphoblasts. the number of infected cells reached a maximum around day 14, when 60-65% ...19816806969
electron microscopical study on the effect of halofuginone on theileria parva.the effect of halofuginone (stenorol) on schizonts of theileria parva was studied by means of the electron microscope. after administration of 1,2 mg halofuginone per kg, it was observed that infected lymphocytes burst apart, whereas the intracellular parasites were at first little affected, showing some expansion of the perinuclear spaces. once they were released from the cells, the schizonts degenerated completely. apparently they are not capable of surviving outside the host cells. probably t ...19816808727
theileria? taurotragi: a probable agent of bovine cerebral theileriosis.a case of bovine cerebral theileriosis was confirmed at autopsy on a farm where 4 animals out of 70 died. all were less than 2 years old and all showed nervous signs. serologically, no evidence was found of theileria mutans or the theileria parva group in young animals born on the farm. six out of 13 calves 6-9 months of age were, however, serologically positive for theileria? taurotragi and it was concluded this species was the probable cause of death of the 4 animals.19816801568
characterization of the effector cell that mediates cytotoxicity against theileria parva (east coast fever) in immune cattle.after fractionation and depletion of peripheral blood leukocytes from cattle that were immune to theileria parva, the effector cells which mediated cytotoxicity against parasitized autologous lymphocytes were considered to be thymusderived lymphocytes.19816972917
the eradication of east coast fever in south africa.an epizootic of east coast fever followed the introduction of a highly fatal strain of theileria parva parva into south africa in 1902. this is a brief historical review of the campaign to control and finally eradicate the disease through tick control, quarantine and the slaughter of exposed cattle. the disease was responsible for an estimated 5.5 million deaths before its final eradication in 1954.19817021829
salivary gland of the tick vector (r. appendiculatus) of east coast fever. i. ultrastructure of the type iii acinus.the brown ear tick rhipicephalus appendiculatus is the vector for east coast fever, a disease that seriously limits livestock production in east africa. the sporozoites of the infectious agent theileria parva develop in the tick salivary gland. this paper describes the organization of the type iii acinus of the gland and establishes unambiguous ultrastructural criteria for identification of the three secretory cell types: the d-cell, e-cell and f-cell. these observations are basic to exploration ...19817198303
sequential study of lymph node and splenic aspirates during theileria parva infection in calves.the development of theileria parva infection in calves with partially exteriorised spleens was studied. macroschizont infected cells were detected in the spleen and prescapular lymph node on the same day following inoculation of stabilate in front of the ear, indicating a haematogenous dissemination of the parasite. macroschizont infection reached a peak on day 14 in the lymph nodes and in the spleen. the time to the appearance of of piroplasms and the development of parasitaemia were similar in ...19817255908
genetically restricted cell-mediated cytotoxicity in cattle immune to theileria parva. 19816451808
cell-mediated immune responses to theileria parva (east coast fever) during immunization and lethal infections in cattle.leucocytes from cattle with lethal or sub-lethal infections with theileria parva were examined for responses in autologous mixed lymphocyte reactions (mlr) and for specific and non-specific cytotoxicity against cultured cell lines. during lethal infections, lymphoblasts isolated from central lymph from days 8 to 14 stimulated proliferation in autologous lymphatic lymphocytes and peripheral blood leucocytes (pbl), although cytotoxicity was not generated in such cultures. after day 14, non-specifi ...19816454652
monitoring theileria parva infection in adult rhipicephalus appendiculatus ticks.a rapid method is described for preparing and staining salivary glands of rhipicephalus appendiculatus ticks infected with theileria parva. the technique, involving the use of a modified methyl green pyronin stained minimizes the risk of losing material and allows examination of stained glands within minutes of preparation. the technique was applied in a series of studies in which ticks were either infected with t. parva under different conditions, or maturation of parasites in adult ticks was s ...19816163125
assessment of theileria infections in rhipicephalus appendiculatus ticks collected from the field.collections of adult rhipicephalus appendiculatus ticks were made from bait cattle and vegetation at two field sites in areas of kenya in which east coast fever caused by theileria parva is endemic. these ticks, together with two experimentally infected batches of ticks, were examined for infection with theileria by four methods. whole salivary glands were stained with methyl green pyronin or feulgen's stain. whole ticks were ground in medium, the suspensions were filtered and centrifuged and th ...19816166132
a comparative study of the disease in cattle caused by theileria parva or t. lawrencei: ii. hematology, clinical chemistry, coagulation studies and complement.theileria lawrencei tick-derived stabilate infection of 8 cattle resulted in the development of panleukopenia and hypoproteinemia. in addition to these changes, t. parva infection caused mild normocytic, normochromic, non-responsive anemia at either of two dose rates. disseminated intravascular coagulation, as indicate by positive protamine paracoagulation tests, prolonged prothrombin and partial thromboplastin times, and thrombocytopenia, developed in cattle infected with either of the theileri ...19827201709
bovine immune response to theileria parva: neutralizing antibodies to sporozoites.the role of antibodies in the neutralization of sporozoites of theileria parva was investigated. it was found that serum obtained from cattle recovered from east coast fever (ecf) and rabbits immunized with sporozoites was capable of neutralizing the parasites. the serum was then fractionated by gel filtration and anion exchange chromatography to identify which antibody class or subclass was responsible for the neutralization. in bovine hyperimmune serum the neutralizing capacity was in the frac ...19826802745
the entry of sporozoites of theileria parva into bovine lymphocytes in vitro. electron microscopic observations.the entry of sporozoites of theileria parva into bovine lymphoid cells in vitro was studied with the electron microscope. endocytosis is completed in less than 10 min. no local mobilization of actin or other cytoskeletal elements is detected in the cytoplasm of the cell being invaded and no engulfing pseudopods are formed. at the site of initial contact, the membranes of parasite and host cell come into very close apposition. as the zippering up of the membranes spreads laterally, the sporozoite ...19826806100
comparison of the antitheilerial effect of wellcome 993c and halofuginone.the efficacy of wellcome compound 993c and halofuginone was compared using cattle artificially infected with theileria parva and using in vitro cultures of t parva. at a total dose of 20 mg/kg administered by the intramuscular route, 993c cured all nine cattle of advanced theileriosis and no major recrudescences of the infection occurred. halofuginone was given by mouth at 1.2 mg/kg and cured five cattle of early clinical theileriosis, but significant recrudescences of infection occurred. halofu ...19826806876
salivary gland of the tick vector of east coast fever. iii. the ultrastructure of sporogony in theileria parva.sporogony of the sporozoan theileria parva in the salivary gland of the tick vector of east coast fever was studied in electron micrographs. the findings differ in several respects from previous interpretations based upon light microscopy. cytokinesis of the primary sporoblast to form secondary and tertiary sporoblasts is not substantiated. instead it is suggested that the parasite develops as a ramifying, multinucleate syncytium rapidly increasing in size and complexity until it gives rise to m ...19826806940
the response of bos taurus and bos indicus cattle types to inoculation of lymphoblastoid cell lines infected with theileria parva schizonts.in a preliminary experiment eight bos indicus type cattle were inoculated with 10(9) cells of a bos taurus lymphoblastoid cell line infected with theileria parva schizonts. four cattle showed patent infections and one died of theileriosis. on challenge of the surviving cattle with a tick derived stabilate of the same stock of t. parva no animal died of theileriosis. to test the susceptibility of bos taurus and bos indicus cattle to cell lines of both cattle types infected with t. parva of the sa ...19826808728
salivary gland of the tick vector of east coast fever. iv. cell type selectivity and host cell responses to theileria parva.responses of cells in the tick salivary gland to parasitism by theileria parva were studied by electron microscopy. the gland is composed of three distinct types of acini (i, ii, iii) which together include ten or more different cell types. of some 30 infected cells observed in the present study, all were e-cells of acinus iii. the parasite thus exhibits a high degree of selectivity for acinus and cell type. the glandular cell invaded undergoes massive hypertrophy and accumulates glycogen deposi ...19826810500
lack of reactivity of sera from theileria parva-infected and recovered cattle against cell membrane antigens of theileria parva transformed cell lines.sera from theileria parva infected, recovered and rechallenged cattle were tested in complement-dependent cytotoxicity, membrane immunofluorescence and antibody-dependent cellular cytotoxicity assays for the presence of antibodies against cell membrane antigens of t. parva transformed cell lines. in the complement-dependent antibody-mediated cytotoxicity assay, sera from lethally infected animals were negative. some recovered cattle showed a positive reaction, but such reactions were also observ ...19826812275
surface membrane components of theileria spp piroplasms and associated complement fixation activity.theileria parva (parva) piroplasms were examined for complement fixation (cf) activity with sera from cattle immune to t parva (parva) (muguga). the piroplasms were found to be highly antigenic, and the antigens responsible for this cf reactivity were completely insoluble in aqueous media. the antigens were traced through a variety of fractionation procedures and the fractions examined by electrophoresis in the presence of sodium docedyl sulphate. antigenically active preparations were found alw ...19826813929
the influence of various bovine sera on the maintenance of theileria parva lymphoblastoid cell culture.theileria parva infected lymphoblastoid bovine cells were grown in a medium based on hepes-buffered rpmi 1640 with glutamine and antibiotics, supplemented with bovine serum. there were no significant differences in growth rate, viability, and percentage of infected cells when the substrate contained 10 or 20 per cent of either commercially available newborn calf serum of serum prepared from adult non-infected friesian cattle or of serum prepared from a friesian calf immunised against east coast ...19826815877
cycle of bovine lymphoblastoid cells parasitised by theileria parva.the events were studied which occurred during different stages of the cell cycle of bovine lymphoblastoid cells infected with the parasite theileria parva. the mean number of nuclei in macroschizonts was about 16 for cells in interphase and 30 for those in metaphase. pulse labelling with 3h thymidine showed that macroschizonts normally incorporated thymidine when the host cell was in early mitosis. thymidine incorporation by macroschizonts thus occurred at a different stage in the cell cycle to ...19826818647
indirect fluorescent antibody test for experimental and epizootiological studies on east coast fever (theileria parva infection in cattle). evaluation of a cell culture schizont antigen fixed and stored in suspension.a schizont antigen for the indirect fluorescent antibody test against theileria parva was prepared from a t parva-infected bovine lymphoblastoid cell line by fixing the cells in suspension with a mixture of acetone and formaldehyde. the antigen was stored in suspension in phosphate buffered saline for one and a half years at -60 degrees c without loss of activity; the antigen could also be lyophilised. the fluorescence of the intracellular schizonts was bright and specific with t parva positive ...19826818649
generation of cell-mediated cytotoxicity to theileria parva (east coast fever) after inoculation of cattle with parasitized lymphoblasts.the participation of genetically restricted cell-mediated lympholysis (cml) in protective immunity against theileria parva was examined in cattle inoculated with autologous and allogeneic parasitized lymphoblasts. the majority of cattle given 10(7) infected allogeneic cells were protected against infection with the homologous parasite. animals inoculated with drug-cured lymphoblasts, normal allogeneic lymph node cells (lnc), or a combination of lnc and parasitized allogeneic cells were fully sus ...19826798110
chemotherapy of theileria parva lawrencei infections in cattle with halofuginone.halofuginone lactate, given once orally at a dosage rate of 1,2 mg/kg body mass on the 1st, 3rd or 5th days of fever, resulted in the recovery of only 1 out of 5 splenectomized cattle. three splenectomized animals, treated on the 1st as well as the 4th day of fever, recovered and were then carriers. six untreated controls all died. the potential value of a chemotherapeutic agent for theileria parva lawrencei infections in south africa is discussed.19836877791
immune responses of cattle to theileria parva (east coast fever): specificity of cytotoxic cells generated in vivo and in vitro.examination of the specificity of cytotoxicity generated in vitro and in vivo against infected bovine lymphoblasts revealed that cytotoxic t lymphocytes (ctl) obtained from cattle immune to theileria parva recognized parasite-induced alterations associated with major histocompatibility complex (mhc) antigens on the membrane of infected autologous cells. by comparison, cytotoxicity generated in vitro in an autologous theilerial-lymphocyte culture (autlc) contained both ctl and activity akin to th ...19836187669
activity of 10 naphthoquinones, including parvaquone (993c) and menoctone, in cattle artificially infected with theileria parva.ten naphthoquinones, including parvaquone (993c) (clexon; wellcome) and menoctone, were tested for activity in cattle artificially infected with theileria parva, the causative organism of east coast fever (ecf). parvaquone cured all 14 cattle treated with a single dose of 20 mg/kg intramuscularly and all five treated twice with 10 mg/kg intramuscularly. menoctone cured seven of 10 cattle treated with a single dose of 5 mg/kg intramuscularly. of 25 untreated control cattle, 22 died of ecf. none o ...19836665318
protein antigens of theileria parva macroschizonts and immune precipitation studies.the proteins of purified macroschizonts from theileria parva, t. lawrencei, and t. taurotragi were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. the major proteins of all species had molecular weights of 120,000, 70,000, 65,000, 62,000, 55,000, 44,000, and 35,000. all further experiments were carried out with t. parva. using 125i surface labelling it was established that proteins with molecular weights of 70,000, 50,000, and 44,000 were membrane constituents. staphylococ ...19836402582
rhipicephalus zambeziensis as a vector of bovine theileriae.rhipicephalus zambeziensis was shown experimentally to transmit theileria parva parva in cattle from nymph to adult and theileria parva lawrencei, theileria parva bovis and theileria taurotragi from larva to nymph and nymph to adult. in a single trial the tick failed to transmit theileria mutans. the tick is believed to be a vector of t. parva lawrencei in the field in zimbabwe.19836405516
infection of mammalian cells with theileria species.experiments were carried out to determine the susceptibility of mammalian cells to infection with different species of theileria in vitro. sporozoites of theileria parva (parva), theileria parva (lawrencei) and theileria taurotragi were isolated from rhipicephalus appendiculatus ticks by grinding infected ticks in medium, filtering the suspension and concentrating by centrifugation. the sporozoites were used in attempts to infect in vitro peripheral blood leucocytes harvested from 16 different m ...19836406967
transmission of theileria parva by a population of rhipicephalus appendiculatus under simulated natural conditions.a 2 hectare paddock on the muguga estate, kiambu district of kenya (altitude 2100 m) free of theileria parva-infected ticks was seeded by applying rhipicephalus appendiculatus nymphs to cattle infected with theileria parva (kiambu 4). it was estimated that over 50 000 engorged nymphs fell onto the pasture from 4 cattle with high parasitaemias during the cold season (june). samples of these ticks were placed in plastic cylinders under the vegetation in the paddock and sexual stages of t. parva we ...19836406968
complement activation and fibrinolysis during infection with theileria parva (east coast fever) in cattle.the role played by complement and fibrinolysis in the pathogenesis of pulmonary oedema and the disseminated, subendothelial, petechial haemorrhages in cattle infected with theileria parva was investigated. there was a marked reduction in total haemolytic complement in animals that died of this disease whereas the survivors showed only transient changes. the reduction in c3 levels in animals with severe disease, however, was equivalent to that in the survivors. neither circulating soluble immune ...19836408786
isoelectric focusing in agarose: a highly discriminatory method for the detection of enzyme heterogeneity.a comparison was made of the effectiveness of starch gel electrophoresis and isoelectric focusing in agarose for the separation of isoenzymes. lactate dehydrogenase (ldh) of theileria parva and glucose phosphate isomerase (gpi) of various cestodes were examined by the two techniques. isoelectric focusing proved to be highly discriminatory, clearly distinguishing cestode orders and taenia spp. which were closely similar by starch gel electrophoresis, and separating seven bands of theileria-specif ...19836411010
ultrastructural characteristics of in vitro parasite-lymphocyte behaviour in invasions with theileria annulata and theileria parva.host-parasite relationships have been studied by electron microscopy using glutaraldehyde-oso4-fixed pellets of lymphoid cultures infected in vitro by theileria annulata and t. parva. intracellular presence of the parasite resulted in a progressive and marked lymphoblastoid transformation. the schizont stage periodically provoked the formation of, and adopted an intimate association with, cytoplasmic annulate lamellae in the interphase cell. annulate lamellae developed from the outer nuclear mem ...19836412424
the early events of infection with theileria parva in cattle: infectivity for cattle of leukocytes incubated in vitro with sporozoites.leukocytes were isolated from bovine blood and, after short periods of incubation in vitro with sporozoites of theileria parva, were washed thoroughly, and their infectivity tested in autologous and allogeneic hosts. using a standard inoculum of 10(6) viable cells, it was found that, after incubation in vitro for either 1 or 24 h, the cells initiated lethal infections in autologous cattle, but failed to infect allogeneic animals. autologous and allogeneic erythrocytes and mouse lymphocytes simil ...19836412425
clinical and diagnostic features of east coast fever (theileria parva) infection of cattle.east coast fever is a tick-borne protozoal disease affecting cattle in a large part of east and central africa. since the vector occurs over an even wider range there is considerable potential for the disease to spread to countries which are currently disease free. this article, describing the clinical and diagnostic features of east coast fever, may remind authorities in these countries of the potential hazards posed by the disease.19836415893
characterisation of stocks of theileria parva by monoclonal antibody profiles.sixteen monoclonal antibodies, raised against macroschizonts of theileria parva, were tested against 10 different stocks of the parasite. the indirect fluorescent antibody test was used to demonstrate that these antibodies showed different binding affinities to macroschizonts of the various stocks. a profile of antibody binding could thus be prepared for each stock. for a given stock the profile was consistently the same irrespective of culture passage level, host cell background and method of a ...19836420853
immunisation against east coast fever: correlation between monoclonal antibody profiles of theileria parva stocks and cross immunity in vivo.stocks of theileria parva, which had been characterised by monoclonal antibody profiles, were used to challenge cattle previously immunised against east coast fever (ecf). when cattle were subjected to homologous challenge, or heterologous challenge with a stock of identical profile to that which had initiated immunity, they showed mild or inapparent reactions. however, when cattle were challenged with a stock of a different profile many underwent severe or fatal ecf reactions. thus, there appea ...19836420854
dose dependent responses of cattle to theileria parva stabilate. 19846423557
cultivation of theileria. i. attempts to complete the cycle of theileria parva in vitro.microschizonts and free merozoites developed in bovine lymphoblastoid cell cultures containing macroschizonts of 6 different strains of theileria parva. clean bovine red cells were added to the cultures, which were incubated in various ways. no penetration of red cells by merozoites was observed, not even when cultures in diffusion chambers were introduced into the peritoneal cavity of non-infected cattle.19846428031
blast transformation of adherent macrophages infected in vitro with sporozoites of theileria parva.rhipicephalus appendiculatus ticks were fed on cows with parasitemia from theileria parva infection (east coast fever). homogenates of salivary glands with infective sporozoites were added to cultures of (i) monocyte-derived adherent macrophages from normal bovine peripheral blood and (ii) macrophages from spleen and bone marrow. it was shown by light, phase-contrast, and electron microscopies and by tests for lysosomal enzymes, phagocytosis of carbon particles, and cell markers (fibronectin and ...19846428284
monoclonal antibody neutralizes the sporozoite stage of different theileria parva stocks.monoclonal antibodies were raised against sporozoites of theileria parva. one of these antibodies (mabd1) neutralized the infectivity of sporozoites for lymphocytes in vitro and for cattle in vivo. neutralization seemed to occur by blocking sporozoite entry into the cell. mabd1 neutralized sporozoites of four unrelated stocks of t. parva, indicating the presence of a common antigenic determinant which may be important in initiating protective immunity.19846433306
titration in cattle of infectivity and immunogenicity of autologous cell lines infected with theileria parva.cell lines infected with theileria parva were derived by infection of bovine peripheral blood lymphocytes with sporozoites in vitro. cattle were inoculated with doses of autologous infected cells ranging from 1 x 10(1) to 1 x 10(8). infection became established in animals which received 1 x 10(2) or more cells. while 1 x 10(2) cells resulted in sub-patent infection with development of immunity to challenge with sporozoites, larger doses of cells gave rise to patent infections of increasing sever ...19846435303
chemotherapy of east coast fever: parvaquone treatment of clinical disease induced by isolates of theileria parva.two experiments were carried out in which parvaquone was used to treat experimentally-induced acute clinical east coast fever infections. in the first experiment, infections with theileria parva parva (kiambu 5) were induced by applying infected rhipicephalus appendiculatus ticks or by inoculation of triturated infected-tick stabilate. the character of the disease was similar with both methods of infection and following a single treatment with parvaquone at 20 mg kg-1, 5 of 7 cattle in each grou ...19846437050
comparison of long acting oxytetracycline and parvaquone in immunisation against east coast fever by infection and treatment.two groups of five cattle were immunised with a field isolate of theileria parva as stabilate and simultaneously treated with long acting oxytetracycline or parvaquone in early clinical disease. the oxytetracycline group suffered a marked fall in leucocyte count and one animal died during immunisation. the parvaquone group suffered a less severe fall in leucocyte count and all survived. the surviving immunised cattle were immune to homologous challenge but susceptible to subsequent challenge wit ...19846438743
interaction of sporozoites of theileria parva with bovine lymphocytes in vitro. i. early events after invasion.sporozoites of theileria parva rapidly enter bovine lymphocytes by a mechanism of passive endocytosis that depends upon progressive circumferential binding of ligands on the parasite to receptors on the host-cell membrane. within 10 min of entry, the micronemes of the sporozoite discharge their content and the enveloping host-cell membrane is lysed. the host cell responds within 30 min of invasion by polymerization of microtubules arrayed tangential to the sporozoite and converging upon the cyto ...19846442474
a histocompatibility barrier to immunization against east coast fever using theileria parva-infected lymphoblastoid cell lines.histocompatibility may be a barrier to the infection of cattle when theileria parva parva-infected tissues or in vitro cultured macroschizont-infected lymphoblastoid cell lines are used for immunization. by inoculating 10(3) and 10(5) infected cells into autologous recipients infection was achieved and immunity engendered. cell lines inoculated into bola matched recipients did not produce patent infections but some recipients developed antibodies to the parasite and 3/5 were immune to challenge. ...19846739121
evidence for a common protective antigenic determinant on sporozoites of several theileria parva strains.the antigenic relationship amongst sporozoites of several theileria parva strans isolated from different parts of east africa was investigated. it was found that antibodies to t. parva ( muguga ) sporozoites neutralized the infectivity of homologous sporozoites as well as those of t. parva (uganda), t. parva lawrencei , t. parva ( kiambu 5), t. parva ( kabete 1) and t. parva ( marikebuni ). the results correlated with those obtained from an in vivo challenge, in that cattle immunized against t. ...19846203832
evaluation of a range of antimicrobial agents against the parasitic protozoa, plasmodium falciparum, babesia rodhaini and theileria parva in vitro.eighteen antimicrobials commonly used in tissue culture were screened in three different protozoan test systems in order to establish their suitability for routine inclusion in protozoal cultivation systems. the human malaria parasite, plasmodium falciparum, was inhibited by more than half the antibiotics tested at concentrations recommended for normal tissue culture use. eight compounds were well tolerated and thus could be used prophylactically to prevent microbial contamination. these antimic ...19846206808
detection of antibody to theileria parva schizonts and cell surface membrane antigens of infected lymphoblastoid cells by immunoperoxidase techniques.peroxidase-labeled antibody procedures were described for detecting bovine antibodies reactive with intracellular theileria parva schizonts and cell surface membrane antigens of infected lymphoblastoid cells. indirect tests were performed where the reacting bovine antibodies were localized with affinity purified rabbit-anti-bovine igg coupled to horseradish peroxidase. a 4- to 8-fold increase in sensitivity for detecting bovine antibodies was obtained with unlabeled rabbit-anti-bovine igg which ...19846208672
the genome of theileria parva: some structural properties.the dna of the protozoan theileria parva, the causal agent of the bovine east coast fever, has been prepared at least 99% pure from the intra-erythrocytic form of the parasite. its buoyant density was found to be 1.696 g/cm3 and its calculated g + c content was 36.7%. fragmentation of t. parva by the restriction enzyme ecori provides some evidence of the presence of repetitive dna sequences.19846325246
identification of a surface antigen on theileria parva sporozoites by monoclonal antibody.a mouse monoclonal antibody (mabd1) that neutralizes sporozoites of different stocks of the protozoan parasite theileria parva has been used to localize and identify a sporozoite antigen. protein a-colloidal gold was used to localize bound mabd1 in immunoelectron microscopic studies. mabd1 bound to sporozoite antigen, which was evenly spread over the surface of all sporozoites. immune complexes were obtained by incubation of sporozoite suspensions with mabd1 followed by zwittergent 3-14 extracti ...19853920654
the entry of sporozoites of theileria parva into bovine lymphocytes in vitro. immunoelectron microscopic observations.in an electron microscopic investigation of the entry of sporozoites of theileria parva into bovine lymphocytes, the fate of the surface coat of the parasite was traced by immunocytochemical methods. a monoclonal antibody (mabd1) raised in mice and directed against a surface antigen of sporozoites, was applied to ultrathin frozen sections of bovine lymphocytes infected in vitro. sites of binding of mabd1 were localized using a protein a-colloidal gold conjugate as an electron-dense label. the su ...19853922761
antitheilerial activity of bw720c (buparvaquone): a comparison with parvaquone.a series of hydroxynaphthoquinones, all derivatives of the antitheilerial hydroxynaphthoquinone parvaquone (993c, clexon; wellcome) was tested for antitheilerial activity against theileria parva (muguga) in vitro. bw720c (buparvaquone) was 20 times more active than parvaquone. when tested in vivo bw720c cured all 13 cattle infected with t parva and all six infected with t annulata treated at a dose rate of 2.5 mg (kg bodyweight)-1 while parvaquone at 20 mg kg-1 cured nine of 10 cattle. all 16 un ...19853929346
production in ascites fluid of biosynthetically labelled monoclonal antibody to theileria parva sporozoites.a hybridoma cell line has been previously produced which secretes monoclonal antibodies able to neutralize sporozoites of theileria parva, the causative agent of east coast fever of cattle. cells from this line were injected intra-peritoneally into pristane-treated balb/c mice. during the last 4 days of hybridoma cell growth, mice were given 4 daily intraperitoneal injections of a mixture of tritiated amino acids in order to biosynthetically radiolabel the monoclonal antibody being produced in a ...19853930611
de novo expression of t cell markers on theileria parva-transformed lymphoblasts in cattle.we describe monoclonal antibodies that detect two new membrane antigens on bovine t cells. one molecule is only expressed on activated t cells and has a m.w. of 100,000. the other antigen is a glycoprotein that is precipitated as two bands of m.w. 150,000 and 158,000 and is expressed on a subpopulation of t cells and all myeloid cells. we show that when bovine lymphocytes are transformed by the protozoan parasite theileria parva, both antigens become expressed on the cell surface. the infected c ...19853934278
comparative autoradiographic study of parasite-host-cell cyclical relationship in lymphoblastoid cell lines infected with theileria annulata and theileria parva in vitro.cyclical interactions between intracellular schizonts of the ankara and hissar strains of theileria annulata and the muguga strain of t. parva and the parasitised host lymphoblasts have been studied autoradiographically by following the incorporation of (3h) thymidine into parasite and host cell nuclei, and also by quantitating the number of schizont nuclei per lymphoblast, at various stages and phases of host cell cycle. the synthesis of dna by theileria schizonts and the parasitised host lymph ...19853937319
new approaches to immunization of cattle against theileria parva.the protozoan parasite theileria parva is the causal agent of an acute, usually fatal disease of cattle characterized by widespread parasitism and destruction of cells of the lymphoid system. immunity against the parasite, can be induced by various infection and treatment regimes. because of the necessity to use live organisms, these methods of immunization are cumbersome and there is the added problem of parasite strain heterogeneity. present evidence suggests that immunity may operate at two l ...19853938738
epidemiology of tick-borne diseases of cattle in zimbabwe. iii. theileria parva group.a survey of the occurrence of antibodies to theileria parva using the ifa test in calves up to one year old at 244 localities in zimbabwe revealed that the parasite occurred throughout the country although the prevalence of positive serological reactors was generally low. outbreaks of theileriosis in high rainfall areas in the north, east and west of the country were attributed to theileria parva bovis transmitted from cattle to cattle by rhipicephalus appendiculatus. outbreaks in high and low r ...19853992667
effects of tick infestation on boran (bos indicus) cattle immunised against theileriosis in an endemic area of kenya.boran (bos indicus) heifers were immunised by infection with local theileria parva parva, t p lawrencei and t mutans stocks and treated with parvaquone and later exposed to natural tick and tick-borne disease challenge in the trans-mara division of kenya. the theileria species parasites in the challenge were maintained in african buffalo and cattle and the tick vectors were supported by several species of wild bovidae and domestic livestock present in the area. thirty immune cattle were observed ...19854081331
bovine alloreactive cytotoxic cells generated in vitro: target specificity in relation to bola phenotype.cytotoxic cells of bovine origin were generated in primary mlc using stimulator cells of bola w8/w11 phenotype. bovine lymphoblasts transformed by the protozoan parasite theileria parva parva acted as target cells in studies of the specificity of cytotoxicity. when responder cells in mlc did not share w8 or w11 with stimulator cells, cytotoxicity was evident with all targets bearing w8 or w11, or both, and was almost entirely restricted to these products of the bola-a locus. when responder and s ...19852409001
theileria parva: expression of a sporozoite surface coat antigen.a monoclonal antibody specific for the theileria parva sporozoite, which recognizes a determinant on the surface coat and blocks sporozoite infectivity, was used to investigate the presence of the determinant on other stages of the parasite lifecycle. immunofluorescence techniques did not demonstrate this determinant on the kinete, schizont, merozoite, or piroplasm stages of the parasite. immunoautoradiography, using a tritiated form of the monoclonal antibody, on sections of infected salivary g ...19852410290
immunity in theileriosis.the theilerioses can be separated on the basis of their principal pathogenic features, into a lymphoproliferative group caused by theileria parva and t. annulata in cattle, and t. hirci in goats and sheep, and a haemoproliferative group caused by t. sergenti and t. mutans both in cattle. in the former group, proliferation of parasites within lymphoid cells followed by lymphodestruction are the main pathogenic features; whereas in the latter group, invasion and destruction of erythrocytes, causin ...198515275582
alloreactive bovine t lymphocyte clones: an analysis of function, phenotype, and specificity.a bovine alloreactive cell population was subjected to complement-dependent lysis with monoclonal antibody (mab) il-a11. the original population and the population depleted of cells bearing the determinant recognized by mab il-a11 were cloned. parent cultures and 21 clones were examined for cytolytic function and for expression of determinants recognized by mab il-a11 and two additional mab, il-a12 and il-a17. clones could be classified according to maximal achievable levels of cytolysis by usin ...19862423592
chemotherapy of east coast fever. treatment of infections induced by isolates of theileria parva with halofuginone.cattle were infected with three isolates of theileria parva and treated with halofuginone lactate during acute clinical disease. the health, weight gain and carrier state of the cattle were monitored for 15 months. limited treatment rapidly reduced fever and parasitosis but parasite recrudescences occurred and 12 out of 21 treated cattle died. persistent carrier states were identified with two t. p. parva isolate infections and a transient carrier state with t. p. lawrencei. three cattle which d ...19862874713
chemotherapy of field cases of east coast fever using halofuginone lactate.the chemotherapeutic effect of halofuginone lactate (terit, hoechst) was tested against natural pathogenic theileria parva infections (east coast fever, ecf) in 24 cattle. halofuginone lactate, administered per os, 1.2 mg per kg b.wt and repeated after 48 h manifested a potent schizonticidal effect, observed between 5 and 11 days post treatment. disappearance of erythrocytic forms (ef) took long, ranging from 6 to 34 days post treatment. differences on efficacy between halofuginone lactate table ...19862882667
passive endocytosis of sporozoites of theileria parva in macrophages at 1-2 degrees c.phagocytosis by macrophages is generally considered to involve two steps which can be experimentally dissociated: attachment, which is not energy-dependent, and interiorization, which does not occur below 15 degrees c. we have previously reported entry of the sporozoites of theileria parva into bovine lymphocytes at 2 degrees c by a process of passive endocytosis which appears to depend entirely upon progressive circumferential binding of ligands on the parasite to receptors on the host cell mem ...19863083113
chemotherapy of east coast fever: the long term weight changes, carrier state and disease manifestations of parvaquone treated cattle.the weight changes, carrier state and nature of chronic disease in cattle following infection with five isolates of theileria parva and treatment with parvaquone were studied over an 18 month period while the cattle were maintained on normal management under strict tick control. cattle infected with the t.p. parva pugu ii isolate gained weight similarly to uninfected control cattle and did not develop a detectable carrier state or show chronic disease. the cattle in the 4 other isolate groups re ...19863084600
induction of immunity against infection with theileria parva (east coast fever) in cattle using plasma membranes from parasitized lymphoblasts.protection against challenge with theileria parva was conferred on three of four calves given three or four inocula of plasma membranes prepared from 6 to 12 x 10(8) autologous parasitized lymphoblasts from cultured cell lines. in contrast, calves remained susceptible to infection following immunization with membranes prepared from allogeneic parasitized lymphoblasts. similarly, calves vaccinated with either gamma-irradiated autologous or allogeneic infected cells also died of east coast fever a ...19863085324
comparative analysis of infection and transformation of lymphocytes from african buffalo and boran cattle with theileria parva subsp. parva and t. parva subsp. lawrencei.this study compared infection and transformation of peripheral blood mononuclear cells (pbm) of boran cattle and african buffalo in vitro to determine whether differences occurred which could account for the greater susceptibility of boran cattle to infection with theileria parva subsp. parva and t. parva subsp. lawrencei. pbm from buffalo and cattle had a similar percentage of cells which bound t. parva subsp. parva sporozoites (24 to 34%) and in which schizonts developed during the first week ...19863087880
bovine cytotoxic t-cell clones specific for cells infected with the protozoan parasite theileria parva: parasite strain specificity and class i major histocompatibility complex restriction.we present information on the specificity of three bovine cytotoxic t-cell clones reactive with lymphoblasts infected with the protozoan parasite theileria parva. the clones were derived from peripheral blood mononuclear cells of an animal immunized with t. parva (muguga stock), after five stimulations in vitro with an autologous parasitized cell line. the three clones belonged to the bot8+ subset of t cells, which is similar to the human cd8+ t-cell subset. on the basis of analysis on a panel o ...19863088572
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