Publications

conservation of neutralizing determinants between the sporozoite surface antigens of theileria annulata and theileria parva.	the sporozoite surface antigens spag-1 of theileria annulata and p67 of theileria parva are postulated to contain determinants necessary for host cell invasion and/or recognition and are both being considered as candidates for inclusion in subunit vaccines. preliminary data suggest that these are related molecules. in this paper we describe the investigation of the relationship between these sporozoite antigens further by analysis of the immunological cross-reactivity using mabs and sera raised ...	1996	8631374
conservation of the sporozoite p67 vaccine antigen in cattle-derived theileria parva stocks with different cross-immunity profiles.	immunity to theileria parva infection in cattle is often parasite stock specific. the antigenic diversity which is expressed at the schizont stage of the parasite together with a wild reservoir of the organism in buffalo has complicated the development of effective disease control by immunization. we have previously shown that about 70% of cattle inoculated with recombinant forms of p67, a sporozoite stage-specific surface antigen from the cattle-derived muguga stock of the parasite, are immune ...	1996	8675307
influence of host and parasite genotypes on immunological control of theileria parasites.	infections with theileria parva in the african buffalo are invariably asymptomatic, whereas infections in cattle usually result in clinical disease, the severity of which varies in different populations of cattle. the parasite exhibits antigenic heterogeneity, which in cattle manifests as differences between parasite strains in their cross-protective properties. a series of studies on t cell responses to t. parva in cattle have demonstrated that class i mhc-restricted cytotoxic t lymphocytes (ct ...	1996	8684836
viability of theileria parva trivalent stabilate after thawing and maintenance at 4 degrees c for up to 15 hours.	two experiments were conducted to determine the effect of prolonged maintenance at 4 degrees c on thawed theileria parva stabilates. samples maintained at 4 degrees c for 1, 12, 15 and 18 h were all infective for cattle. immunized cattle were able to resist potentially lethal challenges 29 days later. these results indicate that the handling of t. parva trivalent stabilates for immunization against east-coast fever in the field should be much easier than previously envisaged.	1996	8690541
a mild theileria parva parasite with potential for immunisation against east coast fever.	twenty-three friesian cattle were inoculated subcutaneously anterior to the left prescapular lymph node with 1 ml of a mild isolate of theileria parva. the cattle developed low macroschizont parasitosis but no clinical reaction was observed. thirty-five days later the cattle were grouped into five groups and challenged with five different theileria parva isolates (four cattle-derived theileria and one buffalo-derived theileria). the cattle were all solidly immune to challenge with the cattle-der ...	1996	8750682
genetic fingerprinting of theileria parva using a telomeric dna probe.	a cloned theileria parva telomeric dna sequence, designated ptputel, was used to characterize t. parva stocks and clones by hybridization to ecori-digested dna. eight of the nine t. parva stocks tested were discriminated by the telomeric restriction-fragment-length polymorphisms (rflps). two isolates derived from buffalo 7014 by tick feeding on different occasions were also differentiated using the probe. the probe gave comparable results on purified piroplasm or schizont-infected lymphocyte dna ...	1996	8801562
characterisation of bovine transferrin receptor on normal activated and theileria parva-transformed lymphocytes by a new monoclonal antibody.	a murine igm monoclonal antibody (mab), il-a77, has been generated that recognises the bovine transferrin receptor (tfr) and will be a useful tool to measure the activation state of bovine lymphocytes and macrophages. the antigen is detected on immature erythroid cells and proliferating lymphocytes. it is undetectable on resting lymphocytes, but appears within 24 h after stimulation with concanavalin a (cona) or pokeweed mitogen (pwm). immune precipitations of lysates of both labeled activated l ...	1996	8807777
comparison of the transmission of theileria parva between different instars of rhipicephalus appendiculatus.	the transmission of theileria parva by nymphal and adult rhipicephalus appendiculatus was compared by the assessment of salivary gland infections in tick batches fed on the same group of infected cattle at the same time. when larval and nymphal r. appendiculatus muguga ticks were fed concurrently on cattle undergoing acute infection with t. parva muguga, the resultant nymphae developed a slightly lower prevalence of infection than did the adult ticks. the abundance of infection was 5-20 times hi ...	1996	8811849
factors influencing infections in rhipicephalus appendiculatus ticks fed on cattle infected with theileria parva.	a large database on the transmission of a stabilate of the theileria parva muguga stock from one breed of cattle using two stocks of rhipicephalus appendiculatus, muguga and ol pejeta was developed and analysed. factors associated with the ticks and cattle, and the infections developing in cattle were studied in relation to the infection variables in the tick batches harvested daily from cattle. generalized linear interactive modelling (glim) was used to determine the importance of factors and i ...	1996	8811850
characterization of the parasite-host cell interactions involved in theileria parva sporozoite invasion of bovine lymphocytes.	sporozoite invasion of bovine lymphocytes by theileria parva is a ph-dependent process that occurs without the need for de novo protein synthesis. the process was inhibited by rgd(s) peptides, fibronectin and, in the presence of serum, by antibodies reactive with fibronectin. invasion was also blocked by a range of sulphated glycoconjugates, but treatment of lymphocytes with heparitinase did not inhibit entry. enzymic modifications of the lymphocyte surface demonstrated that trypsin-insensitive ...	1996	8811851
effects of immunisation against theileria parva on beef cattle productivity and economics of control options.	over 500 cattle of all age groups on 2 farms in zimbabwe were immunised against theileriosis using the "infection and treatment" method and disease prevalence and their productivity assessed during a period of 18 months. the immunising stock, theileria parva (boleni) was isolated in zimbabwe. none of the immunised cattle suffered from theileriosis upon natural exposure whereas 22 unimmunised cattle died of theileriosis and a further 48 required treatment for theileriosis. in the first year, some ...	1996	8815619
an assessment of host resistance to ticks on cross-bred cattle in burundi.	groups of cattle of four different cross-breeds (ankole x friesian, ankole x brown-swiss, ankole x guernsey, ankole x sahiwal) plus a group of pure ankole cattle were immunized against tick-borne diseases: east coast fever, using a theileria parva trivalent vaccine, and anaplasmosis, babesiosis and, subsequently, heartwater. with the exception of two small subgroups of ankole and ankole x sahiwal which were treated by weekly spraying using delnav, all the groups were exposed to natural field cha ...	1996	8834737
theileria parva (kasoba): isolation and challenge of cattle recovered from infection with other theileria parva stocks.	a pathogenic theileria stock was isolated from control cattle during an east coast fever (ecf) field immunization trial at kasoba near karonga town in northern malawi. a stabilate of this stock caused severe fevers and prolonged parasitosis in theileria parva naive cattle, resulting in the death of 5 out of 12 cattle despite treatment. in contrast, this parasite stock caused mild to moderate reactions in 17 cattle immunized with the trivalent t. parva stabilate except in 3 animals which develope ...	1996	8881419
the isolation and characterization of genomic and cdna clones coding for a cdc2-related kinase (thcrk2) from the bovine protozoan parasite theileria.	the tick-transmitted protozoan parasites theileria annulata and theileria parva are important intracellular pathogens of domestic cattle in tropical and subtropical regions. proliferative phases take place within both lymphocytes and erythrocytes. the lymphocyte is stimulated to enter the cell cycle by the parasite and the multinucleate parasite can establish a state in which karyokinesis and cytokinesis occur in phase with the host cell. the link between parasite nuclear division and cytokinesi ...	1996	8930914
theileria parva sporozoite entry into bovine lymphocytes involves both parasite and host cell signal transduction processes.	theileria parva sporozoites rapidly enter bovine lymphocytes. since lymphocytes are normally nonphagocytes sporozoite binding to the host cell surface must initiate events in the host cell, leading to the internalization of the parasite. in the present study inhibitors of various key molecules in cell signal transduction and activation pathways, in combination with a method of quantitation, have been used to examine the possible role(s) of these systems in sporozoite entry. a variety of protein ...	1996	8948324
challenge of theileria parva (boleni) immunised cattle with selected east african theileria stocks.	theileria parva (boleni) stock from zimbabwe was used to immunise 24 susceptible friesian calves by infection and treatment with oxytetracycline. twenty-eight days after immunisation the animals in groups of 6 plus 2 susceptible controls were subjected to challenge: 3 groups with heterologous stocks and one group with the immunising stock. theileria parva (boleni) gave good protection against homologous challenge, the t. parva (muguga, kenya) and buffalo-derived t. parva (serengeti transformed, ...	1995	8966760
subunit vaccines for complex tick-borne pathogens: dream or reality?		1996	8979420
prospects for subunit vaccines against tick-borne diseases.	tick-borne parasites are a serious impediment to the improvement of live-stock production in the developing world. the major parasites affecting cattle include theileria parva, t. annulata, babesia bigemina, b. bovis, anaplasma marginale and cowdria ruminantium. the control of these infections is dependent on the use of acaricides to decrease transmission by the tick vectors, and immunization of susceptible animals with live vaccines. the use of acaricide is hampered by the development of resist ...	1996	8979421
integrated tick and tick-borne disease control trials in crossbred dairy cattle in malawi.	crossbred dairy heifers on a farm in an east coast fever (ecf) endemic area in malawi were immunised against theileria parva, anaplasma spp., babesia bigemina, babesia bovis and cowdria ruminantium. they were treated at infrequent intervals with chlorfenvinphos to limit infestation with adult ticks, without providing complete tick control. in one trial, which tested a threshold dipping regimen, 20 heifers were dipped only once in 6 months to control a flush of boophilus microplus. unimmunised co ...	1996	8983132
characterization of a secretory type theileria parva glutaredoxin homologue identified by novel screening procedure.	the schizont stage of the protozoan parasite theileria parva induces features characteristic of tumor cells in infected bovine t-cell lines. most strikingly t. parva-infected cell lines acquire unlimited growth potential in vitro. their proliferative state is entirely dependent on the presence of a viable parasite within the host cell cytoplasm. it has been postulated that parasite proteins either secreted into the host cell or expressed on the parasite surface membrane are involved in the paras ...	1997	9006954
concerted evolution at a multicopy locus in the protozoan parasite theileria parva: extreme divergence of potential protein-coding sequences.	concerted evolution of multicopy gene families in vertebrates is recognized as an important force in the generation of biological novelty but has not been documented for the multicopy genes of protozoa. a multicopy locus, tpr, which consists of tandemly arrayed open reading frames (orfs) containing several repeated elements has been described for theileria parva. herein we show that probes derived from the 5'/n-terminal ends of orfs in the genomic dnas of t. parva uganda (1,108 codons) and bolen ...	1997	9032293
characterization of some theileria parva stocks from zambia using monoclonal antibodies.	theileria parva parasites have been isolated from different location in zambia where malignant theileriosis has been recorded. a total of 16 bovine lymphocytic cell lines infected with t. parva schizonts were characterized using a panel of anti-schizont monoclonal antibodies (mabs). comparison of the theileria stocks isolated before (old) and after (new) the muguga cocktail of t. parva from kenya was used to vaccinate cattle against theileriosis in zambia revealed differences in their reactivity ...	1997	9035069
molecular characterisation of a cognate 70 kda heat shock protein of the protozoan theileria parva.		1997	9106200
use of the polymerase chain reaction for identification and quantification of theileria parva protozoa in rhipicephalus appendiculatus ticks.	the polymerase chain reaction (pcr) was adapted for detection of theileria parva sporoblasts in rhipicephalus appendiculatus ticks by comparison with staining of histological preparations of ticks with methyl green and pyronin (mgp). two 32mer primers (il174 and il179) were used to amplify theileria parva (muguga isolate) dna from the tpr 1 region of the genome by the pcr. detection of t. parva was carried out with dissected salivary glands and whole ticks preserved in ethanol. adult ticks which ...	1997	9134558
jun nh2-terminal kinase is constitutively activated in t cells transformed by the intracellular parasite theileria parva.	when t cells become infected by the parasite theileria parva, they acquire a transformed phenotype and no longer require antigen-specific stimulation or exogenous growth factors. this is accompanied by constitutive interleukin 2 (il-2) and il-2 receptor expression. transformation can be reversed entirely by elimination of the parasites using the specific drug bw720c. extracellular signal-regulated kinase and jun nh2-terminal kinase (jnk) are members of the mitogen-activated protein kinase family ...	1997	9144200
the indirect fluorescent antibody test based on schizont antigen for study of the sheep parasite theileria lestoquardi.	an indirect fluorescent antibody test (ifat), based on schizont-infected lymphoblastoid cells, was applied to study the course of antibody production in adult sheep inoculated with attenuated, in vitro grown, theileria lestoquardi (theileria hirci) infected cells. bright fluorescence of the intracellular schizonts could first be demonstrated 15 days after inoculation. a 32-64-fold rise in antibody titres was recorded 1 month after infection, and substantial titres were still observed 90 days aft ...	1997	9187025
use of an in vitro infectivity assay in comparison with histological techniques in the study of theileria parva sporozoite maturation.	adult male and female rhipicephalus appendiculatus ticks infected with theileria parva (muguga 3087) were fed on rabbits and the development of infection was monitored daily using light microscopy and an in vitro titration technique able to quantify the infectivity of sporozoite suspensions. the salivary glands stained with methyl green pyronine showed presence of infection in some unfed ticks. the intensity of staining was shown to increase with the number of days the ticks had fed. the in vitr ...	1997	9195713
bulk-freezing of theileria parva stabilates for vaccine production.	the freezing and thawing characteristics of different volume samples of freezing medium and theileria parva stabilates were studied in order to identify suitable conditions for freezing large volumes of stabilates for use in the preparation of vaccines. conventionally, 1.8 ml aliquots are used but are cumbersome to handle in the field preparation of trivalent vaccines. in this study, 75 ml aliquots of the stabilates were found to exhibit freezing and thawing characteristics similar to those of t ...	1996	9198598
immunisation of cattle in zimbabwe using theileria parva (boleni) without concurrent tetracycline therapy.	five hundred and ten cattle were immunised using the theileria parva (boleni) stock without concurrent chemotherapy with tetracycline on 2 farms in zimbabwe, both of which had a history of theileriosis. the stabilate had been titrated in friesian calves to determine a 50% protective dose (pd50) and 2 or 3 (pd50s) were used to immunise the cattle. none of the cattle showed a clinical reaction following the immunisation procedure. however, the cattle were shown to have responded immunologically on ...	1997	9203309
theileria-mediated constitutive expression of the casein kinase ii-alpha subunit in bovine lymphoblastoid cells.	theileria-infected cells are induced to undergo a transformation that is reversible, since their proliferation is inhibited after elimination of the schizonts by the theilericidal drug buparvaquone. the molecular mechanisms of the transformation remain unknown. the experiments described in the present report deal with the role of casein kinase (ck) ii, a serine/threonine protein kinase, in the permanent proliferation of the parasitized cells and show that the ck ii-alpha subunit is expressed in ...	1997	9211502
the prevalence of serum antibodies to tick-borne infections in cattle in smallholder dairy farms in murang'a district, kenya; a cross-sectional study.	the most important tick-borne disease of cattle in eastern, central and southern africa is east coast fever (ecf) caused by theileria parva and transmitted by the tick rhipicephalus appendiculatus. other less-important tick-borne diseases in cattle are benign theileriosis caused by theileria mutans, babesiosis caused by babesia bigemina, anaplasmosis caused by anaplasma marginale and cowdriosis caused by cowdria ruminatum. in murang's district, central province of kenya, five agroecological zone ...	1997	9234414
in vitro infection with theileria parva is associated with il10 expression in all bovine lymphocyte lineages.	the protozoan parasite theileria parva infects and transforms bovine lymphocytes, giving rise to a fatal lymphoproliferative condition known as east coast fever. although immune cattle mount strong cytolytic t lymphocyte responses to the parasite, naive animals appear unable to respond and develop severe immunopathological lesions. we have investigated the patterns of cytokine mrna expressed by 19 bulk and cloned parasite-infected lymphoblast cell lines using a multiplex pcr system. considerable ...	1997	9278944
parasite-mediated nuclear factor kappab regulation in lymphoproliferation caused by theileria parva infection.	infection of cattle with the protozoan theileria parva results in uncontrolled t lymphocyte proliferation resulting in lesions resembling multicentric lymphoma. parasitized cells exhibit autocrine growth characterized by persistent translocation of the transcriptional regulatory factor nuclear factor kappab (nfkappab) to the nucleus and consequent enhanced expression of interleukin 2 and the interleukin 2 receptor. how t. parva induces persistent nfkappab activation, required for t cell activati ...	1997	9356483
distinct cd4+ t cell helper requirements in theileria parva-immune and -naive bovine ctl precursors.	there is strong evidence that class i mhc-restricted parasite-specific cd8+ ctl protect cattle against the protozoan parasite theileria parva. as part of an effort to develop a subunit vaccine for the induction of these responses, we have investigated the factors involved in the generation of t. parva-specific ctl in cattle. purified populations of bovine immune and naive cd8+ t cells were cocultured with autologous t. parva-infected lymphoblasts (tpl) in the presence or absence of immune cd4+ t ...	1997	9379055
effect of different east coast fever control strategies on fertility, milk production and weight gain of sanga cattle in the central province of zambia.	five different east coast fever (ecf) (theileria parva infection) control strategies, based on tick control and/or ecf immunization, were tested in groups of traditionally managed sanga cattle in the central province of zambia over a period of 2.5 years. two groups were kept under intensive tick control (sprayed weekly), one group immunized and one non-immunized. two further groups were under no tick control, one group immunized and one non-immunized, while a fifth group was immunized against ec ...	1997	9423269
reducing a spatial database to its effective dimensionality for logistic-regression analysis of incidence of livestock disease.	large databases with multiple variables, selected because they are available and might provide an insight into establishing causal relationships, are often difficult to analyse and interpret because of multicollinearity. the objective of this study was to reduce the dimensionality of a multivariable spatial database of zimbabwe, containing many environmental variables that were collected to predict the distribution of outbreaks of theileriosis (the tick-borne infection of cattle caused by theile ...	1997	9443328
immunology of infections with theileria parva in cattle.		1998	9509675
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
delivery of the p67 sporozoite antigen of theileria parva by using recombinant salmonella dublin: secretion of the product enhances specific antibody responses in cattle.	the p67 sporozoite antigen of theileria parva has been fused to the c-terminal secretion signal of escherichia coli hemolysin and expressed in secreted form by attenuated salmonella dublin aroa strain sl5631. the recombinant p67 antigen was detected in the supernatant of transformed bacterial cultures. immunization trials in cattle revealed that sl5631 secreting the antigen provoked a 10-fold-higher antibody response to p67 than recombinant sl5631 expressing but not secreting p67. immunized calv ...	1998	9573089
evidence for adp-ribosylation and g protein in theileria parva-transformed bovine lymphocytes.		1998	9574921
ap-1 and atf-2 are constitutively activated via the jnk pathway in theileria parva-transformed t-cells.	bovine t-cells infected by the protozoan parasite theileria parva undergo lymphoblastoid transformation, and proliferate in an uncontrolled manner. while it has been established that the transcription factor nf-kappa b is constitutively activated in t. parva-infected t-cells, little is known about other transcription factors such as ap-1 and atf-2. we demonstrated increased binding activity to the ap-1 and creb/atf-2 consensus binding sites and show that the ap-1 complex is composed of c-jun, ju ...	1998	9610375
an enzyme-linked immunosorbent assay for detection of theileria parva antibodies in cattle using a recombinant polymorphic immunodominant molecule.	field and experimental bovine infection sera were used in immunoblots of sporozoite and schizont lysates of theileria parva to identify candidate diagnostic antigens. four parasite antigens of mr 67,000 (p67), 85,000 (the polymorphic immunodominant molecule, pim), 104,000 (p104), and 150,000 (p150) were selected for a more detailed analysis. the p67 and p104 antigens were present only in the sporozoite lysates, whereas pim and p150 were found in both sporozoite and schizont lysates. the four ant ...	1998	9610640
interferon production by theileria annulata-transformed cell lines is restricted to the beta family.	theileria are tick-transmitted protozoans causing often fatal diseases in ruminants. theileria sporozoites immortalize and transform host cells of haematopoietic origin. transformation is associated with profound functional alterations. for example, bovine cells infected by theileria annulata or t. parva. constitutively produce interferon (ifn). in this study, the type and family of ifn produced by a panel of t. annulata-transformed cell lines and a t. parva-transformed cell line was investigate ...	1998	9618728
immunisation with live attenuated salmonella dublin expressing a sporozoite protein confers partial protection against theileria parva.	cattle immunised with a recombinant form of p67, the major surface antigen of theileria parva sporozoites, have been shown to be protected against parasite challenge. in an attempt to simplify the immunisation procedure live attenuated salmonella strains expressing p67 have been constructed and used to induce anti-p67 immune responses in cattle. all animals immunised with these strains developed strong antibody responses to p67. specific t cell responses could be detected in the majority of immu ...	1998	9627941
effect of different east coast fever control strategies on disease incidence in traditionally managed sanga cattle in central province of zambia.	a clinical trial, including five east coast fever (ecf) control strategies (involving tick control and/or immunisation by infection-and-treatment) in five different groups of traditionally managed sanga cattle, was conducted in central province of zambia over 2.5 years between 1992 and 1995. two groups were kept under intensive tick control by weekly acaricide treatment by hand spray; (one immunised and one non-immunised), two groups were under no tick control (one immunised and one non-immunise ...	1998	9646334
an outbreak of east coast fever in a herd of sanga cattle in lutale, central province of zambia.	an outbreak of east coast fever (ecf) occurred in an experimental herd of sanga cattle maintained under a traditional rangeland grazing system at lutale, central province of zambia. two groups of cattle had been kept under different tick-control regimens for several years prior to the introduction of the disease and epidemiological information on the outbreak were recorded. weekly tick control was no sufficient to achieve full protection against theileria parva infection. systematic body tempera ...	1998	9646337
novel vaccines against theileria parva: prospects for sustainability.	a first-generation subunit vaccine for east coast fever based on the theileria parva p67 sporozoite surface antigen is entering preliminary field trials. intensive efforts are also focused on the identification of a schizont-specific component for incorporation in a second-generation multi-component product. it is clear that many questions remain unanswered regarding the likely performance of these vaccines under field conditions. in particular, their effect on the endemic status of the parasite ...	1998	9650049
vector competence of 7 rhipicephalid tick stocks in transmitting 2 theileria parva parasite stocks from kenya and zimbabwe.	the competence of 7 different stocks of rhipicephalus appendiculatus and r. zambeziensis to transmit 2 different stocks of theileria parva was compared by feeding nymphae of each tick stock simultaneously on infected cattle and assessing the infections in the salivary glands of the resultant adult ticks. there were significant differences in the patterns of infection of the 2 stocks (t. parva muguga and t. parva boleni) in the different stocks of ticks, and these differences were shown to be rep ...	1998	9651937
immunization against east coast fever in field cattle with low infectivity theileria parva stabilate--preliminary assessment.	two theileria parva sporozoite stabilates stored at -196 degrees c, then at -70 degrees c for six weeks (stabilate 1) and more than six months (stabilate 2) were inoculated into four eight-month old male calves, 1 and 2 (stabilate 1), and 3 and 4 (stabilate 2). calves 1 and 2 developed pyrexia, enlargement of lymph nodes, and the former died of east coast fever. calves 3 and 4 showed slight enlargement of lymph nodes without fever. lymph node smears from all calves (from day 10 to 20 post-inocul ...	1998	9652382
the evolution of primate malaria parasites based on the gene encoding cytochrome b from the linear mitochondrial genome.	we report a phylogenetic analysis of primate malaria parasites based on the gene encoding the cytochrome b protein from the mitochondrial genome. we have studied 17 species of plasmodium, including 14 parasitic in primates. in our analysis, four species were used for rooting the plasmodium phylogenetic tree: two from closely related genera (hepatocystis sp. and haemoproteus columbae) and two other apicomplexa (toxoplasma gondii and theileria parva). we found that primate malaria parasites form a ...	1998	9653151
characterization and discrimination of three theileria parva stabilates involved in east coast fever vaccination.	three vaccine stabilates of theileria parva, of which sporozoites are being used against east coast fever, were characterized by immunological and molecular biology techniques before being used for a national vaccination campaign in kenya. t. parva marikebuni stabilates 316 and 3014, and t. parva lanet were used in this study and were discriminated from other kenyan field theileria isolates. ifat results showed that all the animals were producing antibodies regardless of the stock used. primers ...	1998	9668450
a pcr-based field evaluation of theileria infections in cattle and ticks in kenya.	theileria parva is a hemoprotozoan parasite responsible for causing east coast fever in east and central africa. the vaccine currently available is an "infection and treatment" procedure which involves the injection of live sporozoites followed by drug therapy to prevent clinical illness. before introducing potentially new strains of parasite into an area, however, it is crucial to check the disease situation in the field first. we looked at three different areas in kenya: limuru in which many c ...	1998	9668451
detection and differentiation of theileria annulata and theileria parva using macroschizont-derived dna probes.	a lamda gt11 expression library based on t.annulata-infected cells was screened with an antiserum raised in rabbits against partially purified schizonts of t.annulata. two clones were detected, sequenced and designated as sa288 and sb288 (shayan et al., submitted for publication). from the sequences of these two genes oligonucleotide primers were designed for specific amplification of parasite dna by polymerase chain reaction (pcr). we could show that these genes are of parasitic origin and do o ...	1998	9668454
delivery of the theileria parva p67 antigen to cattle using recombinant vaccinia virus: il-2 enhances protection.	to evaluate vaccinia virus as a delivery system for recombinant antigen in cattle, calves were immunized with a recombinant vaccinia virus (rvv) expressing the sporozoite surface antigen (p67) of theileria parva (v-67) combined with those expressing bovine il-4 (v-il4) or il-2 (v-il2). the anti-p67 antibody levels detected in calves inoculated with the combination of v-67 and v-il4 were higher than those produced by animals injected with v-67 alone or v-67 and v-il2. on challenge with cryopreser ...	1998	9682391
proteolytic cleavage of surface proteins enhances susceptibility of lymphocytes to invasion by theileria parva sporozoites.	a flow cytometric method using anti-parasite antibodies was developed to measure binding of theileria parva sporozoites to the target bovine lymphocyte membrane. parasite-host cell interactions could be inhibited by monoclonal antibodies to bovine mhc class i and partially by one of two antibodies to bocd45r. proteolysis of the lymphocyte surface removed cd45r but not mhc class i determinants, and enhanced sporozoite binding. these observations support the hypothesis that cd45r and cd45r antibod ...	1998	9696352
chemoprophylaxis of theileria annulata and theileria parva infections of calves with buparvaquone.	a clinical trial testing the prophylactic effect of a 5 mg kg-1 dose of buparvaquone on either theileria annulata or theileria parva experimental infections of calves demonstrated its efficacy for periods of at least seven days. the drug given 1 h or seven days before 50% lethal t. annulata sporozoite infection protected all eight calves, but prophylaxis was insufficient after 14 days to protect two out of four calves from severe reaction. when immunity was challenged by a lethal second parasite ...	1998	9703615
linkage of two distinct at-rich minisatellites at multiple loci in the genome of theileria parva.	minisatellite tandem repeat elements are well known components of vertebrate genomes, but have not yet been extensively characterized in lower eukaryotes. we describe two unusual, at-rich minisatellites of the protozoan parasite theileria parva whose sequences are unrelated to the g/c-rich i minisatellite superfamily' of vertebrate and plant genomes. the t. parva tandem repeats, one with a conserved sequence t2-5acaca (6-17 copies), and the other with a 6-bp core sequence of either actata or tat ...	1998	9729411
comments on the paper "sustainable tick and tickborne disease control in livestock improvement in developing countries".		1998	9746293
sequence analysis of the major piroplasm surface protein gene of benign bovine theileria parasites in east asia.	relatively benign theileria parasites are widespread among cattle in east asia. although the parasites are presumed to be of the theileria sergenti/theileria buffeli/theileria orientalis group, their taxonomic status and epidemiology have not been well defined. in the present study, theilerial dna samples were collected from various east asian countries, including japan, korea, taiwan, and china. dna sequences encoding a major piroplasm surface protein were amplified by polymerase chain reaction ...	1998	9762568
organisation and informational content of the theileria parva genome.	when compared with other apicomplexan organisms, theileria parva has an exceptionally small, 10-12 mbp, genome. there are only 4 chromosomes, each in the mbp range, and a complete physical map, based on sfii linking data, is available for each one. a number of genes and cdnas have been mapped to specific sfii fragments. telomeres consist of the simple repeat sequence typical of chromosomal ends but sub-telomeric homologies do not extend beyond 5 kbp. the only dispersed repetitive sequences ident ...	1998	9763284
telomeric features of theileria parva mitochondrial dna derived from cycle sequence data of total genomic dna.		1998	9763299
modulation of enzymatic activity of src-family kinases in bovine t cells transformed by theileria parva.	after infection with sporozoites of the protozoon theileria parva (tp) bovine t cells are readily transformed to permanent growth in vivo and in vitro. their transformed state depends on the constant presence of the parasite but membrane signals remain important. non-receptor tyrosine kinases play a critical role in the transduction of membrane signals in haematopoietic cells. we have investigated src-family kinases in bovine t cells transformed by tp. the t cell receptor-associated tyrosine kin ...	1998	9778632
cloning and characterization of a 150 kda microsphere antigen of theileria parva that is immunologically cross-reactive with the polymorphic immunodominant molecule (pim).	to identify the genes encoding novel immunodominant antigens of theileria parva a lambda gt11 library of piroplasm genomic dna was immunoscreened with bovine recovery serum and a gene encoding a 150 kda antigen (p150) was identified. the predicted polypeptide contains an n-terminal secretory signal sequence and a proline-rich region of repeated amino acid motifs. the repeat region is polymorphic between stocks of t. parva in both copy number and sequence, and analysis of the repeat region from 1 ...	1998	9820853
stage-specific activity in vitro on the theileria infection process of serum from calves treated prophylactically with buparvaquone.	an in vitro method for testing activity of buparvaquone in serum on the infection and development of theileria in its bovine host mononuclear cells is described and results compared with the effect exhibited in vivo. serum samples were collected over a time course from calves in a clinical trial of 5 mg kg(-1) buparvaquone prophylaxis on theileria annulata or t. parva experimental infection. to evaluate drug levels and persistence in each animal for a period of 14 days and its effect on the earl ...	1998	9870365
immunohistochemical detection of parasite antigens in theileria parva-infected bovine lymphocytes.	theileria parva is the causal agent of east coast fever (ecf), a fatal disease of cattle characterized by pyrexia, transient lymphadenopathy and panleukopenia. we have evaluated monoclonal antibodies (mab) against three distinct antigens (p67, pim and p32) of the parasite as immunohistological reagents for monitoring the kinetics of infection in cattle. bovine lymphocytes were stained with the mab at various intervals after infection in vitro and in vivo. the p67 sporozoite surface antigen was d ...	1998	9870366
linear peptide specificity of bovine antibody responses to p67 of theileria parva and sequence diversity of sporozoite-neutralizing epitopes: implications for a vaccine.	a stage-specific surface antigen of theileria parva, p67, is the basis for the development of an anti-sporozoite vaccine for the control of east coast fever (ecf) in cattle. by pepscan analysis with a series of overlapping synthetic p67 peptides, the antigen was shown to contain five distinct linear peptide sequences recognized by sporozoite-neutralizing murine monoclonal antibodies. three epitopes were located between amino acid positions 105 to 229 and two were located between positions 617 to ...	1999	10024569
the incidence, calf morbidity and mortality due to theileria parva infections in smallholder dairy farms in murang'a district, kenya.	a prospective observational study was conducted among smallholder dairy farmers in murang'a district, kenya, to estimate the incidence of theileria parva infections, as well as calf morbidity and mortality caused by the infection. the study was conducted between march 1995 and august 1996, in five cohorts of female calves from birth to six months of age from different agro-ecological zones (aezs) and grazing-system strata shown previously to have varying prevalences of t. parva infection. a tota ...	1999	10081789
bovine gammadelta t-cell responses to the intracellular protozoan parasite theileria parva.	t cells bearing the gammadelta antigen receptor (gammadelta t cells) can constitute up to 50% of t cells in the peripheral blood and lymphoid organs of young cattle. we present data showing that gammadelta t cells are involved in immune responses against theileria parva. gammadelta t cells isolated from peripheral blood mononuclear cells (pbmc) of t. parva-naive and -immune cattle proliferated in the presence of fixed or unfixed autologous t. parva-infected lymphoblasts (tpl) and heat-stressed c ...	1999	10225880
is interleukin 2 necessary for the autocrine proliferation of theileria-infected bovine cells?	theileria-infected bovine lymphoblastoid cells are induced to proliferate permanently such that the division of the parasites and that of their host cells occur synchronously. the mechanism by which the parasites induce the transformation of their host cells is unknown. we investigated the growth-factor dependency of a number of theileria-infected cell lines. supernatants of the majority of the cell lines tested in our study showed no growth-enhancing activity. however, supernatants of a limited ...	1999	10227059
theileria parva: sporozoite entry into bovine lymphocytes is not dependent on the parasite cytoskeleton.	the main conclusion from the present study is that t. parva sporozoite entry is dependent on a functional host cell actin cytoskeleton and is not driven by the parasite. treating lymphocytes with cytochalasin d resulted in a dose-dependent reduction in the levels of host cell infection. however, the primary effect was to block sporozoite binding and only at the highest concentration (20 microm) was sporozoite internalization significantly reduced. in fact at lower concentrations (1-10 microm) cy ...	1999	10329362
theileria parva 104 kda microneme--rhoptry protein is membrane-anchored by a non-cleaved amino-terminal signal sequence for entry into the endoplasmic reticulum.	the 104 kda microneme-rhoptry protein (p104) is the only known apical complex organelle-specific protein of theileria parva. p104 exhibits striking structural similarities to circumsporozoite protein and sporozoite surface protein 2 of plasmodium yoelii. their primary sequences contain two hydrophobic segments, located at the amino-and the carboxy-terminus. the p104 amino-terminal hydrophobic region was suggested to be a signal peptide for entry into the endoplasmic reticulum and the extreme car ...	1999	10376990
the intracellular parasite theileria parva protects infected t cells from apoptosis.	parasites have evolved a plethora of strategies to ensure their survival. the intracellular parasite theileria parva secures its propagation and spreads through the infected animal by infecting and transforming t cells, inducing their continuous proliferation and rendering them metastatic. in previous work, we have shown that the parasite induces constitutive activation of the transcription factor nf-kappab, by inducing the constitutive degradation of its cytoplasmic inhibitors. the biological s ...	1999	10377411
protective immune mechanisms against theileria parva: evolution of vaccine development strategies.	theileria parva is an intracellular sporozoan parasite that infects and transforms bovine lymphocytes, causing a severe lymphoproliferative disease known as east coast fever in eastern, central and southern africa. in this article, declan mckeever and colleagues summarize the current understanding of immune mechanisms provoked by the parasite with regard to their role in both pathogenesis and protection. in particular, the influence of genomic polymorphism in parasite and host on the development ...	1999	10377527
n-acetylcysteine blocks apoptosis induced by n-alpha-tosyl-l-phenylalanine chloromethyl ketone in transformed t-cells.	the serine protease inhibitor n-alpha-tosyl-l-phenylalanine chloromethyl ketone (tpck) can interfere with cell-cycle progression and has also been shown either to protect cells from apoptosis or to induce apoptosis. we tested the effect of tpck on two transformed t-cell lines. both jurkat t-cells and theileria parva-transformed t-cells were shown to be highly sensitive to tpck-induced growth arrest and apoptosis. surprisingly, we found that the thiol antioxidant, n-acetylcysteine (nac), as well ...	1999	10381628
review: theileria schizonts induce fundamental alterations in their host cells.	the sporozoites of theileria annulata and t. parva invade bovine leukocytes, where they differentiate into schizonts. the latter can immortalize and induce fundamental changes in their host cells. t. annulata infects mainly major histocompatibility complex class ii cells, whereas t. parva preferentially transforms t-lymphocytes, which proliferate continuously without the need for exogenously added growth factors. most of the cell lines appear to be independent of a growth factor but may express ...	1999	10382602
molecular phylogenetic studies on theileria parasites based on small subunit ribosomal rna gene sequences.	classification of theileria parasites of south-east asian countries is still ambiguous due to the lack of basic studies, especially their molecular genetic information. in this study, we included 6 known species and 14 unclassified theileria parasite isolates: theileria annulata, theileria parva, theileria taurotragi, theileria sergenti, theileria buffeli, theileria types sable, theileria types a, b, b1, b2, c, d, e, f, g, g1, theileria type medan (indonesia), theileria type ipoh (malaysia) and ...	1999	10392966
theileria parva ribosomal internal transcribed spacer sequences exhibit extensive polymorphism and mosaic evolution: application to the characterization of parasites from cattle and buffalo.	we sequenced the rrna genes and internal transcribed spacers (its) of several theileria parva isolates in an attempt to distinguish between the causative agents of east coast fever and corridor disease. the small subunit (ssu) and large subunit (lsu) rrna genes from a cloned t. p. lawrencei parasite were sequenced; the former was identical to that of t. p. parva muguga, and there were minor heterogeneities in the latter. the 5.8s gene sequences of 11 t. parva isolates were identical, but major d ...	1999	10406032
a rab1 homologue with a novel isoprenylation signal provides insight into the secretory pathway of theileria parva.	as a first step in developing compartment-specific markers for protein trafficking within theileria parva, we have isolated cdnas encoding homologues of the small gtp binding proteins rab1 and rab4. the t. parva homologue of rab1 (tprab1), a protein which regulates vesicular transport between the endoplasmic reticulum and cis golgi in other organisms, was unusual in that it contained a unique 17 amino acid c-terminal extension. the c-terminal motif sequence kct (xcx) contrasted with the cxc or x ...	1999	10477182
ceramide synergizes with phorbol ester or okadaic acid to induce ikappab degradation.	ceramide is a lipid second messenger which is generated in response to stimulation of a number of surface receptors, treatment with chemotherapeutic agents, or ionising radiation. depending on the target cell, ceramide induces diverse biological responses including apoptosis, cell-cycle arrest, differentiation, and also proliferation. we studied the effect of ceramide on the degradation of ikappab, the cytoplasmic inhibitor of the transcription factor nf-kappab. we show that ceramide treatment r ...	1999	10486254
comparison of indirect fluorescent antibody test and enzyme linked immunosorbent assay in the detection of exposure of cattle to theileria parva in kenya.	appraisal of the indirect fluorescent antibody test (ifat) and antigen enzyme linked immunosorbent assay (elisa) serological tests as carried out to detect cattle exposed to theileria parva at the national veterinary research centre, muguga (nvrc), kenya is reported. using sera from t. parva naive cattle and cattle experimentally exposed to t. parva, the two tests were appraised in terms of their sensitivity and specificity. ifat and elisa had the same sensitivity of 90% while elisa had a higher ...	1999	10486828
immunization against diseases caused by theileria parva: a review.	theileria parva is the causative agent of three epidemiologically different diseases, east coast fever (ecf), corridor disease and january disease, caused by 3 types of t. parva, t. p. parva, t. p. lawrencei and t. p. bovis, respectively. the history of immunization against these diseases has been marked by salient discoveries such as the immune status in recovered animals, the activity of tetracyclines during the incubation period, the possibility for cryopreserving supernatant of prefed ticks ...	1999	10540307
molecular epidemiology of theileria parva in the field.	molecular tools based on seminested rflp-pcr techniques to characterize field parasites in bloodspots dried on filter paper permitted investigation of the extent and the dynamics of diversity of theileria parva populations in the field. parallel molecular studies explored the long-term genome stability of various isolates by probing southern blots of ecori digested total genomic dna with four different reference nucleic acid probes. three polymorphic single copy loci encoding for antigen genes w ...	1999	10540308
the current epidemiological status of bovine theileriosis in eastern zambia.	results of a longitudinal study conducted in the eastern province of zambia from 1994 to 1997 indicate that it is doubtful whether a state of endemic stability of east coast fever (ecf) can be reached in the near future. even in endemic areas, the mortality of theileria parva infections is still estimated above 50%. the main factors limiting progress towards endemic stability are high innate susceptibility of the zebu cattle, the virulence of the parasite and the climate. the unimodal rainfall p ...	1999	10540309
economics of theileriosis control in zambia.	for an economic analysis of theileriosis control, we adopted the total economic cost (tec) method, which calculates the sum of output losses from tick damage, theileriosis mortality and morbidity, and expenditures for treatment or prevention of the disease. at farm level, the tec can be minimized by a specific combination of vector control and/or immunization and an acceptable level of losses. expenditures for vector control include acaricides, construction of dipping or spraying facilities and ...	1999	10540312
transformation of leukocytes by theileria parva and t. annulata.	theileria parva and t. annulata provide intriguing models for the study of parasite-host interactions. both parasites possess the unique property of being able to transform the cells they infect; t. parva transforms t and b cells, whereas t. annulata affects b cells and monocytes/macrophages. parasitized cells do not require antigenic stimulation or exogenous growth factors and acquire the ability to proliferate continuously. in vivo, parasitized cells undergo clonal expansion and infiltrate bot ...	1999	10547684
enzymes of glucose and glycerol catabolism in in vitro-propagated theileria parva schizonts.	theileria parva schizonts propagated in vitro in peripheral blood lymphocytes were purified and assayed for key enzymes of glucose and glycerol catabolism and the citric acid cycle. the activities of glycolytic enzymes were in the range of 21-100 nmol/min/mg protein. glycerol kinase and alpha -glycerophosphate dehydrogenase activities were more than 16 times lower than the activities of other enzymes catalysing the oxidation of the triose phosphates to lactate. it was suggested that the cataboli ...	1999	10558843
immunity and vaccine development in the bovine theilerioses.	there are three economically important bovine theileria species: theileria annulata, which causes tropical theileriosis and occurs across north africa and most of central asia; theileria parva, which causes east coast fever and is found in east and central africa; and theileria sergenti, which is predominantly a problem in japan and korea. theileria annulata preferentially infects macrophages in vivo. it is controlled largely by means of live, attenuated vaccines, which are produced by prolonged ...	1999	10563395
the use of nocodazole in cell cycle analysis and parasite purification from theileria parva-infected b cells.	theileria parasites transform bovine leukocytes and induce uncontrolled lymphoproliferation only in the macroschizont stage of their life cycle. the isolation of highly purified stage-specific parasite rna and proteins is an essential prerequisite when studying the theileria-host relationship. we therefore improved a protocol based on the cytolytic bacterial toxin aerolysin by taking advantage of the microtubule inhibitor nocodazole. in this report we describe that nocodazole-mediated separation ...	1999	10580273
interference by the intracellular parasite theileria parva with t-cell signal transduction pathways induces transformation and protection against apoptosis.	the intracellular parasite theileria parva transforms bovine t-lymphocytes, inducing uncontrolled proliferation. upon infection, cells cease to require antigenic stimulation and exogenous growth factors to proliferate. earlier studies have shown that pathways triggered via stimulation of the t-cell receptor are silent in transformed cells. this is reflected by a lack of phosphorylation of key signalling molecules and the fact that proliferation is not inhibited by immunosuppressants such as cycl ...	1999	10614498
treatment of east coast fever: a comparison of parvaquone and buparvaquone.	two trials were conducted to compare the efficacy of parvaquone and buparvaquone for the treatment of naturally acquired east coast fever (ecf, theileria parva infection) which, if untreated, is almost invariably fatal in european breeds of cattle. in the first trial 28 naive cattle were exposed in a paddock infested with ticks carrying a virulent form of the disease. twelve were treated with each drug when they developed clinical ecf. all 24 cattle were cured. in the second study, 100 cases of ...	1999	10628697
the occurrence of theileria and cowdria parasites in african buffalo (syncerus caffer) and their associated amblyomma hebraeum ticks.	the polymerase chain reaction and oligonucleotide probing were used to detect theileria and cowdria species in dna extracted from blood and ticks recovered from 24 african buffalo during a gamecapture operation in the kruger national park, south africa. species-specific probing indicated that all but one of the buffalo were carrying at least one theileria species. indirect fluorescent antibody (ifa) serology indicated that all animals had been exposed to theileria parva infection but only 33% we ...	1999	10631711
pathological effects and reduced survival in rhipicephalus appendiculatus ticks infected with theileria parva protozoa.	pathological effects have been demonstrated in a number of arthropod species as a consequence of parasitic infection. this is usually manifest as reduced arthropod survival and/or fecundity. this paper describes the detrimental effects the protozoan parasite, theileria parva has on rhipicephalus appendiculatus ticks. r. appendiculatus ticks were dissected and sectioned at regular intervals during their nymph to adult moult after detaching from a t. parva infected calf, and assessed by light and ...	2000	10726991
theileria parva genomics reveals an atypical apicomplexan genome.	the discipline of genomics is setting new paradigms in research approaches to resolving problems in human and animal health. we propose to determine the genome sequence of theileria parva, a pathogen of cattle, using the random shotgun approach pioneered at the institute for genomic research (tigr). a number of features of the t. parva genome make it particularly suitable for this approach. the g+c content of genomic dna is about 31%, non-coding repetitive dna constitutes less than 1% of total d ...	2000	10731569
reciprocal cross-protection induced by sporozoite antigens spag-1 from theileria annulata and p67 from theileria parva.	theileria annulata and theileria parva both possess a major surface antigen on the sporozoite stage of the life-cycle, called spag-1 and p67, respectively. in each case, these antigens are vaccine candidates and have been shown to induce a degree of homologous protection in earlier work. these antigens share sequence homology and are serologically cross-reactive. here, we confirm that these antigens confer protection against homologous species challenge. more importantly, they mutually confer a ...	2000	10792761
a statistically derived index for classifying east coast fever reactions in cattle challenged with theileria parva under experimental conditions.	a statistically derived disease reaction index based on parasitological, clinical and haematological measurements observed in 309 5 to 8-month-old boran cattle following laboratory challenge with theileria parva is described. principal component analysis was applied to 13 measures including first appearance of schizonts, first appearance of piroplasms and first occurrence of pyrexia, together with the duration and severity of these symptoms, and white blood cell count. the first principal compon ...	2000	10811278
differences in the epidemiology of theileriosis on smallholder dairy farms in contrasting agro-ecological and grazing strata of highland kenya.	a prospective cohort study was conducted in five purposively-sampled agro-ecological zone (aez)-grazing system strata in murang'a district, kenya, between march 1995 and june 1996. the study strata were selected based on a preliminary characterization study to represent the widest range of risks to east coast fever (ecf) in the district and included zero-grazing and open-grazing farms. in total, 225 calves from 188 smallholder farms were examined from birth to 6 months of age and visited within ...	2000	10813159
a highly sensitive, non-radioactive assay for t cell activation in cattle: applications in screening for antigens recognised by cd4(+) and cd8(+) t cells.	we describe a highly sensitive, non-radioactive assay for t cell activation, based on the rapid induction of class ii mhc expression by constitutively negative bovine endothelial cells, when cultured in the presence of supernatants derived from activated bovine t cells. we demonstrate the effectiveness of this assay in detecting rboifngamma and activation of immune cd4(+) and cd8(+) t cell lines and clones in response to specific antigen and transfected cos-7 cells, respectively. we also demonst ...	2000	10821950
cloning, sequence and mrna expression of bovine interleukin-16.	a lambda gt11 cdna library was constructed using mrna isolated from theileria parva-infected bovine lymphocytes. sequencing of random clones of this library resulted in the identification of a cdna encoding bovine interleukin-16 (il-16). the cdna has an open reading frame of 1134 bp, and a 3' untranslated region of 275 nucleotides with a polyadenylation signal 16 bases upstream from the poly (a) tail. the protein predicted by the cdna sequence contains 378 amino acids and the level of amino acid ...	2000	10826703
a 32 kda surface antigen of theileria parva: characterization and immunization studies.	previous studies using monoclonal antibody (mab) 4c9 specific for a 32 kda antigen (p32) of theileria parva demonstrated expression of the antigen on the surface of the sporozoite, making it a potential antigen for sporozoite neutralization. a full-length cdna encoding the major merozoite/piroplasm surface antigen (mmpsa) of t. parva was cloned and expressed in bacteria. the expressed product reacted strongly with mab 4c9, demonstrating identity between the p32 and mmpsa of t. parva. using immun ...	2000	10874718
the bovine cytotoxic t cell: mhc restriction and antigen-specificity.	the analysis of the immune mechanisms operative against the bovine intracellular protozoan parasite theileria parva resulted in the identification and characterisation of the bovine cytotoxic t lymphocyte (ctl) and its important role in protection against this parasite. by the use of polyclonal and monoclonal antibodies specific for bovine mhc antigens and lymphocyte populations and the use of mhc-haplotyped animals it was possible to demonstrate the mhc restriction and antigen-specificity of th ...	2000	10905120