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
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 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
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
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
dna measurements and ploidy determination of developmental stages in the life cycles of theileria annulata and t. parva.the relative dna levels of different developmental stages of theileria annulata and t. parva in the cow and the tick were measured by the cytophotometric dna technique using the fluorochrome hoechst 33258 as a staining dye. the results revealed that sporozoites, merozoites, gamonts, and gametes were haploid, whereas multinucleated intralymphocytic schizonts were polyploid. no difference was observed between t. parva and t. annulata in these stages. for both theileria species, the dna measurement ...19957479648
partial inhibition of theileria parva-infected t-cell proliferation by antisense il2r alpha-chain rna expression.antisense rna expression was used to assess the role of the interleukin 2 receptor (il2r) alpha-chain in proliferation of t cells transformed by infection with the intracellular parasite theileria parva. two vectors were constructed, in which part of the bovine il2r alpha-chain cdna was inserted in either a sense or antisense orientation in the plasmid phs1-cat, which is expressed by induction of the human metallothionein iia (hmt-iia) with cadmium (cd2+). a t. parva-infected t-cell line, tpm(80 ...19957481077
an assay for the identification of antigens recognized by cytotoxic t cells, based on transient transfection of cos cells.the studies reported here describe methodology permitting the direct identification of antigens recognized by cytotoxic t lymphocytes. we demonstrated that bovine alloreactive ctl can detect a bovine mhc molecule transiently expressed in a cos cell population in a standard microcytotoxicity assay. we then showed that alloreactive ctl can detect cells expressing the bovine class i mhc molecule in a population of cells transfected with the plasmid containing the corresponding gene plus 100-fold as ...19957490463
characterization of a late activation antigen defined by monoclonal antibodies of cluster bowc8 (tc23).three monoclonal antibodies (mabs), p13 (#90), il-a78 (#76) and il-a79 (#77), defined a new cluster, called bowc8. the antigen defined by these mabs is a molecule of 160 kda under reducing conditions, and is expressed on lymphocytes late (6 days) after activation. the molecule can be expressed on multiplying t cells, but not on b cells.19937508656
detection of theileria parva in the salivary glands of rhipicephalus appendiculatus: evaluation of staining methods.a comparison of ten methods for staining tick salivary glands for detection of theileria parva infection from ticks fed on rabbits for various periods was undertaken. staining with azure without hydrochloric acid hydrolysis was found to be the most reliable method for detection of the presporozoite stages (sporoblasts) of t. parva in the salivary gland acini of unfed rhipicephalus appendiculatus and could be applied to field ticks. all the stains proved suitable for the detection and quantitatio ...19957536922
parasite strain specificity of bovine cytotoxic t cell responses to theileria parva is determined primarily by immunodominance.the parasite strain specificity of ctl responses to theileria parva varies among cattle immunized with the same parasite stock. we have investigated the influence of class i mhc on the strain specificity of ctl responses to t. parva in 19 cattle of defined class i phenotype immunized with either of two t. parva populations, in which protection to subsequent reciprocal challenge correlated with ctl strain specificity. in the majority of animals the response was restricted by the products of one m ...19957594488
targeting ticks for control of selected hemoparasitic diseases of cattle.development in and transmission of hemoparasites by tick vectors are phenomena closely synchronized with the tick feeding cycle. in all known life cycles, initial infection of tick tissues occurs in midgut epithelial cells and transmission is effected as ticks feed after parasites have developed and multiplied in salivary glands. many factors reviewed affect development and transmission of hemoparasites by ticks including age of ticks, artificial temperature, climate and/or season, tick stage or ...19957597779
theileriosis: progress towards vaccine development through understanding immune responses to the parasite.studies of the immune responses of cattle to theileria parva have provided evidence that immunity to the parasite can operate at two levels, namely the sporozoite and the schizont-infected lymphoblast. antibodies that neutralize the infectivity of sporozoites have been detected in the serum of hyperimmunized cattle, and a recombinant sporozoite surface antigen has been shown to induce neutralizing antibodies and protection against experimental challenge. however, the immunity that develops follo ...19957597782
identification of candidate vaccine antigens of bovine hemoparasites theileria parva and babesia bovis by use of helper t cell clones.current vaccines for bovine hemoparasites utilize live attenuated organisms or virulent organisms administered concurrently with antiparasitic drugs. although such vaccines can be effective, for most hemoparasites the mechanisms of acquired resistance to challenge infection with heterologous parasite isolates have not been clearly defined. selection of potentially protective antigens has traditionally made use of antibodies to identify immunodominant proteins. however, numerous studies have indi ...19957597783
live vaccines against hemoparasitic diseases in vaccines against hemoparasitic diseases in livestock are based on parasites derived from culture (theileria annulata), from blood of infected animals (babesia bovis, babesia bigemina, anaplasma centrale, (attenuated) anaplasma marginale and cowdria ruminantium), and from ticks (theileria parva). the t. annulata attenuated cultured schizont vaccine is safe for all varieties of cattle. blood derived vaccines are recommended mainly for young cattle, the age limit varying with the different vac ...19957597786
estimation of heritability of susceptibility to infection with theileria parva in the tick rhipicephalus appendiculatus.heritability of susceptibility to infection with theileria parva was estimated from full sib families of rhipicephalus appendiculatus ticks. male and female ticks of 2 stocks were mated singly. nineteen full sib families of the muguga stock and 17 full sib families of the kiambu stock were obtained. nymphae of these families were fed on cattle infected with t. parva so that the ticks became replete on days 16 and 17 after infection when the blood was parasitaemic with intraerythrocytic piroplasm ...19957609988
generation and characterization of cloned theileria parva parasites.a 3-step procedure for cloning theileria parva parasites was developed. the first step involved the in vitro infection of a fixed number of bovine lymphocytes with titrated sporozoites. the cell lines obtained from infections initiated using sporozoite/lymphocyte ratios below 1:100 were then selected for cloning as these contained schizont-infected cells, each of which was derived from infection with a single sporozoite. in the second step, these cell lines were cloned by limiting dilution. as s ...19957609989
mhc class i molecules are an essential cell surface component involved in theileria parva sporozoite binding to bovine lymphocytes.the major histocompatibility complex (mhc) class i molecules are ubiquitous cell surface molecules involved in the cell-mediated immune response. we show here, using a number of different, independent approaches, that these proteins are an essential component of the host cell surface receptor involved in theileria parva sporozoite invasion. monoclonal antibodies (mabs) reactive with common determinants on mhc class i molecules and with beta-2 microglobulin inhibited sporozoite entry by specifica ...19957615677
humoral immune responses to theileria parva in cattle as measured by two-dimensional western blotting.humoral immune responses to schizont antigens from six stocks of theileria parva were compared by two-dimensional western blotting using sera from cattle that had been infected with a t. parva stock or a clone. isoelectric points of a polymorphic immunodominant molecule (pim) of schizonts that induces strong antibody responses in cattle ranged from acidic to basic. molecular masses (mr) of the pim of the respective t. parva stocks were as follows: t. parva muguga, 86 kda; mariakani, 83 kda; mari ...19957624293
characterization of the gene encoding the polymorphic immunodominant molecule, a neutralizing antigen of theileria parva.theileria parva, a tick-transmitted protozoan parasite related to plasmodium spp., causes the disease east coast fever, an acute and usually fatal lymphoproliferative disorder of cattle in africa. previous studies using sera from cattle that have survived infection identified a polymorphic immunodominant molecule (pim) that is expressed by both the infective sporozoite stage of the parasite and the intracellular schizont. here we show that mab specific for the pim ag can inhibit sporozoite invas ...19957636202
development and evaluation of pcr assay for detection of low levels of cowdria ruminantium infection in amblyomma ticks not detected by dna probe.the sensitivities of a pcr assay and a dna probe assay were compared for the detection of cowdria ruminantium in amblyomma ticks that were fed on c. ruminantium-infected, clinically reacting, and recovered carrier animals. the pcr assay and dna probe detected infection in 86.0 and 37.0%, respectively, of 100 ticks fed on a febrile animal. in 75 ticks fed on carrier animals, pcr and the dna probe detected infection in 28.0 and 1.33% of ticks, respectively. this demonstrates that the dna probe has ...19957699036
isolation of theileria parva (sao hill) and theileria parva (west kilimanjaro) and their cross-immunity with theileria parva (kasoba).two theileria parva stocks were isolated from control cattle during east cost fever (ecf) field immunization trials at sao hill and west kilimanjaro in the southern and northern parts of tanzania respectively. both parasite stocks caused severe clinical ecf which required antitheilerial treatment for 3 of the 5 experimentally infected cattle. cattle recovering from infection with the two t. parva stocks did not develop a fever and only 1 of 4 animals developed scanty schizont parasitosis for one ...19947709032
sequence and expression of a 90-kilodalton heat-shock protein family member of theileria parva.a theileria parva specific full-length cdna clone, t7, which encodes a protein with more than 60% homology to heat shock protein 90 (hsp90) of other organisms, has been identified. t7 appears to be a single copy gene. the gene is expressed as a protein of 87 kda in both the sporozoite and schizont stages of t. parva. the protein was not found in the piroplasm stage, although the corresponding transcript was detected, suggesting post-transcriptional regulation of the gene. in the schizont stage t ...19947739669
nitric oxide inhibits establishment of macroschizont-infected cell lines and is produced by macrophages of calves undergoing bovine tropical theileriosis or east coast fever.nitric oxide (no) was produced when bovine peripheral blood mononuclear cells (pbmc) or purified, adherent pbmc (macrophages) were incubated in vitro with bovine recombinant interferon gamma (bo rifn-gamma). no was produced by cells from naive, uninfected calves as well as by cells from cattle either infected with or recovered from infection with theileria annulata or theileria parva. pbmc of cattle undergoing tropical theileriosis (t. annulata infection) or east coast fever (t. parva infection) ...19957761113
theileria parva carrier state in naturally infected and artificially immunised cattle.rhipicephalus appendiculatus adult ticks, collected in the field from zebu (bos indicus) and exotic (bos tarus) cattle with high antibody titres to theileria parva schizont antigen, transmitted theileria parva infection typical of east coast fever to susceptible cattle. uninfected r. appendiculatus nymphs applied to naturally recovered zebu and exotic cattle kept under tick-free conditions in the laboratory for 16 and 7 months respectively, transmitted fatal theileriosis to susceptible cattle. c ...19957770947
effects of haemagglutination (lectin) inhibitory sugars on theileria parva infection in rhipicephalus appendiculatus.we have previously described the presence of haemagglutinins in tissues of the tick, rhipicephalus appendiculatus and determined their sugar specificities by inhibition experiments. in this study, haemagglutination inhibitory sugars are shown to have an effect in vivo on the abundance of theileria parva infected salivary gland acini in rhipicephalus appendiculatus. a significant increase (p < 0.05) was observed in t. parva acinar infection rates in the salivary glands of r. appendiculatus fed on ...19957797369
characterization of an insect cell-derived theileria parva sporozoite vaccine antigen and immunogenicity in cattle.previous data showed that six out of a group of nine cattle inoculated with ns1-p67, a recombinant form of a 67-kda theileria parva sporozoite surface protein, were immune to east coast fever. this bacterially expressed antigen encoded all 709 amino acid residues of p67 fused to the c-terminal end of 87 residues derived from ns1, a structural protein of influenza virus, and a linker dna sequence. ns1-p67 lacked reactivity with tpm 12, a monoclonal antibody to native p67, and had an estimated mol ...19957822014
molecular characterization of theileria parasites: application to the epidemiology of theileriosis in zimbabwe.forty theileria schizont-infected lymphocyte culture isolates from zimbabwe were characterized using a panel of antischizont monoclonal antibodies (mabs) and 4 theileria parva dna probes containing cloned extrachromosomal element, tpr repetitive, ribosomal and telomeric sequences. the theileria isolates were assigned as t. parva or t. taurotragi on the basis of reactivities with mabs and restriction fragment length polymorphisms (rflps) detected using the extra-chromosomal element probe. cattle- ...19947831093
casein kinase ii alpha transgene-induced murine lymphoma: relation to theileriosis in cattle.infection of cattle with the protozoan parasite theileria parva results in a fatal lymphoproliferative syndrome that is associated with the overexpression of casein kinase ii. the role of this enzyme in the pathogenesis of lymphoproliferative disorders was investigated by expressing the catalytic subunit in lymphocytes of transgenic mice. adult transgenic mice displayed a stochastic propensity to develop lymphoma; co-expression of a c-myc transgene in addition to casein kinase ii resulted in neo ...19957846532
a review on vaccination against protozoa and arthropods of veterinary importance.the recent advances in immunology and biotechnology have stimulated much research on the control of parasitic diseases through vaccination. this is a review of the state of the art regarding important protozoan and arthropod veterinary parasites. a live oocyst vaccine for avian coccidiosis is still in use but much work has been done on the identification, cloning, and assay of protective antigens. the sporozoites of eimeria tenella have been the preferred subject and at least four recombinant an ...19947886919
parasite strain specificity of precursor cytotoxic t cells in individual animals correlates with cross-protection in cattle challenged with theileria parva.class i major histocompatibility complex-restricted parasite-specific cytotoxic t lymphocytes (ctl) are known to be a major component of the bovine immune response to the protozoan parasite theileria parva, but formal proof for their role in protection of cattle against infection with t. parva has been lacking. animals immunized with one stock of t. parva show variations in the degree of protection against heterologous challenge and also in the parasite strain specificity of their ctl responses. ...19957890382
theileriosis in zambia: etiology, epidemiology and control zambia, theileriosis manifests itself in the form of corridor disease (cd), caused by theileria parva lawrencei, and east coast fever (ecf), caused by t. parva parva. of the approximately 3 million cattle in zambia, 1.4 million are at risk to theileriosis. ecf is found in the northern and eastern provinces of the country, while cd appears in southern, central, lusaka and copperbelt provinces. theileriosis is a major constraint to the development of the livestock industry in zambia, with losse ...19947933764
immunity to a parasite that transforms t lymphocytes.the past year has seen the first direct evidence that parasite-specific cd8+ t cells can protect cattle against patent infection with theileria parva. these studies were based on the adoptive transfer between monozygous twins of lymphocytes responding to a challenge with the parasite. immunization trials are also continuing with a candidate neutralizing vaccine based on the dominant antigen of the t. parva sporozoite surface. this progress has considerably enhanced the prospects for an improved ...19947946043
a rapid, single-step purification method for immunogenic members of the hsp 70 family: validation and application.gelatin affinity chromatography has been developed as a simple one-step procedure for purification of members of the hsp 70 kda family from mdbk cells (a bovine epithelioid cell line), rat liver microsomes and three different protozoan parasites. the ability of the isolated proteins to bind to denatured proteins like gelatin together with their apparent molecular masses, constitutive and inducible expression and their release from gelatin-agarose beads by atp suggested that these proteins are mo ...19947983383
characterization of theileria parva which infects waterbuck (kobus defassa).theileria-free waterbuck (kobus defassa) born in captivity were successfully infected with theileria parva sporozoites derived from ticks infected by feeding on african buffalo (syncerus caffer). all waterbuck underwent mild infections with the development of sporadic schizont and piroplasm parasitosis when inoculated with sporozoite doses lethal to cattle. a carrier state of t. parva was demonstrated by feeding clean r. appendiculatus nymphs on two of these infected waterbuck. tick batches from ...19948052510
severe anaemia due to haematopoietic precursor cell destruction in field cases of east coast fever in tanzania.examinations were made on erythrocytes, thrombocytes, leukocytes, lymph nodes, thymus, haemal nodes and bone marrow in field cases of east coast fever (ecf) in tanzania. seventy-six clinically sick short-horn zebu and taurine-zebu crosses, positive for theileria parva piroplasms and schizonts and 55 apparently healthy cattle were studied. the syndrome observed was characterised by severe pancytopenia, with massive normocytic, normochromic anaemia, panleukopenia and thrombocytopenia, but no retic ...19948073608
detection of polymorphisms among theileria parva stocks using repetitive, telomeric and ribosomal dna probes and anti-schizont monoclonal antibodies.a total of 21 theileria parva stocks from 6 countries were characterized using t. parva repetitive and ribosomal dna probes, a plasmodium berghei telomeric oligonucleotide and a panel of anti-schizont monoclonal antibodies (mabs). hybridization of the repetitive dna probe to southern blots of ecori-digested t. parva dna revealed 20 different restriction fragment patterns among dna samples isolated from infections initiated using 16 parasite stocks. the panel of anti-schizont mabs defined 8 diffe ...19938102796
a 7.1 kb linear dna molecule of theileria parva has scrambled rdna sequences and open reading frames for mitochondrially encoded proteins.theileria parva, an intralymphocytic protozoan parasite of cattle, contains a linear 7.1 kb dna element with terminal inverted repeat sequences. the molecule is transcribed into low molecular weight rna, and both dna strands encode short stretches of unique sequences, usually < 100 nucleotides, which are similar to large (lsu) or small (ssu) ribosomal subunit rna. phylogenetically conserved conformational rrna domains were assembled from the discontinuous rdna sequences using comparative seconda ...19948112303
adoptive transfer of immunity to theileria parva in the cd8+ fraction of responding efferent lymph.evidence that class i major histocompatibility complex-restricted cytotoxic t lymphocytes (ctl) are involved in immunity to malaria has highlighted the potential importance of these cells in protection against intracellular parasites. parasite-specific ctl are a prominent feature of the immune response of cattle to theileria parva, a related apicomplexan parasite. the relationship between the appearance of these cells in the blood of immune cattle under challenge and the clearance of infection s ...19948127915
the naming game: the changing fortunes of east coast fever and theileria parva.since first being recognised at the turn of the century, east coast fever of cattle and its causal parasite theileria parva have undergone numerous name changes as scientists have observed differences in the distribution, severity, characteristics and host associations of the disease within africa. these changes have caused considerable confusion to scientists and affected the control of infections caused by t parva in the field. the justification for the decisions affecting the nomenclature of ...19938128551
progress towards a vaccine against theileria parva: relevance for heartwater research.such progress has been made in the last decade in the characterization of bovine immunity to theileria parva. the evidence is overwhelming that cattle that become immune through infection can clear subsequent challenge infections by deploying parasite-specific cytotoxic t lymphocytes (ctl). furthermore, high titres of neutralising antibodies are generated against the sporozoite surface after multiple exposure to the parasite, and these can neutralise infection in vitro. although unlikely to be o ...19938134638
transmission of theileria parva to cattle by rhipicephalus appendiculatus adults fed as nymphae in vitro on infected blood through an artificial membrane.a technique is described for the efficient feeding of rhipicephalus appendiculatus nymphae on cattle blood through an artificial membrane bearing tactile and olfactory stimuli. the effect of four anticoagulation methods on the feeding of nymphae was compared and heparinized blood was found to be the most efficacious, followed by defibrinated blood. blood treated with acid citrate dextrose (acd) or ethylenediamine tetraacetate (edta) inhibited nymphal feeding. nymphae fed on heparinized and defib ...19938233588
the molecular basis of transformation of lymphocytes by theileria parva infection.the protozoan intracellular parasites, theileria parva and theileria annulata, infect cattle and cause severe and fatal leukocytic proliferative diseases. the proliferation is dependent on the presence of the parasites in the host cell cytoplasm. t. parva-infected cells proliferate permanently in cell culture and exhibit many features characteristic of tumor cells. the proliferation is reversible by treatment with parasite-specific drugs. constitutive expression of interleukin-2, its receptor an ...19938257788
theileria parva: detection of genomic polymorphisms by polymerase chain reaction amplification of dna using arbitrary primers.genomic dna fingerprints were generated from theileria parva piroplasm dna by polymerase chain reaction amplification using arbitrary decamers as primers. four of 12 primers tested generated amplified fragments which were polymorphic between different t. parva stocks or clones. hybridization of radiolabeled total amplification products to southern blots of t. parva piroplasm and uninfected bovine dna confirmed that none of the amplified fragments were derived from any contaminating bovine dna wh ...19938344406
progress in research on tick-borne diseases: theileriosis and heartwater.the rapid population growth in subsaharan africa necessitates a great increase in animal production in the more humid zones. vector-borne diseases occurring in these zones will assume more importance, but are difficult to control. they include theileriosis and heartwater. recent developments in research on these diseases are presented. indigenous animal populations in endemic areas, subjected to natural selection, are far less susceptible than exotic stock. heartwater, caused by the rickettsia c ...19938372422
discrimination between six species of theileria using oligonucleotide probes which detect small subunit ribosomal rna sequences.the complete small subunit ribosomal rna (srrna) gene of theileria parva was cloned and sequenced. two primers were designed which permitted the specific amplification of part of the theileria srrna gene from theileria-infected cell line samples which were predominantly (> 95%) bovine dna. the sequence of the central (variable) region of the srrna genes of t. annulata, t. taurotragi, t. mutants and two unidentified parasites referred to as theileria sp. (buffalo) and theileria sp. (marula) were ...19938414670
the growth of cell culture-attenuated rinderpest virus in bovine lymphoblasts with b cell, cd4+ and cd8+ alpha/beta t cell and gamma/delta t cell phenotypes.cloned bovine lymphoblastoid cell lines, transformed by the protozoan parasite theileria parva were infected with cell culture-attenuated rinderpest virus vaccine. the virus grew readily in lymphoid b cells, cd4+ and cd8+ alpha/beta t cells and gamma/delta t cells producing new infectivity, viral antigens, c.p.e. and total cell death. there did not appear to be a predilection for any particular phenotype of lymphoblast. the results imply that if the vaccine causes immunosuppression, it could do ...19938429305
differential in vitro and in vivo expression of mhc class ii antigens in bovine lymphocytes infected by theileria parva.the expression of major histocompatibility complex class ii (mhc ii) non-polymorphic antigens detected by four monoclonal antibodies was investigated in theileria parva-infected and non-infected cloned lymphoid cell lines, bulk cultures, and in peripheral blood mononuclear cells (pbmc) and lymph node cells (lnc) of experimentally infected calves. compared with non-infected cell lines, both immunofluorescence microscopy and flow cytofluorometry analysis of infected lines of alpha beta t-cell, gam ...19938430496
tick salivary gland extract and interleukin-2 stimulation enhance susceptibility of lymphocytes to infection by theileria parva sporozoites.intracellular parasites show host cell specificity, and precise information on the range of host cells is a prerequisite for the identification of host molecules that account for the specificity and are involved in entry processes. the sporozoite stage of the tick-borne protozoan parasite theileria parva binds to and enters bovine lymphocytes, but precise information on the susceptibility of other cell types present at the tick attachment site is unavailable. we quantitatively examined the susce ...19938454354
evidence for the induction of casein kinase ii in bovine lymphocytes transformed by the intracellular protozoan parasite theileria parva.theileria parva is an obligate, intracellular, parasitic protozoan that causes east coast fever, an acute leukemia-like disease of cattle. t. parva and the related parasite, theileria annulata, are unique among protozoa in that their intralymphocytic stages induce transformation of bovid lymphocytes. comparison of in vitro protein kinase activities between uninfected il-2-dependent t lymphoblasts and t. parva-infected lymphocytes revealed a 4.7- to 12-fold increase in total phosphorylation and t ...19938467809
proliferation of theileria annulata and theileria parva macroschizont-infected bovine cells in scid mice.theileria annulata and theileria parva macroschizont-infected bovine cells formed tumours at the inoculation site when injected subcutaneously into c.b.-17 scid mice. t. annulata tumours showed more vigorous growth than t. parva tumours. the tumours did not regress and infected cells spread to other tissues. intraperitoneal injection of high doses of t. annulata-infected cells resulted in the development of ascites: the infected cells colonized abdominal organs, in particular mesenteric tissue. ...19938468139
preliminary analysis of the transmission dynamics of theileria parva in eastern africa.two mathematical models are developed that investigate the transmission dynamics of theileria parva by the ixodid tick rhipicephalus appendiculatus to cattle in endemically stable areas. a method of estimating the rate of infection to cattle of t. parva at the endemically stable state is given. empirical estimates of all the parameters in the model are available. the degree to which animals that have recovered from theileriosis (the 'carrier' state) are able to transmit the infection to tick nym ...19938488062
production of interferon by theileria annulata- and t. parva-infected bovine lymphoid cell lines.theileria annulata and t. parva-infected lymphoblastoid cells were examined for their capacity to produce interferon (ifn). supernatants of such cells were tested in biological assay for their antiviral activity. only t. parva-infected cells of t-cell origin were capable of producing ifn-gamma. supernatants of some but not all t. annulata-infected cells showed also antiviral activity, which was greatly reduced after exposure to a ph of 2. northern-blot analysis of the cells using an ifn-gamma cd ...19938493239
selection of diversity at putative glycosylation sites in the immunodominant merozoite/piroplasm surface antigen of theileria parasites.the immunodominant merozoite/piroplasm surface antigen of theileria parasites has potential as a diagnostic reagent and as a component of a sub-unit vaccine. this molecule is known to be antigenically diverse, and it is important to determine the nature and extent of this heterogeneity. in the present study nucleotide sequences, representing alleles of the gene (tams1) encoding this molecule in theileria annulata were compared to each other and to sequences of homologous genes in theileria serge ...19958538686
mobilization of intrasporozoite ca2+ is essential for theileria parva sporozoite invasion of bovine lymphocytes.the entry of theileria parva sporozoites into bovine lymphocytes occurs rapidly and involves a defined series of events. in the present study the role of calcium in sporozoite entry was examined. depletion of ca2+ from the external medium had little effect on sporozoite entry suggesting that the initial sporozoite-host cell interaction is a ca(2+)-independent process. sporozoite entry could, however, be inhibited by a range of ca2+ channel blockers (verapamil, nicardipine, diltiazem) and calmodu ...19958549593
pathogenicity of theileria parva is influenced by the host cell type infected by the parasite.theileria parva has been shown to infect and transform b cells and t cells at similar frequencies in vitro. however, the majority of parasitized cells in the tissues of infected cattle are alpha/beta t cells. the aim of this study was to determine whether the cell type infected with t. parva influenced the pathogenicity of the parasite. the initial approach, which involved inoculation of cattle with autologous cloned cell lines of different phenotypes, failed to resolve the issue, because of pro ...19968550207
cd45ro expression on bovine t cells: relation to biological function.the 180,000 mw isoform of cd45 (cd45ro) has been identified in cattle with a novel monoclonal antibody (mab) (il-a116). this has allowed a more precise analysis of t-cell function in relation to cd45 isoform expression. within the cd4+ and cd8+ t-cell populations, cd45ro+ and cd45ro- subsets were evident. most cd4+ and cd8+ t cells that expressed the cd45ro isoform did not express the 220,000 and 205,000 mw isoforms recognized by mab cc76. in contrast, the wc1+, cd2-, cd4-, cd8-, gamma delta t-c ...19958567018
structure and sequence variation of the genes encoding the polymorphic, immunodominant molecule (pim), an antigen of theileria parva recognized by inhibitory monoclonal antibodies.the polymorphic, immunodominant molecule (pim) of theileria parva is the predominant antigen recognized by sera from infected cattle and by monoclonal antibodies (mab) used to differentiate parasite strains. as such, the antigen is under consideration as a diagnostic antigen, and since the mabs can neutralize sporozoite infectivity in vitro, in immunization experiments. initial comparison of two pim cdna sequences suggested that the pim genes consist of conserved 5' and 3' termini flanking a cen ...19958577324
identification of neutralization and diagnostic epitopes on pim, the polymorphic immunodominant molecule of theileria parva.the polymorphic immunodominant molecule (pim) of theileria parva is expressed by the schizont and sporozoite stages of the parasite. we have recently cloned the cdna encoding the pim antigen from two stocks of the parasite: the cattle-derived t. parva (muguga) stock and a buffalo-derived stock. the cdnas were used in transient-transfection assays to assess the reactivity of the antigen with monoclonal antibodies (mab) previously raised against schizont-infected cells and used for parasite strain ...19968613398
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 ...19968631374
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 ...19968675307
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 ...19968684836
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.19968690541
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 ...19968750682
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 ...19968801562
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 ...19968807777
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 ...19968811849
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 ...19968811850
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 ...19968811851
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 ...19968815619
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 ...19968834737
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 ...19968881419
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 ...19968930914
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 ...19968948324
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, ...19958966760
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 ...19968979421
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 ...19968983132
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 ...19979006954
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 ...19979035069
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 ...19979134558
the indirect fluorescent antibody test based on schizont antigen for study of the sheep parasite theileria 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 ...19979187025
use of an in vitro infectivity assay in comparison with histological techniques in the study of theileria parva sporozoite 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 ...19979195713
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 ...19969198598
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 ...19979203309
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 ...19979211502
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 ...19979234414
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 ...19979278944
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 ...19979356483
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 ...19979379055
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 ...19979423269
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 ...19979443328
immunology of infections with theileria parva in cattle. 19989509675
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 ...19989573089
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 ...19989610375
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 ...19989610640
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 ...19989618728
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 ...19989627941
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 ...19989646334
an outbreak of east coast fever in a herd of sanga cattle in lutale, central province of 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 ...19989646337
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