Publications

production of interferons by bovine and ovine cell lines infected with theileria annulata or theileria parva.	three bovine cell lines and four ovine cell lines infected with theileria parva or theileria annulata were examined for the production of interferon (ifn). biologically active ifn was detected in the tissue culture supernatants of four of the cell lines. only one, a bovine cell line infected with t. parva, produced ifn-gamma as measured by specific neutralization with a monoclonal antibody to bovine ifn-gamma. this observation was confirmed by analysing rna from the cell lines on northern blots ...	1991	1712932
distinction of naive and memory bocd4 lymphocytes in calves with a monoclonal antibody, cc76, to a restricted determinant of the bovine leukocyte-common antigen, cd45.	a murine igg1 monoclonal antibody (mab), cc76, has been produced that, based on findings of the relative molecular mass of polypeptides that it recognized, staining of leukocytes in blood and tissues, and the biological properties of the t lymphocyte subpopulations with which it reacts, is considered to identify an isoform of the leukocyte common antigen (lca) family of molecules in cattle. the mab is more similar to human cd45r which detect products requiring the presence of the b exon within t ...	1991	1716214
exposure of ankole and crossbred cattle to theileriosis in rwanda.	susceptible ankole (sanga: bos indicus/bos taurus) and crossbred ankole x jersey (b. taurus) and ankole x sahiwal (b. indicus) cattle derived from a farm in rwanda with no recent history of theileriosis, were infected with theileria parva stocks from rwanda either by feeding infected rhipicephalus appendiculatus ticks on the ears, inoculation of tick derived stabilate or natural exposure to tick challenge. the ankole cattle originated from local stock born and bred in east coast fever (ecf) ende ...	1991	1796523
re-assessment of tick control after immunization against east coast fever in the eastern province of zambia.	east coast fever, caused by the protozoon theileria parva and transmitted by the ixodid tick rhipicephalus appendiculatus is one of the most important cattle diseases in east and central africa, responsible for considerable direct losses and necessitating expensive control measures. traditionally, the disease was controlled by means of intensive tick control. the belgian animal disease control project was requested to study the disease epizootiology and vector ecology in order to formulate and i ...	1991	1793284
dna probes detect theileria parva in the salivary glands of rhipicephalus appendiculatus ticks.	the ability of theileria parva-specific dna probes to detect t. parva sporoblasts and sporozoites in samples prepared from the salivary glands of infected rhipicephalus appendiculatus ticks was evaluated. the two dna probes used, pgtpm-23 and igtpm-58, were selected from a genomic library of t. parva (muguga) piroplasm dna. in all, 25-200 adult ticks infected with each of 6 different t. parva stocks were tested. one salivary gland from each tick was processed for dna hybridization, whereas the o ...	1991	1792229
a simple and efficient method for purifying and quantifying schizonts from theileria parva-infected cells.	an improved method for the purification of theileria parva schizonts from infected bovine cells is described. the technique is simpler and more rapid than previously described methods and gives rise to greater yields of schizonts with negligible contamination by host-cell components. in addition, a fluorescent staining technique was developed whereby live schizonts purified from infected cells can be enumerated and sorted using the flow cytometer. an assessment of the quality of schizonts prepar ...	1991	1924254
theileria parva: influence of vector, parasite and host relationships on the epidemiology of theileriosis in southern africa.	the protozoan parasite theileria parva, transmitted by the ixodid tick rhipicephalus appendiculatus, is the cause of east coast fever (ecf) and the related syndromes of corridor disease and january disease in cattle of eastern, central and southern africa. it is likely that buffalo (syncerus caffer) are the natural host of t. parva. in eastern and southern africa, there exists both buffalo-adapted and cattle-adapted t. parva. disease caused by buffalo-adapted parasites is called corridor disease ...	1991	1907728
epidemiological observations on theileriosis following field immunisation using infection and treatment.	thirty-seven high grade cattle were immunised against corridor disease (theileria parva lawrencei infection) on a farm with a history of heavy and often lethal theilerial challenge. nineteen cattle were immunised by treating with two doses of long-acting oxytetracyclines given at 20 mg/kg on days 0 and 4 after sporozoite stabilate inoculation, while the other 18 were treated with naphthoquinone buparvaquone, given as a single dose of 2.5 mg/kg simultaneously with stabilate inoculation. all the c ...	1991	1907045
agarose entrapment method for the production of sfii linking library for theileria parva.	we have developed a simple method for isolation of sfii linking clones from a eukaryotic genomic dna. the method involves the physical separation of the small proportion of plasmids in a plasmid genomic library that are linearized by sfii digestion, from the bulk of molecules that remain circular, by ordinary electrophoresis through high-percentage gels of seaplaque agarose. following the isolation of linearized molecules, their recircularization, and introduction into escherichia coli, 55% of r ...	1991	1931184
effects of gamma interferon, tumor necrosis factor alpha, and interleukin-2 on infection and proliferation of theileria parva-infected bovine lymphoblasts and production of interferon by parasitized cells.	theileria parva is a protozoan parasite that infects bovine b cells and alpha beta and gamma delta t cells and transforms them into continually proliferating cells. cd4+ t. parva-antigen-specific immune t cells have been shown to produce cytokines in response to stimulation with parasitized cells, and t. parva-infected lymphocytes produce and consume t-cell growth factors and interleukin-2 (il-2). to ascertain the role of t-cell cytokines on t. parva infections, we evaluated recombinant gamma in ...	1991	1937812
cell surface phenotype of two cloned populations of bovine lymphocytes displaying non-specific cytotoxic activity.	monoclonal antibodies specific for t cell differentiation antigens were tested on four cloned populations of lymphocytes derived from the peripheral blood mononuclear cells of an animal immunised with theileria parva. the clones were defined functionally in terms of cytotoxic activity, mhc restriction and expression of messenger rna for cd3 and t cell receptor (tcr). two clones contained rna transcripts for cd3, tcr-alpha and beta and were positive for cd2, cd5 and cd6; one of these was a typica ...	1991	1826981
an unusual repetitive gene family in theileria parva which is stage-specifically transcribed.	tpr1 is a repetitive dna element from theileria parva which has previously been shown to be of value in strain characterisation. further characterisation, described here, has shown that tpr1 is present in long tandem arrays. the sequence of 8.1 kb from one end of an array has been determined. the sequence showed that tpr1 is a 1.44-kb element which contains an orf extending from its 5' end to the 3' end. the sequenced region contains 4 large orfs; 2 of these consisted only of tpr1 whilst the thi ...	1991	1840629
[activation of trans-acting transcription factors in t-lymphocytes infected by the intracellular parasitic protozoan theileria parva].	the intracellular protozoan parasite, theileria parva, causes a lymphoproliferative disease of t-cells in cattle and uncontrolled lymphocyte proliferation in culture. we have identified and characterized in infected cells the trans-acting transcription factors nf-kappa b, ap1 and nf1 controlling lymphocyte-specific expression of several genes. theileria infected lymphocytes contain constitutively high levels of active nf-kappa b in nuclear fraction. factor ap1 had high levels of binding activity ...	1991	1874431
lymphocytes infected with theileria parva require both cell-cell contact and growth factor to proliferate.	lymphocytes infected with the intracellular parasite theileria parva proliferate continuously as lymphoblastoid cell lines. we have previously shown that the continuous proliferation of the t. parva-infected (tpi) cell line tpm(803) is mediated in part by an autocrine mechanism (dobbelaere, d. a. e. et al., proc. natl. acad. sci. usa 1988. 85:4730). we now report that continuous proliferation also requires surface stimulation through cell-cell contact. under standard culture conditions this surf ...	1991	1899385
the entry of theileria parva sporozoites into bovine lymphocytes: evidence for mhc class i involvement.	we have examined the process of theileria parva sporozoite entry into susceptible bovine lymphocytes and have begun to identify one of the possible molecular interactions involved in the process. the entry process involves a defined series of events and we have used a number of experimental procedures in combination with a method of quantitation to examine various aspects of this process. t. parva sporozoites are nonmotile organisms and the initial sporozoite-lymphocyte interaction is a chance e ...	1991	1901066
characterization of a polymorphic immunodominant molecule in sporozoites and schizonts of theileria parva.	this study examines several aspects of a polymorphic, immunodominant molecule (pim) found in the protozoan parasite, theileria parva. the antigen is present in all t.p. parva stocks examined, and in the related subspecies, t.p.bovis and t.p.lawrencei. it is the predominant antigen recognized by antisera from immune cattle on western blot analysis of schizont-infected lymphocytes, and is the only antigen which has been shown to react with anti-schizont monoclonal antibodies (moabs) on western blo ...	1991	1901640
analysis of the reactivity of anti-bovine cd8 monoclonal antibodies with cloned t cell lines and mouse l-cells transfected with bovine cd8.	mouse l-cells transfected with bovine cd8 and two theileria parva-infected cloned t cell lines expressing bovine cd8 were used to screen the panel of ten monoclonal antibodies (mabs) submitted to the workshop. eight of the ten mabs reacted with the transfectant and both the cloned t cell lines. however, two mabs cc58 and bat82a did not recognise the transfectant and only reacted with one of the t cell lines. further biochemical studies indicated that the eight mabs react with both homo- and hete ...	1991	1902341
activity of buparvaquone against theileria cervi in white-tailed deer.	buparvaquone, a naphthoquinone with known efficacy against theileria parva parva in cattle, was tested for activity against theileria cervi piroplasms in both an in vitro culture system and in vivo in experimentally infected white-tailed deer. the in vitro data showed a significant decrease in the incorporation of 3h-hypoxanthine by infected red blood cells treated with buparvaquone when compared to that seen with imidocarb and chloroquine treatment. in both intact and splenectomized deer treate ...	1991	1902608
further evaluation of the use of buparvaquone in the infection and treatment method of immunizing cattle against theileria parva derived from african buffalo (syncerus caffer).	three experiments were undertaken to determine the efficacy of different doses of buparvaquone in the infection and treatment immunization of cattle against theileria parva derived from african buffalo (syncerus caffer). two of these experiments also compared buparvaquone with standard doses of long- and short-acting formulations of oxytetracycline. in addition, different dilutions of stabilates were used in the experiments. in the first experiment, a 10(-1.0) dilution of stabilate was used to i ...	1992	1496799
how individual cells develop from a syncytium: merogony in theileria parva (apicomplexa).	the central problem for theileria parva during merogony is how to form numerous individual, uninucleate merozoites from a syncytial schizont so that each merozoite contains a single nucleus and a prescribed assortment of organelles. the way t. parva packages all the requisite organelles into free merozoites is by binding these organelles to the nuclear envelope, which in turn becomes associated, both directly and through the rhoptry complex, with the schizont plasma membrane. formation of the me ...	1992	1569119
constitutive il-2 mrna expression in lymphocytes, infected with the intracellular parasite theileria parva.	theileria parva-infected lymphoblastoid cell lines of t or b cell origin were examined for il-2 mrna expression. t. parva-infected t cell lines could be of the cd4-cd8-, cd4+cd8-, cd4-cd8+, or cd4+cd8+ phenotype and express alpha beta or gamma delta tcr. by northern blot analysis and amplification by the polymerase chain reaction, il-2 mrna could be detected in all t. parva-infected cell lines tested. il-2 mrna expression was also shown to be dependent on the continuous presence of the parasite ...	1992	1624803
growth of theileria annulata and theileria parva macroschizont-infected bovine cells in immunodeficient mice: effect of irradiation and tumour load on lymphocyte subsets.	bovine cells infected with macroschizonts of the protozoan parasites theileria annulata and theileria parva formed solid tumours when injected into irradiated balb/c and irradiated balb/c nude mice. t. annulata tumours grew more vigorously than t. parva tumours, when initiated with similar doses of infected cells in mice exposed to the same doses of gamma-irradiation. in irradiated balb/c mice, tumours of both species of parasites began to regress 2-3 weeks after injection of cells but grew with ...	1992	1644524
a recombinant sporozoite surface antigen of theileria parva induces protection in cattle.	at present immunization against theileria parva is by infection with live sporozoites and simultaneous treatment with a long-acting oxytetracycline. this method has major limitations in that live organisms are used and the immunity engendered is parasite stock specific. in an attempt to develop an alternative immunization procedure, the gene encoding p67, a major surface antigen of sporozoites, has been expressed by using the plasmid expression vector pmg1. the gene, which has been characterized ...	1992	1731322
standardization of a technique for analysing the frequency of parasite-specific cytotoxic t lymphocyte precursors in cattle immunized with theileria parva.	a limiting dilution microculture system was optimized to quantify the frequency of theileria parva-specific cytotoxic t lymphocyte precursors (ctlp) in peripheral blood mononuclear cells (pbmc) from immune cattle. optimal results were obtained with responder cell input levels ranging from 2 x 10(4)/well to 6.25 x 10(2)/well, along with 1-5 x 10(3)/well stimulator cells in standard supplemented rpmi 1640 medium containing 2.5-5% t cell growth factors. thirty-six microtitre wells were established ...	1992	1570170
restriction mapping of the genome of the protozoan parasite theileria parva.	we have used a modified linking clone strategy and pulsed-field gel electrophoresis to derive a map of the 29 sfi i and 4 not i sites in the 10 million base pair genome of the protozoan parasite theileria parva. this was achieved in the absence of classical genetic information. the map reveals four chromosomes. several genes, including those for parasite antigens, have been located on the map, as has the single locus carrying the major repetitive sequence in this organism. the map forms the basi ...	1992	1608931
theileria parva: cd4+ helper and cytotoxic t-cell clones react with a schizont-derived antigen associated with the surface of theileria parva-infected lymphocytes.	theileria parva is a protozoan parasite which infects and transforms bovine lymphocytes, resulting in a fatal lymphoproliferative disease. there is evidence that immunity to the intralymphocytic schizont stage is mediated by t cells. we have previously reported derivation of cd4+ t-cell clones which recognize parasite-derived antigens presented on the surface of infected cells in conjunction with mhc molecules and partial characterization of the antigens. the present study further evaluated one ...	1992	1353459
immune cd4+ t cells specific for theileria parva-infected lymphocytes recognize a 24-kilodalton protein.	theileria parva is a protozoan parasite that infects and transforms bovine lymphocytes. here we report the partial purification of a t. parva-specific protein from infected lymphocytes that is recognized by cd4+ parasite-specific t-cell clones derived from immune cattle. t. parva-infected lymphocytes were homogenized in dulbecco's phosphate-buffered saline in the presence of protease inhibitors. the antigen was purified from a postmicrosomal supernatant by using a combination of deae-cellulose c ...	1992	1354201
cloning and characterization of the casein kinase ii alpha subunit gene from the lymphocyte-transforming intracellular protozoan parasite theileria parva.	theileria parva is an obligate intracellular protozoan parasite which is the causative agent of east coast fever, an acute, leukemia-like disease of cattle. the intralymphocytic stage of the parasite induces blastogenesis and clonal expansion of quiescent bovid lymphocytes. experiments in our laboratory have shown a marked increase of casein kinase ii- (ck ii-) like activity in t. parva-transformed lymphocytes. we have also detected ck ii activity in purified t. parva schizonts. to explore the s ...	1992	1378299
improved isolation of rinderpest virus in transformed bovine t lymphoblast cell lines.	bovine t lymphoblast cell lines transformed by the protozoan theileria parva were compared with bovine kidney (bk) and vero cells for their ability to isolate various strains of rinderpest virus from tissues and infected secretions. all of the strains of rinderpest virus that were tested, including attenuated cell-culture, caprinised and lapinised vaccines, and both mild and virulent pathogenic strains, readily induced syncytial cytopathic effect (cpe) in t lymphoblasts. the cpe could often be d ...	1992	1410806
transformation of theileria parva derived from african buffalo (syncerus caffer) by tick passage in cattle and its use in infection and treatment immunization.	a sporozoite stabilate (st. 199) of theileria parva was obtained by feeding nymphal rhipicephalus appendiculatus on an african buffalo (syncerus caffer) and was used to immunize cattle by the infection and treatment method. nymphal ticks were applied to one of the steers 90 days later and it was shown that the resultant adult tick had become infected. using tick/cattle passage, two passage lines of t. parva were established. by the fifth tick/cattle passage, the parasite stocks had changed their ...	1992	1496792
characterisation of the gene encoding a candidate vaccine antigen of theileria parva sporozoites.	we have cloned and characterised the gene encoding the 67-kilodalton stage-specific surface antigen, p67, of theileria parva (muguga) sporozoites. the gene which is present in a single copy, is divided into 2 exons by an intron 29 bp long and is transcribed into mrna of about 2500 nucleotides. the gene is present in all stocks of t. parva and there is a related gene in theileria annulata. the deduced amino acid sequence of 709 residues predicts that p67 is a membrane protein and that it lacks ta ...	1992	1565135
cytokines inhibit the development of trophozoite-infected cells of theileria annulata and theileria parva but enhance the proliferation of macroschizont-infected cell lines.	the following bovine (bo) and human (hu) cytokines--bo rtnf-a, bo rifn-g, hu ifn-a, hu ril-1, hu ril-2--significantly inhibited the in vitro development of trophozoite-infected cells of three stocks of theileria annulata and of theileria parva (muguga). however, none of these cytokines inhibited the proliferation of established t. annulata or t. parva macroschizont-infected cell lines. indeed, bo rtnf-a and hu ril-2 consistently enhanced the proliferation of macroschizont-infected cell lines of ...	1992	1570169
interactions between chemotherapy and immunity in bovine theileriosis.	in bovine theileriosis the use of chemotherapy to control an infection sufficiently long to permit the establishment of a solid protective immune response has been developed as a routine vaccination procedure. infections with theileria parva and t. annulata can be prevented by the administration of carefully controlled numbers of sporozoites simultaneously with a long acting tetracycline and this form of immunization has been widely used for the control of east coast fever in africa with conside ...	1992	1308933
analysis of theileria parva immunodominant schizont surface antigen by two-dimensional polyacrylamide gel electrophoresis and immunoblotting.		1992	1584754
detection of a carrier state in theileria parva-infected cattle by the polymerase chain reaction.	two sets of oligonucleotide primers, one derived from a repetitive sequence and the other from the gene encoding a 67 kda sporozoite antigen of theileria parva, were used to amplify parasite dna from the blood of t. parva-infected carrier cattle using the polymerase chain reaction (pcr). pcr amplification products were obtained from 15 carrier cattle infected with one of 4 different t. parva stocks. successful amplifications were performed using dna from 2 cattle infected with t. p. parva pemba ...	1992	1350672
the cytotoxic t cell: mhc restriction, strain specificity and role in immunity to theileria parva infection.		1992	1416743
a clinical trial of buparvaquone in the treatment of east coast fever.	a clinical trial was conducted to test buparvaquone (butalex; coopers pitman-moore) in the treatment of east coast fever under field conditions in kenya. data from 229 cases were analysed following treatment with one (69), two (142) or three (18) doses at 2.5 mg/kg. the majority of cattle (95.2 per cent) were exotic (bos taurus) or improved (bos taurus cross bos indicus) and 39.3 per cent were infected with anaplasma marginale. there was an overall recovery rate of 85.6 per cent, with 90.1 per c ...	1992	1441098
development and persistence of cowdria ruminantium specific antibodies following experimental infection of cattle, as detected by the indirect fluorescent antibody test.	different breeds of cattle were experimentally infected with palm river, a zimbabwean isolate, or ball-3, a south african isolate of cowdria ruminantium, derived from tissue culture or tick or blood stabilates. c. ruminantium specific antibody responses were detected by an indirect fluorescent antibody test (ifat) using c. ruminantium-infected bovine aortic endothelial (bae) cell cultures as antigen. the first detection of antibodies to c. ruminantium generally coincided with the peak of the feb ...	1992	1441219
immunisation of cattle against theileriosis in nakuru district of kenya by infection and treatment and the introduction of unconventional tick control.	one hundred and one cross european-boran cattle (50 cows and 51 calves), on a farm in nakuru district, kenya, were immunised against theileriosis using theileria parva lawrencei and theileria parva parva stocks from another district of kenya. the stabilates used were t.p.lawrencei (mara iii) used at 10(-1.7) dilution and t.p.parva (kilae) used at 10(-1.0) dilution. the stabilates were combined and inoculated simultaneously with a short-acting formulation of oxytetracycline hydrochloride given in ...	1992	1496782
the effect of high and low dose theileria parva infection on the reproductive function of boran/friesian heifers.	two separate experiments were carried out to find the effect of infection with low and high doses of theileria parva sporozoites on the cyclical status of boran/friesian cross heifers. in each experiment, ten heifers were infected and another four heifers acted as controls. routine monitoring of estrous behavior, determination of serum progesterone concentrations and palpation of the ovaries per rectum were used to assess the cyclical status of each animal. two and eight animals died in the t . ...	1993	16727380
a sporozoite-based vaccine for theileria parva.	east coast fever, which is caused by theileria parva infection in cattle, is of major economic importance in eastern and central africa. until recently, the only available method of immunization against east coast fever was the infection with live sporozoites and simultaneous treatment with a long-acting oxytetracycline. this method has two major disadvantages: (i) it uses live organisms; and (2) the immunity engendered is parasite strain specific. in this article, antony musoke, vishvonath nene ...	1993	15463675
genome analysis of theileria parva.	recent technological developments in the field of genome analyses have advanced our knowledge of the structures of prokaryotic and eukoryotic genomes. examples of these range from small bacterial genomes, such as escherichia coli, to the more complex genomes of caenorhabditis elegans, drosophila, humans and mouse. here, subhash morzona and john young review developments in mapping the genome of on economically important protozoan parasite o f cattle, theileria parva. this map provides a framewor ...	1993	15463676
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 ...	1993	8128551
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 ...	1993	8454354
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.	1993	7508656
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. ...	1993	8468139
analysis of dinucleotide frequency and codon usage in the phylum apicomplexa.	dinucleotide frequency (dif) and codon usage (cu) were analysed in gene sequences from four parasitic protozoa, babesia bovis, theileria parva, toxoplasma gondii and eimeria tenella, of the phylum apicomplexa. in keeping with the 'genome hypothesis', cu was found to be non-random and species specific in these organisms, although cu among members of the same subclass was found to be very similar. several low-usage (lu) codons were identified, and the usage of lu codons appears to be related to th ...	1993	8482530
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 ...	1993	8488062
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 ...	1993	8102796
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 ...	1993	8233588
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 ...	1993	8134638
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 ...	1993	8414670
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 ...	1993	8430496
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 ...	1993	8467809
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 ...	1993	8372422
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 ...	1993	8257788
characterisation of a glutamine- and proline-rich protein (qp protein) from theileria parva.	we have isolated a clone from a theileria parva infected lymphocyte cdna library which has the potential to encode a protein of 480 amino acids. this protein is particularly rich in glutamine and proline and has some short repeated amino acid motifs based on the sequences qpxp and qpxq. we have called it the 'qp protein'. southern blotting suggests that the qp protein gene is present as a single copy in the t. parva muguga genome. northern blotting revealed that the gene is transcribed in both s ...	1993	8264721
antibody select procedure for characterization of expression clones.		1993	8220723
characteristics of tick, rhipicephalus appendiculatus, glands distinguished by surface lectin binding.	incubation of fluorescein-conjugated and biotinylated lectins with rhipicephalus appendiculatus salivary glands revealed differences between the basal laminae of the haemocoelic surfaces of the three acinal types. there were some similarities in the lectin binding characteristics of the surfaces of type ii and type iii acini when con a, pna and tva were applied, indicating the presence of galactose, mannose and glucose moieties on the acinal surfaces. the binding of bpa, hpa and haa lectins, spe ...	1993	8311579
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 ...	1993	8344406
antibodies against major histocompatibility complex class ii antigens directly inhibit the growth of t cells infected with theileria parva without affecting their state of activation.	we have analyzed the effect of antibodies (abs) directed against major histocompatibility complex (mhc) class ii abs on the proliferation of theileria parva-infected (tpi) t cells. anti-mhc class ii abs exert a direct effect on tpi t cells causing an acute block in their proliferation. the inhibition does not involve apoptosis and is also entirely reversible. the rapid arrest of dna synthesis caused by anti-mhc class ii abs is not due to interference with the state of activation of the t cells s ...	1993	8350052
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 ...	1993	8429305
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 ...	1993	8493239
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 ...	1994	8127915
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 ...	1994	7886919
theileriosis in zambia: etiology, epidemiology and control measures.	in 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 ...	1994	7933764
discrimination between theileria parva and t. taurotragi in the salivary glands of rhipicephalus appendiculatus ticks using oligonucleotides homologous to ribosomal rna sequences.		1994	8036242
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 ...	1994	8112303
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 ...	1994	7946043
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 ...	1994	7983383
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 ...	1994	8052510
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 ...	1994	8073608
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 ...	1994	7739669
evidence for two single copy units in theileria parva ribosomal rna genes.	bacteriophage clones containing ribosomal rna genes of theileria parva were isolated from genomic dna libraries. physical mapping studies revealed 2 ribosomal dna units, which were distinguishable by restriction enzyme site polymorphisms in flanking sequences. the cloned ribosomal dna units were mapped to 2 separate t. parva chromosomes. analysis of sequences contained in lambda embl3 recombinants, together with southern blot analysis of genomic dna and data on the copy number of the rrna genes, ...	1994	7808475
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- ...	1994	7831093
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 ...	1994	7709032
induction of signal transduction pathways in lymphocytes infected by theileria parva.		1994	15275514
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
the entry of theileria parva merozoites into bovine erythrocytes occurs by a process similar to sporozoite invasion of lymphocytes.	the entry of theileria parva merozoites into bovine erythrocytes in vivo is described and compared to sporozoite invasion of lymphocytes. merozoites make initial contact with erythrocytes with any part of their surface and invasion of the host cell does not require the re-orientation of the apical end of the merozoite towards the surface of the erythrocyte. after the initial attachment the merozoite and host cell membranes form a continual close junction with the two apposed membranes separated ...	1995	11023409
optimization of the in vitro feeding of rhipicephalus appendiculatus nymphae for the transmission of theileria parva.	an apparatus for artificial feeding of rhipicephalus appendiculatus nymphae was modified to improve feeding performance. heparinized blood was supplied above a treated artificial membrane while the ticks attached below on its undersurface. the feeding apparatus was incubated at 37 degrees c in an atmosphere of 3% co2 concentration and a relative humidity of 75-80%. under these conditions, 91% of the engorged nymphae attained a mean weight of 6-11 mg, and an average of 93% of those nymphae moulte ...	1995	11023410
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 ...	1995	7615677
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. ...	1995	7890382
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 ...	1995	7479648
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 ...	1995	7490463
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 ...	1995	7624293
live vaccines against hemoparasitic diseases in livestock.	live 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 ...	1995	7597786
characterisation of the telomeres at opposite ends of a 3 mb theileria parva chromosome.	bacteriophage lambda clones containing theileria parva genomic dna derived from two different telomeres were isolated and the nucleotide sequences of the telomeric repeats and adjacent telomere-associated (tas) dna were determined. the t.parva telomeric repeat sequences, a tandem array of ttttaggg or tttaggg interspersed with a few variant copies, showed a high degree of sequence identity to those of the photosynthetic algae chlamydomonas reinhardtii (97% identity) and chlorella vulgaris (87.7% ...	1995	7596822
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 ...	1995	7597779
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 ...	1995	7481077
casein kinase ii in theileriosis.		1995	7846527
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 ...	1995	7822014
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) ...	1995	7761113
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 ...	1995	7770947
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 ...	1995	7797369
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 ...	1995	7536922
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 ...	1995	7594488
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 ...	1995	7597782
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 ...	1995	7699036
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 ...	1995	7636202
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 ...	1995	7609988