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potential value of localized skin reactions (chancres) induced by trypanosoma congolense transmitted by glossina morsitans centralis for the analysis of metacyclic trypanosome populations.goats infected with trypanosoma congolense transmitted by glossina morsitans centralis and then treated with the trypanocidal drug diminazene aceturate are immune to tsetse-transmitted infection with a homologous, but not heterologous trypanosome clone. immune animals fail to develop localized skin reactions (chancres) and do not become infected, whereas on heterologous challenge chancres appear followed by parasitaemia. in this study, the feasibility of using chancre reactions to characterize s ...19873601446
the virulence of trypanosoma congolense can be determined by the antibody response of inbred strains of mice.three inbred strains of mice, balb/c, c57bl/6 and cba/j were infected with three clones of trypanosoma congolense, dind/3.1, sam/28.1 and kar/57.1, which were obtained from three different stocks. dind/3.1 was of high virulence for balb/c and cba/j but of negligible virulence for c57bl/6. sam/28.1 was of high virulence and kar/57.1 of negligible virulence for the three strains of mice. in each case, high virulence was correlated with a late, transient and low titre protective antibody response m ...19873601447
cibarial infections of trypanosoma vivax and t. congolense in glossina.in a percentage of laboratory bred glossina infected with trypanosoma congolense or t. vivax, trypanosomes colonized the cibarium as well as the midgut and/or the proboscis. field-caught tsetse flies also had t. congolense and t. vivax cibarial infections. t. congolense cibarial infections occurred in all species of glossina examined: g. tachinoides, g. palpalis palpalis, g. morsitans morsitans and g. m. submorsitans. t. vivax was only found in the cibarium of g. tachinoides. trypanosomes were f ...19873615393
subcellular localization of a variable surface glycoprotein phosphatidylinositol-specific phospholipase-c in african trypanosomes.african trypanosomes contain a membrane-bound enzyme capable of removing dimyristylglycerol from the membrane-attached form of the variable surface glycoprotein (mfvsg; ferguson, m. a. j., k. halder, and g. a. m. cross, 1985, j. biol chem., 260:4963-4968). although mfvsg phospholipase-c has been implicated in the removal of the vsg from the trypanosome surface (cardoso de almeida, m. l., and m. j. turner, 1983, nature (lond.)., 302:349-352; ferguson, m. a. j., k. halder, and g. a. m. cross, 1985 ...19873624307
bovine trypanosomiasis in southern tanzania: parasitological and serological survey of prevalence.in a survey for bovine trypanosomiasis blood smears from 1,617 cattle at 72 sites were examined. trypanosomes were found in 93 cattle, representing 16% of the cattle in herds in which trypanosomiasis was confirmed. of the positive cattle 56% had infections with t. congolense, 17% t. vivax and 2.2% t. brucei. five cattle had mixed infections and in 18 cattle the species was not identified. sera from 1,352 cattle were tested using microelisa. ten out of 16 sites, at which no trypanosomes were foun ...19873660451
stable introduction of exogenous dna into trypanosoma brucei.the lack of a homologous transformation system for trypanosomes is a serious handicap to the study of gene expression in these protozoans. attempts to develop such a system have been complicated by the lack of suitable homologous vectors and ignorance of the requirements for mrna synthesis which is discontinuous in trypanosomes. we have found that trypanosoma congolense, a close relative of t. brucei, contains exceptionally small chromosomes, which can be isolated whole and distinguished from th ...19873665883
use of species-specific dna probes for detection and identification of trypanosome infection in tsetse flies.species- and subspecies-specific trypanosome dna hybridization probes have been employed in the detection and identification of trypanosome infections in glossina morsitans centralis. several ways of sample preparation including the use of tsetse organ suspensions, proboscides and dissected midguts, as well as tsetse abdominal content touch-blots were explored. the results of hybridization of radio-isotope-labelled species-specific dna probes to tsetse samples indicated that it was possible to d ...19873670893
the effect of trypanosoma congolense infection on the oestrous cycle of the goat. 19873676690
trypanosoma congolense: lack of correlation between the resistance of cattle subjected to experimental cyclic infection or to field challenge.twelve male cattle of the baoulé breed were exposed to natural trypanosome challenge in an area of high glossina density, to characterize them as trypanoresistant or trypanosensitive. weekly blood samples were taken for the determination of parasitemia and packed cell volume, as a measure of anemia. seven zebu cattle were also exposed to challenge at the same time. the zebu proved to be trypanosensitive with high parasitemia, pronounced anemia and died or were drug treated in extremis. five baou ...19873678447
pathobiochemical alterations in experimental chronic and acute trypanosomal infection in mice.during an experimental chronic infection of inbred mice with trypanosoma congolense several physiological parameters become altered. splenomegaly followed later by hepatomegaly are predominant. lactate dehydrogenase and aminotransferase activities of the plasma are elevated, the number of erythrocytes and thrombocytes decreases, whereas monocytic cells are detected in higher concentrations. gamma-globulins and transferrin become elevated. some of the pathobiochemical alterations depend directly ...19873694125
characterization of trypanosoma congolense serodemes in stocks isolated from cattle introduced onto a ranch in kilifi, kenya.a herd of 20 cattle was introduced on a ranch in kilifi, coast province of kenya, where they were in contact with glossina austeni for 6 months. in total, 65 trypanosome isolates were made from these animals. examination of the isolates revealed that 61 were trypanosoma congolense and 4 were t. theileri. out of the 61 t. congolense isolates, 55 were successfully passaged and cloned in mice to provide trypanosome populations for further analyses. the stocks and their clones were inoculated into g ...19873295687
a new method for fixation and preservation of trypanosomal antigens for use in the indirect immunofluorescence antibody test for diagnosis of bovine trypanosomiasis.a new method for fixation of trypanosomes for use in the indirect immunofluorescent antibody test (ifat) is described. the method involves fixation of live trypanosomes, in suspension, using a mixture of 80% cold acetone and 0.25% formalin in saline. the fixed trypanosomes were stored in suspension at -60 degrees c, 4 degrees c or at room temperature for at least one year without loss of antigenicity. using trypanosomes prepared this way as antigens in ifat, species-specific antibodies were dete ...19873299658
monoclonal antibodies that distinguish trypanosoma congolense, t. vivax and t. brucei.monoclonal antibodies (moabs) were derived against in-vitro-propagated procyclic forms of trypanosoma congolense, t. vivax, t. brucei brucei and t.b. rhodesiense in order to identify antigens for use in immunodiagnosis of african trypanosomiasis. the antibodies have been tested against procyclic and bloodstream form trypanosomes of 13 t. congolense, six t. vivax six t.b. brucei, four t.b. rhodesiense, five t.b. gambiense and three t. simiae isolates from different geographical areas by indirect ...19873306569
enhanced resistance of highly susceptible balb/c mice to infection with trypanosoma congolense after infection and cure.balb/c and c57bl/6 mice were cured with berenil after infection with cloned organisms of trypanosoma congolense and challenged with homologous or heterologous variants. the mice were fully protected against infection with 10(3) but not 10(5) organisms of the homologous variant. normal balb/c mice infected with 10(5) organisms developed uncontrolled parasitemia and had a mean survival time of 8.4 days. challenge of drug-cured balb/c mice with 10(5) organisms of the homologous variant established ...19873309242
purification of african trypanosomes can cause biochemical changes in the parasites.bloodstream forms of african trypanosomes are routinely purified from blood components by a combination of centrifugation and chromatography on deae cellulose at ph 8.0. here we report that the nonphysiological conditions used for deae chromatography of the parasites result in changes in the atp levels of the trypanosomes and an enhanced release from the parasites of proteins such as variable surface glycoprotein, peptidase, and phospholipase. some of these changes can be reduced by the addition ...19873323477
variant surface glycoproteins of trypanosoma congolense bloodstream and metacyclic forms are anchored by a glycolipid tail.the variant surface glycoproteins (vsgs) of both metacyclic and bloodstream forms of trypanosoma congolense are shown to be anchored to the plasma membrane through a glycolipid similar to that found in trypanosoma brucei. release of soluble vsg from both metacyclic and bloodstream forms is associated with the exposure of an antigenic determinant homologous to the cross-reacting determinant of t. brucei vsgs. release of soluble vsg of t. congolense can be achieved by lysates of both bloodstream a ...19872437450
characterization of epitopes on a variant surface glycoprotein from trypanosoma congolense by six monoclonal antibodies.monoclonal antibodies were isolated from mice immunized with variant surface glycoprotein of trypanosoma congolense. five out of the six monoclonals were able to detect epitopes at the cell surface in an indirect immunofluorescence analysis. one antibody did not react. using protein-a-containing bacterial adsorbent all monoclonal antibodies precipitate glycosylated as well as non-glycosylated variant surface glycoprotein. carbohydrate chains therefore do not appear to be part of the immunodeterm ...19872443352
glycosyl-sn-1,2-dimyristylphosphatidylinositol is the membrane anchor for trypanosoma equiperdum and t. (nannomonas) congolense variant surface glycoproteins.we have analysed the structures of the trypanosoma (nannomonas) congolense and t. equiperdum variant surface glycoprotein (vsg) membrane anchors. myristic acid uptake, phospholipase treatment, and nitrous acid deamination showed that, for each species, the anchor is glycosyl-sn-1,2-dimyristylphosphatidylinositol, as has been previously described for t. brucei. osmotic lysis of these trypanosomes resulted in the release of soluble vsg, lacking fatty acid. in both species and in t. evansi, an endo ...19872957588
suppressive action of samorin on the cyclical development of pathogenic trypanosomes in glossina morsitans centralis.male glossina sexually sterilized by gamma-irradiation are as efficient vectors of trypanosomiasis as fertile males. an attempt was made, using isometamidium chloride (samorin), to interfere with the cyclical development of trypanosomes in sterile males, destined for use in the sterile insect release (sir) method of tsetse eradication. the infection rate with mature trypanosoma congolense broden was effectively reduced in sterile male glossina morsitans centralis machado, when the flies were fed ...19872979543
identification and selection of cattle naturally resistant to african trypanosomiasis.cattle were exposed to natural trypanosome challenge in an area of high glossina density (samandéni, burkina faso) for various periods of time during 1982, 1983, 1984 and 1985. all of 30 zebu proved to be sensitive to trypanosomiasis i.e. they died or were treated in extremis in 10 +/- 4 weeks. twenty-one (31%) baoulé were as sensitive as the zebu while 47 (69%) were resistant i.e. they survived in good condition. twenty ndama/baoulé crosses, indigenous to samandéni were all resistant. weekly bl ...19872884840
epidemiology of animal trypanosomiasis on a cattle ranch in kilifi, kenya.a study of the epidemiology of animal trypanosomiasis was carried out on a 2500 ha cattle ranch, with a history of trypanosomiasis, in the coast province of kenya in 1982. the tsetse survey on the ranch revealed one breeding focus of glossina austeni in a thicket of approximately 50 ha. trypanosomes were detected in 20% of the 46 dissected tsetse. during the study period of 9 months, 0.8% of the 3315 samples collected from 2300 ayrshire x sahiwal crossbred cattle were found infected with trypano ...19872884841
trypanosoma (nannomonas) congolense: properties of hexokinase and phosphofructokinase from cultured procyclic trypomastigotes and bloodstream forms.the distribution and kinetics of two key glycolytic enzymes hexokinase (hk) and phosphofructokinase (pfk) were studied in animal-infective bloodstream forms (haematozoic trypomastigotes) and uninfective procyclic forms (insect trypomastigotes) of trypanosoma congolense. the results show that in both forms of t. congolense hk and pfk are particulate and are probably localized in a membrane-delimited organelle, the glycosome. hexokinases of bloodstream and procyclic forms of t. congolense are kine ...19872892364
trypanosoma congolense: differentiation to metacyclic trypanosomes in culture depends on the concentration of glutamine or proline.the effect of glutamine on the number of metacyclic trypanosomes produced in insect form cultures of trypanosoma congolense treu 1457 was investigated. when cultured in the absence of glutamine, trypanosomes did not develop to metacyclic forms. while metacyclics were produced in all cultures maintained with glutamine in the concentration range 2-20 mm, optimum numbers were obtained between 4 and 12 mm glutamine. this pattern was constant in flasks cultured for over two months. the substitution o ...19872892365
dose and stage dependency for the development of local skin reactions caused by trypanosoma congolense in goats.intradermal inoculation of metacyclic forms of trypanosoma congolense propagated in vitro caused skin reactions in goats similar to the local skin reaction (chancre) induced by the bite of an infected tsetse fly. the onset, size and duration of these local skin reactions were dose-dependent. whereas one cultured metacyclic t. congolense was sufficient to cause a local skin reaction in a goat, over 10(7) bloodstream forms of t. congolense were necessary to elicit a detectable skin reaction and wh ...19872892366
high density lipoprotein levels in the serum of trypanosensitive and trypanoresistant cattle. changes during trypanosoma congolense infection.nonpermissiveness to trypanosome infection has been correlated in some instances with the presence of toxic serum factors, e.g. high density lipoproteins (hdl) of human serum can lyse t.b. brucei. the present study examines the possibility of a role for such factors in west african cattle that are resistant to trypanosomiasis. cattle used in this study were previously selected as resistant or sensitive to trypanosomiasis under heavy natural glossina challenge. - a comparison of the direct effect ...19872892367
the effect of the trypanocidal drugs berenil and samorin on infections of glossina morsitans centralis by trypanosoma congolense. 19872892374
adaptation of trypanosoma congolense stocks to in vitro culture does not change their sensitivity to isometamidium. 19872892376
mini-exon gene repeats of trypanosoma (nannomonas) congolense have internal repeats of 190 base pairs.genomic dna hybridizations reveal that the mini-exon gene repeats of trypanosoma (nannomonas) congolense contain from one to greater than 20 internal tandem repeats of 190 base pairs (bp). the sequences of two mini-exon gene repeats were determined, one with three internal 190 bp repeats and one with a single 190 bp sequence. these internal repeats appear just after a very dc/dt-rich region, in the non-transcribed spacer regions between adjacent mini-exon transcription units. they do not occur i ...19872823133
a repetitive deoxyribonucleic acid sequence distinguishes trypanosoma simiae from t. congolense.the dominant repetitive deoxyribonucleic acid (dna) sequence in the genome of a clone of trypanosoma (nannomonas) simiae has been identified and cloned as a recombinant plasmid. the recombinant plasmid was used in hybridization analyses of dna samples obtained from various trypanosome species and subspecies. the results indicated that the t. simiae repetitive dna sequence hybridized with dna derived only from t. simiae; it did not hybridize with dna derived from clones or stocks of t. congolense ...19872827093
sequences of two kinetoplast minicircle dnas of trypanosoma (nannomonas) congolense.random minicircle dna molecules were released from isolated kinetoplast network dna of trypanosoma congolense by bamhi digestion and cloned into plasmid puc19. the sequences of two cloned minicircles (958 bp and 964 bp) were determined. both minicircles contain the 13 bp sequence, 5'-ggggttggtgtaa-3', thought to be the replication origin of minicircles in other trypanosomatids. the two minicircles have extensive homology in the 120 bp preceeding, and the 20 bp following, this 13-mer but only sca ...19873041215
a preliminary comparison of trypanosoma simiae and t. congolense by isoenzyme electrophoresis.trypanosoma simiae, although similar to t. congolense in morphology and mode of development in the tsetse vector, is regarded as a separate species mainly because it is highly pathogenic to the domestic pig and fails to infect rodents. to establish whether the two species are distinct biochemically, we compared by isoenzyme electrophoresis 2 isolates of t. simiae with 7 stocks of t. congolense, together with one of t. brucei. all isoenzyme patterns of the 6 enzymes examined differed in t. simiae ...19862872783
[sensitivity of the card agglutination test (testryp caat) in porcine infection with trypanosoma (nannomonas) congolense in the people' republic of the congo]. 19862872859
infectivity to cattle of metacyclic forms of trypanosoma (nannomonas) congolense propagated in vitro. i. development of localized skin reactions following intradermal inoculation.skin reactions similar to those induced by tsetse infected with trypanosoma congolense were elicited in cattle at sites of intradermal inoculation of in vitro propagated parasites which morphologically resembled metacyclic trypanosomes. the time to detection of the reaction, the time to maximal size and the maximal size attained were dependent on the number of parasites inoculated, although it was possible to induce a skin reaction with as few as 20 trypanosomes. all cattle became infected with ...19862877547
evaluation of sinefungin for the treatment of trypanosoma (nannomonas) congolense infections in goats.caprine trypanosoma (n.) congolense infections were treated with sinefungin, an antifungal antibiotic nucleoside. single doses from 10 to 20 mg/kg bodyweight given intramuscularly were not curative for goats; single doses of 25 and 50 mg/kg were toxic, and caused death. five and 7.5 mg/kg administered twice daily over a three-day period, resulted in a cure in 2 animals, while 2 others relapsed. all animals relapsed when given a single daily dose of 5 or 7.5 mg/kg for 4 consecutive days. when suc ...19862878488
parasite kinetics and immune responses in efferent prefemoral lymph draining skin reactions induced by tsetse-transmitted trypanosoma congolense.localised skin reactions (chancres) occurred on the flanks of cattle at the sites of deposition by tsetse flies of metacyclic forms of trypanosoma congolense. marked enlargement of the draining prefemoral lymph nodes accompanied the development of the skin reactions. lymph from these nodes was collected through polyethylene cannulae inserted into the efferent lymphatics, and examined for trypanosomes, cells and antibody content. within 6-9 days after infected tsetse fly bite, trypanosomes were d ...19863705421
minichromosomal variable surface glycoprotein genes and molecular karyotypes of trypanosoma (nannomonas) congolense.employing orthogonal-field-alternation gel electrophoresis (ofage), we have separated chromosome-sized dna molecules from trypanosoma (nannomonas) congolense clones, the clones being derived from several distinct antigenic repertoires. trypanosome clones that belong to a specific antigenic repertoire appear to have a chromosome pattern characteristic of that particular repertoire. hybridization of the separated chromosomes with cloned dna fragments encoding variable surface glycoproteins reveale ...19863710162
susceptibility and immune responses of zebu and taurine cattle of west africa to infection with trypanosoma congolense transmitted by glossina morsitans centralis.following tsetse-transmitted infection with trypanosoma congolense, major differences in development of localised skin reactions, the ability to control parasitaemia, the degree of anaemia and in antibody response to trypanosomes were found between the reputedly trypanotolerant breeds of cattle (n'dama, n'dama/baoule crosses, baoule) and the trypanosusceptible west african zebu. the local skin reactions that developed in the zebu were large and severe while those that occurred in the other breed ...19863716196
effect of concurrent infections with trypanosoma congolense in rabbits on the development of immunity after trypanocidal drug treatments. 19863729593
extrachromosomal inheritance of susceptibility to trypanosome infection in tsetse flies. ii. susceptibility of selected lines of glossina morsitans morsitans to different stocks and species of trypanosome.two lines of glossina m. morsitans, selected for susceptibility and refractoriness to infection with a single stock of trypanosoma congolense, have now been shown to be susceptible or refractory to different stocks of t. congolense and, also, to different stocks of t. b. brucei and t. b. gambiense. the mean midgut infection rates of the susceptible line obtained in different experiments with t. congolense, t. b. brucei and t. b. gambiense were, respectively, 66%, 56% and 55%; the corresponding m ...19863729601
two enzymically distinct stocks of trypanosoma congolense.two stocks of trypanosoma congolense, isolated from a sheep and a goat on the kenyan coast, were found to be distinctly different from 112 other stocks of the same species after comparing, by isoenzyme electrophoresis, trypanosomes originating from various parts of africa. the results show a marked genetic distinction that may be of epidemiological or taxonomic significance.19863738239
isometamidium chloride prophylaxis against trypanosoma congolense challenge and the development of immune responses in boran cattle.twenty-four boran cattle were injected with isometamidium chloride (1 mg/kg bodyweight) to investigate the duration of drug-induced prophylaxis against infection by metacyclic forms of trypanosoma congolense and to determine if specific antibody responses to the organism were mounted by animals under chemoprophylactic cover. complete protection against either single challenge by five tsetse flies infected with t congolense, or repeated challenge at monthly intervals by five tsetse flies, lasted ...19863739193
interference between different serodemes of trypanosoma congolense in the establishment of superinfections in goats following transmission by tsetse.when domestic ruminants cyclically infected with trypanosoma congolense are superinfected with a different serodeme of the same species, an interference phenomenon occurs which delays the development of the second cyclical infection. experiments were carried out to investigate the influence of the time interval between the two infections on the degree of interference and to follow the course of the superinfection clinically, serologically and histologically. goats infected with tsetse-transmitte ...19863748602
morphological changes in trypanosoma congolense after proteolytic removal of the surface coat.bloodstream forms of trypanosoma congolense were exposed to proteases at various concentrations, and the consequences of this treatment were continuously examined by electron microscopy. unexpectedly, proteolysis did not simply result in the removal of the surface coat, but in dramatic morphological changes characterized by membrane adhesions, subsequently leading to flagella/plasmamembrane and to plasmamembrane/plasmamembrane fusions. the resulting axonemal internalization and rearrangement of ...19863782927
comparison of diagnostic techniques during subclinical single infections of trypanosomiasis in goats.parasitological diagnostic techniques were compared in caprine hosts in which single subclinical infection with trypanosoma vivax, trypanosoma congolense or trypanosoma brucei brucei had been established. the haematocrit centrifuge technique (hct) was the most sensitive for the diagnosis of t. vivax and t. b. brucei while the buffy coat method (bcm) proved superior to all other techniques for t. congolense. except with the miniature anion-exchange/centrifugation technique (maec), each of the con ...19863788024
plasma testosterone in trypanosoma congolense-infected toggernburg goats.trypanosomiasis induces histological testicular degenerative changes leading to suppression of spermatogenesis in goats and laboratory animals. we present evidence associating these changes with trypanosome-induced endocrine dysfunction. toggenburg goats were infected with approximately 100,000 trypanosomes. they were bled every 2 days, and the plasma testosterone was analyzed by radioimmunoassay. testes were perfused with and fixed in bouin's fixative for histological evaluation. the infected p ...19863789879
haematological observations on bovine trypanosomiasis of holstein-friesian breed.haematological investigation was conducted on 20 cases of bovine trypanosomiasis caused by trypanosoma congolense and t. vivax in imported holstein-friesian cattle using standard techniques. comparison of the results with the values obtained for clinically normal animals whose blood samples were consistently negative for trypanosomes indicated that natural bovine trypanosomiasis was associated with a significant (p less than 0.001) fall in haemoglobin concentration, packed cell volume and number ...19863793394
mechanisms of self-cure from trypanosoma congolense infection in mice.the mechanism(s) of resistance to african trypanosomiasis caused by trypanosoma congolense was investigated by using the dinderesso/80/crta/3 isolate to which c57b1/6 are resistant (low parasitemia and self-cure) and balb/c sensitive (high parasitemia and death). the resistance of c57b1/6 is similar to that found in some natural hosts of african trypanosomes such as certain indigenous west african cattle and wild bovidae. the antibody response to epitopes exposed on the variant surface glycoprot ...19863484768
interleukin-1 and interleukin-2 production in resistant and susceptible inbred mice infected with trypanosoma congolense.in vitro production of interleukin-1 (il-1) by lps-stimulated adherent peritoneal exudate and spleen cells and alveolar macrophages, and interleukin-2 (il-2) by concanavalin a-stimulated splenocytes were measured in resistant (c57bl/6j) and susceptible (a/j) inbred mice during the early stages of subacute infections with the african trypanosome, trypanosoma congolense. production of il-1 was severely depressed in both mouse strains as early as 24 hr after intraperitoneal injection of bloodstream ...19863485076
thiol-dependent proteases of african trypanosomes. analysis by electrophoresis in sodium dodecyl sulphate/polyacrylamide gels co-polymerized with fibrinogen.the proteases of several species of african trypanosomes were analysed by electrophoresis in sodium dodecyl sulphate/polyacrylamide gels containing fibrinogen or collagen. after electrophoresis the gels were incubated in the presence of enzyme activators and/or inhibitors and then stained with coomassie brilliant blue. the areas where the proteolytic activity had degraded the fibrinogen did not stain and so formed clear bands against a blue background. the proteases were found to have ph optima ...19863514210
improved method for isolating trypanosoma congolense from mice. 19863523863
analysis of trypanosome variable antigen types in cultures of metacyclic and mammalian forms of trypanosoma congolense.cultured metacyclic forms of trypanosoma congolense display a characteristic repertoire of metacyclic variable antigen types (m-vats) similar to that exhibited in vitro in the tsetse fly. there appeared to be no change in expression of m-vats in cultures of two stocks of t. congolense even after several passages, cryopreservation or long-term cultivation in vitro. metacyclic forms transformed into mammalian forms when transferred to cultures of bovine aorta endothelial cells and whilst one stock ...19863528995
effect of chronic trypanosomiasis on immunization against east coast fever.two experiments were carried out in which uninfected cattle, or cattle chronically infected with trypanosoma congolense, were immunized by the infection and treatment method against east coast fever (ecf; theileria parva infection). chronic trypanosomiasis did not prevent cattle mounting an effective immunological response to ecf immunization and resisting subsequent lethal challenge. there appeared to be no difference in the level or quality of immunity between uninfected cattle and trypanosome ...19863564324
the alternative pathway of complement in sheep during the course of infection with trypanosoma congolense and after berenil treatment.experimental t. congolense infections in sheep resulted in a striking decrease in parameters of the alternative complement pathway (acp), ie. factor b, c3 and haemolytic complement activity (ha) initiated via the acp. the levels of factor b, c3 and ha declined before, during and after the first wave of parasitemia which reached a peak at day 8. levels of 20 to 25% of normal values (factor b) and 20% (c3, ha) persisted throughout the course of the infection. after berenil treatment, when no paras ...19863088536
evidence for genetic diversity in trypanosoma (nannomonas) congolense.genetic proximity between two karyotypic groups of trypanosoma congolense was investigated using as hybridization probes: total genomic dna, a 35 nucleotide long synthetic oligonucleotide, and non-variant antigen type (non-vat) specific complementary dnas. the phylogenetic relationship between trypanosoma brucei and t. evansi, both of which are accepted species in the subgenus trypanozoon, was used as a reference to assess the phylogenetic proximity of the two groups of t. congolense. results in ...19863024094
antibody responses in resistant and susceptible inbred mice infected with trypanosoma congolense.antibody responses were evaluated in inbred mice previously shown to be susceptible (a/j) or resistant (c57bl/6j and b6af1 hybrid) to infections with relatively avirulent trypanosoma congolense. titres and the isotype distribution antibodies specific for the trypanosome variant surface glycoprotein (vsg) were determined by indirect immunofluorescence in sera of mice after primary infections with trypanosoma congolense and after challenge infections with the same variant following drug cure. the ...19863949371
size-fractionation of the small chromosomes of trypanozoon and nannomonas trypanosomes by pulsed field gradient gel electrophoresis.we have compared the molecular karyotypes of trypanosomes from different subgroups within subgenus trypanozoon by pulsed field gradient (pfg) gel electrophoresis. although the overall karyotype was similar, there was much variation in the size of chromosomes between different stocks. two of three stocks of trypanosoma (trypanozoon) brucei gambiense had remarkably small mini-chromosomes: 25-50 kilobase pairs compared to 50-150 kilobase pairs for the mini-chromosomes of other trypanozoon stocks. t ...19863960051
the role of humoral immune responses in determining susceptibility of a/j and c57bl/6 mice to infection with trypanosoma congolense.the relative resistance of c57bl/6 mice to infection with trypanosoma congolense as compared to a/j mice was found to be independent of the infective dose of trypanosomes and required an intact immune system, as sublethal levels of gamma irradiation abolished the differences in susceptibility between the two strains. c57bl/6 mice produced earlier and quantitatively superior antibody responses both to the variable surface glycoprotein and to common membrane antigens on the trypanosome than a/j mi ...19853991236
extrachromosomal inheritance of susceptibility to trypanosome infection in tsetse flies. i. selection of susceptible and refractory lines of glossina morsitans morsitans.differences in susceptibility to infection with trypanosoma congolense between f1 families of glossina morsitans morsitans indicated that susceptibility is maternally inherited in this species of tsetse fly. twelve f1 families, six selected for susceptibility and six selected for refractoriness to infection, have been bred for up to 13 generations. the reciprocal differences demonstrated in the f1 generation persisted in these selected families over many generations, indicating that susceptibili ...19854026443
suppression of trypanosoma congolense, t. vivax and t. brucei infection rates in tsetse flies maintained on goats immunized with uncoated forms of trypanosomes grown in vitro.significant suppression in the incidence of cyclical development of trypanosoma congolense, t. vivax and t. brucei occurred in glossina morsitans centralis maintained on goats immunized with in vitro-propagated uncoated forms of t. congolense, t. vivax and t. brucei, respectively. this was observed when tsetse given a t. congolense-infected feed were subsequently maintained on uninfected immunized goats and also when uninfected tsetse were fed on immunized goats infected with t. congolense, t. v ...19854034247
effects of vasopressor drugs on number of trypanosoma congolense in ruminant blood.the effects of intravenous administration of vasopressor drugs on parasite concentration was studied in cows and sheep infected with trypanosoma congolense. ephedrine (usp), adrenaline (bp) and insulin increased jugular concentration of the parasite. maximum effects were reached between 1 1/2 and 2 h with ephedrine and at 2 1/2-3 h with adrenaline. increases in parasitaemia resulting from epinephrine were sustained only in sheep and adrenaline gave similar effects in both ruminants. only epineph ...19854039866
association between intracellular rickettsial-like infections of midgut cells and susceptibility to trypanosome infection in glossina spp. 19854050033
susceptibility of different breeds of goats in kenya to experimental infection with trypanosoma congolense.to assess whether there was any evidence of genetic resistance to african trypanosomiasis, five breeds of goat (east african, galla, and crossbreds between east african and galla, nubian or toggenburg) were experimentally infected with trypanosoma congolense either by needle inoculation or by tsetse-transmission. the goats had not been previously exposed to trypanosomiasis. with both methods of infection all breeds were found to be highly susceptible and suffered severe disease. following tsetse ...19854060238
comparison of the effects of african trypanosomiasis in four breeds of dairy goats.the consequences of experimental infection with trypanosoma congolense and later superinfection with t brucei were compared among four breeds of goats: toggenburg, nubian, alpine and saanen. no major differences were found with regard to packed cell volume, bodyweight or parasitaemia. when these four breeds were considered for introduction into areas having african trypanosomiasis, none appeared to have a comparative advantage with regard to innate resistance to trypanosomes.19854070793
west african dogs as a model for research on trypanotolerance.autochthonous dogs from liberia/west africa were reared trypanosome-free and brought to west berlin/germany. together with beagle dogs they were infected cyclically by tsetseflies with trypanosoma congolense. while the european dogs died soon of the trypanosomal infection, the african dogs developed milder parasitaemias and remained clinically unaffected. the authors' opinion is, that this dog model could make a contribution to research on trypanotolerance.19854089479
trypanosoma (nannomonas) congolense: identification of two karyotypic groups.orthogonal-field-alternation gel electrophoresis and dna blot hybridizations have been used to investigate the genomic relationships among trypanosome clones of subgenus nannomonas. the results indicate that trypanosoma (nannomonas) congolense comprises at least two distinct groups of parasites that differ in both molecular karyotype and repetitive dna sequences. a description of these two groups and their distinction from trypanosoma (nannomonas) simiae is presented.19854092683
survival and reproductive performance of female glossina morsitans morsitans when maintained on livestock infected with salivarian trypanosomes. 19854096568
involvement of suppressor cells induced with membrane fractions of trypanosomes in immunosuppression of trypanosomiasis.we showed that infection with trypanosoma congolense in mice led to suppression of listeria-induced delayed type hypersensitivity (dth). mice were pre-treated with irradiated t. evansi, which caused rapid and effective suppression of dth. a membrane fraction obtained by homogenizing t. evansi variant in a hypotonic buffer solution and centrifuging it at 150,000g produced suppression of listeria-induced dth when injected i.p. into mice as early as 1 day before listeria immunization. furthermore, ...19853158865
the behaviour of trypanosomes within the midguts of wild-caught tsetse from zimbabwe.trypanosomes infecting the midgut of wild-caught tsetse from zimbabwe were found on electron microscopic examination to be penetrating the peritrophic membranes and so entering the ecto-peritrophic space in the mycetome region of the midgut. other trypanosomes entered midgut cells, behaviour similar to that previously reported in laboratory-infected tsetse colonies.19853832497
induction of protective immunity in cattle by tsetse-transmitted cloned isolates of trypanosoma congolense.cattle infected with cyclically (tsetse)-transmitted clones of trypanosoma congolense were treated with the trypanocidal drug diminazene aceturate ('berenil') at various intervals during development of local skin reactions (chancres), in order to investigate the role played by trypanosomes in the skin in the induction of protective immunity. cattle, treated on or before day 12 after infection and prior to detection of trypanosomes in the blood, showed a range of susceptibility to cyclically-tran ...19853834843
identification of an antigen specific to trypanosoma congolense by using monoclonal antibodies.using indirect immunofluorescence assays on acetone-fixed smears of a series of different parasites, we have shown that two monoclonal antibodies bind specifically to trypanosoma congolense organisms. the antibodies bind to both bloodstream trypomastigotes and procyclic culture forms of the parasite and are thus not stage specific. immunoprecipitation and immunoblot analysis showed that both monoclonal reagents bound a protein of approximately 31,000 m.w. this antigen appeared to be located on t ...19853880577
cultivation of african and south american trypanosomes of medical or veterinary importance. 19853896374
role of carbohydrates within variant surface glycoprotein of trypanosoma congolense. protection against proteolytic attack.the effects of tunicamycin on different aspects of structure and biosynthesis of variant surface glycoprotein from trypanosoma congolense have been studied. deglycosylated variant antigen becomes synthesized in vitro, is transported through the cell, and is deposited on the cell surface in equivalent amounts compared to the glycosylated species. in contrast to the glycosylated molecule only marginal amounts of high-molecular-mass fragments can be removed from the parasitic cell by externally add ...19853896788
sulphydryl-dependent enzymes from african trypanosomes. 19853898094
adenosine cycle in african trypanosomes.african trypanosomes can convert adenosine to adenosine monophosphate. however, in trypanosoma brucei, as in t. vivax and t. congolense, most of the adenosine is broken down to adenine before conversion to the nucleotide by adenine phosphoribosyltransferase. trypanosoma brucei and t. vivax use the purine nucleoside hydrolase for adenosine cleavage while t. congolense uses purine nucleoside phosphorylase for the nucleoside cleavage. trypanosoma vivax also deaminates adenine to hypoxanthine before ...19853920982
kinetoplast dna from trypanosoma vivax and t. congolense.we have analysed kinetoplast dna (kdna) of the african trypanosomes trypanosoma vivax and t. congolense. the maxi-circles from these organisms resemble those of t. brucei in size, but only to a limited extent in sequence as judged from restriction enzyme digests and dna x dna hybridization. the kdna networks of t. vivax have three distinguishing features: they contain the highest maxi-circle concentration of any kdna (at least twice that of t. brucei); they contain the smallest mini-circles (465 ...19852989683
in vitro cultivation of trypanosoma congolense: establishment of infective mammalian forms in continuous culture after isolation from the blood of infected mice.bloodstream form trypomastigotes of four cloned stocks of trypanosoma congolense from west africa were successfully adapted to continuous in vitro culture at 28 degrees c using bovine aorta endothelial cell monolayers and eagle's minimum essential medium supplemented with 20% normal bovine serum or foetal calf serum. the trypanosomes maintained in vitro morphologically resembled bloodstream forms and remained infective for vertebrate hosts. they also induced local skin reactions in rabbits and w ...19852862772
influence of the salmon mutant of glossina morsitans morsitans on the susceptibility to infection with trypanosoma congolense.four phenotypes of a sex-linked, maternally influenced semi-lethal eye color mutant of glossina morsitans morsitans westwood were fed on trypanosoma congolense broden infected guinea pigs. infection rates were evaluated 25 days later by means of dissection. procyclic as well as mature infections were significantly more common among females with salmon-colored eyes (sal/sal) than among heterozygous (+/sal, phenotypically wild-type) females. a tendency was found for more mature infections among sa ...19852862776
in vitro cultivation of trypanosoma congolense: the production of infective forms from metacyclic trypanosomes cultured on bovine endothelial cell monolayers.after transfer to bovine endothelial cell monolayers cultured in eagle's minimal essential medium at 28 degrees c or 37 degrees c metacyclic trypanosomes of three cloned stocks of trypanosoma congolense became morphologically similar to parasites found in the bloodstream of the vertebrate host. the trypanosomes resumed division and grew in close association with the mammalian cells, which were essential for growth. these dividing infective forms had the ability to cause local skin reactions and ...19852862783
the probability of tsetse acquiring trypanosome infection from single blood meal in different localities in kenya.the probability of tsetse, glossina pallidipes, acquiring a trypanosome infection from a single blood meal was estimated in five localities on the kenya coast which were selected for differences in habitat and host availability. the probability that one blood meal contained infective trypanosoma congolense was 0.0077 in rural areas with domestic animals, 0.0019 in extensive areas of natural habitat with wild hosts and 0.0013 in an area with domestic animals under regular chemoprophylaxis. the re ...19852865875
isolation and cell-free synthesis of variant surface glycoproteins from trypanosoma congolense.two trypanosoma congolense stocks, 1/148 fly and treu 921, were cloned in a/j strain mice immunosuppressed with cyclophosphamide. the cloned populations, amnat 1.1 and amnat 3.1, each characterized by a different variant antigen type, were checked for homogeneity by the indirect fluorescent antibody test using 6-day antisera developed in rabbits. the variant surface glycoproteins (vsgs) from both amnat clones were purified to homogeneity. electrophoresis on sodium dodecyl sulfate (sds)-polyacryl ...19852412115
cloning and analysis of trypanosoma (nannomonas) congolense ilnat 2.1 vsg gene.genes encoding various trypanosoma (trypanozoon) brucei variable surface glycoproteins (vsgs) show considerable conservation among different members of this species, known as isotypes. the occurrence of isotypes in other salivarian trypanosomes has not been well documented. we have cloned sequences encoding trypanosoma (nannomonas) congolense ilnat 2.1 vsg, and used it in dna blot hybridization analyses of this and other t. congolense clones originating from geographically separate regions of ea ...19852412117
comparative structural analysis of calmodulins from trypanosoma brucei, t. congolense, t. vivax, tetrahymena thermophila and bovine brain.calmodulin is an intracellular calcium receptor protein utilized extensively by eukaryotic cells to mediate responsiveness to calcium signals. the present study evaluates the effects on protein structure of amino acid substitutions in trypanosome calmodulin. calmodulin conformation, hydrophobicity and antigenic determinants are compared among trypanosoma brucei, trypanosoma congolense, trypanosoma vivax, tetrahymena thermophila and bovine brain. trypanosome calmodulin differs from brain and tetr ...19852417117
trypanosoma vivax, t. congolense or t. brucei infection rates in glossina morsitans when maintained in vitro on the blood of goat or calf.tenerals of glossina morsitans morsitans and g. m. centralis were infected with trypanosoma vivax, t. congolense or t. brucei by feeding mainly on infected goats and then maintained either in vivo on uninfected calves, goats or rabbits, or fed in vitro upon heparinised or defibrinated blood of goats or calves for 21 days for t. vivax and t. congolense and 30 days for t. brucei and then dissected. the observed differences in the infection rates for all three trypanosome species maintained on diff ...19846143482
cerebral trypanosomiasis in cattle with mixed trypanosoma congolense and t. brucei brucei infections.six boran steers were infected simultaneously with trypanosoma congolense and t. brucei brucei while another group of 3 was inoculated with t. b. brucei one year after infection with t. congolense. three further steers were infected with t. b. brucei alone. whereas, the six animals which received simultaneous infections developed clinical signs of cerebral trypanosomiasis as evidenced by depression, ataxia and occasional circling, those infected with t. b. brucei alone did not. at necropsy, 4 ou ...19846150618
the appearance of isometamidium resistant trypanosoma congolense in west africa.the frequent reappearance of patent parasitemia, mainly trypanosoma congolense, in cattle maintained under isometamidium prophylaxis in the upper volta indicated that drug-resistant forms might be appearing. to investigate this possibility, trypanosome stocks were isolated in mice, their isometamidium sensitivity estimated and compared to that of stocks isolated before drug use was widespread. most t. congolense stocks isolated in 1982-1983 were 4-8 times less sensitive to isometamidium than tho ...19846150619
maintenance of glossina morsitans morsitans on antiserum to procyclic trypanosomes reduces infection rates with homologous and heterologous trypanosoma congolense stocks.three experimental groups of male glossina morsitans morsitans were infected at their first feed with procyclic forms of different stocks of trypanosoma congolense and subsequently maintained on a diet containing rabbit antiserum to one of these stocks. control flies were similarly infected but were then maintained on normal rabbit serum. dissection of the flies 19-21 days post infection showed a reduction in both immature and mature infection rates in all groups fed on antiserum by comparison w ...19846150620
in vitro cultivation of trypanosoma congolense: the production of infective metacyclic trypanosomes in cultures initiated from cloned stocks.glossina morsitans were infected with two cloned stocks of t. congolense. the proboscides, foreguts and midguts of infected flies were then used as sources of trypanosomes in vitro at 28 degrees c in the presence of bovine dermal collagen explants. cultures were established in which trypanosomes differentiated into adhering colonies of epimastigote forms which could then be maintained and subcultured in eagle's minimum essential medium supplemented with foetal calf serum for over 40 weeks. withi ...19846152116
capacity of a cis-diammineplatinum[ii]-polyglutamic acid complex to cure trypanosoma congolense infections in mice.a cis-diammineplatinum(ii)-polyglutamic acid complex proved to have marked trypanocidal activity in vivo. when 5 mg of platinum per kg was administered daily for 5 days or when 20 mg of platinum per kg was administered on days 1, 3, and 6, five of five treated trypanosoma congolense-infected mice were cured. in contrast, cis-platin was ineffective at all doses tested. we believe that the complex has a much higher therapeutic ratio than does uncomplexed drug because it is less toxic.19846201136
common and isolate-restricted antigens of anaplasma marginale detected with monoclonal antibodies.anaplasma marginale-infected erythrocytes were examined for the presence of maturation, isolate-restricted, and isolate-common antigens by indirect immunofluorescence with monoclonal antibodies. a panel of 18 monoclonal antibodies was used; none of the antibodies reacted with anaplasma ovis, babesia bigemina, babesia bovis, trypanosoma brucei, trypanosoma congolense, or uninfected bovine erythrocytes. antigens common to all six a. marginale isolates were detected by nine antibodies. single isola ...19846205996
in vitro studies on the biosynthesis of the surface glycoprotein of trypanosoma congolense.tritiated leucine, glucosamine, mannose, and galactose were incorporated into the variant specific surface glycoprotein (vsg) of trypanosoma congolense in vitro. the uptake of the precursors is shown by sds-polyacrylamide electrophoresis and fluorography, by assay of the radioactivity in immunoprecipitates obtained with specific antisera, and by the isolation of the labeled antigens by affinity chromatography on concanavalin a-sepharose and isoelectric focusing. the in vitro labeled vsg exhibits ...19846470988
continuous cultivation of animal-infective bloodstream forms of an east african trypanosoma congolense stock. 19846486939
studies on the influence of non-steroidal anti-inflammatory drugs upon trypanosomiasis in goats and sheep.the non-steroidal anti-inflammatory drug (nsaid) flurbiprofen caused a rise in parasitaemia in goats infected with trypanosoma vivax, trypanosoma congolense and trypanosoma brucei. all trypanosome-infected goats treated with flurbiprofen showed many dividing trypanosomes. this also included the short-stumpy forms of t. brucei. in t. vivax-infected goats flurbiprofen treatment resulted in 100% mortality in the acute and chronic stages of the infection. the increase in parasitaemia of t. brucei in ...19846512919
[parasitological, clinical and serological findings in dahomey cattle experimentally infected with trypanosoma congolense and t. brucei]. 19846525154
a special case of trypanosoma congolense infection produced in laboratory mice. 19846527201
detection of circulating trypanosomal antigens by enzyme immunoassay.antisera raised against trypanosoma evansi and t. congolense were used in a double antibody sandwich enzyme immunosorbent assay (elisa) to detect trypanosomal antigens in sera from experimentally infected rabbits and goats. assays quantitated using reference antigen preparations and the homologous antisera showed that antigens could be detected at protein concentrations of 1.5 microgram ml-1. the antisera also cross-reacted with soluble antigens prepared from t. brucei and t. vivax at similar pr ...19846532328
[probable number of trypanosoma (nannomonas) congolense transmitted by glossina morsitans]. 19846544954
[demonstration of resistance to trypanocides among the species of trypanosoma congolense recently isolated in burkina]. 19846544959
comparison of blood smear and indirect fluorescent antibody techniques in detection of haemoparasite infections in trade cattle in nigeria.the incidence of blood parasites in trade cattle was surveyed with emphasis on tick-borne parasites, using blood smears and immunofluorescent antibody (ifa) techniques. with the blood smear method, about 9 and 8.9% of cattle examined were found positive for babesia bigemina and anaplasma marginale, respectively. percentage infections with other parasites were 3.33, 1.92, 0.75, 0.75 and 0.58, respectively, for babesia bovis, trypanosoma brucei, anaplasma centrale, eperythrozoon and theileria spec ...19846369761
experimental trypanosoma (nannomonas) congolense infection in microtus montanus.seventy-two voles (microtus montanus) were infected with a strain of trypanosoma congolense of low virulence in mice to study their susceptibility and value as a tool for testing chemotherapeutic agents. the infection in microtus was highly virulent. parasitaemia was low to moderate. significant spleen and body weight changes were observed. blood capillaries of the heart, brain, kidneys and lungs were markedly dilated and numerous parasites were present in the dilatations, particularly in the he ...19846383235
a calcium dependent endoribonuclease from trypanosoma congolense cytoplasm.a major endoribonuclease whose activity depends on the presence of calcium ions was isolated from the cytoplasm of trypanosoma congolense. like the ca2+-dependent endoribonuclease of t. brucei cytoplasm, this enzyme degraded poly(a) preferentially but also degraded to a lesser extent poly(u), trna and rrna to give 5'-phosphoribosyl oligonucleotides. neither enzyme hydrolyzes poly(g) or dna. both ribonucleases are inhibited by polyanions and heavy metal ions, and are heat-labile; n-ethylmaleimide ...19846431285
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