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expression of acquired immunity to heligmosomoides polygyrus in mice concurrently infected with trypanosoma congolense.the effects of concurrent heligmosomoides polygyrus and trypanosoma congolense infection on the expression of acquired resistance to homologous nematode challenge were studied in female outbred to mice. mice were infected with 500 infective larvae (l3) of h. polygyrus and the infection was terminated by anthelminthic treatment on day 12, when the worms were adults. eight days later sub-groups of these pre-exposed mice, and of similar mice which had not experienced the previous infection with h. ...19979363495
plasma luteinizing hormone levels in response to gonadotropin-releasing hormone agonist and clonidine in trypanosoma congolense-infected female goats.trypanosomiasis, a parasitic disease of humans and animals, occurs over a wide area of africa and imposes a large socioeconomic burden on the people. in the present study, we investigated whether trypanosomiasis-induced reproductive disorders were due to pituitary or hypothalamic dysfunction by determining plasma luteinizing hormone (lh) response to gonadotropin-releasing hormone (gnrh) agonist or clonidine in trypanosoma congolense-infected female goats. with gnrh agonist administration, the to ...19979365802
cd5+ b lymphocytes are the main source of antibodies reactive with non-parasite antigens in trypanosoma congolense-infected cattle.mice infected with african trypanosomes produce exceptionally large amounts of serum igm, a major part of which binds to non-trypanosome antigens such as trinitrophenol and single-strand dna. in this paper, we describe that in cattle infected with trypanosoma congolense and t. vivax, similar antibodies are found, although they bind mainly to protein antigens, such as beta-galactosidase, ovalbumin and ferritin. the parasite non-specific igm antibodies appear around the same time as the parasite-s ...19979415031
factors affecting trypanosome infection rate in tsetse fly (diptera: glossinidae) populations.wide variations in trypanosome infection rate are observed in different tsetse fly (glossina spp.) populations environmental factors and features proper to the vector, mammalian host and infecting-trypanosome species acting in the acquisition and development of infective-trypanosome infection in tsetse are examined.19979419848
long-term effects of an experimental infection with trypanosoma congolense on reproductive performance of trypanotolerant djallonké ewes and west african dwarf does.ten west african dwarf (wad) does and 12 djallonké ewes were artificially infected with a west african strain of trypanosoma congolense and observed over two years. the infected animals showed a chronic anaemia together with a persistent parasitaemia but very low mortality and increase in body weights was not significantly different from the control. in the infected sheep significant differences were found in offspring production at three and five months due to a higher mortality among the lambs ...19979429253
bovine stem cell factor: production of a biologically active protein and mrna analysis in cattle infected with trypanosoma congolense.the cdna coding for the soluble form of bovine stem cell factor (boscfala165) was cloned and recombinant protein was produced in bacteria as a histidine tagged-protein. the protein was purified from the inclusion bodies in one step by metal chelation chromatography under denaturing conditions. recombinant bovine scf was shown to act synergistically with interleukin 3 (il-3) and erythropoietin (epo) in stimulating the growth of bone marrow progenitor cells such as colony forming units-granulocyte ...19979437826
effect of experimental infection with trypanosoma congolense and scrotal insulation on leydig cell steroidogenesis in the ram.testicular steroid content and leydig cell steroidogenesis in vitro were investigated in rams on days 28 and 58 after trypanosoma congolense infection and were compared with those of rams in which testicular temperature had been raised artificially by insulation of the scrotum for 58 d. testicular testosterone content increased significantly on day 28 after infection but was lower than that of controls on day 58 while it increased in scrotal-insulated rams compared with that of controls by day 5 ...199716728138
pathophysiology of trypanosoma congolense infection in two breeds of sheep, scottish blackface and finn dorset.the pathophysiology of trypanosoma congolense infection was studied in two breeds of sheep, the scottish blackface (sb) and finn dorset (fd), which were known from previous studies to differ significantly in their susceptibility to haemonchosis, in which anaemia is also the primary pathophysiological effect. it was found that infected sb and fd lambs developed similar intensities of parasitaemia. however, infected sb lambs developed a higher degree of anaemia, more severe thrombocytopaenia and h ...19979066067
the influence of dietary protein on some blood biochemical parameters in scottish blackface sheep experimentally infected with trypanosoma congolense.the present study investigated the influence of dietary protein on some blood biochemical parameters, namely lipids, proteins, iron, glucose and b-hydroxybutyrate, in scottish blackface sheep infected with trypanosoma congolense, and given either a low protein (51.5 g digestible crude protein per day) or a high protein (116 g digestible crude protein per day) diet. both low and high protein diets were isocaloric and animals were monitored for 10 weeks after infection. it was observed that infect ...19979066068
detection of trypanosoma brucei, t. congolense and t. vivax infections in cattle, sheep and goats using latex agglutination.a monoclonal antibody-based latex agglutination test for detection of circulating trypanosome antigens in animal serum was evaluated for the ability to detect natural t. brucei, t. congolense and t. vivax infections in cattle, sheep and goats in ghana. the test detected antigens in 180/422 (42.7%) of cattle, 27/131 (20.6%) of sheep and 14/79 (17.7%) of the goats. by comparison, the microplate-based antigen-elisa gave similar results (p > 0.01), detecting trypanosome antigens in 41.7% of the catt ...19979076533
the primary structure of trypanosoma (nannomonas) congolese variant surface glycoproteins.the complete nucleotide sequences were determined for three transcripts each encoding a different variant surface glycoprotein (vsg) of trypanosoma (nannomonas) congolense. the nucleotide sequence was determined also for a transcript encoding a fourth vsg, but this was truncated. the data obtained confirm absence of the canonical polyadenylation signal, lack of conserved sequence elements in the 3' untranslated region, and heterogeneity in the spliced-leader acceptor site in the t. congolense vs ...19979085918
concentrations of isometamidium in the sera of cattle challenged with drug-resistant trypanosoma congolense.the relationship between serum concentrations of the prophylactic trypanocidal drug isometamidium chloride and protection against tsetse challenge with two populations of trypanosoma congolense was investigated in boran (bos indicus) cattle, using an isometamidium-elisa. isometamidium chloride (samorin) was administered to cattle at a dose rate of 1.0 mg/kg body weight by deep intramuscular injection. thereafter, the animals were challenged at monthly intervals with either a drug-sensitive clone ...19979088422
detection of trypanosoma congolense and t. brucei subspecies in cattle in zambia by polymerase chain reaction from blood collected on a filter paper.to facilitate epidemiology studies of african trypanosomiasis in cattle in zambia, we adapted a polymerase chain reaction (pcr) method using blood spotted on filter papers. for easy preparation of template dna from the dried blood, we adapted a simple dna extraction method using chelex-100, an anion-exchange resin. using primers directed for repetitive nuclear dna sequences, species-specific dna amplifications were detected from the blood of rats infected with zambian isolates of t. congolense a ...19979089719
susceptibility of three breeds of ugandan goats to experimental infection with trypanosoma congolense.this study has indicated that differences in susceptibility to trypanosoma congolense infection exist among the 3 main breeds of goats in uganda namely, kigezi, mubende and small east african (sea). the kigezi goats appeared to be the most susceptible suffering more severe anaemia, greater retardation of growth and more deaths than the other 2 breeds following experimental infection with try-panosoma congolense. the small east african goats appeared to be least susceptible. following treatment a ...19979090009
long-term occurrence of trypanosoma congolense resistant to diminazene, isometamidium and homidium in cattle at ghibe, ethiopia.ten trypanosome isolates were collected at random from cattle at ghibe, ethiopia, in february 1993 and all shown to be savannah-type trypanosoma congolense. when inoculated into naïve boran (bos indicus) calves, all 10 isolates were resistant to diminazene aceturate (berenil), isometamidium chloride (samorin) and homidium chloride (novidium) at doses of 7.0 mg/kg body weight (b.w.), 0.5 mg/kg b.w. and 1.0 mg/kg b.w., respectively. in order to determine whether this multiple-drug resistance was e ...19979107367
sensitivity of segregation analysis to data structure and transformation: a case study of trypanotolerance in mice.sensitivity of segregation analysis for data structure and data transformation was studied using data from two trials in which mice were challenged at three months of age with a cloned isolate of trypanosoma congolense and survival time was recorded. data included records from three inbred strains (c57bl/6 (tolerant), a/j, and balb/c (both susceptible)) and their crosses. data were standardized and normalized using a modified power transformation. segregation analysis was applied to both untrans ...19979134708
prophylactic effects of isometamidium- and ethidium-sustained release devices against trypanosoma congolense in cattle.two successive experiments were carried out in which three cows were treated by intramuscular injection of either 0.5 mg/kg isometamidium or 1 mg/kg ethidium and compared with another group of three cows which received a subcutaneously implanted sustained release device (srd) containing the same dose of drug. the prophylactic effect of both drug formulations was evaluated by exposing the animals at monthly intervals to glossina morsitans morsitans infected with trypanosoma congolense. the averag ...19979140511
modelling trypanosoma congolense parasitaemia patterns during the chronic phase of infection in n'dama cattle.we reanalyzed parasitaemia profiles of the trypanotolerant n'dama cattle (bos taurus), consecutively infected with the same four clones of trypanosoma congolense. our analysis shows that each individual parasitaemia is characterized by progressively longer intervals between parasites waves. this pattern is most visible during the chronic phase of infection. in addition, the last of the four infections had a significantly larger overall duration of inter-wave intervals. we retrieved these pattern ...19979149284
the daily feeding rate of tsetse (diptera: glossinidae) on cattle at galana ranch, kenya and comparison with trypanosomiasis incidence.at galana ranch, south-eastern kenya, for 2 days each month from january to may 1993. glossina pallidipes and g. longipennis were sampled around a heifer for 30 min every hour from 06:00 to 19:00. there was a seasonal decline in tsetse abundance; estimates of the total number attracted to the heifer in 1 day ranged from 556 g. pallidipes in january to 0 in may and 122 g. longipennis in february to 27 in may. the number of tsetse estimated to have fed on the heifer in 1 day during peak months was ...19979164602
effect of diminazene aceturate on the infectivity and transmissibility of drug-resistant trypanosoma congolense in glossina morsitans centralis.to determine the duration after treatment of cattle with diminazene aceturate that the drug influences the tsetse infectivity and transmissibility of a drug-resistant trypanosoma congolense, six boran cattle were infected with t. congolense il 3338 via the bites of glossina morsitans centralis. at the first peak of parasitaemia, different groups of 120 teneral g. m. centralis were fed on one occasion on each animal, 1 h before treatment with diminazene aceturate at a dose of 3.5 mg kg-1 body wei ...19979195705
effect of different cytokines on the growth of trypanosoma congolense cultured under axenic conditions.we previously reported that susceptible balb/c mice had high amounts of interleukin-4 (il-4) and interleukin-10 (il-10) in their plasma after infection with trypanosoma congolense and the levels of these cytokines decreased dramatically after berenil treatment. these observations instigated us to speculate that these cytokines might be directly affecting the growth of these parasites. previously, it was reported that interferon gamma (ifn-gamma) had a growth stimulatory effect on t. brucei bruce ...19979195706
the influence of supplementation with cotton seed cake on the resistance of ugandan goats to primary and secondary challenges with trypanosoma congolense and on their response to treatment.the present study investigated the influence of supplementation with cotton seed cake on the resistance of the small east african breed of goats to primary and secondary challenges with trypanosoma congolense and on their response to chemotherapy with diminazene aceturate. the supplemented group received 300 g of cotton seed cake per day in addition to about 500 g of fresh napier grass which was available to the unsupplemented group. it was observed that the supplemented infected (si) group tend ...19979195711
cross-resistance associated with development of resistance to isometamidium in a clone of trypanosoma congolense.resistance to isometamidium was increased 94-fold in a clone of trypanosoma congolense (clone il 1180) by repeated subcurative treatment of infected mice for 11 months. this was associated with 3.4-, 33-, and 4.2-fold increases in resistance to diminazene, homidium, and quinapyramine, respectively. both t. congolense il 1180 and the resistant derivative were able to undergo cyclical development in glossina morsitans centralis tsetse flies, producing hypopharyngeal infection rates of 40.0 and 39. ...19979210695
the role of anti-variable surface glycoprotein antibody responses in bovine trypanotolerance.it has been reported that some breeds of cattle such as the n'dama mount a more effective antibody response to the variable surface glycoprotein coat of trypanosomes and that this may contribute to their ability to control the infection. thus we have investigated antibody responses to surface exposed epitopes of the variable surface glycoprotein in trypanosoma congolense-infected n'dama (trypanotolerant) and boran (susceptible) cattle. similar titres and isotypes were found in both n'damas and b ...19969223176
influence of trypanosoma congolense infection on some blood inorganic and protein constituents in sheep.the present study was designed to investigate the changes in plasma concentrations of zinc, copper, calcium, magnesium, inorganic phosphate, total protein, albumin, globulin, and serum iron and iron-binding capacity in sheep infected with trypanosoma congolense. it was observed that infection did not have a significant effect on the plasma concentrations of zinc, copper, calcium, magnesium and inorganic phosphate. the serum iron concentrations in infected animals were higher, but not significant ...19969239939
trypanosoma congolense: b-lymphocyte responses differ between trypanotolerant and trypanosusceptible cattle.trypanosomiasis is a serious constraint to livestock production in sub-saharan africa. some breeds of cattle are genetically more resistant to the pathogenic effects of trypanosome infection. we measured b-cell activation and the quantity and isotype of antibody produced at the cellular level in six trypanotolerant n'dama and five trypanosusceptible boran cattle. the frequencies of spleen cells secreting total and parasite-specific igm and igg were measured prior to and 16, 28, and 35 days after ...19968654538
acquisition of resistance to the tick amblyomma variegatum in boran cattle, bos indicus and the effects of trypanosoma congolense and babesia bigemina on host resistance.resistance was induced in cattle to the tick amblyomma variegatum by five consecutive infestations with nymphs and adults. using the principal component analysis (pca), it was found that percentage of adults engorged, percentage of adults which died, percentage of nymphs which engorged, percentage of nymphs which moulted and percentage of nymphs which died, were the main indicators of resistance against a. variegatum. the percentages of nymphs which engorged or moulted after the third infestatio ...19968686177
are stable flies (diptera: stomoxyinae) vectors of trypanosoma vivax in the central african republic?the epidemiology of trypanosoma vivax infections was studied at a riverside site in the ouro-djafoun livestock area situated in the central african republic during the period between july 1991 and july 1992. this paper examines the possibility that stable flies (diptera: stomoxyinae) were also vectors of this trypanosome species in a non-cyclic way. previous studies have revealed that the usual cyclic transmission by the tsetse fly glossina fuscipes fuscipes was probably not the only transmissio ...19968721295
in vivo trypanocidal activities of new s-adenosylmethionine decarboxylase inhibitors.a series of novel aromatic derivatives based on the structure of methylglyoxal bis(guanylhydrazone) (mgbg) was examined for trypanocidal activities in human and veterinary trypanosomes of african origin. one agent, cgp 40215a, a bicyclic analog of mgbg which also resembles the diamidines diminazene (berenil) and pentamidine, was curative of infections by 19 isolates of trypanosoma brucei subspecies as well as a trypanosoma congolense isolate. several of these isolates were resistant to standard ...19968726018
trypanosoma congolense infection in sheep: cellular phenotypes in lymph and lymph nodes associated with skin reactions.intradermal inoculation of sheep with culture-derived metacyclic forms of trypanosoma congolense resulted in the development of localized skin reactions (chancres) and enlargement of the draining lymph nodes 7 days after infection. changes in the expression of surface antigens of lymphocytes in lymph leaving the affected skin reactions and in the associated lymph nodes were monitored by cannulating the afferent and efferent lymphatic ducts. trypanosomes appeared in afferent and efferent lymph 3 ...19968729080
bioavailability, pharmacokinetics, and tissue distribution of 14c homidium after parenteral administration to boran cattle.the absorption, distribution and elimination characteristics of 14c homidium have been described in non-infected and trypanosoma congolense-infected cattle treated with 14c homidium chloride by either intramuscular (i.m.) or intravenous (i.v.) injection at a dose level of 1 mg/kg body weight. results show that the mean (+/-sd) elimination of the drug from plasma followed a biexponential process, with half-lives of 0.084 +/- 0.006 h and 97.66 +/- 16.28 h for the distribution and elimination phase ...19968735423
effect of nutritional level on bodyweight, degree of anaemia and carcase composition of sheep infected with trypanosoma congolense.the influence of nutritional level on the bodyweight, degree of anaemia and carcase composition of 24 sheep infected experimentally with trypanosoma congolense was investigated. the infection caused a marked retardation of growth in the animals fed a low protein ration whereas the infected and control animals fed a high protein ration grew at similar rates. both groups of infected animals developed similar degrees of anaemia but the infected group fed the high protein diet tended to sustain a hi ...19968745251
field evaluation of a dot-elisa for the detection and differentiation of trypanosome species in infected tsetse flies (glossina spp.).a rapid, visually read, dot-elisa developed for the detection and differentiation of trypanosome species in tsetse flies (glossina spp.), was field tested alongside the standard fly dissection method on a range in south eastern kenya. of 104 g. pallidipes dissected, 2 were found to be infected with trypanosomes in their midguts. by the dissection method the infecting trypanosome species could not be identified, as both flies had no salivary gland infections. however, using the dot-elisa, the 2 f ...19968851860
ultrastructural changes on various trypanosoma spp. after a 30-year storage period in liquid nitrogen.four trypanosoma species were examined for damage following prolonged storage in liquid nitrogen (-196 degrees c). the stabilates were successfully recovered after a cryopreservation period of approximately 30 years. the structure of specimens was studied by means of light microscopy and scanning (sem) and transmission (tem) electron microscopy. all of the species tested--t. evansi, t. equinum, t. brucei, and t. congolense--proved to be infective to mice. however, as compared with controls, the ...19968897507
pharmacokinetics, bioavailability and tissue residues of [14c]isometamidium in non-infected and trypanosoma congolense-infected boran cattle.in this paper, pharmacokinetics, bioavailability and tissue residues are reported in non-infected and trypanosoma congolense-infected boran steers following either intravenous or intramuscular injection of [14c]isometamidium at a dose rate of 1 mg kg-1 body weight. two differently labelled compounds of isometamidium were used; 6-14c (ismm-1) and ring-u-14c (ismm-2). the cattle were divided into 5 groups: group 1 consisted of 3 non-infected cattle treated with ismm-1 by intravenous injection; gro ...19968910653
use of insecticide-impregnated targets for the control of tsetse flies (glossina spp.) and trypanosomiasis occurring in cattle in an area of south-west ethiopia with a high prevalence of drug-resistant trypanosomes.in the ghibe valley, south-west ethiopia, a tsetse control trial using deltamethrin-impregnated targets was started in may 1990. the mean relative density of the main vector, glossina pallidipes, fell from 2.1 flies per trap per day in the 12 months prior to introduction of tsetse control to 0.41 flies per trap per day in the 12 months after tsetse control was initiated. the annual mean prevalence of trypanosoma congolense infections in cattle fell from 32% in the 2 years before tsetse control t ...19968911444
heterophile antibodies to chicken erythrocytes in sheep infected with trypanosoma congolense.high hemagglutinin titres against chicken erythrocytes were detected in the sera of trypanosoma congolense-infected sheep. adsorption of sheep sera with solubilized t. congolense resulted in marked reduction of hemagglutinin titre. heat inactivation of the sera at 56 degrees c for 30 min had no demonstrable effects on the hemagglutinin titre. sera collected from the sheep before trypanosome infection did not agglutinate chicken erythrocytes. on the other hand, erythrocytes of horse, donkey and d ...19968917863
nitric oxide synthesis is depressed in bos indicus cattle infected with trypanosoma congolense and trypanosoma vivax and does not mediate t-cell suppression.infection with african trypanosomes causes the diseases sleeping sickness in humans and nagana in cattle in sub-saharan africa. suppression of cellular immune responses is a feature of trypanosomiasis in bovine, human, and murine hosts. some aspects of immunosuppression in the murine model are mediated by nitric oxide (no) produced by gamma interferon (ifn-gamma)-activated macrophages. we have investigated whether a similar mechanism is responsible for t-cell unresponsiveness in bovine trypanoso ...19968926077
trypanosoma congolense: a comparison of t-cell-mediated responses in lymph nodes of trypanotolerant and trypanosusceptible cattle during primary infection.a comparison of t-cell-mediated immune responses in trypanotolerant n'dama and susceptible boran cattle during primary infection with tsetse-transmitted trypanosoma congolense was conducted to assess whether different patterns of t-cell activation occurred during trypanosome infection. proliferation and ifn-gamma synthesis in response to trypanosome antigens and to the mitogen con a were measured in lnc before infection and 10 and 35 days postinfection. phenotypic analysis of lnc was also carrie ...19968948321
localisation of acid phosphatase activity on the surface of bloodstream forms of trypanosoma congolense.in vitro, living bloodstream forms of trypanosoma congolense were shown to hydrolyse p-nitrophenyl phosphate, a substrate for phosphatases. this activity appears to be from an acid phosphatase because it was enhanced at low ph values, was inhibited by the acid phosphatase inhibitor sodium fluoride, and was not inhibited by the alkaline phosphatase inhibitor tetramisole. the activity did not appear to be secreted into the surrounding medium by the living parasites although phosphatase activity co ...19968948332
photoinactivation of trypanothione reductase and glutathione reductase by al-phthalocyanine tetrasulfonate and hematoporphyrin.the irradiation of trypanosoma congolense trypanothione reductase (tr), human erythrocyte (hgr) and yeast glutathione reductase (ygr) with visible light in the presence of al-phthalocyanine tetrasulfonate (a1pcs4) or hematoporphyrine (hp) caused a time-dependent inactivation of these enzymes. tr was inactivated more rapidly than either hgr or ygr. half-maximal rates of inactivation were determined in the presence of 100 microm hp and 1.4-17 microm alpcs4. the photosensitized irradiation modified ...19968561807
differentiation between culture-derived insect stages of t. brucei, t. vivax, t. congolense and t. simiae using a monoclonal antibody-based dot-elisa.a sensitive and specific nitrocellulose (nc) membrane-based dot-elisa, utilizing a panel of monoclonal antibodies (mabs), was developed for differentiation between in vitro-derived procyclic forms of trypanosoma brucei, t. congolense and t. simiae, and epimastigotes of t. vivax. trypanosomes in suspension were applied onto nc membrane in dots and probed with unlabelled trypanosome species-specific mabs. bound mab was revealed by enzyme labelled anti-mouse igg and precipitable chromogenic substra ...19968587802
a high prevalence of mixed trypanosome infections in tsetse flies in sinfra, côte d'ivoire, detected by dna amplification.the prevalence of various species and subgroups of trypanosomes in the sinfra area of côte d'ivoire was determined using the polymerase chain reaction (pcr). using this technique to amplify specific satellite dna targets, it was possible to identify developmental-stage trypanosomes in the midguts and the proboscides of tsetse without expansion of parasite populations. the predominant tsetse species in the area was glossina palpalis, while g. pallicera and g. nigrofusca were also present. microsc ...19968587804
effects of castration on luteinizing hormone secretion and response to gonadotrophin-releasing hormone in sheep infected with trypanosoma congolense.the effects of trypanosomiasis on the endocrine function of the hypothalamo-pituitary-gonadal axis were investigated before and after castration of scottish blackface rams infected with trypanosoma congolense and uninfected controls. blood samples were collected at 15-min intervals for 6 h before and at 10, 20, 40, 60, 80, 100 and 120 min after injection of synthetic gonadotrophin-releasing hormone (gnrh, 20 micrograms iv) 2 days before infection and 26 and 54 days after infection, with castrati ...19968590946
trypanosoma congolense: high erythropoietic potential in infected yearling cattle during the acute phase of the anemia.n'dama (bos taurus) cattle are known to tolerate trypanosome infections, developing less severe anemia and lower parasitemia, compared to boran (bos indicus) cattle. young calves were also reported to be more resistant to trypanosomiasis than adult cattle. to explore the basis for this resistance, the erythropoietic response was evaluated in four native yearling n'dama calves and four age-matched boran calves which developed anemia over a 140- day primary infection with trypanosoma congolense cl ...19968617336
a promotor directing alpha-amanitin-sensitive transcription of garp, the major surface antigen of insect stage trypanosoma congolense.the major surface antigen of procyclic and epimastigote forms of trypanosoma congolense in the tsetse fly is garp (glutamic acid/alanine-rich protein), which is thought to be the analogue of procyclin/parp in trypanosoma brucei. we have studied two t.congolense garp loci (the 4.3 and 4.4 loci) whose transcription is alpha-amanitin sensitive. whilst a transcriptional gap 5' of the first garp gene in the cloned region of the 4.4 locus could not be detected, such a gap was present in the 5' flank o ...19968628650
comparative evaluation of the prophylactic effect of slow release devices containing homidium bromide and isometamidium on trypanosoma congolense in rabbits.two consecutive experiments were carried out to evaluate the prophylactic effect of biodegradable slow release devices (srd), containing either isometamidium or homidium bromide. rabbits subcutaneously implanted with srd, were challenged with different trypanosoma congolense stocks at regular intervals between 1 and 6.5 months after treatment. in a first experiment the efficacy of two types of isometamidium-srd (poly(d,l-lactide) and poly(d,l-lactide-co-glycolide)) was compared with the classica ...19968966986
pharmacokinetics of the chemoprophylactic and chemotherapeutic trypanocidal drug isometamidium chloride (samorin) in cattle.pharmacokinetics of the prophylactic and therapeutic trypanocidal drug isometamidium chloride were examined comprehensively for the first time in cattle using a recently described, highly sensitive elisa. cattle were administered single intravenous (n = 4) or intramuscular (n = 5) doses of isometamidium at a rate of 1.0 mg x kg(-1) body weight. concentration data were analyzed over at least 14 days (intravenous treatment) or 30 days (intramuscular treatment) using compartmental and noncompartmen ...19968971142
thyroid status and adenosine triphosphatase activity in experimental trypanosoma congolense infection in rabbits.the effect of trypanosome infection on the plasma levels and ratios of tri-iodothyronine (t3) and thyroxine (t4) as well as the activity of mitochondrial adenosine triphosphatase (atpase) were investigated. three groups of sexually mature white new zealand rabbits were used. group 1 consisted of the normal non-infected rabbits, group 2 were experimentally infected with trypanosoma congolense and group 3 were infected but given replacement doses of thyroxine. the infected animals (group 2) showed ...19968979423
a comparative study of the parasitological buffy coat technique and an antigen enzyme immunoassay for trypanosome diagnosis in sequential trypanosoma congolense infections in n'dama, gobra zebu and n'dama x gobra crossbred cattle.the buffy coat/dark ground techniques (bct) and an antigen enzyme immunoassay (ag-elisa) were compared for the diagnosis of trypanosome infection in n'dama, gobra zebu and n'dama x gobra (f1) crossbred cattle following two sequential experimental trypanosoma congolense infections. both first and second challenge were performed by intradermal needle inoculation of trypanosome bloodstream forms. during the course of the first challenge, the overall trypanosome percentage of positive cases detected ...19968988308
trypanosome characterization by polymerase chain reaction in glossina palpalis gambiensis and g.tachinoides from burkina faso.following the discovery of four cases of african human trypanosomiasis, an entomological survey was conducted along the mouhoun river in southwest burkina faso to collect glossina palpalis gambiensis and g.tachinoides. among 226 flies dissected, 4.87% (eleven individuals) were infected in midgut or proboscis, but never in the salivary glands. polymerase chain reaction analysis was undertaken, and was able to characterize all the proboscis infections, and half of the midgut infections. only trypa ...19968994137
[evaluation of vectorial capacity of glossina tachinoides (diptera, glossinidae) infected by trypanosoma (nannomonas) congolense: epidemiological implications].a total of 182 glossina tachinoides were infected with trypanosoma congolense savannah type. infection rates were determined according to microscopical examination of dissected flies and pcr on proboscis. different techniques of trypanosomes detection in the saliva of live tsetse flies were compared. results show a high percentage of immature infection rates. pcr amplification of trypanosomes in tsetse flies proboscis confirm parasitological observations. the salivation technique showed fluctuat ...19969008737
[experimental infection of glossina morsitans morsitans (mall) with trypanosoma congolense (zre/g143/90). parasite cycle and vector competence in the tsetse fly].this report presents an experimental study of the life cycle of trypanosoma congolense (zre/g 143/90) in relation to the vectorial competence of glossina morsitans (mall). the rate of engorgement at the time of an infectious meal and the mortality before day 15 of the life cycle were not significantly different between male and female flies. the mesocyclic forms of trypanosomes were regularly observed in the proventriculus, crop duct, oesophagus, cibarium and proboscis, except in the crop. on da ...19969026227
improvement of blood and fly gut processing for pcr diagnosis of trypanosomosis.we have adapted a simple and efficient technique to detect trypanosomes in human blood, without dna purification, and increased the sensitivity threshold to 1 parasite in 1 ml. we have then applied it for detection of parasites in midguts of tsetse flies, negative by microscopy. this technique has been developed for field conditions and could greatly facilitate epidemiological studies.19969033912
glycosyl-phosphatidylinositols of trypanosoma congolense: two common precursors but a new protein-anchor.the parasitic protozoan trypanosoma congolense exhibits a dense surface coat which is pivotal for immunoevasion of the parasite. this dense surface coat is made of a single protein species, the variant surface glycoprotein, which is present in a high copy number. the protein is anchored to the plasma membrane by a glycosyl-phosphatidylinositol membrane anchor. a detailed study of the structure of t. congolense strain 423 (clone benat 1.3) variant surface glycoprotein glycosyl-phosphatidylinosito ...19968757286
evaluation of three antigen detection tests (monoclonal trapping elisa) for african trypanosomes, with an isolate of trypanosoma vivax from french guyana.preliminary studies in french guyana with sheep experimentally infected with a local isolate of trypanosoma vivax tended to show poor sensitivity and/or specificity of the monoclonal antibodies used in kits for the antigen-detection (ag) elisa for t. vivax, t. brucei, and t. congolense. to reevaluate these kits, 4 calves were infected at ilrad, nairobi, kenya, with the same isolate. blood samples were taken daily for 51 days, and examined directly on blood smears and buffy coat, and using ag-eli ...19968784499
effect of tsetse control on trypanosome prevalence in livestock: problems of experimental design and statistical interpretation--a case study in northern côte d'ivoire.as part of a study on livestock productivity under trypanosomosis risk in the region of boundiali, northern côte d'ivoire, 21 herds of cattle (n'dama, baoulé and zebu crosses) and 20 flocks of djallonké and djallonké x sahel sheep were monitored monthly for body weight, packed red cell volume and trypanosomal parasitaemia over various periods between january 1984 and december 1992. a tsetse control campaign using biconical traps impregnated with alpha-cypermethrin started in december 1987. tsets ...19968804163
evaluation of an antigen detection-elisa test for the diagnosis of trypanosomiasis in naturally infected cattle.the sensitivity and the specificity of the antigen detection elisa proposed by nantulya and lindqvist (1989) for the diagnosis of african animal trypanosomiasis have been assessed in naturally-occurring infections. 1633 cattle were sampled in trypanosomiasis endemic area and examined for trypanosomes by darkground/phase contrast buffy-coat method described by murray et al. (1977) and for circulating antigen by elisa. fifty sera from markoye, a tsetse free area in north of burkina faso, and 49 se ...19958826113
trypanosoma congolense: tissue distribution of long-term t- and b-cell responses in cattle.memory t- and b-cell responses to trypanosome antigens were measured in peripheral blood mononuclear cells, spleen and lymph node cells obtained from four trypanotolerant n'dama cattle which had been exposed to six experimental infections with trypanosoma congolense. these cattle were treated with trypanocidal drugs following each infection and had remained aparasitemic for 3 years prior to this study. the antigens used were whole trypanosome lysate, variable surface glycoprotein, a 33-kda cyste ...19958847087
resistance to diminazine aceturate by trypanosoma congolense from cattle in the zambezi valley of zimbabwe.the susceptibility of 14 stocks of trypanosoma congolense, recently isolated from cattle, to therapeutic doses of diminazene aceturate and to isometamidium chloride was assessed in laboratory mice. eight isolates were readily susceptible to the normal therapeutic dose of diminazene, two were resistant to the drug at 14 mg kg-1, and four were totally resistant at 28 mg kg-1. all the isolates were susceptible to isometamidium chloride at 0.5 mg kg-1. these observations highlight the need for regul ...19958644445
trypanosoma congolense infection in sheep: ultrastructural changes in the skin prior to development of local skin reactions.events occurring in the skin of sheep prior to development of trypanosoma congolense-induced local skin reactions (chancres) were studied using electron microscopy. three days after infection, few trypanosomes were present in the dermal collagen. however, these parasites were more abundant 5 days after infection, and were also found in dermal lymphatics and in the connective tissue matrix between collagen bundles. mast cells in the skin obtained 5 days after infection showed evidence of degranul ...19958644458
mechanical transmission of trypanosoma spp. by african stomoxyinae (diptera: muscidae).ten taxa of stomoxyinae were tested for their ability to transmit trypanosoma brucei, t. vivax, t. evansi and t. congolense to mice within 3 min of interrupted feeding on highly parasitaemic blood. t. brucei was the easiest parasite to transmit with an 11.5% success rate, followed by t. vivax at 3.4%, and t. evansi at 0.9%. t. congolense was not transmitted in 129 attempts. stomoxys niger sspp. and four unstudied species (s. varipes, s. taeniatus, s. pallidus, haematobosca squalida) were capable ...19958525279
successful application of deltamethrin pour on to cattle in a campaign against tsetse flies (glossina spp.) in the pastoral zone of samorogouan, burkina faso.1,500-2,000 head of cattle were treated with deltamethrin 1% spot on in an area of high tsetse densities, notably of glossina morsitans submorsitans. after four treatments at monthly intervals, the time between two treatments was increased to two months. 11 months after the commencement of the campaign the fly population had decreased from initially 54.2 flies/trap/day to densities varying between 0.06-2.0 flies/trap/day, mostly g. palpalis gambiensis. blood-meal analysis showed that this specie ...19958533022
the influence of energy intake on the pathophysiology of trypanosoma congolense infection in scottish blackface sheep.the intensity of parasitaemia, degree of anaemia, live body weight gains and blood biochemical changes were measured in two groups of scottish blackface sheep infected experimentally with trypanosoma congolense and allowed either a high (9.9 mj metabolisable energy (me) day-1) or a low (6.1 mj me day-1) energy intake. it was observed that infected animals on the low energy intake had a longer mean prepatent period, but following patency they developed more severe anaemia and greater growth retar ...19958533279
a comparison of glossina morsitans centralis originating from tanzania and zambia, with respect to vectorial competence for pathogenic trypanosoma species, genetic variation and inter-colony fertility.two laboratory strains of glossina morsitans centralis originating from different fly-belts (one from singida, in tanzania, and the other from mumbwa, in zambia) were compared with respect to vectorial competence for pathogenic trypanosoma species, genetic variation and inter-colony fertility. the vectorial competence of g.m.centralis of tanzanian origin for trypanosma vivax and t. congolense is similar to, whereas for t.brucei brucei it is lower than the colony of zambian origin. nevertheless, ...19958541585
genetics of resistance to trypanosoma congolense in inbred mice: efficiency of apparent clearance of parasites correlates with long-term survival.to study the genetic parameters of resistance to trypanosoma congolense infection, highly susceptible balb/c and relatively resistant c57bl/6 mice were crossed to produce reciprocal f1 and f2 offspring. mice were infected with t. congolense and monitored for parasitemia within the first 2 wk and also for their survival periods. balb/c mice showed unrestrained parasite growth to the time of death (median survival period, msp = 12.0 days), whereas in c57bl/6 mice, parasitemia reached an initial pe ...19958544057
[trypanosoma congolese in different species of horse flies (diptera: tabanidae) in burkina faso].four out of six azawak zebu bulls raised in northern burkina faso were found to be infected with trypanosomes, including trypanosoma congolense, six months after they had been transferred, uninfected, to the cirdes experimental farm at banankélédaga (southwest burkina faso). entomological surveys are carried out regularly in the area around this farm but, in one year, only 10 tsetse flies were captured, none of which showed infection in the midgut. however, a large number of tabanids were captur ...19958552844
[improving the salivation technic in the tsetse fly for the detection of infective metatripanosomes: study of the effect of biologic and non-biologic factors in the probing behavior of the tsetse fly].the probing and salivation behaviour on a warm slide of three tsetse fly species or subspecies (glossina morsitans morsitans, glossina palpalis gambiensis, glossina tachinoides) was examined with respect to various parameters (species, sex, age, starvation period, trypanosome infection, quality of support). each fly was given the opportunity to probe the warm slide (38 degrees c) for 5 minutes (we mean by probing an attempt to touch the glass slide by the proboscis in a biting position). g.m mor ...19958552846
[standardization and evaluation of a manual salivation method for the detection of trypanosoma infection in the tsetse fly (diptera: glossinidae)].two methods of salivation of tsetse flies, namely manual salivation and method of bruce et al. were simultaneously evaluated on 1,702 male uninfected glossina palpalis palpalis (zaire), g. palpalis gambiensis (bobo-dioulasso), g. p. gambiensis (maisons-alfort) et g. morsitans morsitans (mall) fasted for 23, 48 and 72 hours. the risk of salivation was 0.66 by the manual method and 0.01 by the method of bruce et al. the manual salivation method was standardised on 79 male g. m. morsitans (mall) in ...19958552848
trypanosomatid cysteine protease activity may be enhanced by a kininogen-like moiety from host serum.african trypanosomes contain cysteine proteases (trypanopains) the activity of which can be measured by in vitro digestion of fibrinogen, after electrophoresis in fibrinogen-containing sds/polyacrylamide gels. when assessed by this procedure, trypanopain from trypanosoma brucei (trypanopain-tb) is estimated to have a molecular mass of 28 kda. however, two additional bands of trypanopain activity (87 kda and 105 kda) are observed if serum is added to the trypanopain before electrophoresis. format ...19957832773
trypanosomosis in intensively reared muturu calves in nigeria. 19958966766
rise in erythropoietin concentrations in experimental trypanosoma congolense infection of calves.a bioassay was used to measure erythropoietin (epo) concentrations in calves with haemorrhagic anaemia due to blood loss and in calves with anaemia due to trypanosoma congolense infection. the bioactivity of epo was measured in the assay by its stimulatory effect on 125i-deoxyuridine incorporation in spleen cells from phenylhydrazine-treated mice. erythropoietin concentrations in blood-volume-depleted calves were elevated 6 h after blood loss, maximal (1225 mu/ml) at 33 h and below detection lim ...19958746957
glutathione reductase (ec 1.6.4.2.) in experimental trypanosomiasis.the activity of glutathione reductase (ghsr) in extracts of kidney, liver and testis of rats infected with trypanosoma congolense decreased with every wave of parasitemia. the implications of these observations as they relate to the risk of oxidative stress are discussed.19957758150
expression of trypanosoma congolense antigens in spodoptera frugiperda insect cells.transcripts which encode two metacyclic-form-specific variable surface glycoproteins (mvsgs) of trypanosoma congolense il3000 have been cloned into baculovirus expression vectors using a novel transfer vector, pacl11. one of the recombinant baculoviruses (acvsg1) expressed a mvsg as a glycoprotein with a signal peptide which was cleaved in this expression system, whereas the other one (acvsg2) expressed an unprocessed protein. from 1 liter of culture containing 10(9) spodoptera frugiperda cells ...19957758544
apparent rarity of diminazene-resistant trypanosomes in goats infected with a diminazene-resistant population of trypanosoma congolense.experiments were carried out in goats to determine the frequency with which diminazene-resistant trypanosomes occur in parasite populations before and after the intramuscular treatment of the goats with diminazene aceturate. trypanosoma congolense il 3274, a diminazene-resistant clone, was used to initiate infections in three groups of five goats. the goats in the first group were treated with diminazene aceturate at a dose of 7.0 mg kg-1 bodyweight within 10 seconds of infection; one of the goa ...19957761687
effects of trypanosoma congolense on pituitary and adrenocortical function in sheep: changes in the adrenal gland and cortisol secretion.the effect of trypanosomiasis on adrenal function was studied in 10 pubertal scottish blackface rams infected with trypanosoma congolense and nine uninfected controls. plasma cortisol concentration was measured by radioimmunoassay in samples obtained twice a week for three weeks before infection and three times a week for 79 days after infection. there was a significant (p < 0.001) increase in cortisol concentration in all the infected rams after the onset of parasitaemia nine to 16 days after i ...19957761698
effects of trypanosoma congolense on pituitary and adrenocortical function in sheep: responses to exogenous corticotrophin-releasing hormone.to investigate whether the aberrations in adrenocortical and gonadal activity observed in trypanosomiasis may be induced by the refractoriness of the pituitary to hypothalamic liberins, the responses of the pituitary and adrenal glands and the testes to stimulation with ovine corticotrophin-releasing hormone (ocrh) were studied in rams 23 days (acute phase) and 65 days (chronic phase) after they were infected with trypanosoma congolense. on both occasions a peak of plasma acth was observed withi ...19957761699
three genes and two isozymes: gene conversion and the compartmentalization and expression of the phosphoglycerate kinases of trypanosoma (nannomonas) congolense.the glycosome, a microbody organelle found only in kinetoplastid protozoa, compartmentalizes the first six enzymes of glycolysis. in order to better understand the regulation and targeting of glycolytic enzymes in trypanosomes, we have cloned and analyzed the three genes of the phosphoglycerate kinase (pgk) complex of trypanosoma (nannomonas) congolense. the organization of the genes within the complex is similar to that of trypanosoma brucei brucei. the nucleotide and amino-acid sequences, incl ...19957770090
trypanosoma congolense infection in two dogs.trypanosomiasis, caused by trypanosoma congolense, was diagnosed for the first time in israel in two boxer dogs imported from kenya. the dogs developed clinical signs two days after arrival and succumbed to the disease within four days. the major clinical and clinicopathological findings included anaemia, haemorrhages, lymphadenomegaly, hepatosplenomegaly and neurological signs. histopathology showed lymphocytic-plasmacytic infiltration in the skin, brain, meninges, kidney and liver.19957723295
feeding behaviour of tsetse flies (glossina pallidipes austen) on trypanosoma-infected oxen in kenya.an incomplete ring of electric nets was placed around oxen which were either uninfected, infected with trypanosoma vivax, or infected with t. congolense. the numbers of fed and unfed glossina pallidipes caught on the nets were used to estimate the attractiveness of the oxen to tsetse, and the feeding success of the tsetse on the oxen. oxen infected with t. congolense attracted more g. pallidipes than the other groups of oxen. taking into consideration daily variation in the abundance or activity ...19957724237
trypanosoma congolense: comparative effects of a primary infection on bone marrow progenitor cells from n'dama and boran cattle.using in vitro clonogenic assays, the changes in haemopoietic progenitor cell levels were compared in the bone marrow of three adult trypanotolerant n'dama cattle and three age-matched trypanosusceptible boran cattle over 17 weeks (119 days) of a primary trypanosoma congolense (clone il 1180) infection. as the infection progressed, a clear tendency of the parasitaemia to decrease was seen in the n'damas, while it remained high throughout the infection in the borans. the decline in the colony-for ...19957729476
trypanosoma congolense: developmental regulation of protein kinases and tyrosine phosphorylation during the life cycle.in higher eukaryotes, key steps in the control of growth and proliferation are regulated by protein phosphorylation. however, little is known about the role of protein phosphorylation in the developmental cycles of pathogenic protozoa. in trypanosoma brucei, only the bloodform and procyclic form stages can be obtained in sufficient numbers for biochemical analyses. however, the entire life cycle of trypanosoma congolense can be generated in vitro, providing sufficient material for analyses of th ...19957729486
relationships between host blood factors and proteases in glossina morsitans subspecies infected with trypanosoma congolense.host blood effects on trypanosoma congolense establishment in glossina morsitans morsitans and glossina morsitans centralis were investigated using goat, rabbit, cow and rhinoceros blood. meals containing goat erythrocytes facilitated infection in g.m.morsitans, whereas meals containing goat plasma facilitated infection in g.m.centralis. goat blood effects were not observed in the presence of complementary rabbit blood components. n-acetyl-glucosamine (a midgut-lectin inhibitor) increased infect ...19957787223
characterization of concanavalin a-binding glycoproteins from procyclic culture forms of trypanosoma congolense, t. simiae and t. brucei brucei.concanavalin a-binding glycoproteins were obtained from procyclic culture forms (pcfs) of trypanosoma congolense, t. simiae, and t. b. brucei strains. sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) analysis revealed that glycoproteins of 38.5, 30.5, and 27 kda were conserved between the different species and strains of the procyclic parasites. there were few similarities in the profiles of the high-molecular-weight glycoconjugates between the parasites. monoclonal antibody ...19957539528
catalytic and potentiometric characterization of e201d and e201q mutants of trypanosoma congolense trypanothione reductase.trypanothione reductase is a member of the structurally and functionally well-characterized family of flavoprotein reductases, which catalyze the reduced pyridine nucleotide dependent reduction of their disulfide, peroxide, or metal ion substrates. trypanothione reductase is found in a wide variety of trypanosoma species, where the enzyme serves physiologically to protect the organism from oxidative stress and assists in maintaining low intracellular levels of hydrogen peroxide. the redox potent ...19957548022
trypanosoma congolense: proliferative responses and interleukin production in lymph node cells of infected cattle.t-cell-mediated immune responses to defined antigens of trypanosoma congolense were measured in cattle undergoing primary infection. the antigens used were the variable surface glycoprotein and two invariant antigens, a 33-kda cysteine protease (congopain) and a recombinant form of a 69-kda heat-shock protein. proliferative responses were highest during the second week postinfection and were detected in cells obtained from the lymph node draining the site of infection but not in peripheral blood ...19957556557
molecular characterization of trypanosome species and subgroups within subgenus nannomonas.restriction fragment length polymorphism (rflp) analysis of both genomic and kinetoplast dna from representative stocks from 3 trypanosoma congolense subgroups (savannah, forest, and kilifi), t. simiae and t. godfreyi, was used to investigate the relatedness of the different groups within subgenus nannomonas. dna probes for beta-tubulin and the ribosomal dna (rdna) locus were isolated from a t. congolense savannah genomic library; additional probes were generated by pcr amplification of mini-exo ...19957567098
[absence of interaction between trypanosoma theileri infections with the diagnosis of animal trypanosomiasis by detection of circulating antigens].this work presents data gathered at the cirdes (centre international de recherche-développement sur l'elevage en zone subhumide) during epidemiological monitoring. the prevalence levels of trypanosoma vivax, trypanosoma congolense and trypansoma brucei obtained using antigen-detection elisa were compared in non-infected animals and in animals infected with trypanosoma theileri. the aim was to investigate whether there were any serological cross-reactions between t. theileri and the pathogenic tr ...19957569224
disposition of diminazene aceturate (berenil) in trypanosome-infected pregnant and lactating cows.three cows were repeatedly infected with different strains of trypanosoma congolense and treated intramuscularly each time with a different dose of diminazene aceturate (berenil). biphasic decline was observed of the maximal plasma drug levels, which were attained at 15 min after the first treatment and at 30 min after the second and third treatments. the rate constants for the distribution and terminal phases depended on the period of exposure to parasitaemia of the animal at the time of treatm ...19957571326
the effect of l-thyroxine on the anaemia response in trypanosoma congolense infected rabbits.the development of anaemia is a major pathological manifestation in chronic trypanosomosis. the anaemia in african trypanosomosis coincides with a marked decrease in plasma concentration of both thyroxine (t4) and 3,5,3' triiodothyronine (t3). to evaluate the effect of trypanosome-induced hypothyroidism on the development of anaemia, sexually mature white new zealand rabbits were used. three groups were set up, each of ten rabbits: one group was infected with trypanosoma congolense; the second g ...19957571327
[antigenic variation and the problem of vaccines against african trypanosomes].african trypanosomes evade the immune response of their host through continuous changes of their major surface antigen, the vsg. this antigenic variation is achieved by either alternative activation of different expression sites for the vsg gene, or dna rearrangements occurring within a given site. several minor but invariant surface proteins have recently been characterized. this is especially the case for some surface receptors, which appear to be located in an invagination of the plasma membr ...19957581198
are cd8 t cells involved in control of african trypanosomiasis in a natural host environment?murine models have suggested that cd8 t cells might play a major parasite-promoting role in african trypanosomiasis. to assess the role of these cells in a natural host environment, we have depleted cd8 cells from boran cattle in vivo and subsequently infected these animals with trypanosoma congolense by tsetse fly challenge. following administration of a mouse monoclonal anti-bovine cd8 antibody, we have been able to achieve a depletion of more than 99.9% in peripheral blood, spleen, prescapula ...19957621872
partial protection against natural trypanosomiasis after vaccination with a flagellar pocket antigen from trypanosoma brucei rhodesiense.cattle that were inoculated with an antigen derived from the flagellar pocket of trypanosoma brucei rhodesiense and then infected with trypanosoma congolense and trypanosoma vivax were compared with unvaccinated cattle when both groups of cattle were placed in regions of kenya endemic for tsetse flies known to harbour t. congolense and t. vivax. in one trial, 90 cattle were employed, 40 untreated controls, 30 cattle given prior treatment with samorin, and 20 inoculated with a flagellar pocket (f ...19957625108
frequency of diminazene-resistant trypanosomes in populations of trypanosoma congolense arising in infected animals following treatment with diminazene aceturate.the frequency of trypanosomes resistant to diminazene aceturate at a dose of 25 mg/kg of body weight was investigated for populations of trypanosoma congolense il 3274 which reappeared in infected mice after intraperitoneal treatment with diminazene aceturate at the same dosage. at inoculum sizes of 10(2), 10(3), 10(4), 10(5), and 10(6) trypanosomes per mouse, the relapse populations were used to initiate infections in five groups of 100 mice each by the intravenous route. immediately after infe ...19957625797
kinetoplastid membrane protein-11 (kmp-11) is differentially expressed during the life cycle of african trypanosomes and is found in a wide variety of kinetoplastid parasites.an abundant 11-kda membrane protein was purified from african trypanosomes by organic solvent extraction and octyl-sepharose chromatography. this protein cross-reacts with monoclonal antibodies originally generated against the lipophosphoglycan-associated protein of leishmania donovani. immunoblot analysis showed that the 11-kda molecule was present in a variety of species of kinetoplastids. it was found in several species and subspecies of african trypanosomes and was present in low amounts in ...19957630374
a novel in vitro screening assay for trypanocidal activity using the fluorescent dye bcecf-am.a cell viability assay, using fluorescence measurements has been developed for the screening of new compounds against african trypanosomes. 2',7'-bis-(carboxyethyl)-5(6)-carboxyfluorescein-pentaacetoxymethyles ter (bcecf-am), an esterase substrate, was used in the assay as a marker for cell viability. fluorescence was quantified using an automated fluorescence scanner for multi-well plates. trypanosoma brucei rhodesiense, t. congolense, t. evansi and t. equiperdum from continuously growing cultu ...19957631128
expression of garp, a major surface glycoprotein of trypanosoma congolense, on the surface of trypanosoma brucei: characterization and use as a selectable marker.procyclic and epimastigote forms of trypanosoma congolense express an immunodominant glutamic acid/alanine-rich protein (garp) that covers the parasite surface. although garp shows no sequence similarity to procyclins from t. brucei, the general characteristics of the two sets of surface glycoproteins suggest that they have analogous functions, in much the same way that variant surface glycoproteins with unrelated primary sequences fulfil the same function in bloodstream form trypanosomes. since ...19957637714
hydrogen peroxide destaining: a new method for removing non-specific stains in nitrocellulose membrane-based dot-elisa for the detection of trypanosomes in tsetse flies (glossina spp.).gut samples prepared from laboratory-reared tsetse flies and applied in dots onto nitrocellulose (nc) membrane were found to stain the membrane with differing coloration and intensity. the stains were, predominantly, either reddish to brown or blackish-brown to black and occasionally greenish to almost colourless, depending on the stage of digestion of the bloodmeal in the fly. nc membrane strips applied with tsetse gut samples from t. brucei infected and uninfected control flies were tested wit ...19957490455
the accumulation and compartmentalization of isometamidium chloride in trypanosoma congolense, monitored by its intrinsic fluorescence.interaction of the trypanocide isometamidium chloride with components of trypanosoma congolense results in characteristic shifts in the intrinsic fluorescence of the drug. the specificity of this interaction was investigated by analysing the effects of various physicochemical manipulations on its fluorescence properties. the characteristic shifts involved a preferential increase in the intensity of one emission peak over the other, resulting in a systematic increase in the ratio of fluorescence ...19957492332
flagellum-mediated adhesion of trypanosoma congolense to bovine aorta endothelial cells.we studied the interaction between trypanosoma congolense and bovine aorta endothelial (bae) cell monolayers. our findings suggest that trypanosomes adhere predominantly to the flattened, peripheral cell surface domains as well as to filamentous endothelial outgrowths that are present during in vitro cultivation in non-confluent monolayers. adhesion is mediated exclusively by the flagellum in a distinct geometrical order with respect to the flagellar cytoskeleton. thus, it is possible to define ...19957501641
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