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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
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
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
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
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
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
identification of trypanosomes isolated by kivi from wild mammals in côte d'ivoire: diagnostic, taxonomic and epidemiological considerations.in côte d'ivoire, a comparative study was carried out on 122 wild mammals by parasitological and serological examination and by in vitro isolation of trypanosomes from fresh blood (kivi). thirteen isolated stocks were studied by isoenzymes and compared with trypanosoma congolense and t. brucei bouaflé group reference stocks. of the 122 animals, only 22 were positive on blood smears while 88 were kivi positive and 92 were catt/t. b. gambiense positive. for six stocks identified by isoenzymes as t ...19979241383
a comparison of the enzymatic properties of the major cysteine proteinases from trypanosoma congolense and trypanosoma cruzi.congopain and cruzipain, the major cysteine proteinases from trypanosoma congolense and trypanosoma cruzi, were compared for their activities towards a series of new, sensitive fluorogenic substrates of the papain family of cysteine proteinases and for their sensitivity to inhibition by cystatins and related biotinylated peptidyl diazomethanes. low ki values, in the 10 pm range, were found for the interaction of both proteinases with natural cystatin inhibitors. the kinetic constants for the hyd ...19979274870
cytoskeletal architecture and components involved in the attachment of trypanosoma congolense epimastigotes.scanning and transmission electron microscopy of trypanosoma congolense epimastigotes attached to a plastic substratum shows them to elaborate a complex flagellum filament system and plaque with a highly organized structure. non-ionic detergent extraction of these cells shows that the resulting cytoskeletons remain attached to the plaque. the subpellicular corset of microtubules can be removed by salt or ca2+ treatment leaving the axoneme, paraflagellar rod, associated filaments and the plaque. ...19979280895
molecular characterization of trypanosome isolates from naturally infected domestic animals in burkina, faso.a total of 33 trypanosome cryostabilates isolated from domestic animals (bovine and dogs) were analysed using the polymerase chain reaction (pcr). the pcr was undertaken on diluted and treated buffy coat solutions according to an easy protocol of purification, using primers specific to trypanosoma (nannomonas) congolense of savannah, riverine-forest, kilifi and tsavo types, t. (n) simiae, t. (trypanozoon) brucei and t. (duttonella) vivax. the results showed a lack of pcr sensitivity when target ...19979299694
modulation of mitochondrial electrical potential: a candidate mechanism for drug resistance in african trypanosomes.bloodstream forms of four populations of the livestock pathogen trypanosoma congolense, isolated from different natural infections, have been shown to exhibit a wide range of sensitivities to the trypanocide isometamidium chloride (samorin(r)). in mice the 50% curative doses (cd50) for samorin range from 0.007 to 20 mg/kg body weight. uptake of isometamidium chloride demonstrated michaelis-menten-type kinetics in all the populations, with km values in the range 0.35-0.87 microm, and vmax varied ...19979307025
comparison of the susceptibility of different glossina species to simple and mixed infections with trypanosoma (nannomonas) congolense savannah and riverine forest types.teneral glossina morsitans mositans, g.m.submorsitans, g.palpalis gambiensis and g.tachinoides were allowed to feed on rabbits infected with trypanosoma congolense savannah type or on mice infected with t.congolense riverine-forest type. the four tsetse species and subspecies were also infected simultaneously in vitro on the blood of mice infected with the two clones of t.congolense via a silicone membrane. the infected tsetse were maintained on rabbits and from the day 25 after the infective fe ...19979330255
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
lack of correlation of anaemia with splenomegaly and hepatomegaly in trypanosoma brucei and trypanosoma congolense infections of rats.isolates of trypanosoma brucei and trypanosoma congolense from the blood of cattle were used to infect growing rats. despite the use of similar infective doses, t. brucei parasitaemia appeared earlier than t. congolense parasitaemia. after the same period of parasitaemia, the degrees of anaemia, splenomegaly and hepatomegaly were similar in both infections. the percentage decrease in packed cell volume was not correlated with splenic and hepatic weights. neither infection significantly affected ...19979447486
the interaction of trypanosoma congolense and haemonchus contortus in djallonké sheep.the interaction between trypanosoma congolense and haemonchus contortus was studied in 5 groups of 8 djallonké sheep. two groups received a single infection with either h. contortus or t. congolense, and 2 groups were infected with t. congolense followed by h. contortus (th) or vice versa (ht). one group was kept as uninfected controls. mortality due to infection was observed only in the dual infection groups. in the th group, the effects were more acute whereas in the ht group they were more ch ...19979467745
the influence of dietary protein on live bodyweight, degree of anaemia and erythropoietic responses of scottish blackface sheep infected experimentally with trypanosoma congolense.the present study investigated the influence of dietary protein on the intensity of parasitaemia, degree of anaemia and erythropoietic responses, in sheep experimentally infected with trypanosoma congolense and given either a high protein diet (116 g digestible crude protein [dcp] per day) or a low protein diet (51.5 g dcp per day). it was observed that infected and control animals on the high protein diet grew at similar rates while infected animals on the low protein diet experienced marked re ...19979491456
susceptibility of the namchi and kapsiki cattle of cameroon to trypanosome infection.two indigenous cameroonian taurine cattle breeds (namchi and kapsiki) were evaluated for trypanosusceptibility following inoculation with trypanosoma congolense. the degree of zebu ancestry in the experimental animals was assessed using 6 microsatellite markers which are known to have certain unique alleles which are diagnostic of bos indicus genetic input. their response to the infection was compared to that of known trypanotolerant (n'dama) and trypanosusceptible (ngaoundere gudali) cattle. th ...19979493294
organization, sequence and stage-specific expression of the phosphoglycerate kinase genes of leishmania mexicana mexicana.in leishmania mexicana two genes were detected coding for different isoforms of the glycolytic enzyme phosphoglycerate kinase. this situation contrasts with that observed in other trypanosomatidae (trypanosoma brucei, trypanosoma congolense, crithidia fasciculata) analyzed previously, which all contain three different genes coding for isoenzymes a, b and c, respectively. all attempts to detect in l. mexicana a type a pgk, or a gene encoding it, proved unsuccesful. we have cloned and characterize ...19979497040
characterisation of phosphoglycerate kinase genes in leishmania major and evidence for the absence of a third closely related gene or isoenzyme.we have characterised the phosphoglycerate kinases (pgks) in l. major and studied their mrna and protein expression. interestingly we have found evidence for only two tandemly linked pgk genes which correspond to the pgk gene b and c homologue in trypanosoma and crithidia. the primary structure of the leishmanial pgk genes b and c are virtually identical and differed only by the presence of a 62 amino acid extension at the carboxyl terminal of the pgk gene c homologue which is therefore likely t ...19979497041
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
on the interpretation of age-prevalence curves for trypanosome infections of tsetse flies.epidemiological models are used to analyse 8 published data sets reporting age-prevalence curves for trypanosome infections of the tsetse fly glossina pallidipes. a model assuming a fixed maturation period and a rate of infection which is independent of fly age is adequate for trypanosoma vivax-type infections, explaining 98% of observed variance in prevalence by site and age, allowing that the rate of infection may be site dependent. this model is not adequate for t. congolense-type infections ...19989509024
immune responses of cattle to african trypanosomes: protective or pathogenic?trypanosomosis in domestic livestock negatively impacts food production and economic growth in many parts of the world, particularly in sub-saharan africa. current methods of control are inadequate to prevent the enormous annual socio-economic losses resulting from this disease. hope for a vaccine based on the variant surface glycoprotein coat was abandoned several years ago when the complexity of the parasite's antigenic repertoire was appreciated. as a result, research is now focused on identi ...19989512986
[imported arthropod-borne parasites and parasitic arthropods in dogs. species spectrum and epidemiologic analysis of the cases diagnosed in 1995/96].between january 1995 and december 1996 nonendemic or only regionally occurring arthropodborne parasites including ehrlichiae and parasitic arthropods in germany were detected in 484 dogs, whereby at least 15 species were involved. listed in decreasing order, leishmania infections occurred most frequently, followed by infections/infestations with babesia canis, ehrlichia canis, rhipicephalus sanguineus, dirofilaria immitis and dermacentor reticulatus. the other species, namely babesia gibsoni, tr ...19989531673
unravelling the procyclin coat of trypanosoma brucei. 19989574930
cloning of a cdc2-related protein kinase from trypanosoma cruzi that interacts with mammalian cyclins.two cdc2-related protein kinases (crk), tzcrk3 and tzcrk1, from the protozoan parasite trypanosoma cruzi were cloned. tzcrk3 encodes a 35 kda protein sharing 51.5% amino acid identity with human cdc2 and 82% identity with trypanosoma brucei crk3. tzcrk1 encodes a 33 kda protein sharing 52.7% identity with human cdc2 and a high degree of identity (> 78%) with t. brucei crk1, leishmania mexicana crk1 and trypanosoma congolense crk1. a recombinant tzcrk1 protein was able to phosphorylate histone hi ...19989580532
haematological changes in n'dama and gobra zebu bulls during trypanosoma congolense infection maintained under a controlled feeding regimen.haematological changes were monitored in gobra-zebu and n'dama bulls following infection with trypanosoma congolense. the cattle were offered a diet which provided levels of protein and energy above maintenance requirement and a pair feeding regimen was used in order to eliminate the confounding anorexic effects of trypanosomosis on the traits studied. packed red cell volume (pcv), red blood cells (rbc) and haemoglobin (hb) were monitored weekly. mean corpuscular haemoglobin (mch), mean corpuscu ...19989638271
immunoregulation in experimental murine trypanosoma congolense infection: anti-il-10 antibodies reverse trypanosome-mediated suppression of lymphocyte proliferation in vitro and moderately prolong the lifespan of genetically susceptible balb/c mice.we infected highly susceptible balb/c and relatively resistant c57bl/6 mice with cloned trypanosoma congolense and followed the effects of these infections on the circulating parasite numbers, mouse mortality and cytokine expression. c57bl/6 mice controlled their parasitaemia and survived for up to 163 +/- 12 days, while balb/c mice could not control their parasitaemia and succumbed to the infection within 8.4 +/- 0.5 days. susceptible balb/c mice had dramatically higher plasma levels of il-10 t ...19989651931
functional and molecular characterization of a glycosomal ppi-dependent enzyme in trypanosomatids: pyruvate, phosphate dikinase.trypanosomatids are parasitic protists that have an atp-dependent glycolysis with no indication of ppi-dependent metabolism. most of the glycolysis takes place in peroxisome-like organelles, the glycosomes. we characterized in trypanosoma brucei a single-copy gene encoding a ppi-dependent enzyme, pyruvate, phosphate dikinase (ppdk), which was expressed functionally in escherichia coli. specific antibodies detected a 100-kda protein in procyclic forms but not in mammalian forms of t. brucei, indi ...19989653123
effects of trypanosoma congolense and nutritional supplements on establishment and outcome of pregnancy in trypanotolerant djallonké ewes.interactions between trypanosoma congolense and nutritional statue were studied in 42 ewes, bred at the peak of parasitaemia after synchronisation of oestrus. as experimental design a randomised block design was used with four treatment combinations (2 x 2 factors), of which two were on restricted diet (l), the remainder on an unrestricted diet (h) and half of each nutritional group infected with t. congolense (li, hi) remainder serving as controls (lc, hc). severity of parasitaemia was not infl ...19989672672
trypanosome infections and survival in tsetse.the effect of trypanosome infection on vector survival was observed in a line of glossina morsitans selected for susceptibility to trypanosome infection. the differential effects of midgut and salivary gland infections on survival were examined by exposing flies to infection with either trypanosoma congolense which colonizes midgut and mouthparts or trypanosoma brucei rhodesiense which colonizes midgut and salivary glands. a comparison of the survival distributions of uninfected flies with those ...19989695107
factors influencing the prevalence of trypanosome infection of glossina pallidipes on the ruvu flood plain of eastern tanzania.we report the pattern of infection of glossina pallidipes with trypanosoma vivax and t. congolense at a site in the coast region of eastern tanzania, studied between november 1993 and december 1994. of the 2315 flies dissected 114 (4.9%) were t. congolense positive, 77 (3.3%) were t. vivax positive and 2 (0.1%) were t. brucei positive. fly age was determined by the pteridine fluorescence method. prevalence of infection was most strongly affected by month and the linear effect of age with the int ...19989698260
detection and identification of trypanosomes by polymerase chain reaction in wild tsetse flies in cameroon.the prevalence of various species and subgroups of trypanosomes in infected flies from three sleeping sickness foci in cameroon was determined by the use of polymerase chain reaction (pcr). the predominant tsetse species found were glossina palpalis palpalis. microscopical examination of 943 non-teneral tsetse flies revealed an average infection rate of 10.4%. a total of 90 flies were analyzed for trypanosome identification with primer sets specific for trypanosoma (trypanozoon) brucei s.l., t. ...19989707369
inhibition of trypanosomal cysteine proteinases by their propeptides.the ability of the prodomains of trypanosomal cysteine proteinases to inhibit their active form was studied using a set of 23 overlapping 15-mer peptides covering the whole prosequence of congopain, the major cysteine proteinase of trypanosoma congolense. three consecutive peptides with a common 5-mer sequence yhnga were competitive inhibitors of congopain. a shorter synthetic peptide consisting of this 5-mer sequence flanked by two ala residues (ayhngaa) also inhibited purified congopain. no re ...19989737969
[vectorial competence of glossina palpalis palpalis, glossina p. gambiensis and glossina morsitans morsitans flies for a clone of trypanosoma (nannomonas) congolense il 1180].the authors report on the results of experimental infections of teneral (age < 32 hours) and non-teneral (age between 80 and 96 hours) glossina palpalis palpalis, g. p. gambiensis and g. morsitans morsitans with trypanosoma congolense il 1180. flies were infected once on a parasitaemic rat. teneral flies, both sexes indiscriminate, showed a procyclic and metacyclic infection rate respectively of 0.0588 and 0.7272 for g. p. palpalis; 0.0525 and 0.0416 for g. p. gambiensis; 0.6493 and 0.7300 for g ...19989754312
trypanosoma congolense infection of trypanotolerant n'dama (bos taurus) cattle is associated with decreased secretion of nitric oxide by interferon-gamma-activated monocytes and increased transcription of interleukin-10.the mechanisms whereby trypanotolerant n'dama cattle control infection with trypanosoma congolense are unknown. previous studies have suggested that the monocytes of n'dama cattle are more highly activated during infection than those of trypanosusceptible boran cattle. however, we have recently reported that the monocytes of boran cattle have a reduced capacity to secrete nitric oxide during trypanosome infection. we therefore evaluated the production of nitric oxide by monocytes of trypanotoler ...19989767609
effects of trypanosoma congolense and nutritional supplements in djallonké ewes on live weight during pregnancy, post partum weight, haematology parameters and lamb performance.the effects of trypanosoma congolense infection and nutritional supplements on live weight changes during pregnancy, haematology traits and offspring performance were studied in 42 djallonké ewes. a randomised block design was used to allocate ewes to four treatment combinations, of which two were on a restricted diet (l) and the remainder on an unrestricted diet (h). half of each nutritional group were infected with t congolense (li, hi), the remainder serving as controls (lc, hc). the degree o ...19989769075
susceptibility to trypanosomosis of three bos indicus cattle breeds in areas of differing tsetse fly challenge.studies to assess the differences in susceptibility to trypanosomosis among bos indicus cattle breeds (maasai zebu, orma boran and galana boran) were conducted under conditions of varying tsetse fly challenge at the nguruman escarpment in south-western kenya, for a period of 1 year. it was found that under tsetse challenge quantified as high, maasai zebu and orma boran were less susceptible than galana boran to trypanosome infections, as judged by the significantly lower incidence of infection, ...19989777722
in vitro and in vivo activities of trybizine hydrochloride against various pathogenic trypanosome species.trybizine hydrochloride [o,o'-bis(4,6-diamino-1,2-dihydro-2, 2-tetramethylene-s-triazine-1-yl)-1,6-hexanediol dihydrochloride] was active in vitro against the sleeping sickness-causing agents trypanosoma brucei subsp. rhodesiense and t. brucei subsp. gambiense; against a multidrug-resistant organism, t. brucei subsp. brucei; and against animal-pathogenic organisms trypanosoma evansi, trypanosoma equiperdum, and trypanosoma congolense; but not against the intracellular parasites trypanosoma cruzi ...19989797216
study of the effect of gamma-irradiation on bovine serum samples on the ability of monoclonal antibodies to detect invariant antigens of trypanosoma congolense, t. vivax and t. brucei in enzyme-linked immunosorbent assays.samples of bovine serum from uninfected and african trypanosomes-infected animals were tested before and after gamma-irradiation, using three sandwich enzyme-linked immunosorbent assays (elisa). each test system utilized a different monoclonal antibody, reputedly allowing the specific detection of conserved-invariant cytoplasmic antigens of trypanonosomes, t. congolense, t. vivax, and t. brucei, respectively. results have identified two groups of samples. the first contained samples where there ...19989806491
review of tsetse flies and trypanosomosis in south africa.the history of tsetse flies and nagana (trypanosomosis) in south africa, and especially in zululand, is reviewed. four valid tsetse fly species have been recorded from south africa. glossina morsitans morsitans disappeared from the most northerly parts of south africa during the rinderpest epizootic between 1896-1897. of the three remaining species that occurred in zululand, now part of kwazulunatal province, g. pallidipes was the most common vector of nagana in cattle, but was eradicated from t ...19989809324
experimental murine trypanosoma congolense infections. i. administration of anti-ifn-gamma antibodies alters trypanosome-susceptible mice to a resistant-like phenotype.the mechanisms regulating resistance or susceptibility to african trypanosomes have been enigmatic. in this study, we assessed the production of several cytokines (il-4, ifn-gamma, and tnf-alpha) in vivo and in vitro using genetically susceptible (balb/c) or resistant (c57bl/6) mice infected with cloned trypanosoma congolense and the role of these cytokines in pathogenesis of this infection. plasma of infected balb/c mice contained higher levels of il-4 and ifn-gamma than the plasma of infected ...19989820527
sensitivity and specificity of antigen-capture elisas for diagnosis of trypanosoma congolense and trypanosoma vivax infections in cattle.sensitivity and specificity of the fao/iaea antigen-elisa kits for diagnosis of bovine trypanosomosis were investigated using sera from experimental cattle infected by tsetse challenge with cloned populations of trypanosoma congolense (three populations) or t. vivax (one population). the kits are based on monoclonal antibodies that recognise internal antigens of tsetse-transmitted trypanosomes. ten cattle were infected with each trypanosome population for at least 60 days, and in combination wit ...19989823059
selection of susceptible and refractory lines of glossina morsitans centralis for trypanosoma congolense infection and their susceptibility to different pathogenic trypanosoma species.in a single generation of selection, two lines of glossina morsitans centralis were established that differed significantly in susceptibility to trypanosoma congolense clone il 1180. reciprocal crosses demonstrated that susceptibility was a maternally inherited trait. differences between the lines, to all phases of the trypanosome infection, were maintained for eight generations, whereas differences in susceptibility to midgut infections were maintained for twenty-eight generations. thereafter, ...19989824823
mechanical transmission of trypanosoma evansi and t. congolense by stomoxys niger and s. taeniatus in a laboratory mouse model.mechanical transmission of trypanosoma evansi (south american origin) and t. congolense of kilifi dna type (kenyan origin) was studied in laboratory mice using the african stable flies stomoxys niger niger and s. taeniatus. altogether, 355 flies were interrupted after feeding on infected blood and then transferred immediately to an uninfected mouse to complete feeding. microscopy and subinoculation of triturated flies into uninfected mice demonstrated the survival of t. congolense in stomoxys fo ...19989824826
determination of the disulfide bonds within a b domain variant surface glycoprotein from trypanosoma congolense.the disulfide bonds within a variant surface glycoprotein from trypanosoma congolense have been determined. l-[35s]cysteine metabolically labeled protein was digested with trypsin, and radiolabeled peptides were separated by reversed-phase high performance liquid chromatography, and putative cystine-containing peptides were subdigested with other proteases and analyzed after further purification by amino acid sequencing and mass spectrometry. all eight cysteine residues of the protein, located w ...19989829995
haematological changes and antibody response in trypanotolerant sheep and goats following experimental trypanosoma congolense infection.ten west african dwarf (wad) female goats and twelve djallonké ewes were artificially infected with a west african strain of trypanosoma congolense and monitored during 36 weeks over an acute phase (weeks 0-12) and chronic phase (weeks 13-36) to evaluate their haematological and immunological response. parasitaemia, packed cell volume, red blood cells, haemoglobin, white blood cells and trypanosomal antibodies were assessed. mean corpuscular volume and mean corpuscular haemoglobin concentration ...19989831952
experimental murine trypanosoma congolense infections. ii. role of splenic adherent cd3+thy1.2+ tcr-alpha beta- gamma delta- cd4+8- and cd3+thy1.2+ tcr-alpha beta- gamma delta- cd4-8- cells in the production of il-4, il-10, and ifn-gamma and in trypanosome-elicited immunosuppression.trypanosome-induced suppression of t and b cell responses to parasite-related and -unrelated ags is considered a major mechanism of evasion of the host's immune defenses by the parasite. reduced t and b cell responses have been attributed to suppressor t cells, suppressor macrophages, or both. we have previously shown that endogenously produced il-10 and ifn-gamma mediate the suppression of t cell responses in trypanosoma congolense-infected mice. here, we show for the first time that splenic cd ...19989834105
comparison and evolutionary analysis of the glycosomal glyceraldehyde-3-phosphate dehydrogenase from different kinetoplastida.in this work, we present the sequences and a comparison of the glycosomal gapdhs from a number of kinetoplastida. the complete gene sequences have been determined for some species (crithidia fasciculata, herpetomonas samuelpessoai, leptomonas seymouri, and phytomonas sp), whereas for other species (trypanosoma brucei gambiense, trypanosoma congolense, trypanosoma vivax, and leishmania major), only partial sequences have been obtained by pcr amplification. the structure of all available glycosoma ...19989847415
trypanosoma brucei ssp. and t congolense: mixed human infection in côte d'ivoire. 19989861372
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