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immunodepression in trypanosome-infected mice. vi. comparison of immune responses of different lymphoid organs.mitogen stimulation of cells from various lymphoid organs of c3h/he mice chronically infected with an isolate of trypanosoma congolense was studied at different time intervals after infection, using concanavalin a (con a) and lipopolysaccharide (lps). at the same time, changes in the percentages of t, b and null lymphocytes in these organs were determined by immunofluorescence staining. the responses of t and b lymphocytes in the spleen were totally depressed, and the cellular composition was dr ...19816452282
antigenic variation and the surface glycoproteins of trypanosoma congolense.two trypanosoma congolense variant-specific glycoproteins, which are expressed sequentially during a relapsing infection, have been purified. the proteins, termed vsg-1 and vsg-2, both have a molecular weight of 53,000 as determined by sds polyacrylamide electrophoresis. when either antigen is electrophoresed through a ph gradient on an isoelectric focusing (ief) gel, it gives a characteristic spectrotype of three bands. the ief components of each vsg are antigenically similar to each other but ...19816163660
trypanosoma congolense: surface glycoproteins of two early bloodstream variants. i. production of a relapsing infection in rodents. 19816168484
cultivation of infective forms of trypanosoma congolense from trypanosomes in the proboscis of glossina morsitans.two stocks of trypanosoma congolense were established in culture at 28 degrees c using trypanosomes from the proboscides of infective glossina morsitans. successful primary cultures were initiated by placing an infected tsetse proboscis beside a bovine dermal collagen explant in eagle's minimum essential medium supplemented with foetal calf serum. the trypanosomes multiplied rapidly in the medium and also gradually formed an adherent layer o the plastic surface of the culture vessel. three prima ...19817208105
a comparative evaluation of the parasitological techniques currently available for the diagnosis of african trypanosomiasis in cattle.the parasitological techniques currently in use for the diagnosis of african trypanosomiasis were compared in a series of experiments for their capacity to detect trypanosoma congolense, t. vivax and t. brucei in the blood of cattle. the darkground/phase contrast buffy coat method proved to be more sensitive than the haematocrit centrifugation technique, thick, thin and wet blood films in detecting t. congolense and t. vivax. on the other hand with t. brucei, mouse inoculation was the most sensi ...19826131590
immunosuppression in bovine trypanosomiasis: response of cattle infected with trypanosoma congolense to foot-and-mouth disease vaccination and subsequent live virus challenge.the primary and secondary antibody responses to foot-and-mouth disease virus vaccine were examined in cattle infected with trypanosoma congolense and the response of some of these animals to live foot-and-mouth disease virus challenge was assessed. infected groups of cattle had rather lower antibody responses than uninfected control cattle after primary vaccination but the antibody titres were not significantly depressed until after secondary vaccination. these levels remained depressed for the ...19826285433
trypanosoma congolense: surface glycoproteins of two early bloodstream variants. iii. immunochemical characterization. 19827056338
early events following challenge of cattle with tsetse infected with trypanosoma congolense: development of the local skin reaction.a local skin reaction (chancre) was elicited in susceptible cattle after the successful feeding of glossina morsitans morsitans infected with one of two different cloned isolates of trypanosoma congolense. the chancre first appeared as a small 2 to 3 mm nodule at the site of the challenge as early as day 5 and reached maximum activity by days 10 to 13 when it had developed into a raised, indurated, hot, painful swelling measuring up to 100 mm in diameter. thereafter it declined in size and activ ...19827072104
immune depression in african trypanosomiasis: the role of antigenic competition.the capacity of trypanosome-infected cattle to mount an immune response to a simultaneous or subsequent challenge with other trypanosomes was investigated using various clones of trypanosoma congolense and t. brucei. in animals infected simultaneously with equal numbers of trypanosomes of two different clones, the variant-specific antibody response to one clone was severely depressed while the response to the other was not affected. in cattle infected with one clone and then subsequently challen ...19827075022
inheritance of susceptibility to trypanosoma congolense infection in glossina morsitans. 19827092373
trypanosoma congolense: thrombocyte survival in infected steers. 19827095072
the susceptibility of glossina palpalis palpalis at different ages to infection with trypanosoma congolense. 19827103580
cultivation of procyclic trypomastigotes of trypanosoma congolense in a semi-defined medium with direct adaptation from bloodstream forms.bloodstream forms of trypanosoma congolense added to the semi-defined medium 109-c (minimum essential medium with earle's salts, 60 mm hepes, haemin, and heat-inactivated fbs) and incubated at 28 degrees c transformed into procyclic trypomastigotes. established cultures of the procyclic forms yielded up to 4.5 x 10(7) parasites/ml. the cultivated populations consisted only of trypomastigotes and were not infective for mice. the amino acids consumed to the greatest extent were glutamine, proline, ...19827113354
ethidium bromide: pharmacokinetics and efficacy against trypanosme infections in rabbits and calves.[14c]ethidium bromide has been used to determine drug levels in tissues and body fluids of rabbits and calves following intramuscular injection. uninfected and trypanosoma brucei- or trypanosoma congolense-infected animals were studied. blood and tissue fluid level reached a maximum with 1 h and then fell rapidly; after 96 h 80-90% of the radioactivity injected had been excreted, approximately one third in urine and two thirds in faeces. by 1 h after injection of 1 mg [14c]ethidium/kg into a t. ...19827122121
interference in the establishment of superinfections with trypanosoma congolense in cattle.to examine the influence of an established infection on subsequent challenge with another unrelated trypanosome serodeme, cattle were subjected to two challenges, 5 to 6 wk apart, with unrelated isolates of trypanosoma congolense. the primary infection inhibited the establishment of the second infection despite the initial absence of detectable antibody to the trypanosomes used for the second challenge. this was true whether the second challenge consisted of bloodstream forms of the parasite or ...19827131183
in vitro phagocytic activity of neutrophils of various cattle breeds with and without trypanosoma congolense infection.a simple in vitro-technique using latex beads was used for the investigation of the phagocytic activity of neutrophils in bovines of different breeds, infected and non-infected with t. congolense. it was found that the n'dama, assumed to be trypanotolerant, have a significantly higher number of neutrophils and neutrophils with phagocytic activity per mm3 blood, compared to the more susceptible zebu, the baoulé and the crossbreed m75, ranging between these two breeds. the first appearance of t. c ...19827135473
cytotoxic effect of unilamellar detergent dialysis liposomes on trypanosoma brucei and trypanosoma congolense bloodstream forms in vitro. 19827138525
activation of the alternative pathway of bovine complement by trypanosoma congolense.homogenates of trypanosoma congolense and particulate and supernatant fractions thereof were, by two different techniques, shown to activate bovine complement via the alternative pathway. (1) all three preparations converted complement factor bbov to its split product b gamma 2 as demonstrated (a) qualitatively by immunoelectrophoresis and (b) quantitatively by radial immunodiffusion. (2) lysis of guinea-pig erythrocytes by bovine complement via the alternative pathway was inhibited by whole hom ...19827145463
purification of trypanosoma brucei variable surface glycoproteins: analysis of degradation occurring during isolation.trypanosoma brucei variable surface glycoproteins (vsgs), isolated from some antigenic types of trypanosomes, degraded during isolation. we show that this degradation occurred immediately after breakage of the organism, presumably because of liberation of internal enzymes, and resulted in heterogeneity of isolated vsgs with respect to charge and/or molecular weight. degradation and consequent heterogeneity of these vsgs could be abolished by releasing vsg from the trypanosome surface without bre ...19827177702
curative effect of alpha-difluoromethylornithine on fatal trypanosoma congolense infection in mice.the curative effect of alpha-difluoromethylornithine (dfmo) on fatal t. congolense infection in mice was investigated using various concentrations administered orally in drinking water. permanent cure was achieved in mice receiving 4% for 3 days or 2% for 5 days. mice receiving less became parasitemic again but then, without any further treatment, resisted death due to trypanosomes for an average of 34.5 days, while untreated controls were dead within 8 days after trypanosomes were first seen in ...19826814025
the response of the murine lymphoid system to a chronic infection with trypanosoma congolense. ii. the lymph nodes, thymus and liver. 19826752363
study on a proteolytic enzyme from trypanosoma congolense. purification and some biochemical properties.a protease has been purified from trypanosoma congolense bloodstream forms by osmotic disruption, freeze-thawing of the cells, followed by chromatography using thiopropyl-sepharose and gel filtration. the enzyme is a thiolprotease. a combination of sds-polyacrylamide gel electrophoresis and contact print zymograms using casein as substrate showed a single proteolytic band with a molecular weight of 31 000. the isoelectric point of the enzyme as ascertained by isoelectric focusing extended from p ...19826755218
partial protection of rats against trypanosoma congolense by passive transfer of igm. 19826891856
the effect of double infections with trypanosomes and gastrointestinal nematodes on the productivity of sheep and goats in south mozambique.the effect of simultaneous infections with trypanosomes (trypanosoma vivax and trypanosoma congolense) and gastrointestinal nematodes on the productivity of sheep and goats was studied in 20 animals (6 male goats and 14 male sheep) at a farm near maputo. the animals were divided into 4 groups which received either treatment against gastrointestinal nematodes, or against trypanosomes, or treatment against both, or no treatment at all. in two-weekly and later in weekly intervals body weight, packe ...19826892177
immune mechanisms in c57bl mice genetically resistant to trypanosoma congolense infection. i. effects of immune modulation.the effect of immune modulation on the pattern and course of infection with t. congolense was investigated in a strain of mice (c57bl) which is known to possess a significant degree of trypanotolerance, and a susceptible strain (cflp) which rapidly succumbs to infection. immunosuppression of c57bl mice by splenectomy, cyclophosphamide treatment or gamma irradiation reduced their survival to near that of susceptible strains of mice. in contrast, attempts to enhance the immune response of suscepti ...19836828326
the susceptibility of gamma-irradiated glossina palpalis palpalis at different ages to infection with trypanosoma congolense. 19836859970
the effect of trypanosoma congolense infection on acquired immunity to the tick rhipicephalus appendiculatus. 19836882069
congenital transmission of trypanosoma congolense in mice.pregnant mice were infected with a strain of t. congolense which produces a chronic infection, to determine if congenital infection can occur. some of the mice were killed before delivery and tissues of foetuses injected into clean male mice. other mothers were allowed to deliver and the tissues of some of the 1-day-old young inoculated into male mice while the remaining members of each litter were suckled by the infected mother until weaning. some but not all males infected from foetuses and 1- ...19836886090
antibody levels during bovine hemoparasitic diseases: trypanosomiasis, anaplasmosis, and babesiosis. 19836399967
immune depression in bovine trypanosomiasis: effects of acute and chronic trypanosoma congolense and chronic trypanosoma vivax infections on antibody response to brucella abortus vaccine.cattle were vaccinated with brucella abortus (s19) vaccine during acute (25 days) and chronic (25 weeks) trypanosoma congolense and chronic trypanosoma vivax (25 weeks) infections in order to determine the effect of such infections on the antibody response to the vaccine. it was found that the specific antibody responses of igg1 and igg2 sub-classes were profoundly depressed (80%) in both the acute and chronic infections with t. congolense. whereas igm antibody response was also profoundly depre ...19836408588
comparative aspects of purine metabolism in some african trypanosomes.some enzymes of purine salvage were detected in the cell-free preparations from bloodstream forms of african trypanosomes: trypanosoma vivax; t. brucei and t. congolense. extracts of trypanosomes cleave adenosine and inosine hydrolytically except in t. congolense where adenosine cleavage was mediated by a phosphorylase. all the trypanosomes apparently lacked adenosine deaminase. adenine aminohydrolase was found only in t. vivax while adenosine monophosphate deaminase was detected in t. brucei an ...19836419098
rat liver glucose-6-phosphate dehydrogenase isozymes: influence of infection with trypanosoma.glucose-6-phosphate dehydrogenase (g6pd) changes were studied in livers of rats inoculated with trypanosoma lewisi, trypanosoma rhodesiense, trypanosoma congolense and trypanosoma brucei. marked increases in g6pd were directly related to the degree of parasitemia. no essential differences in g6pd levels were seen in animals inoculated with physiological saline when compared with uninoculated controls. elevation of g6pd was observed only from day 10 to 20 in rats inoculated with t. lewisi. after ...19836349921
improved field diagnostic technique for trypanosomiasis by use of a minicentrifuge. 19836356572
specific antibody responses to the variable surface glycoproteins of trypanosoma congolense in infected cattle.sera from cattle infected with three trypanosoma congolense clones (ilnat 2.1, ilnat 3.1 and ilrad 588) derived from different stocks were analysed for the presence of specific antibodies against the surface glycoproteins (vsgs) of the infecting trypanosomes using the solid and liquid-phase radioimmunoassays and the neutralization of infectivity test. high levels of igm, igg1 and igg2 antibodies against the vsgs of the infecting variable antigen types (vats) as well as other vats that arose duri ...19836622055
alternative pathway activation of complement by african trypanosomes lacking a glycoprotein coat.an in vitro culture trypanosoma congolense cell line was established using the mammalian cell feeder layer system. one of the principle characteristics of this parasite was its ability to multiply in culture at 35 degrees c, as an uncoated trypanosome (lacking a glycoprotein surface coat) unlike the original blood stream form from which it was derived. this trypanosome was lysed when incubated in normal human serum in contrast to the parasite which possessed a surface coat. the lytic reaction as ...19836634218
observation on drug resistance of trypanosoma (nannomonas) congolense and trypanosoma (duttonella) vivax in cattle at a feedlot in the northern ivory coast.studies carried out on feedlot cattle show berenil at 7 mg/kg to be the treatment of choice in trypanosomiasis although repeated doses may be necessary. resistant strains of trypanosoma (duttonella) vivax and trypanosomas (nannomonas) congolense survived dosages of between 0.5 mg/kg and 1.0 mg/kg of trypamidium and were cross resistant to homidium bromide.19836636303
studies in rabbits on the disposition and trypanocidal activity of the anti-trypanosomal drug, diminazene aceturate (berenil).after intramuscular injection of 3.5 mg kg-1 to rabbits, diminazene aceturate shows biphasic pharmacokinetics with maximum blood and interstitial fluid concentrations occurring after 15 min and 3 h respectively. seven days after treatment, 40-50% of the dose had been excreted in the urine and 8-20% in faeces. highest diminazene residues were determined in liver: 7 days after dosage, residues of 40.53 +/- 4.00 micrograms g-1 were present, corresponding to 35-50% of the dose. the recommended dose ...19836652366
natural agglutinins to african trypanosomes.agglutinins to uncoated culture forms of the african trypanosomes, t. congolense and t.b. brucei were detected in sera from a variety of mammals not exposed to the parasites. the agglutinins in bovine serum were shown to be specific antibodies with opsonic properties selective for the species of trypanosome. these findings suggest a possible role for the glycoprotein coat in preventing access of cross-reacting antibodies to the plasma membrane of african trypanosomes.19836657292
interference with anti-trypanosome immune responses in rabbits infected with cyclically-transmitted trypanosoma congolense.rabbits were infected with two clones of antigenically distinct stocks of trypanosoma congolense transmitted through glossina morsitans. local skin reaction development and the appearance of neutralizing antibodies were followed in animals infected with one or other of the trypanosome stocks, with both stocks simultaneously or with both stocks consecutively. there was little difference in local skin reaction development on rabbits infected with a single stock or with both stocks simultaneously b ...19836657293
immune mechanisms in c57b1 mice genetically resistant to trypanosoma congolense infection. ii. aspects of the humoral response.some aspects of the humoral response in trypanotolerant c57b1 mice and susceptible a/j mice were investigated to determine the possible basis of trypanotolerance. when the hepatic uptake of 75se-labelled t. congolense by infected mice was measured as an index of antibody production, it was found that only c57b1 mice could remove circulating labelled parasites, this ability persisting for several weeks after infection. estimation of the immunoglobulin concentrations in both strains of mice showed ...19836657296
enzyme polymorphism and the distribution of trypanosoma congolense isolates.conditions were established for demonstrating, by electrophoresis, polymorphism in 12 soluble enzymes from trypanosoma congolense. three enzymes had identical mobilities in every stock, variation occurring among the remaining nine. enzyme profiles were determined in 78 stocks collected from various hosts in a number of african countries, and were used by the computer to establish relationships within the collection. the major groupings formed solely from the isoenzymes corresponded remarkably cl ...19836660953
infection, immunity and the development of local skin reactions in rabbits infected with cyclically-transmitted stocks of trypanosoma congolense.the development of local skin reactions following bites by tsetse flies (glossina morsitans) infected with trypanosoma congolense was observed in normal rabbits, in rabbits with concurrent infections with t. congolense and in rabbits challenged after immunization by infection and treatment. local reactions developed in normal rabbits within seven days of fly bite and were resolved by approximately 19 days after infection. in rabbits with concurrent infections no typical local reactions developed ...19836660964
increase in jugular circulation of trypanosoma congolense in infected calves caused by effective trypanocides. 19836681919
effect of trypanocides on jugular concentration of trypanosoma congolense in the west african dwarf sheep.the effects of various trypanocides on parasitaemia was investigated in sheep experimentally-infected with trypanosoma congolense strain 58/98. intravenous injection of berenil at the height of the first parasitaemic wave increased jugular parasite concentration by 12 and 16 times at the 9th and 20th minute post-treatment, respectively. with pentamidine, maximum counts were 5.0-8.6 times zero-time concentration during the same periods. peak effects of samorin, novidium and ethidium were observed ...19836686383
trypanosoma congolense: susceptibility of cattle to cyclical challenge.cattle primed by cyclical infection with glossina morsitans morsitans infected with cloned derivatives of trypanosoma congolense and treated with the trypanocidal drug berenil after 3 or 4 weeks were immune to cyclical challenge with homologous clones 3 to 5 weeks later. in these animals, localized skin reactions (chancres) and parasitemia did not develop. the same results were obtained in cattle given a homologous superinfection without prior treatment. on the other hand, cattle subjected to a ...19836133773
a simple classification of different types of trypanosomiasis occurring in four camel herds in selected areas of kenya.camels from herds in four different areas of kenya were sampled at regular intervals over periods of 9-15 months and examined for the presence of trypanosomiasis. five hundred and eight camels divided into three age categories were studied. trypanosomiasis caused by t. evansi, t. brucei and t. congolense was shown to be present in varying degrees in all the herds. camels were divided into 5 types according to mortality, the presence or absence of circulating trypanosomes and antibody, and the pr ...19836141655
a quantification of the risk of trypanosomiasis infection to cattle on the south kenya coast.the number of trypanosome-infected bites received by cattle grazed around an 8 ha area of forest harbouring a semi-isolated population of glossina pallidipes austen was estimated. the absolute size of the tsetse population was determined by mark-release-recapture techniques, the tsetse host range by the identification of blood-meals, and trypanosome infection rates by dissection of samples of tsetse. feeding frequency was estimated and the number of cattle present was known. it was estimated tha ...19836142631
reverse transcription of trypanosome variable antigen mrnas initiated by a specific oligonucleotide primer.african trypanosomes change their antigenicity by successively expressing different members of a group of related but highly diverse proteins, the variant surface glycoproteins (vsgs). we describe a synthetic oligonucleotide that can prime specifically reverse transcription of vsg mrna out of total trypanosome poly(a)+ rna. the specificity of this priming was verified by cdna sequence analysis of the transcription products and by the demonstration of variant-specific hybridization of the individ ...19836188156
all metacyclic variable antigen types of trypanosoma congolense identified using monoclonal antibodies.vaccination against the tsetse-borne trypanosomiases has proved impossible because of the trypanosome's ability to generate a seemingly inexhaustible number of variable antigen types in the blood or tissues of the host. each variable antigen is a glycoprotein which forms a surface coat on the trypanosome and each glycoprotein is the product of a single gene. the full repertoire of such antigens has not been identified for any trypanosome serodeme (genotype) as yet, but the number of genes coding ...19836196642
capacity of a cis-diammineplatinum[ii]-polyglutamic acid complex to cure trypanosoma congolense infections in mice.a cis-diammineplatinum(ii)-polyglutamic acid complex proved to have marked trypanocidal activity in vivo. when 5 mg of platinum per kg was administered daily for 5 days or when 20 mg of platinum per kg was administered on days 1, 3, and 6, five of five treated trypanosoma congolense-infected mice were cured. in contrast, cis-platin was ineffective at all doses tested. we believe that the complex has a much higher therapeutic ratio than does uncomplexed drug because it is less toxic.19846201136
common and isolate-restricted antigens of anaplasma marginale detected with monoclonal antibodies.anaplasma marginale-infected erythrocytes were examined for the presence of maturation, isolate-restricted, and isolate-common antigens by indirect immunofluorescence with monoclonal antibodies. a panel of 18 monoclonal antibodies was used; none of the antibodies reacted with anaplasma ovis, babesia bigemina, babesia bovis, trypanosoma brucei, trypanosoma congolense, or uninfected bovine erythrocytes. antigens common to all six a. marginale isolates were detected by nine antibodies. single isola ...19846205996
trypanosoma vivax, t. congolense or t. brucei infection rates in glossina morsitans when maintained in vitro on the blood of goat or calf.tenerals of glossina morsitans morsitans and g. m. centralis were infected with trypanosoma vivax, t. congolense or t. brucei by feeding mainly on infected goats and then maintained either in vivo on uninfected calves, goats or rabbits, or fed in vitro upon heparinised or defibrinated blood of goats or calves for 21 days for t. vivax and t. congolense and 30 days for t. brucei and then dissected. the observed differences in the infection rates for all three trypanosome species maintained on diff ...19846143482
cerebral trypanosomiasis in cattle with mixed trypanosoma congolense and t. brucei brucei infections.six boran steers were infected simultaneously with trypanosoma congolense and t. brucei brucei while another group of 3 was inoculated with t. b. brucei one year after infection with t. congolense. three further steers were infected with t. b. brucei alone. whereas, the six animals which received simultaneous infections developed clinical signs of cerebral trypanosomiasis as evidenced by depression, ataxia and occasional circling, those infected with t. b. brucei alone did not. at necropsy, 4 ou ...19846150618
the appearance of isometamidium resistant trypanosoma congolense in west africa.the frequent reappearance of patent parasitemia, mainly trypanosoma congolense, in cattle maintained under isometamidium prophylaxis in the upper volta indicated that drug-resistant forms might be appearing. to investigate this possibility, trypanosome stocks were isolated in mice, their isometamidium sensitivity estimated and compared to that of stocks isolated before drug use was widespread. most t. congolense stocks isolated in 1982-1983 were 4-8 times less sensitive to isometamidium than tho ...19846150619
maintenance of glossina morsitans morsitans on antiserum to procyclic trypanosomes reduces infection rates with homologous and heterologous trypanosoma congolense stocks.three experimental groups of male glossina morsitans morsitans were infected at their first feed with procyclic forms of different stocks of trypanosoma congolense and subsequently maintained on a diet containing rabbit antiserum to one of these stocks. control flies were similarly infected but were then maintained on normal rabbit serum. dissection of the flies 19-21 days post infection showed a reduction in both immature and mature infection rates in all groups fed on antiserum by comparison w ...19846150620
in vitro cultivation of trypanosoma congolense: the production of infective metacyclic trypanosomes in cultures initiated from cloned stocks.glossina morsitans were infected with two cloned stocks of t. congolense. the proboscides, foreguts and midguts of infected flies were then used as sources of trypanosomes in vitro at 28 degrees c in the presence of bovine dermal collagen explants. cultures were established in which trypanosomes differentiated into adhering colonies of epimastigote forms which could then be maintained and subcultured in eagle's minimum essential medium supplemented with foetal calf serum for over 40 weeks. withi ...19846152116
resistance of cattle to tsetse-transmitted challenge with trypanosoma brucei or trypanosoma congolense after spontaneous recovery from syringe-passaged infections.groups of cattle were inoculated intravenously with cloned populations of bloodstream forms of trypanosoma brucei or trypanosoma congolense. all five steers infected with t. brucei iltat 2.1 and six of the eight steers infected with t. congolense il 13-e14 became aparasitemic within 16 and 32 weeks postinfection, respectively. examination of sera from animals infected with t. brucei by indirect immunofluorescence and neutralization assays revealed the presence of antibodies against all the metac ...19846693173
serum factors and the maturation of trypanosoma congolense infections in glossina morsitans.removal of certain components from pig or cow blood greatly reduces the maturation rate of trypanosoma congolense infections in glossina morsitans fed on such diets. in particular, delipidation of serum has the same effect as complete removal of dietary serum with few midgut infections reaching maturity. the addition of gamma-globulin to red cells partially restores the ability of immature infections to transform suggesting that serum lipids or other serum factors are not acting directly on midg ...19846695534
sequences homologous to variant antigen mrna spliced leader in trypanosomatidae which do not undergo antigenic variation.trypanosomes which parasitize mammals have evolved mechanisms to evade immune attack, such as the occupation of 'safe' intracellular sites (for example, trypanosoma cruzi), or antigenic variation, exemplified by the salivarian trypanosomes (for example, trypanosoma brucei). antigenic variation is mediated by sequential expression of single variant surface glycoprotein (vsg) genes, and often involves transposition of the active gene. every vsg transcript examined shares the same 5' terminal 35-nu ...19846709074
the role of antibody and complement in the cellular response to trypanosoma congolense.the in vitro cytotoxic response of bovine granulocytes and monocytes and of murine peritoneal macrophages against trypanosoma congolense in the presence of antibody, antibody plus complement or complement alone was assessed using luminol aided chemiluminescence as a second parameter for effector cell activation. neither cell type exhibited any trypanolysis exceeding that of antibodies and complement alone. the kinetics of the chemiluminescence response in the course of these reactions closely co ...19846713731
trypanosoma congolense: genetic control of resistance to infection in mice.primary isolates of trypanosoma congolense show a range of virulence in nmri mice. stabiliates derived from an isolate (dinderesso/80/crta/3) which showed moderate virulence in most nmri mice (moderate parasitemia and survival) were used in inbred mice. c57bl/6 were resistant with low parasitemia and survival. parasitemias were higher in males than females. balb/c were the most sensitive of the strains tested and died with fulminating parasitemia. inheritance of resistance, defined as low parasi ...19846714359
growth of trypanosoma brucei gambiense, t. b. rhodesiense, and t. congolense in bone marrow cultures of genetically anemic sl/sld mice. 19846737165
glycosyltransferase activities in golgi complex and endoplasmic reticulum fractions isolated from african trypanosomes.highly enriched golgi complex and endoplasmic reticulum fractions were isolated from total microsomes obtained from trypanosoma brucei, trypanosoma congolense, and trypanosoma vivax, and tested for glycosyltransferase activity. purity of the fractions was assessed by electron microscopy as well as by biochemical analysis. the relative distribution of all the glycosyltransferases was remarkably similar for the three species of african trypanosomes studied. the golgi complex fraction contained mos ...19846746739
structural studies on the major oligosaccharides in a variant surface glycoprotein of trypanosoma congolense.the carbohydrate moieties in the four isotypes of a variant surface glycoprotein from trypanosoma congolense were analyzed. all variant surface glycoprotein isotypes were found to contain up to 15% by weight of d-galactose, d-mannose, and n-acetyl-d-glucosamine in molar ratios approaching 1:3.2:3.9 (isotypes i-iii) or 1:2.4:2.4 (isotype iv); in addition, the presence of sialic acid could be demonstrated. after metabolic labelling with d-[6-3h]glucosamine, the four isoglycoproteins were successiv ...19846749184
comparison of blood smear and indirect fluorescent antibody techniques in detection of haemoparasite infections in trade cattle in nigeria.the incidence of blood parasites in trade cattle was surveyed with emphasis on tick-borne parasites, using blood smears and immunofluorescent antibody (ifa) techniques. with the blood smear method, about 9 and 8.9% of cattle examined were found positive for babesia bigemina and anaplasma marginale, respectively. percentage infections with other parasites were 3.33, 1.92, 0.75, 0.75 and 0.58, respectively, for babesia bovis, trypanosoma brucei, anaplasma centrale, eperythrozoon and theileria spec ...19846369761
experimental trypanosoma (nannomonas) congolense infection in microtus montanus.seventy-two voles (microtus montanus) were infected with a strain of trypanosoma congolense of low virulence in mice to study their susceptibility and value as a tool for testing chemotherapeutic agents. the infection in microtus was highly virulent. parasitaemia was low to moderate. significant spleen and body weight changes were observed. blood capillaries of the heart, brain, kidneys and lungs were markedly dilated and numerous parasites were present in the dilatations, particularly in the he ...19846383235
in vitro studies on the biosynthesis of the surface glycoprotein of trypanosoma congolense.tritiated leucine, glucosamine, mannose, and galactose were incorporated into the variant specific surface glycoprotein (vsg) of trypanosoma congolense in vitro. the uptake of the precursors is shown by sds-polyacrylamide electrophoresis and fluorography, by assay of the radioactivity in immunoprecipitates obtained with specific antisera, and by the isolation of the labeled antigens by affinity chromatography on concanavalin a-sepharose and isoelectric focusing. the in vitro labeled vsg exhibits ...19846470988
continuous cultivation of animal-infective bloodstream forms of an east african trypanosoma congolense stock. 19846486939
studies on the influence of non-steroidal anti-inflammatory drugs upon trypanosomiasis in goats and sheep.the non-steroidal anti-inflammatory drug (nsaid) flurbiprofen caused a rise in parasitaemia in goats infected with trypanosoma vivax, trypanosoma congolense and trypanosoma brucei. all trypanosome-infected goats treated with flurbiprofen showed many dividing trypanosomes. this also included the short-stumpy forms of t. brucei. in t. vivax-infected goats flurbiprofen treatment resulted in 100% mortality in the acute and chronic stages of the infection. the increase in parasitaemia of t. brucei in ...19846512919
[parasitological, clinical and serological findings in dahomey cattle experimentally infected with trypanosoma congolense and t. brucei]. 19846525154
a special case of trypanosoma congolense infection produced in laboratory mice. 19846527201
detection of circulating trypanosomal antigens by enzyme immunoassay.antisera raised against trypanosoma evansi and t. congolense were used in a double antibody sandwich enzyme immunosorbent assay (elisa) to detect trypanosomal antigens in sera from experimentally infected rabbits and goats. assays quantitated using reference antigen preparations and the homologous antisera showed that antigens could be detected at protein concentrations of 1.5 microgram ml-1. the antisera also cross-reacted with soluble antigens prepared from t. brucei and t. vivax at similar pr ...19846532328
[probable number of trypanosoma (nannomonas) congolense transmitted by glossina morsitans]. 19846544954
[demonstration of resistance to trypanocides among the species of trypanosoma congolense recently isolated in burkina]. 19846544959
a calcium dependent endoribonuclease from trypanosoma congolense cytoplasm.a major endoribonuclease whose activity depends on the presence of calcium ions was isolated from the cytoplasm of trypanosoma congolense. like the ca2+-dependent endoribonuclease of t. brucei cytoplasm, this enzyme degraded poly(a) preferentially but also degraded to a lesser extent poly(u), trna and rrna to give 5'-phosphoribosyl oligonucleotides. neither enzyme hydrolyzes poly(g) or dna. both ribonucleases are inhibited by polyanions and heavy metal ions, and are heat-labile; n-ethylmaleimide ...19846431285
trypanosoma (nannomonas) congolense: analysis by fluorescein-conjugated plant lectins of surface saccharides of cloned variant antigen types differing in infectivity for mice.surface saccharides of 4 cloned vats (variant antigen types) of trypanosoma (nannomonas) congolense, amnats (amherst nannomonas antigen types) 1.1, 1.2, 2.1, and 3.1, derived from 3 different stocks, were compared by fluorescein-conjugated, plant lectins using a quantitative fluorescence method. it was ascertained by the id63 assay that the 4 amnats differed in their infectivity for mice. the lectins employed for amnats 1.1, 2.1, and 3.1 were concanavalin a (con a), wheat germ agglutinin (wga), ...19846439842
comparison of the levels of autofluorescence caused by fixatives in fluorescence assay on trypanosomes. 19846441838
the role of humoral immune responses in determining susceptibility of a/j and c57bl/6 mice to infection with trypanosoma congolense.the relative resistance of c57bl/6 mice to infection with trypanosoma congolense as compared to a/j mice was found to be independent of the infective dose of trypanosomes and required an intact immune system, as sublethal levels of gamma irradiation abolished the differences in susceptibility between the two strains. c57bl/6 mice produced earlier and quantitatively superior antibody responses both to the variable surface glycoprotein and to common membrane antigens on the trypanosome than a/j mi ...19853991236
extrachromosomal inheritance of susceptibility to trypanosome infection in tsetse flies. i. selection of susceptible and refractory lines of glossina morsitans morsitans.differences in susceptibility to infection with trypanosoma congolense between f1 families of glossina morsitans morsitans indicated that susceptibility is maternally inherited in this species of tsetse fly. twelve f1 families, six selected for susceptibility and six selected for refractoriness to infection, have been bred for up to 13 generations. the reciprocal differences demonstrated in the f1 generation persisted in these selected families over many generations, indicating that susceptibili ...19854026443
suppression of trypanosoma congolense, t. vivax and t. brucei infection rates in tsetse flies maintained on goats immunized with uncoated forms of trypanosomes grown in vitro.significant suppression in the incidence of cyclical development of trypanosoma congolense, t. vivax and t. brucei occurred in glossina morsitans centralis maintained on goats immunized with in vitro-propagated uncoated forms of t. congolense, t. vivax and t. brucei, respectively. this was observed when tsetse given a t. congolense-infected feed were subsequently maintained on uninfected immunized goats and also when uninfected tsetse were fed on immunized goats infected with t. congolense, t. v ...19854034247
effects of vasopressor drugs on number of trypanosoma congolense in ruminant blood.the effects of intravenous administration of vasopressor drugs on parasite concentration was studied in cows and sheep infected with trypanosoma congolense. ephedrine (usp), adrenaline (bp) and insulin increased jugular concentration of the parasite. maximum effects were reached between 1 1/2 and 2 h with ephedrine and at 2 1/2-3 h with adrenaline. increases in parasitaemia resulting from epinephrine were sustained only in sheep and adrenaline gave similar effects in both ruminants. only epineph ...19854039866
association between intracellular rickettsial-like infections of midgut cells and susceptibility to trypanosome infection in glossina spp. 19854050033
susceptibility of different breeds of goats in kenya to experimental infection with trypanosoma congolense.to assess whether there was any evidence of genetic resistance to african trypanosomiasis, five breeds of goat (east african, galla, and crossbreds between east african and galla, nubian or toggenburg) were experimentally infected with trypanosoma congolense either by needle inoculation or by tsetse-transmission. the goats had not been previously exposed to trypanosomiasis. with both methods of infection all breeds were found to be highly susceptible and suffered severe disease. following tsetse ...19854060238
comparison of the effects of african trypanosomiasis in four breeds of dairy goats.the consequences of experimental infection with trypanosoma congolense and later superinfection with t brucei were compared among four breeds of goats: toggenburg, nubian, alpine and saanen. no major differences were found with regard to packed cell volume, bodyweight or parasitaemia. when these four breeds were considered for introduction into areas having african trypanosomiasis, none appeared to have a comparative advantage with regard to innate resistance to trypanosomes.19854070793
west african dogs as a model for research on trypanotolerance.autochthonous dogs from liberia/west africa were reared trypanosome-free and brought to west berlin/germany. together with beagle dogs they were infected cyclically by tsetseflies with trypanosoma congolense. while the european dogs died soon of the trypanosomal infection, the african dogs developed milder parasitaemias and remained clinically unaffected. the authors' opinion is, that this dog model could make a contribution to research on trypanotolerance.19854089479
trypanosoma (nannomonas) congolense: identification of two karyotypic groups.orthogonal-field-alternation gel electrophoresis and dna blot hybridizations have been used to investigate the genomic relationships among trypanosome clones of subgenus nannomonas. the results indicate that trypanosoma (nannomonas) congolense comprises at least two distinct groups of parasites that differ in both molecular karyotype and repetitive dna sequences. a description of these two groups and their distinction from trypanosoma (nannomonas) simiae is presented.19854092683
survival and reproductive performance of female glossina morsitans morsitans when maintained on livestock infected with salivarian trypanosomes. 19854096568
kinetoplast dna from trypanosoma vivax and t. congolense.we have analysed kinetoplast dna (kdna) of the african trypanosomes trypanosoma vivax and t. congolense. the maxi-circles from these organisms resemble those of t. brucei in size, but only to a limited extent in sequence as judged from restriction enzyme digests and dna x dna hybridization. the kdna networks of t. vivax have three distinguishing features: they contain the highest maxi-circle concentration of any kdna (at least twice that of t. brucei); they contain the smallest mini-circles (465 ...19852989683
in vitro cultivation of trypanosoma congolense: establishment of infective mammalian forms in continuous culture after isolation from the blood of infected mice.bloodstream form trypomastigotes of four cloned stocks of trypanosoma congolense from west africa were successfully adapted to continuous in vitro culture at 28 degrees c using bovine aorta endothelial cell monolayers and eagle's minimum essential medium supplemented with 20% normal bovine serum or foetal calf serum. the trypanosomes maintained in vitro morphologically resembled bloodstream forms and remained infective for vertebrate hosts. they also induced local skin reactions in rabbits and w ...19852862772
influence of the salmon mutant of glossina morsitans morsitans on the susceptibility to infection with trypanosoma congolense.four phenotypes of a sex-linked, maternally influenced semi-lethal eye color mutant of glossina morsitans morsitans westwood were fed on trypanosoma congolense broden infected guinea pigs. infection rates were evaluated 25 days later by means of dissection. procyclic as well as mature infections were significantly more common among females with salmon-colored eyes (sal/sal) than among heterozygous (+/sal, phenotypically wild-type) females. a tendency was found for more mature infections among sa ...19852862776
in vitro cultivation of trypanosoma congolense: the production of infective forms from metacyclic trypanosomes cultured on bovine endothelial cell monolayers.after transfer to bovine endothelial cell monolayers cultured in eagle's minimal essential medium at 28 degrees c or 37 degrees c metacyclic trypanosomes of three cloned stocks of trypanosoma congolense became morphologically similar to parasites found in the bloodstream of the vertebrate host. the trypanosomes resumed division and grew in close association with the mammalian cells, which were essential for growth. these dividing infective forms had the ability to cause local skin reactions and ...19852862783
the probability of tsetse acquiring trypanosome infection from single blood meal in different localities in kenya.the probability of tsetse, glossina pallidipes, acquiring a trypanosome infection from a single blood meal was estimated in five localities on the kenya coast which were selected for differences in habitat and host availability. the probability that one blood meal contained infective trypanosoma congolense was 0.0077 in rural areas with domestic animals, 0.0019 in extensive areas of natural habitat with wild hosts and 0.0013 in an area with domestic animals under regular chemoprophylaxis. the re ...19852865875
isolation and cell-free synthesis of variant surface glycoproteins from trypanosoma congolense.two trypanosoma congolense stocks, 1/148 fly and treu 921, were cloned in a/j strain mice immunosuppressed with cyclophosphamide. the cloned populations, amnat 1.1 and amnat 3.1, each characterized by a different variant antigen type, were checked for homogeneity by the indirect fluorescent antibody test using 6-day antisera developed in rabbits. the variant surface glycoproteins (vsgs) from both amnat clones were purified to homogeneity. electrophoresis on sodium dodecyl sulfate (sds)-polyacryl ...19852412115
cloning and analysis of trypanosoma (nannomonas) congolense ilnat 2.1 vsg gene.genes encoding various trypanosoma (trypanozoon) brucei variable surface glycoproteins (vsgs) show considerable conservation among different members of this species, known as isotypes. the occurrence of isotypes in other salivarian trypanosomes has not been well documented. we have cloned sequences encoding trypanosoma (nannomonas) congolense ilnat 2.1 vsg, and used it in dna blot hybridization analyses of this and other t. congolense clones originating from geographically separate regions of ea ...19852412117
comparative structural analysis of calmodulins from trypanosoma brucei, t. congolense, t. vivax, tetrahymena thermophila and bovine brain.calmodulin is an intracellular calcium receptor protein utilized extensively by eukaryotic cells to mediate responsiveness to calcium signals. the present study evaluates the effects on protein structure of amino acid substitutions in trypanosome calmodulin. calmodulin conformation, hydrophobicity and antigenic determinants are compared among trypanosoma brucei, trypanosoma congolense, trypanosoma vivax, tetrahymena thermophila and bovine brain. trypanosome calmodulin differs from brain and tetr ...19852417117
involvement of suppressor cells induced with membrane fractions of trypanosomes in immunosuppression of trypanosomiasis.we showed that infection with trypanosoma congolense in mice led to suppression of listeria-induced delayed type hypersensitivity (dth). mice were pre-treated with irradiated t. evansi, which caused rapid and effective suppression of dth. a membrane fraction obtained by homogenizing t. evansi variant in a hypotonic buffer solution and centrifuging it at 150,000g produced suppression of listeria-induced dth when injected i.p. into mice as early as 1 day before listeria immunization. furthermore, ...19853158865
the behaviour of trypanosomes within the midguts of wild-caught tsetse from zimbabwe.trypanosomes infecting the midgut of wild-caught tsetse from zimbabwe were found on electron microscopic examination to be penetrating the peritrophic membranes and so entering the ecto-peritrophic space in the mycetome region of the midgut. other trypanosomes entered midgut cells, behaviour similar to that previously reported in laboratory-infected tsetse colonies.19853832497
induction of protective immunity in cattle by tsetse-transmitted cloned isolates of trypanosoma congolense.cattle infected with cyclically (tsetse)-transmitted clones of trypanosoma congolense were treated with the trypanocidal drug diminazene aceturate ('berenil') at various intervals during development of local skin reactions (chancres), in order to investigate the role played by trypanosomes in the skin in the induction of protective immunity. cattle, treated on or before day 12 after infection and prior to detection of trypanosomes in the blood, showed a range of susceptibility to cyclically-tran ...19853834843
identification of an antigen specific to trypanosoma congolense by using monoclonal antibodies.using indirect immunofluorescence assays on acetone-fixed smears of a series of different parasites, we have shown that two monoclonal antibodies bind specifically to trypanosoma congolense organisms. the antibodies bind to both bloodstream trypomastigotes and procyclic culture forms of the parasite and are thus not stage specific. immunoprecipitation and immunoblot analysis showed that both monoclonal reagents bound a protein of approximately 31,000 m.w. this antigen appeared to be located on t ...19853880577
cultivation of african and south american trypanosomes of medical or veterinary importance. 19853896374
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