| trypanosoma congolense: manifestation of resistance to berenil and samorin in cloned trypanosomes isolated from zambian cattle. | four trypanosoma congolense clones derived from a mumbwa field isolate proved to be resistant to berenil with a minimum curative dose (mcd) value of 40 mg/kg and to samorin with an mcd of 4 mg/kg for mice. two other clones, one being resistant to berenil with an mcd of 45 mg/kg but susceptible to 1 mg/kg samorin, and the other being resistant to samorin with mcd of 16 mg/kg but susceptible to 7 mg/kg berenil, were experimentally rendered resistant to each of the respective drugs they were suscep ... | 1992 | 1486237 |
| immunohistology of lymph nodes draining local skin reactions (chancres) in sheep infected with trypanosoma congolense. | marked enlargement of lymph nodes draining local skin reactions (chancres) occurred in sheep following intradermal inoculation of cultured metacyclic forms of trypanosoma congolense. histologically, these lymph nodes were characterized by follicular hypertrophy and hyperplasia, compression and relative reduction of the paracortical areas and expansion of the medullary regions. immunohistochemical staining with monoclonal antibodies to ovine lymphocyte subsets and fc receptor (fcr) bearing macrop ... | 1991 | 1717523 |
| trypanosoma (nannomonas) congolense: changes in respiratory metabolism during the life cycle. | all four life cycle stages (bloodstream, procyclic, epimastigote, and metacyclic) of trypanosoma congolense il 3000 were assayed with an oxygen electrode (polarograph) for the presence of terminal oxidases and carbon-source preference. in addition, these stages were used for histochemical analysis of mitochondrial activity using rhodamine 123, nitroblue tetrazolium, and diaminobenzidine. morphometry was used to compare mitochondrial volumes and surface area among the different life cycle stages. ... | 1991 | 1720394 |
| endocytosed transferrin in african trypanosomes is delivered to lysosomes and may not be recycled. | it has been shown in mammalian systems that the passage of transferrin-colloidal gold (tf-au) through the endocytic system is influenced by the size of the gold colloid (neutra, m. r. et al., j. histochem. cytochem. 33, 1134-1144 (1985); woods, j. w. et al., eur. j. cell biol. 50, 132-143 (1989)). however, in both trypanosoma brucei brucei and trypanosoma congolense, widely varying sizes of tf-au (tf-au5 and tf-au15) have been shown to proceed to lysosomes (webster, p., eur. j. cell biol. 49, 29 ... | 1992 | 1493805 |
| relationships between trypanosome infection measured by antigen detection enzyme immunoassays, anaemia and growth in trypanotolerant n'dama cattle. | relationships were evaluated between trypanosome infection as measured by antigen detection enzyme immunoassays (antigen elisa), anaemia as determined by average packed red cell volume (pcv), and animal performance as assessed by daily weight gain in 99 n'dama cattle in gabon exposed to natural tsetse challenge at 11.5 months of age and recorded 14 times over a 13 week period. approximately half the animals were found to be infected for an average of five of the 14 times that they were examined: ... | 1992 | 1496781 |
| the influence of buffalo and bovine serum on transformation of trypanosoma congolense from metacyclic forms to bloodstream forms in vitro. | the transformation of trypanosoma congolense metacyclics into bloodstream forms was studied in vitro using light and electron microscopy. the trypanosomes were maintained in culture at 28 degrees c using a medium supplemented with foetal bovine serum. the metacyclics were harvested and separated from the procyclic and epimastigote forms by using anion exchange chromatography. isolated metacyclics were incubated with different concentrations of buffalo or bovine serum at 35 degrees c for periods ... | 1992 | 1519019 |
| cloning, sequencing, and demonstration of polymorphism in trypanothione reductase from crithidia fasciculata. | trypanothione reductase (tr) is a target for drug design since it is unique to trypanosomatids, substituting for the otherwise ubiquitous enzyme, glutathione reductase. we report the cloning and sequencing of several cdnas and genes encoding crithidia fasciculata tr, the structure of which has recently been solved by crystallography. single base polymorphisms are detected in cdnas (containing 80% of the coding sequence) and two different genomic clones, including a glutamine to glutamate change ... | 1992 | 1542316 |
| trypanosomiasis in different breeds of cattle from benin. | blood of different breeds of cattle, namely lagune from the atlantic province, borgou and borgou x zebu from the borgou province, and somba and zebu from the atacora province of benin, were examined for trypanosome infection. thick and thin blood smears for trypanosomes, the card agglutination test (catt), indirect immunofluorescent antibody test (ifat) and trypanolytic test for antibodies to trypanosomes were used. trypanosomes were detected in 19.3% (range 9.8-31.4%) of animals by examination ... | 1991 | 1763478 |
| an outbreak of trypanosomosis on the jos plateau, nigeria. | | 1991 | 1796524 |
| the interaction of trypanosoma congolense and haemonchus contortus infections in trypanotolerant n'dama cattle. | the interactions between trypanosoma congolense and haemonchus contortus infections were studied in n'dama calves. a total of 38 n'dama bulls was divided into four groups and each group infected either with h. contortus 1 week after infection with t. congolense or with t. congolense 4 weeks after infection with h. contortus, or with either infection singly. parasitological (faecal egg counts, parasitaemia), haematological (packed cell volume, white blood cell counts, albumin) and clinical parame ... | 1992 | 1413448 |
| pig trypanosomiasis: comparative anaemia and histopathology of lymphoid organs. | anaemia with characteristic clinical symptoms, haematological changes and histopathology of lymphoid organs, was observed following experimental infection of pig with pathogenic species of trypanosoma brucei brucei and trypanosoma congolense, the former being more virulent than the latter. mean incubation periods were 4 and 7 days, and generalized fluctuating levels of parasitaemia and pyrexia without mortality were observed. other symptoms included hyperaemia, petechial haemorrhages leading to ... | 1991 | 1824133 |
| changes in levels of transaminases in goats experimentally infected with trypanosoma congolense. | goats were experimentally infected with trypanosoma congolense and then treated with berenil after 9 days of infection. the infection produced increases in glutamate oxalacetate transaminase (got) and glutamate pyruvic transaminase (gpt) values. mean got values in infected west african dwarf goats were generally lower than in infected red sokoto goats. treatment with berenil did not produce any significant effect on their levels probably because of the relapse infection recorded in this study. | 1992 | 1339996 |
| experimental infection with a haemorrhage-causing trypanosoma vivax in n'dama and boran cattle. | n'dama cattle control experimental infections with clones of trypanosoma congolense of varying degrees of virulence, but nothing is known about their capacity to control infections caused by highly virulent, east african stocks of t. vivax. thus four n'damas and four trypanosusceptible borans were infected with a tsetse-transmitted stock of t. vivax il2337. in ayrshire cattle this stock is known to cause severe haemorrhagic disease. no differences were observed in the parasitaemia between the tw ... | 1992 | 1355307 |
| rickettsia-like organisms, puparial temperature and susceptibility to trypanosome infection in glossina morsitans. | maintaining the puparial stage of successive generations of a population of tsetse 3 degrees c lower than normal reduced the numbers of rickettsia-like organisms (rlo) carried by emerging flies. the susceptibility of these flies to midgut infection with trypanosoma congolense was also significantly reduced compared with control flies held at normal temperature. these results support the view that the relationship between rlo and susceptibility is quantitative-teneral flies with heavier rlo infec ... | 1991 | 1852487 |
| suppression of t-cell responsiveness during tsetse-transmitted trypanosomiasis in cattle. | in the present study, we demonstrate that lymph node cells from cattle infected with t. congolense through tsetse fly challenge were unable to proliferate in vitro following activation with the t-cell mitogen concanavalin a. this was associated with a simultaneous suppression of interleukin 2 (il-2) production and interleukin 2 receptor (il-2r) expression. however, the capacity of the cells to secrete interferon gamma following the mitogenic activation was not affected by the infection. | 1992 | 1355308 |
| the influence of the size of the initial inoculum on the efficacy of isometamidium (samorin) on a stock of trypanosoma congolense. | the effect of the number of trypanosomes in the initial inoculum on the minimum curative dose, was determined for an experimental infection of trypanosoma congolense in mice treated with isometamidium. mice were infected by the intravenous route and were then treated three hours later by intraperitoneal injection. the minimum curative dose was shown to be dependent on the size of the initial inoculum, with a difference of a factor of 7.5 as the initial inoculum was increased from 10(3) to 10(6) ... | 1992 | 1359748 |
| diminazene aceturate residues in the tissues of healthy, trypanosoma congolense and trypanosoma brucei brucei infected dogs. | the tissue distribution and residue profile of diminazene aceturate was investigated in healthy dogs and in dogs infected with trypanosoma congolense and trypanosoma brucei brucei. the drug was administered at 3.5 mg/kg i.m. and tissue samples were taken post mortem from the animals at 48, 72, 120, 168 and 240 h after injection. the drug was distributed to various organs and tissues of the body with the highest concentrations occurring in liver and kidney. higher drug levels were obtained in the ... | 1991 | 1868320 |
| transport of isometamidium (samorin) by drug-resistant and drug-sensitive trypanosoma congolense. | the uptake kinetics of a 14c-labelled trypanocidal compound isometamidium chloride (samorin, rmb animal health ltd, uk) was measured in drug-resistant and drug-sensitive trypanosoma congolense. it was established that drug uptake was significantly more rapid and quantitatively greater in drug-sensitive parasites. there was clear evidence that drug uptake in both the resistant and sensitive trypanosomes was by a specific, receptor-mediated process. this specific drug transport was energy-dependen ... | 1992 | 1641246 |
| effect of isometamidium on trypanosoma congolense infectivity. | isometamidium chloride (samorin, rmb, england) is a widely used and highly effective trypanocide for the treatment of bovine trypanosomiases. however, the appearance of isometamidium-resistant populations of t. congolense in africa makes it necessary to develop methods for the rapid and reliable detection of drug resistance in the laboratory. currently available tests are time-consuming and/or expensive. in the present study, the short-term in vitro incubation of trypanosomes in a range of isome ... | 1991 | 1897115 |
| [infection of glossina palpalis palpalis (diptera, glossinidae) by trypanosomes in the forest zone of gagnoa in the ivory coast]. | 2,153 glossina palpalis palpalis caught in biconical traps from different biotopes in relation with human activities in the forest areas of côte d'ivoire were used to calculate the trypanosome infection rates. the results showed that there was no preferential biotope for glossina infected by trypanosomes. the most widespread species of trypanosomes infecting glossina p. palpalis is t. congolense (10.13%) followed by t. vivax (8.22%) and seldomly by t. brucei (0.70%). female glossina are infected ... | 1991 | 1665576 |
| clone-specific immune colostrum induces increased resistance in goat kids challenged with trypanosoma congolense. | the course of infection and the humoral immune response to trypanosoma congolense clone ilnat 3.1 were studied in test goat kids receiving colostrum from dams immunized with the surface coat of ilnat 3.1 and control kids that received colostrum from nonimmunized dams. at 24-48 h after birth, all test kids had detectable serum antibodies to the trypanosome clone. there was no difference in the prepatent period between the test and control kids following challenge with 10(3) t. congolense ilnat 3. ... | 1991 | 1678573 |
| pathogenicity of tsetse-transmitted trypanosoma congolense for waterbuck (kobus defassa) and boran cattle (bos indicus). | five waterbuck (kobus defassa) and four boran cattle (bos indicus) were infected with trypanosoma congolense il2895 using glossina morsitans morsitans. at the same time, two waterbuck and two cattle were inoculated intravenously with bloodstream forms. with both methods of challenge, cattle had short prepatent periods followed by a continuous high parasitaemia. all cattle became severely anaemic and had to be treated with trypanocidal drugs to prevent death. in contrast, tsetse and intravenous c ... | 1991 | 1685298 |
| infection rates in glossina morsitans morsitans fed on waterbuck and boran cattle infected with trypanosoma congolense. | teneral glossina morsitans morsitans were fed on waterbuck (kobus defassa) and boran cattle (bos indicus) infected experimentally with trypanosoma congolense clone il2895. infection rates in tsetse varied from 9 to 31% when fed on cattle, and from 2 to 59% when fed on waterbuck. in waterbuck, infections were often detected through the development of parasites in tsetse at times when parasitaemia could not be detected through microscopic examination of blood. male and female, and 1- and 2-day-old ... | 1991 | 1685299 |
| trypanosoma congolense: re-expression of a deleted metacyclic variable antigen type in vivo and in vitro. | the expression of variable antigen types (vats) was determined among dividing populations of t. congolense growing in vivo in rabbit chancres and in vitro on bovine aorta endothelial cell monolayers. experiments were performed in which a single metacyclic vat (m-vat) was deleted from a cultured metacyclic population by neutralisation with a monoclonal antibody and complement. subsequent expression of the deleted m-vat and two unrelated m-vats was determined by an indirect immunofluorescent antib ... | 1991 | 1685300 |
| the effect of diminazene aceturate and isometamidium chloride on cultured procyclic forms of susceptible and drug-resistant trypanosoma congolense. | cultures of insect forms of trypanosoma congolense stocks and clones with different susceptibilities to trypanocidal drugs in vivo were initiated from bloodstream trypomastigotes harvested from mammalian hosts and maintained axenically in vitro at 27 degrees c. growth inhibition of procyclic forms of susceptible and drug-resistant t. congolense occurred after incubation for 48 h with 0.1 ng isometamidium chloride ml or 500 ng diminazene aceturate/ml. procyclic forms were propagated in vitro in t ... | 1991 | 1685301 |
| analysis of peripheral leucocyte populations in n'dama and boran cattle following a rechallenge infection with trypanosoma congolense. | monoclonal antibodies, flow cytometry and routine haematological techniques were used to analyse circulating leucocyte populations in trypanotolerant (n'dama) and trypanosusceptible (boran) cattle following a homologous rechallenge with trypanosoma congolense clone il13-e3. the n'damas developed a low, transient parasitaemia and did not develop anaemia. the borans became parasitaemic and developed chronic anaemia but three of the five animals eventually self-cured, whilst, a group of primary-cha ... | 1991 | 1711196 |
| characterisation of a cysteine protease from bloodstream forms of trypanosoma congolense. | a cysteine protease (trypanopain-tc) with cathepsin-l-like properties has been purified from trypanosoma congolense. the enzyme has an apparent molecular mass of 31-32 kda by sds/page and 66 kda by gel chromatography. it has a pi 7.4 and a high affinity for concanavalin a. trypanopain-tc catalyses the limited proteolysis of a variety of protein substrates such as fibrinogen, serum albumin and trypanosome variant-surface glycoprotein. it has minimal or no activity against casein or elastin. a var ... | 1992 | 1740149 |
| stability of metacyclic variable antigen types (m-vats) during the early stages of infection with trypanosoma congolense. | expression of nine metacyclic variable antigen types (m-vats) of trypanosoma congolense in chancres from infected rabbits was determined using monoclonal antibodies raised against metacyclic forms of trypanosomes. trypanosomes present in chancres 7-9 days post infection expressed m-vats present in metacyclic populations of the parasites. the majority of m-vats expressed showed little proportional change from those observed on metacyclic trypanosomes during this period although expression of one ... | 1990 | 1971489 |
| homidium bromide as a chemoprophylactic for cattle trypanosomiasis in kenya. | homidium bromide was used in a strategic chemoprophylactic regime to control trypanosomiasis in boran cattle in kenya. trypanosome infection rates in cattle receiving homidium bromide prophylaxis were compared with those in control cattle which received no prophylaxis but were treated with diminazene aceturate when infected. homidium bromide was administered twice during the year after which no infections were detected for periods of nineteen weeks and seventeen weeks respectively. the drug sens ... | 1990 | 1971490 |
| improved identification of nannomonas infections in tsetse flies from the gambia. | trypanosomes from 36 midgut infections were isolated in procyclic culture from glossina morsitans submorsitans and g. palpalis gambiensis in the gambia. twenty-eight stocks (78%) were identified using dna probes specific for: (a) trypanosoma (nannomonas) congolense savannah type, (b) t. (n.) congolense riverine-forest type, (c) t. (n.) simiae and (d) trypanozoon, t. simiae and savannah type t. congolense were found only in g.m. submorsitans while the riverine-forest type t. congolense was restri ... | 1990 | 1980568 |
| reduced accumulation of isometamidium by drug-resistant trypanosoma congolense. | the accumulation of the trypanocide isometamidium chloride (samorin, rmb animal health ltd., uk) by a range of clones of trypanosoma congolense with varying sensitivity to the drug, was measured by methods based on the fluorescence of isometamidium. fluorescence microscopy and flow cytometry showed a reduction in drug accumulation by resistant clones. fluorescence spectrophotometry demonstrated an inverse correlation between the intensity of cell-associated fluorescence and the level of resistan ... | 1991 | 1745550 |
| salivary gland infection: a sex-linked recessive character in tsetse? | male tsetse, when infected in the laboratory with trypanosomes of the subgenus trypanozoon, usually produce greater salivary gland infection rates than females of the same species. we show that a single sex-linked gene model can be fitted to most recently published data for salivary gland infection rates in tsetse. the maturation of trypanosoma congolense infections is shown to be independent of fly sex. the possible effects of genetic control of maturation of trypanozoon infections in tsetse po ... | 1990 | 1980807 |
| the role of the macrophage in induction of immunosuppression in trypanosoma congolense-infected cattle. | impairment of t-cell function in boran (bos indicus) cattle during primary infection with trypanosoma congolense ilnat 3.1 was found to occur in peripheral blood, spleen and, in particular, the lymph nodes. lymph node cells from infected cattle failed to proliferate in response to mitogenic stimulus and suppressed proliferation of both normal peripheral blood mononuclear cells and lymph node cells in co-culture assays. the addition of indomethacin, to inhibit prostaglandin synthesis, had no effe ... | 1991 | 1748479 |
| porcine trypanosomosis in nigeria: infections in local and exotic pigs in the nsukka area of anambra state. | a twelve-month survey in three local government areas (lga) in nsukka zone, anambra state, nigeria revealed that out of 150 local and exotic breeds of pig examined, 46 (30.7%) were infected with trypanosomes. both single and mixed infections of trypanosoma brucei and t. congolense were observed. however, t. brucei was the predominant trypanosome encountered. the husbandry system in practice was the most significant factor influencing the prevalence of trypanosomes in the pigs. in addition signif ... | 1991 | 1763434 |
| immunolocalization of a cysteine protease within the lysosomal system of trypanosoma congolense. | a cysteine protease has been purified from bloodstream forms of trypanosoma congolense by affinity chromatography on cystatin-sepharose. a polyclonal antibody was raised against the purified enzyme and used for immunocytochemical localization of the enzyme by electron microscopy. antibody labeling of the cysteine protease, using colloidal gold-labeled protein a (pra-au), was observed over amorphous material within subcellular organelles which have the appearance of lysosome-like bodies. this int ... | 1991 | 1802711 |
| sensitivity of an antigen detection enzyme immunoassay for diagnosis of trypanosoma congolense infections in goats and cattle. | the sensitivity of a monoclonal antibody-based antigen-detection enzyme immunoassay (antigen-elisa) for the diagnosis of trypanosoma congolense was evaluated using sera from experimentally infected goats and cattle. ten goats (galla x east african masai) and 7 steers (bos indicus) were infected with different clones of t. congolense and left to run a chronic course for 46 and 24 mo, respectively. during this period, monthly blood samples were collected and analyzed for the presence of trypanosom ... | 1991 | 2010855 |
| plasma levels of proteins of the alternative complement pathway in inbred mice that differ in resistance to trypanosoma congolense infections. | inbred balb/c, a/j, and c57b1/6j mice were infected with trypanosoma congolense (trans mara strain), clone tc13, and monitored for parasitemia, survival times, and plasma levels of complement components c3, c5, factor b, and factor h. parasitemia was highest in balb/c, intermediate in a/j, and lowest in c57bl/6j mice. the mean survival times were 11.5 +/- 0.9, 23.8 +/- 2.3, and 119 +/- 26 days for balb/c, a/j, and c57bl/6j mice, respectively. preinfection levels of factor h were significantly co ... | 1991 | 1838113 |
| suppression of interleukin 2 secretion and interleukin 2 receptor expression during tsetse-transmitted trypanosomiasis in cattle. | infection with trypanosoma congolense in cattle was found to be associated with a profound suppression of the host's immune system. lymph node cells from infected cattle were unable to secrete interleukin 2 (il 2) in vitro following mitogenic stimulation and the exogenous supply of il 2 did not restore t cell proliferative responses. this was associated with an impaired expression of the alpha chain of the il 2 receptor (il 2r alpha). co-culture experiments, where cells from an infected animal w ... | 1992 | 1547821 |
| trypanosome-induced hypothyroidism in cattle. | three boran (bos indicus) cattle infected with t. congolense il 1180, and two uninfected control boran cattle were used to study the effect of trypanosomiasis on the function of the thyroid gland. on a weekly basis, plasma thyroxine (t4) was measured by 125i-radioimmunoassay. results indicated that t. congolense caused a significant decline in plasma t4 concentration in infected animals. | 1992 | 1551017 |
| cellular phenotypes in trypanosoma congolense infected sheep: the local skin reaction. | mononuclear cell subpopulations in local skin reactions (chancres) in sheep infected with metacyclic forms of trypanosoma congolense were studied by indirect immunoperoxidase staining using a panel of monoclonal antibodies (moabs) specific for ovine leucocyte subsets. morphometric analysis revealed significant increases in numbers of cells expressing cd5, cd4, cd8, cd45r (mainly b cells), major histocompatibility complex (mhc) class ii antigens, fc receptors (fcr) on macrophages (vpm32) and fcr ... | 1990 | 2084609 |
| trypanosoma congolense: the in vitro akinetoplastic induction sensitivity assay. | incubation of trypanosoma congolense in diminazene aceturate (berenil) or isometamidium chloride (samorin) induced akinetoplastic (ak) forms in vitro. the ak values (expressed in percent) obtained were found to be useful for rapid assessment of relative drug sensitivities. in susceptible clones, ak forms were induced at all drug concentrations tested, whereas in resistant clones they were induced only at higher concentrations. the berenil-resistant clone exhibited ak values of 0.9% +/- 0.6%--8.9 ... | 1992 | 1557326 |
| cell surface interactions between trypanosoma congolense and macrophages during phagocytosis in vitro. | trypanosoma congolense bloodstream forms preincubated with a high titer of anti-variant surface antigen (vsg)-specific antibody, a low amount of anti-vsg plus complement-active mouse serum (ms), ms alone, and trypsin were cocultivated with mouse peritoneal macrophages in vitro. immunofluorescence as well as transmission and scanning electron microscopy revealed that upon attachment to the macrophages' surface, trypanosomes opsonized with anti-vsg/ms formed opsonized filopodia, which were rapidly ... | 1992 | 1560418 |
| metacyclic form-specific variable surface glycoprotein-encoding genes of trypanosoma (nannomonas) congolense. | a complementary dna expression library in phage lambda gt11 was synthesized using mrna from in vitro-produced metacyclic forms of a clone of trypanosoma (nannomonas) congolense. the unamplified library was screened with antiserum from a goat immune to infection with metacyclic (m)-forms of t. congolense ilrad nannomonas antigen repertoire 2(ilnar2). of the 100 antiserum-reactive phage clones identified, 22 were analyzed further: 21 of the clones contained overlapping portions of a single transcr ... | 1992 | 1572537 |
| comparative study on rickettsia-like organisms in the midgut epithelial cells of different glossina species. | the midgut epithelium of glossina morsitans centralis, g. austeni, g. pallidipes, g. palpalis palpalis, g. p. gambiensis, g. fuscipes fuscipes, g. tachinoides and g. brevipalpis from ilrad-bred colonies was examined, by electron microscopy, for the presence and distribution of rickettsia-like organisms (rlos). rlos were present in the midgut epithelial cells of all non-teneral tsetse. in g.m. centralis, g. pallidipes and, to a much lesser extent, g. brevipalpis, rlos were numerous and were prese ... | 1991 | 1852486 |
| identification and characterization of two repetitive non-variable antigens from african trypanosomes which are recognized early during infection. | the present paper describes two repetitive proteins representing common antigens of african trypanosomes which are non-variant and which are recognized early in infection by the host immune system. these antigens were identified by their ability to immunoreact with bovine serum taken during the early phase of a cyclic trypanosomal infection. screening of a cdna library from t. b. gambiense with such early infection serum identified a protein which contains a repetitive motif consisting of 68 ami ... | 1992 | 1614728 |
| haemolymph lectin and the maturation of trypanosome infections in tsetse. | the tsetse immune system has recently been shown to be involved in trypanosome maturation; lectin secreted in the midgut, normally responsible for preventing the establishment of midgut infections, induces established midgut trypanosomes to mature. we now show that a second lectin, present in tsetse haemolymph, is essential to complete the maturation process. interactions between tsetse lectins and parasite surface coats probably determine trypanosome transmissibility and may be partly responsib ... | 1990 | 2132968 |
| kinetic isotope effect analysis of the reaction catalyzed by trypanosoma congolense trypanothione reductase. | african trypanosomes are devoid of glutathione reductase activity, and instead contain a unique flavoprotein variant, trypanothione reductase, which acts on a cyclic derivative of glutathione, trypanothione. the high degree of sequence similarity between trypanothione reductase and glutathione reductase, as well as the obvious similarity in the reactions catalyzed, led us to investigate the ph dependence of the kinetic parameters, and the isotopic behavior of trypanothione reductase. the ph depe ... | 1992 | 1633154 |
| therapeutic effect of berenil and samorin in mice infected with four trypanosome populations isolated from zambian cattle. | four populations of trypanosoma congolense and trypanosoma brucei brucei were isolated from cattle under different management practices and environments in zambia. all four isolates had varied responses to both diminazene aceturate (berenil) and isometamidium chloride (samorin) as curative drugs in infected mice. trypanosomes from a traditionally managed herd in a high-tsetse-challenge area had the strains most resistant to berenil, with maximum curative dose of 45 mg kg-1 body weight. another i ... | 1991 | 1897118 |
| effects of the combination of dl-alpha-difluoromethylornithine and diminazene aceturate in trypanosoma congolense infection of dogs. | the therapeutic activity of a combination of difluoromethylornithine (dfmo) with diminazene aceturate was investigated in mongrel dogs experimentally infected with trypanosoma congolense. the criteria used in the assessment of the trypanocidal effect of the therapy include the examination of the blood for parasites, as well as clinical and haematological changes at intervals following treatment. diminazene aceturate and dfmo alone and in combination produced intermittent aparasitaemia in the dog ... | 1990 | 2238433 |
| susceptibility of n'dama and boran cattle to tsetse-transmitted primary and rechallenge infections with a homologous serodeme of trypanosoma congolense. | eight trypanotolerant n'dama cattle controlled an infection of trypanosoma congolense ilnat 3.1 transmitted by glossina morsitans centralis, more efficiently than a group of similarly infected trypanosusceptible boran cattle. all eight n'damas maintained their pcv above 15% throughout the primary infection whereas the pcv of six of the eight borans dropped below 15%; these latter animals were treated with diminazene aceturate to prevent possible death. lymphocyte, neutrophil and platelet counts ... | 1991 | 1923566 |
| susceptibility of n'dama and boran cattle to sequential challenges with tsetse-transmitted clones of trypanosoma congolense. | the susceptibility of n'dama cattle (bos taurus) to four consecutive infections with different tsetse-transmitted clones of trypanosoma congolense was compared with that of borans (bos indicus). all animals were aged 13 months at the start of the study and had been born and raised free from trypanosomiasis under the same management and nutritional conditions, thereby limiting environmental factors that could have influenced susceptibility. while cattle of both breeds were equally susceptible to ... | 1991 | 1923567 |
| engineering the substrate specificity of glutathione reductase toward that of trypanothione reduction. | glutathione reductase (ec 1.6.4.2; cas registry number 9001-48-3) and trypanothione reductase (cas registry number 102210-35-5), which are related flavoprotein disulfide oxidoreductases, have marked specificities for glutathione and trypanothione, respectively. a combination of primary sequence alignments and molecular modeling, together with the high-resolution crystal structure of human glutathione reductase, identified certain residues as potentially being responsible for substrate discrimina ... | 1991 | 1924337 |
| immunohistochemical demonstration of trypanosoma evansi in tissues of experimentally infected rats and a naturally infected water buffalo (bubalus bubalis). | trypanosoma evansi was demonstrated by an immunohistochemical technique in formalin-fixed paraffin-embedded tissues of experimentally infected rats. trypanosoma evansi was visible readily, nuclei were stained darkly, the cytoplasm was stained moderately, and the cell membranes were delineated clearly. the parasites were present in small- to large-sized blood vessels of all organs, in extravascular spaces of ventricles and neuropil of the brain, and in interstitial tissues of the lung and testes. ... | 1990 | 2319414 |
| experimental infection of n'dama cattle with trypanosomes using glossina palpalis gambiensis caught in the wild. | the transmissibility of trypanosome infection to n'dama cattle by tsetse flies caught in the field was examined. wild-caught glossina palpalis gambiensis were transferred singly into small numbered cages and allowed to feed on 14 uninfected n'dama cattle. following a completed feed the tsetse were dissected and infection in the proboscis, the salivary glands and the gut was recorded. each animal was bitten by a number of tsetse ranging from five up to 64 flies. following dissection of the tsetse ... | 1990 | 2321260 |
| trypanosoma congolense: complement independent immobilization by a monoclonal antibody. | | 1990 | 2323399 |
| [interpretation of the catt (card agglutination trypanosomiasis test) in the screening for human trypanosomiasis due to trypanosoma brucei gambiense]. | mass screening for gambiense sleeping sickness is usually done with the card agglutination trypanosomiasis test (catt) in series (total blood catt followed by a serum catt if the first test is positive) and the search for trypanosomes in cervical adenopathies. at present, the double positives (blood catt and serum catt) as well as the subjects in whom the trypanosome was found (in the blood or gland juice) are treated. the existence of patients whose gland punction was proved positive whereas th ... | 1991 | 1958107 |
| parasite kinetics and cellular responses in goats infected and superinfected with trypanosoma congolense transmitted by glossina morsitans centralis. | trypanosoma congolense infected tsetse were fed on the flanks of goats at sites drained by the prefemoral lymph node. the efferent lymphatic of this lymph node was surgically cannulated and the lymph was collected daily and examined for appearance of parasites, lymph flow and cells. trypanosomes were detected in the lymph 4 days after infection, which was 2 days prior to the appearance of the local skin reaction or the presence of parasites in the blood. once the animal became parasitaemic, tryp ... | 1990 | 1967506 |
| the effect of temperature and storage on the infectivity and motility of african animal trypanosomes in the blood of different hosts. | blood from mice, rats, goats or cattle infected with trypanosoma congolense, t. vivax or t. brucei was stored at 0-4 degrees c, 20-25 degrees c, 30-35 degrees c or 36-40 degrees c. each sample was examined after set intervals to determine the maximum period the trypanosomes could remain motile and infective. t. brucei in blood remained motile for 96 h at 0-4 degrees c, being the longest period that was observed, but remained infective for only 8 h. t. vivax survived poorly in rodent blood, but d ... | 1990 | 1967509 |
| expression of resistance to isometamidium and diminazene in trypanosoma congolense in boran cattle infected by glossina morsitans centralis. | investigations were conducted on the sensitivity to isometamidium chloride (samorin) and diminazene aceturate (berenil) of derivatives of three of the trypanosoma congolense stocks isolated between 1978 and 1983 from zebu cattle in the bobo-dioulasso region of burkina faso. boran cattle were used in the drug-sensitivity tests and were infected using glossina morsitans centralis. the results showed that t. congolense stock il 2466 isolated in 1978 was sensitive to the standard therapeutic dose of ... | 1990 | 1969704 |
| evaluation of a field test for trypanotolerance in young n'dama cattle. | in three separate tests in 1987, 1988 and 1989, a total of 436 one-year-old n'dama cattle were maintained for 12, 18 and 24 weeks under a medium natural tsetse-trypanosome challenge in gabon, central africa. matching health and performance data were recorded on 4, 10 and 13 occasions respectively, to allow simultaneous evaluation of the effect of different criteria of trypanotolerance on animal performance. under trypanosome prevalences of 25, 31 and 9%, respectively, ability to control the deve ... | 1990 | 1980803 |
| differential expression of a family of putative adenylate/guanylate cyclase genes in trypanosoma brucei. | the expression site for the variant surface glycoprotein (vsg) gene of trypanosoma brucei contains several genes of unknown function (esags, for expression site-associated genes). among these, esag 4 shows homology to eukaryotic adenylate/guanylate cyclase genes, in the region encoding the presumptive enzyme catalytic domain. this gene belongs to a family of related sequences, and hybridizes to the genomic dna of other trypanosomatids, such as trypanosoma congolense, trypanosoma vivax and trypan ... | 1990 | 1982555 |
| endopeptidase variations among different life-cycle stages of african trypanosomes. | lysates of different life-cycle stages of trypanosoma congolense, trypanosoma vivax and trypanosoma brucei were analysed for endopeptidase activity, using reaction conditions which permitted a distinction to be made between lysosomal and non-lysosomal activity [lonsdale-eccles, j. d. & grab, d. j. (1987) eur. j. biochem. 169, 467-475]. hydrolysis of z-arg-arg-nhmec (z = benzyloxycarbonyl, nhmec = 7-amino-4-methylcoumaryl) and z-gly-gly-arg-nhmec occurred predominantly at alkaline ph and was obse ... | 1991 | 1991468 |
| mutational analysis of parasite trypanothione reductase: acquisition of glutathione reductase activity in a triple mutant. | african trypanosomes contain a cyclic derivative of oxidized glutathione, n1,n8-bis(glutathionyl)spermidine, termed trypanothione. this is the substrate for the parasite enzyme trypanothione reductase, a key enzyme in disulfide/dithiol redox balance and a target enzyme for trypanocidal therapy. trypanothione reductase from these and related trypanosomatid parasites is structurally homologous to host glutathione reductase but the two enzymes show mutually exclusive substrate specificities. to ass ... | 1991 | 2007114 |
| application of luminol-dependent chemiluminescence to assay opsonizing antibodies to procyclic forms of trypanosoma congolense in the sera of dogs experimentally infected with heterologous stocks. | luminol-dependent chemiluminescence (lcl) responses of dog granulocytes were used to assay opsonizing antibodies to procyclic culture forms of t. congolense. a high degree of sensitivity was demonstrated and lcl levels were high, when the phagocytic cells were incubated with the sera of infected dogs even at dilutions as high as 1:400 as compared to pre-infection or negative sera. the levels of opsonizing antibodies were elevated in all the dogs throughout the time of observation. the technique ... | 1990 | 2382102 |
| variation in resistance to isometamidium chloride and diminazene aceturate by clones derived from a stock of trypanosoma congolense. | nine clones were derived from a drug-resistant trypanosoma congolense stock (il 2856) and characterized in mice for their sensitivity to isometamidium chloride and diminazene aceturate. all clones were derived from the stock without drug selection and expressed high levels of resistance to isometamidium chloride (50% curative dose [cd50] values ranging from 1.5 to 5.1 mg/kg) and intermediate to high levels of resistance to diminazene aceturate (cd50 values ranging from 5.1 to 21.0 mg/kg). by con ... | 1991 | 2038504 |
| redox enzyme engineering: conversion of human glutathione reductase into a trypanothione reductase. | the substrate specificity of the human enzyme glutathione reductase was changed from its natural substrate glutathione to trypanothione [n1,n8-bis(glutathionyl)spermidine] by site-directed mutagenesis of two residues. the glutathione analogue, trypanothione, is the natural substrate for trypanothione reductase, an enzyme found in trypanosomatids and leishmanias, the causative agents of diseases such as african sleeping sickness, chagas disease, and oriental sore. the rational bases for our mutat ... | 1991 | 2059620 |
| trypanosoma congolense bloodstream forms evade complement lysis in vitro by shedding of immune complexes. | in the presence of antibodies against the variant surface glycoprotein (vsg) and guinea pig complement, trypanosoma congolense bloodstream forms were lysed. parasites, which had been preincubated with antibodies at 37 degrees c before addition of complement, escaped from complement lysis in a time- and temperature-dependent process. preincubation caused removal of the antibodies from the cell surface by formation of filopodia and accumulation of the immune complexes between aggregated cells. add ... | 1990 | 2081529 |
| identification of midgut trypanolysin and trypanoagglutinin in glossina palpalis sspp. (diptera: glossinidae). | a midgut trypanolysin and an agglutinin from glossina palpalis subspecies were isolated and partially characterized using anion-exchange chromatography and polyacrylamide gel electrophoresis. fplc fractions of midgut extracts of glossina palpalis palpalis caused agglutination and lysis of two trypanosome species (trypanosoma congolense and trypanosoma brucei brucei), although glossina palpalis gambiensis caused only agglutination. the trypanolysin and agglutinin were active only in the posterior ... | 1990 | 2092294 |
| [improvement of the reproducibility of the elisa test for detecting anti-trypanosoma congolese antibodies in cattle]. | simplicity and the potential automatization make the elisa test a universal tool for the detection of antibodies, and, more recently, of antigens. but the reproducibility of results is not very good, due to many varying factors. we tried to improve the reproducibility of the elisa test for the detection of anti-trypanosoma congolense antibodies in cattle. for that, buffers are always used at room temperature to avoid temperature gradients in the plates. all volumes are increased to 200 microlite ... | 1990 | 2092352 |
| [sensitivity of double microcentrifugation for the research of trypanosomes]. | the double microcentrifugation technique, described by kratzer and ondiek (1989) for the parasitological diagnosis of trypanosomes, has been tested both in the laboratory and in the field. the limits of detection obtained here were not as low as those described in the original experiment, but the sensitivity of this technique for the detection of trypanosoma brucei, t. congolense and t. vivax was better than the phase contrast buffy coat method. this technique, which is easy to apply in the fiel ... | 1990 | 2103054 |
| immunosuppression in caprine trypanosomiasis: effects of acute trypanosoma congolense infection on antibody response to anthrax spore vaccine. | trypanosoma congolense infected goats were vaccinated with bacillus anthracis spore vaccine to determine the effect of such infection on the humoral immune response to the vaccine. the anti-anthrax antibody levels were severely depressed in infected goats. when trypanocidal therapy was administered to t. congolense infected goats 14 days after infection they developed antibody levels against bacillus anthracis similar to uninfected controls. | 1990 | 2115214 |
| multiple superovulations in n'dama heifers. | five n'dama heifers were superovulated with follicle stimulating hormone (fsh-p or folltropin) a total of six times each. the superovulations were carried out between ongoing experimental trypanosoma congolense infections. twenty-four (80%) of the 30 superovulations had a good ovarian response with 21 (70%) producing an average of 2.7 +/- 0.4 (mean +/- s.e.m.) embryos. the highest embryo production was achieved at the third and fourth superovulation, after which both the number of embryos and th ... | 1990 | 2120824 |
| in vitro cultivation of trypanosoma congolense bloodstream forms in the absence of feeder cell layers. | bloodstream forms of trypanosoma congolense (2 clones: ilnat3.1 and il3000, and 4 stocks: il2079, il2466, il3266 and cp-81) were continuously cultivated in vitro at 34-36 degrees c in the absence of feeder cell layers, using hmi-93 medium which was modified from iscove's modified dulbecco's mem (flow laboratories, irvine, scotland). the modification was done by supplementing the medium with 0.05 mm bathocuproine sulphonate, 1.5 mm l-cysteine, 0.5 mm hypoxanthine, 0.12 mm 2-mercaptoethanol, 1 mm ... | 1991 | 1852490 |
| in vitro drug sensitivity of trypanosoma congolense isolates. | the sensitivity of trypanosoma congolense isolates to diminazene and isometamidium was determined using an incorporation assay based on the uptake of [3h]-hypoxanthine in the presence of serial drug dilutions. the bloodstream forms of the different isolates exhibited variation in their sensitivity to the drugs that correlated well with the in vivo drug response. for diminazene, the sensitivity of the most sensitive population was 40 times that of the least sensitive population. for isometamidium ... | 1991 | 1866422 |
| [ticks and hemoparasitoses of livestock in senegal. iii. the northern sudan area]. | the authors describe the results of a study on ticks and hemoparasitoses of cattle and small ruminants in the senegalese north-sudanian area. for 15 months, 40 bovine, 40 sheep and 40 goats received a routine dipping treatment, aimed at the determination of the tick population dynamics together with an accurate localization of the preferential sites for the different species. the following parasites were collected from the animals: hyalomma marginatum rufipes, h. truncatum, rhipicephalus lunulat ... | 1989 | 2485548 |
| elusive trypanosomes. | professor kershaw's encouragement of the development of anion-exchange separation of african trypanosomes from blood led to two decades of activity when, for the first time, considerable progress was made in the intrinsic characterization of these parasites. such characterization depended on establishing high infections in laboratory rodents. however, the collection of samples from the field was restricted by the failure of certain trypanosomes either to infect, or to multiply adequately in, rod ... | 1991 | 1888216 |
| role of the chancre in induction of immunity to tsetse-transmitted trypanosoma (nannomonas) congolense in goats. | local skin reactions (chancres) developed in goats at the sites of deposition, by tsetse flies, of metacyclics of trypanosoma congolense. the chancres developed much faster and were more pronounced when ten infected tsetse were allowed to feed on a spot as compared to only one fly per spot. the initial host cellular reaction in the chancre was predominantly polymorphonuclear, followed at the peak of development of the chancre by a predominantly lymphoblastic and plasmacytic reaction. trypanosome ... | 1990 | 2251766 |
| use of dna probes to identify trypanosoma congolense and t. simiae in tsetse flies from the gambia. | species- and strain-specific dna probes were used to identify patent midgut infections in glossina morsitans submorsitans and g. palpalis gambiensis captured at four sites in the gambia. 52% of mature nannomonas infections and 12% of immature infections were identified. trypanosoma (nannomonas) simiae accounted for the majority of identified infections in g.m. submorsitans, indicating the importance of distinguishing this species from the closely related t.(n) congolense when assessing the trypa ... | 1989 | 2566262 |
| comparison of the susceptibility to deltamethrin of female glossina morsitans morsitans westwood, 1850 (diptera: glossinidae) uninfected and infected with trypanosoma (nannomonas) congolense broden, 1904 (kinetoplastida, trypanosomatidae). | the susceptibility of pregnant female glossina morsitans morsitans westwood, 1850 infected with trypanosoma (nannomonas) congolense broden, 1904 to deltamethrin, a synthetic pyrethroid insecticide, was compared to that of pregnant uninfected females. the results showed that infected flies have a significantly higher mortality rate than uninfected ones, and have a reduced longevity compared with uninfected control flies. these experiments suggest that the effects of trypanosome infection on gloss ... | 1990 | 2256771 |
| characterization of trypanosoma congolense serodemes in stocks isolated from chipata district, zambia. | six stocks of trypanosoma congolense were cloned from 17 stocks isolated from eastern zambia and used to initiate insect-form in vitro cultures producing metacyclic trypanosomes. serological assays were then developed using these in vitro-derived metacyclics as a reference collection of antigens. monoclonal antibodies recognized 8 metacyclic variable antigen types (m-vats) of one stock, t. congolense treu 1885, representing 70-80% of that stock's m-vat repertoire, and in an indirect fluorescent ... | 1990 | 2263418 |
| pathological changes in male genitalia of cattle infected with trypanosoma vivax and trypanosoma congolense. | samples for histological studies were taken from the genitalia of 14 bulls (five infected with trypanosoma vivax, five with t. congolense and four uninfected control animals), slaughtered 12, 22 or 30 weeks post-infection. infection with y58 strain of t. vivax and strain 2295 of t. congolense caused various grades of lesions in the male reproductive organs, especially the testes and epididymides. t. congolense produced more severe degenerative changes than t. vivax. it is concluded that in long- ... | 1990 | 2331595 |
| [animal reservoir hosts of trypanosoma brucei gambiense in zaire: trypanosome infections in two foci in bas-zaire]. | the prevalence of trypanosoma spp. infections in domestic animals was estimated in a forest (boma) and a savanna (kimpese) sleeping focus in bas-zaire. the miniature anion-exchange centrifugation technique was used to determine the infection rates with t. congolense, t. vivax and t. brucei spp. in 505 animals. t. congolense predominated in both foci with the highest prevalence in pigs (76.2%), followed by sheep (31.3%), dogs (30.6%) and goats (7.4%). t. vivax was seen only on two occasions. in t ... | 1989 | 2617030 |
| antigen-detection enzyme immunoassays for the diagnosis of trypanosoma vivax, t. congolense and t. brucei infections in cattle. | species-specific monoclonal antibodies against trypanosoma vivax, t. congolense and t. brucei were used to develop antigen-capture enzyme-linked immunosorbent assays (antigen-elisa) for the diagnosis of bovine trypanosomiasis. each assay was subsequently used for the detection of species-specific circulating antigens in sera of cattle experimentally infected by tsetse transmission. in t. vivax and in t. congolense-infected animals, circulating antigens were detected as early as 10-12 days post-i ... | 1989 | 2617031 |
| trypanosome infection rate of glossina morsitans submorsitans in bahr el arab, south darfur province, sudan. | trypanosome infection rate of glossina morsitans submorsitans in bahr el arab fly belt, sudan was investigated in four areas using fly rounds with screen and bait animals together with traps during the dry season february to may 1985. the overall infection rate of tests flies captured in the four areas was 5.1%. the infection rate of vivax group trypanosomes comprised 64.7% of total infections, congolense group 31.2% and brucei group trypanosomes 3.9%: 27.3% of the vivax and 31.3% of the congole ... | 1989 | 2617680 |
| effect of novidium (homidium chloride) chemotherapy on genital lesions induced by trypanosoma vivax and trypanosoma congolense infections in zebu bulls. | zebu bulls chronically infected with trypanosoma vivax and t. congolense were treated at the 12th week post-infection with novidium and slaughtered at different times after treatment to determine histological evidence of healing of the genital lesions. though trypanosomes disappeared from the blood soon after chemotherapy, there was incomplete resolution of genital lesions even 10-18 weeks later. where there is severe degeneration of the testes and epididymes chemotherapy may be ineffective in l ... | 1990 | 2331596 |
| trypanosoma congolense: an in vitro assay to distinguish drug-resistant from drug-sensitive populations. | an in vitro assay to distinguish drug-resistant from drug-sensitive populations of trypanosoma congolense has been developed. the incorporation of radiolabelled hypoxanthine by procyclic trypanosomes in vitro was measured after 48 h exposure to different concentrations of trypanocides. in the presence of either isometamidium chloride (samorin) or diminazene aceturate (berenil), the ability of procyclics of a drug-sensitive stock (treu 1627) to incorporate hypoxanthine at 28 degrees c was impaire ... | 1990 | 2336447 |
| comparative haematological changes following trypanosoma vivax and t. congolense infections in zebu bulls. | a comparative study of haematological changes subsequent to trypanosoma vivax and trypanosoma congolense infections was carried out using 24 zebu bulls during a period of 12 weeks. eight bulls were infected with t. vivax, another eight with t. congolense and eight served as controls. infected bulls developed chronic trypanosomiasis which was characterized by many clinical manifestations including intermittent pyrexia. elevated rectal temperatures of up to 105 and 106 degrees f were recorded, res ... | 1990 | 2343522 |
| serum haemolytic complement activity and c3 levels in bovine trypanosomosis under natural conditions of challenge--early indications of individual susceptibility to disease. | twenty-five baoule (bos taurus) and 12 zebu (bos indicus) cattle, which were part of an experiment aimed at characterizing cattle for resistance to trypanosomosis under natural challenge in burkina faso, were monitored for complement levels. total haemolytic activity of the alternative complement pathway and c3 in sera taken weekly were estimated. the results were analysed in relation to the course of the disease, parasitological data, packed red cell volume (pcv) and body weight. all the animal ... | 1990 | 2343531 |
| trypanosoma congolense: erythrocyte indices, plasma iron turnover and effects of treatment in infected cattle. | early during the course of trypanosoma congolense infection in cattle decreases in pcv occurred and coincided with increases in both mcv and mch. the indices reached highest levels between eight and 12 weeks post-infection. by week 20 of infection mcv and mch had decreased to pre-infection levels even though a substantial anemia persisted. serum iron levels were elevated at eight weeks postinfection. (infected 271 mg dl-1 v. control 140 mg dl-1) but decreased to low levels in infected animals by ... | 1989 | 2619395 |
| susceptibility of african buffalo and boran cattle to trypanosoma congolense transmitted by glossina morsitans centralis. | four african buffalo (syncerus caffer) and four boran cattle (bos indicus) were each exposed to the bites of 10 tsetse flies infected with trypanosoma congolense. although both groups of animals became infected, the buffalo showed no clinical signs of trypanosomiasis while the cattle suffered from the disease characterized by pronounced skin reactions, high parasitaemia and severe anaemia. the prepatent periods in the buffalo varied from 18 to 27 days in comparison with 11 to 14 days in the catt ... | 1990 | 2343539 |
| recombinant dna probes reveal simultaneous infection of tsetse flies with different trypanosome species. | the utility of recombinant dna probes in the detection of natural trypanosome infection of tsetse flies has been assessed in lambwe valley, near the shores of lake victoria, kenya. the tsetse flies were surveyed during two different seasons in 1988. three different probes used each contained highly repetitive dna sequences specific for a species or subspecies of trypanosomes of the nanomonas subgenus. a fourth probe contained repetitive sequences common to trypanosome species of the trypanozoon ... | 1990 | 2362604 |
| biomedical science and the third world. under the volcano. trypanothione reductase. | | 1989 | 2698087 |
| chemoprophylaxis of trypanosomiasis, due to trypanosoma (nannomonas) congolense, in rabbits using a slow release device containing homidium bromide. | the prophylactic activity of a subcutaneously implanted slow release device, containing homidium bromide, was assessed in rabbits, challenged with different stocks of t. congolense, and compared with the classical treatment of 1 mg homidium bromide/kg b.w. intramuscularly. the prophylactic activity of the intramuscular injection was less than a month, while the slow release device protected the rabbits against seven challenges with t. congolense during a period of more than 300 days. | 1989 | 2698124 |
| interference in the establishment of tsetse-transmitted trypanosoma congolense, t. brucei or t. vivax superinfections in goats already infected with t. congolense or t. vivax. | an interference phenomenon that delays superinfection with a trypanosome species different from that used for the initial infection has been found to occur in goats. following tsetse transmission of trypanosoma brucei to goats already infected with t. congolense, there was a delay in chancre development, as well as in the appearance of t. brucei and anti-t. brucei antibodies in the blood when compared to previously uninfected goats. however, there was no delay in the establishment of a tsetse-tr ... | 1989 | 2705284 |
| occurrence of human serum-resistant trypanosoma congolense in goats and sheep in nigeria. | an assessment of the role of dogs, goats and sheep as reservoir hosts of african trypanosomes infective for humans (sleeping sickness) was carried out in nigeria during a 2-year study period. twelve stocks of trypanosoma (trypanozoon) brucei, 10 stocks of trypanosoma congolense and 11 stocks of trypanosoma vivax were isolated from a total of 699 animals, comprising 286 sheep, 221 goats and 192 dogs. the potential infectivity of the isolates for man was tested in vitro using the blood incubation ... | 1989 | 2741299 |
| susceptibility of african buffalo and boran cattle to intravenous inoculation with trypanosoma congolense bloodstream forms. | this study compares the susceptibility of african buffalo (syncerus caffer) and boran cattle (bos indicus) to intravenous infection with t. congolense blood stream forms. the trypanosomes multiplied in the buffaloes and the boran and reached levels of detectable parasitaemia 4 days after infection in the boran and 10 days after infection in the buffalo. the cattle developed severe anaemia and had to be treated 60 days after infection to save them from dying whereas the buffaloes did not develop ... | 1990 | 2382098 |
| effect of chemotherapy on elevated ejaculation time and deteriorated semen characteristics consequent to bovine trypanosomiasis. | the effect of the trypanocidal drug novidium on elevated ejaculation time and deteriorated semen characteristics was studied in zebu cattle infected with t. vivax and t. congolense. two groups, comprising six bulls per group, were infected with trypanosoma vivax or trypanosoma congolense while three bulls served as controls. chemotherapy was carried out 12 weeks post-infection on three bulls from each group, leaving three bulls untreated while three bulls served as uninfected controls. blood sam ... | 1990 | 2397378 |
| interference between drug-resistant and drug-sensitive stocks of trypanosoma congolense in goats. | a study was undertaken in goats to investigate the ability of two unrelated stocks of trypanosoma congolense, one of which is highly sensitive to isometamidium chloride and one which is drug-resistant, to become established in the presence of an existing infection with the other stock. the goats, which were initially infected with the sensitive strain and were then challenged with the resistant strain, were cured by treatment at 0.1 mg kg-1 isometamidium, indicating that the resistant stock did ... | 1989 | 2772408 |
| association of infectivity, parasitaemia and virulence in a serodeme of trypanosoma congolense. | quantitative methods were adopted to study the course of trypanosoma congolense infection in mice and goats. the ease of initiating infection with a single organism (clone) was found to show a smooth correlation with the virulence of 24 isolates. virulence of t. congolense was found to be directly related to the degree of viability of the parasite but inversely proportional to the capacity of the host to limit parasitaemia. isolates obtained from the goat in the early stage of the infection were ... | 1990 | 2399650 |
| conserved sequences in the u2 snrna-encoding genes of kinetoplastida do not include the putative branchpoint recognition region. | the u2 small nuclear rna (snrna) of trypanosoma brucei gambiense, a flagellated protozoon of the order kinetoplastida, is 148 nucleotides (nt) long, and thus the smallest u2 snrna identified so far. to examine the evolutionary conservation of this rna among kinetoplastida, we have cloned and sequenced the u2 genes from trypanosoma congolense and leishmania mexicana amazonensis, which are 145 and 141 nt in length, respectively. the sequences of the kinetoplastida u2 snrnas are essentially identic ... | 1990 | 2401409 |