Search PubMed⌕ Search

Biomedical subjects

P Truc

Publications and source records attributed to P Truc.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of the in vitro drug sensitivity of Trypanosoma brucei gambiense strains from West and Central Africa isolated in the periods 1960-1995 and 1999-2004.

The situation of human African trypanosomiasis remains serious with one of the main threats being the increasing number of relapses or treatment failures after melarsoprol treatment. In order to investigate and to compare drug sensitivities of trypanosomes isolated at different time periods and in different locations, two sets of Trypanosoma brucei gambiense strains were used. One set was isolated in the time period 1960-1981 and the other one in 1995-2004 from different locations of West and Central Africa. These isolates were not selected based on the treatment outcome but on availability. The drug sensitivity profile for all available drugs in use and the diamidine compound DB75 was established. IC(50) values were not significantly different between the "old" and "new" stocks. No indications for emerging drug resistance to any drug could be observed. The results indicate a relative stability of in vitro sensitivity of T. b. gambiense to trypanocidal drugs in space (West and Central Africa) and time (1960-2004).

Africa, Central↗
PubMed2006

Treatment and follow-up of the first case of human trypanosomiasis caused by Trypanosoma evansi in India.

The first reported human case of trypanosomiasis caused by Trypanosoma evansi was treated using suramin. Patient follow-up indicates that the drug and specific regimen used were well tolerated. Clinical, serological and parasitological investigations at 6 months indicate complete cure of the patient. Suramin should be considered in the treatment of other cases of human T. evansi infection, if they occur.

Follow-Up Studies↗
PubMed2006

A rare case of human trypanosomiasis caused by Trypanosoma evansi.

Human trypanosoma infections like the ones seen in Africa and South America are unknown in India. The only exception in literature is of two documented cases of a self-limiting febrile illness, being attributed to Trypanosoma lewisi like parasites. We are reporting an unusual case of trypanosomiasis from the rural parts of Chandrapur district in Maharashtra. An adult male farmhand who used to practice veterinary medicine also, presented with history of febrile episodes on and off since five months and drowsiness before admission to this Institute. Though routine blood and other investigations were within normal limits, the peripheral smear showed a large number of trypanosomes which morphologically resembled the species Trypanosoma evansi, the aetiological agent of surra - a form of animal trypanosomiasis. A battery of assays covering the spectrum of parasitology, serology, and molecular biology confirmed the infecting parasite to be T. evansi. Failure to demonstrate the central nervous system (CNS) involvement, as evidenced by the absence of parasite in cerebrospinal fluid (CSF) advocated the use of suramin - the drug of choice in early stage African trypanosomiasis without any CNS involvement. Suramin achieved cure in our patient. The case is being reported because of its unique nature as the patient was not immunocompromised and showed infestation with a parasite which normally does not affect human beings.

Animals↗
PubMed2004

A procedure for isolating and freezing metacyclic Trypanosoma brucei gambiense forms in the field.

An adaptation of a modified procedure using anion-exchange centrifugation was evaluated to isolate and freeze in field conditions a high number of bloodstream forms of Trypanosoma brucei gambiense for direct in vitro culture. Pellets of trypanosomes were obtained from 62 patients in Central Africa. The presence of trypanosomes was detected in all 62 eluates. The isolation system was efficient. Preliminary results of in vitro culture of 10 thawed samples of trypanosomes were highly promising because no fungal or bacterial contamination was noticed even after 2 weeks of culture.

Animals↗
PubMed2004

A study of host preference in tsetse flies using a modified heteroduplex PCR-based method.

A study of host preference in tsetse flies using a modified heteroduplex PCR-based method is described. Domestic and wild animal blood samples were collected to extract the corresponding reference DNAs. In Campo (south Cameroon), tsetse flies (mainly Glossina palpalis palpalis) were trapped and 41 bloodmeals were collected. All reference DNAs and 37 bloodmeal DNAs (90.7%) were successfully amplified and hybridised. Twelve bloodmeals (32.4%) were of human origin, 13 (35.4%) were from Sitatunga (Tragelaphus spekei) (an antelope) while 12 (32.4%) were not identified using our set of reference DNAs. The results confirmed the occurrence of frequent contacts between wild animals and this population of tsetse flies.

Animals↗
PubMed2004

Characterization of Trypanosoma brucei s.l. infecting asymptomatic sleeping-sickness patients in Côte d'Ivoire: a new genetic group?

Six villagers in the Sinfra focus of sleeping sickness in Côte d'Ivoire who in 1995 were asymptomatic and refusing treatment, despite then being serologically and parasitologically positive for trypanosomes, were followed-up, while still refusing treatment, until 2002. In 2002, five of the six cases remained serologically positive but no trypanosomes could be found in any of them by use of the classical parasitological methods. A PCR-based assay, however, revealed that all six had the DNA of Trypanosoma brucei s.l. in their blood, so confirming the low sensitivity of the classical parasitological tests. The analysis of satellite, minisatellite and microsatellite markers indicated that, in 2002, all six cases were infected with a 'new' distinct genetic group of T. brucei s.l. and four were co-infected with T. b. gambiense group 1. The epidemiological consequences of such co-infections are discussed. The 'new' group of T. brucei had a molecular pattern that differed from those of the classical T. b. gambiense group 1 and the 'bouaflé' group.

Animals↗
PubMed2002

Genetic characterization of Trypanosoma brucei gambiense and clinical evolution of human African trypanosomiasis in Côte d'Ivoire.

Human African trypanosomiasis is a parasitic infection caused by protozoa belonging to Trypanosoma brucei subspecies. The clinical evolution of this disease is complex and might be because of the parasite itself, as genetic diversity has been observed in T. brucei ssp. We investigated the relationship between the genetic diversity of trypanosomes and the diversity of clinical patterns in Côte d'Ivoire. We studied clinical sleeping sickness cases, and genetically analysed the trypanosomes isolated from these patients. An important genetic monomorphism among stocks isolated in Côte d'Ivoire was observed by using various markers: isoenzymes electrophoresis, random amplified polymorphism DNA and PCR of microsatellite sequences. At the same time, the diversity of clinical patterns and evolutions was confirmed by clinical analysis. The existence of an individual susceptibility to disease (human trypanotolerance) should be taken into account even if our genetic conclusions might be distorted because the isolation success rates were particularly poor. In fact, we observed that the isolation success rate varied significantly depending both on the focus of origin (P=0.0002) and on the ethnic group (P=0.0317) of the patient. Further investigations are required in order to study a possible selective impact of the use of the kit for in vitro isolation of trypanosomes as an isolation technique.

Animals↗
PubMed2002

IgM quantification in the cerebrospinal fluid of sleeping sickness patients by a latex card agglutination test.

An increased IgM concentration in cerebrospinal fluid (CSF), occurring as a consequence of massive intrathecal IgM synthesis, is a marker of interest for diagnosis of the meningo-encephalitic stage in human African trypanosomiasis. However, in current practice, IgM in CSF is not determined because of the lack of a simple and robust test that is applicable in African rural regions where the disease prevails. We describe the development of a sensitive semiquantitative card agglutination test, LATEX/IgM, for IgM quantification in CSF. The test is simple and fast and the lyophilized reagent remains stable even at 45 degrees C. CSF end-titres obtained with LATEX/IgM parallel the IgM concentrations determined by nephelometry and enzyme-linked immunosorbent assay. Detection of intrathecal IgM synthesis is the most sensitive marker for CNS involvement in sleeping sickness. At a cut-off value of >or= 8, the sensitivity and specificity of LATEX/IgM for intrathecal IgM synthesis are 89.4 and 92.7%. As a consequence, patients with LATEX/IgM end-titres >or= 8 are likely to have intrathecal IgM synthesis, thus central nervous system involvement and therefore should be treated accordingly. Further studies should concentrate on the relationship between the LATEX/IgM end-titres, presence of intrathecal IgM synthesis and occurrence of treatment failures in patients treated with pentamidine.

Animals↗
PubMed2001

[Methodology to determine risk zones for sleeping sickness in Côte d'Ivoire by the spatial approach].

Earth observation technology is a rapidly expanding field in which new outlets for sensor data are being found daily. However medical applications are still limited. The main obstacle is the lack of methods to link spatial data to an epidemiological data base within a given disease context. This obstacle was recently overcome in the Sinfra region of Cote d'Ivoire where a number of researchers have been working on human African trypanosomiasis (HAT) for over ten years. A geographical information system was developed to allow testing of various spatial relationships especially between the population density and disease prevalence using various methods of geostatistical analysis. Spot satellite data was then used to draw a map showing population density. The data base was used to validate processing by explaining the presence of errors due mainly to locality. Finally as a first experimental application for this methodology, a map showing the risk of HAT transmission over the entire Sinfra region was drawn based on satellite data.

Cote d'Ivoire↗
PubMed2001

[Distribution and spread of human African trypanosomiasis: value of genetic identification of the trypanosomes].

Numerous factors extrinsic to trypanosome populations have been implicated in the distribution and spread of human African trypanosomiasis (HAT), but quantification of these factors has proven difficult. An easier method of monitoring HAT consists of tracking parasites by genetic identification of trypanosomes in hosts and vectors. This method requires distinction between Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense followed by determination of the genotype of each subspecies in the host and vector. The role of vertebrate hosts in the distribution and spread of HAT has been confirmed by genetic identification of trypanosomes. Despite the ever-improving performance of biomolecular techniques, identification must be carried out on natural populations actually circulating in the biological fluids of the host and vector. This precaution is necessary to rule out the biasing effect of in vivo or in vitro isolation of trypanosomes.

Animals↗
PubMed2000

Preliminary evaluation of LATEX/T. b. gambiense and alternative versions of CATT/T. b. gambiense for the serodiagnosis of human african trypanosomiasis of a population at risk in Côte d'Ivoire: considerations for mass-screening.

A study was conducted to compare classical card agglutination test for trypanosomiasis (CATT)/T. b. gambiense with CATT-EDTA and LATEX/T. b. gambiense as alternative field tests for serodiagnosis of Human African Trypanosomiasis. The tests were performed on freshly collected blood in an endemic and a low prevalence area in Côte d'Ivoire. Diagnostic performance of each test was assessed using Quantitative Buffy Coat as the parasitological reference and immune trypanolysis as the serological reference test. According to the parasitological data, CATT-EDTA on 10 microl and LATEX/T. b. gambiense on blood diluted 1:4, detecting all confirmed cases with good specificity (respectively 94.6% and 98.1%) yielded better results than the classical CATT did (one false negative and 92.5% specific). However, when immune trypanolysis data and feasibility are taken into account, the classical CATT remains the test of choice for mass screening under the given field conditions.

Agglutination Tests↗
PubMed2000

Characterization of Trypanozoon isolates using a repeated coding sequence and microsatellite markers.

Genetic variation of microsatellite loci is a widely used method for linkage analysis, individual identification or inter-population studies. Here we analyse a repeated DNA coding sequence and eleven new microsatellites identified within the Trypanosoma (Trypanozoon) brucei genome. Ninety-seven isolates belonging to the five species and subspecies Trypanosoma evansi, T. equiperdum, T. brucei brucei, T. b. rhodesiense and T. b. gambiense were compared regarding the genetic patterns of these markers. The results reveal a great heterogeneity of the genotypes related to the repeated coding sequence and five microsatellites, some of which show a high degree of polymorphism. This allows us to define group-specific genotypes or alleles; in particular, we show that one specific pattern clearly segregates the human pathogen T. b. gambiense group I.

Amino Acid Sequence↗
PubMed2000

Characterization of Trypanozoon isolates using a repeated coding sequence and microsatellite markers.

Genetic variation of microsatellite loci is a widely used method for linkage analysis, individual identification or inter-population studies. Here we analyse a repeated DNA coding sequence and eleven new microsatellites identified within the Trypanosoma (Trypanozoon) brucei genome. Ninety-seven isolates belonging to the five species and subspecies Trypanosoma evansi, T. equiperdum, T. brucei brucei, T. b. rhodesiense and T. b. gambiense were compared regarding the genetic patterns of these markers. The results reveal a great heterogeneity of the genotypes related to the repeated coding sequence and five microsatellites, some of which show a high degree of polymorphism. This allows us to define group-specific genotypes or alleles; in particular, we show that one specific pattern clearly segregates the human pathogen T. b. gambiense group 1.

Journal Article↗
PubMed1999

Identification of bloodmeals in haematophagous Diptera by cytochrome B heteroduplex analysis.

We developed a DNA assay for bloodmeal identification in haematophagous insects. Specific host cytochrome B gene sequences were amplified by PCR and classified on the basis of their mobility in a heteroduplex assay. In the blackfly Simulium damnosum s.l. (Diptera: Simuliidae), human cytochrome B DNA sequences were identifiable up to 3 days following ingestion of the bloodmeal. In the tsetse Glossina palpalis (Diptera: Glossinidae) collected from tsetse traps in Ivory Coast, bloodmeals were identified as taken from domestic pigs on the basis of their heteroduplex pattern and DNA sequence. Evidently the cytochrome B sequence shows sufficient interspecific variation to distinguish between mammalian host samples, while exhibiting minimal intraspecific variation. The stability of DNA in bloodmeals, for several days post-ingestion by haematophagous insects, allows PCR-HDA assays to be used reliably for host identification.

Animals↗
PubMed1999

Use of polymerase chain reaction in human African trypanosomiasis stage determination and follow-up.

Stage determination of human African trypanosomiasis is based on the detection of parasites and measurements of biological changes in the cerebrospinal fluid (CSF) (concentration of white blood cells > 5 cells per mm3 and increased total protein levels). The patient is treated accordingly. Demonstration of the absence or presence of trypanosomes by the double centrifugation technique is still the only test available to clinicians for assessing treatment success. In this study, however, we evaluate the polymerase chain reaction (PCR) as a tool for assessing the disease stage of trypanosomiasis and for determining whether treatment has been successful. All 15 study patients considered to be in the advanced stage of the disease were PCR positive; however, trypanosomes were demonstrated by double centrifugation in only 11 patients. Of the five remaining patients, who were considered to be in the early stage, PCR and double centrifugation were negative. Following treatment, 13 of the 15 second-stage patients were found to be negative for the disease in at least two samples by PCR and double centrifugation. Two others were still positive by PCR immediately and one month after the treatment. Trypanosome DNA detection using PCR suggested that the two positive patients were not cured but that their possible relapse could not be identified by a search for parasites using the double centrifugation technique. Further evaluation of the PCR method is required, in particular to determine whether PCR assays could be used in studies on patients who fail to respond to melarsoprol, as observed in several foci.

Animals↗