RESUMEN
The aetiological diagnosis of human African trypanosomiasis (HAT) is based on the detection of the parasite, but currently available parasitological tests have low sensitivity and are hampered by fluctuating parasitaemia. The identification of seropositive individuals on whom to focus parasitological examination is based on antibody detection by means of the Card Agglutination Trypanosomiasis Test (CATT/T.b.gambiense). A complicating phenomenon is the occurrence of serologically positive but parasitologically unconfirmed results (isolated CATT positivity). This work presents a two-year longitudinal serological, parasitological and molecular follow-up of CATT-positive individuals including repeated examinations of each individual, to study the evolution over time of seropositivity at both the population and the individual levels. At the population level, the rate of seropositivity decreased during the first months of the survey, and afterwards showed remarkable stability. At the individual level, the results reveal the extreme heterogeneity of this population, with subjects showing fluctuating results, others with a short transient CATT positivity, and subjects that maintain their seropositivity over time. The stability of seropositivity and the pattern of results obtained with both immunological and parasitological examinations support the view that individual factors, such as immune response to infection, might be involved in the isolated CATT positivity phenomenon.
Asunto(s)
Trypanosoma brucei gambiense/aislamiento & purificación , Tripanosomiasis Africana/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Pruebas de Aglutinación , Animales , Anticuerpos Antiprotozoarios/sangre , Niño , Côte d'Ivoire/epidemiología , Femenino , Estudios de Seguimiento , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Estudios Seroepidemiológicos , Trypanosoma brucei gambiense/inmunología , Tripanosomiasis Africana/sangre , Tripanosomiasis Africana/diagnósticoRESUMEN
Ten blood samples randomly collected from cows on a farm nearby Antwerp, Belgium, were inoculated into KIVI culture medium (Kit for In Vitro Isolation of trypanosomes) and RPMI 10%+feeder medium. Within 3 weeks of incubation all KIVI cultures and four RPMI 10%+feeder revealed presence of Trypanosoma theileri. Some practical implications regarding the use of KIVI for isolation of pathogenic African trypanosomes from cattle and other Bovidae are discussed.
Asunto(s)
Enfermedades de los Bovinos/parasitología , Trypanosoma/aislamiento & purificación , Tripanosomiasis/veterinaria , Animales , Bélgica , Bovinos , Medios de Cultivo , Tripanosomiasis/parasitologíaRESUMEN
A rapid latex agglutination test (LATEX/T. b. gambiense) for detection of antibodies in patients infected with Trypanosoma brucei gambiense is presented. The reagent is coated with a mixture of three variable surface antigens of bloodstream form trypanosomes. Two hundred and forty sera and 79 CSF samples from patients with parasitologically confirmed trypanosome infection along with 173 sera and 38 CSF samples from non-trypanosomiasis patients have been tested. At 1:16 serum dilution, test specificity was 99%, while sensitivity ranged from 83.8 to 100% depending on the geographical origin of the samples. Undiluted CSF samples from non-trypanosomiasis and from first stage patients scored negative while 42 out of 66 CSF samples from second stage patients were positive. Stability and reproducibility of the lyophilized reagent were excellent.
Asunto(s)
Anticuerpos Antiprotozoarios/sangre , Anticuerpos Antiprotozoarios/líquido cefalorraquídeo , Pruebas de Fijación de Látex , Trypanosoma brucei gambiense/inmunología , Tripanosomiasis Africana/diagnóstico , Animales , Antígenos de Protozoos/inmunología , Humanos , Pruebas Serológicas , Glicoproteínas Variantes de Superficie de Trypanosoma/inmunologíaRESUMEN
Infectivity of Trypanosoma brucei rhodesiense to humans is due to its resistance to a lytic factor present in human serum. In the ETat 1 strain this character was associated with antigenic variation, since expression of the ETat 1.10 variant surface glycoprotein was required to generate resistant (R) clones. In addition, in this strain transcription of a gene termed SRA was detected in R clones only. We show that the ETat 1.10 expression site is the one selectively transcribed in R variants. This expression site contains SRA as an expression site-associated gene (ESAG) and is characterized by the deletion of several ESAGs. Transfection of SRA into T.b. brucei was sufficient to confer resistance to human serum, identifying this gene as one of those responsible for T.b. rhodesiense adaptation to humans.
Asunto(s)
Genes Protozoarios , Trypanosoma brucei rhodesiense/genética , Trypanosoma brucei rhodesiense/patogenicidad , Glicoproteínas Variantes de Superficie de Trypanosoma/genética , Animales , Variación Antigénica , Secuencia de Bases , Sangre , ADN Protozoario , Expresión Génica , Humanos , Datos de Secuencia Molecular , Transcripción Genética , Trypanosoma brucei rhodesiense/inmunologíaRESUMEN
In seven goats experimentally infected with a pleomorphic clone of Trypanosoma brucei brucei, parasitaemia was monitored weekly for 6 weeks by wet blood film and microhaematocrit buffy coat examination. Dried blood samples on filter paper were concomitantly collected and tested by PCR using three different primer sets, putatively specific for Trypanozoon, T. vivax and T. congolense. With the originally designed ORPHON5J Trypanozoon primers, PCR tests became positive after 1 week (six animals) or 2 weeks (one animal) of infection and remained consistently positive until the end of the experiments, thus yielding an overall positivity rate of 97%, as compared with 74% for all parasitological tests together. The T. vivax and T. congolense primers yielded no positive PCR results.
Asunto(s)
Enfermedades de las Cabras/diagnóstico , Reacción en Cadena de la Polimerasa/veterinaria , Trypanosoma brucei brucei/genética , Tripanosomiasis Africana/veterinaria , Animales , Cartilla de ADN/química , ADN Protozoario/sangre , ADN Protozoario/química , Electroforesis en Gel de Agar , Femenino , Enfermedades de las Cabras/parasitología , Cabras , Hematócrito/veterinaria , Microscopía de Contraste de Fase/veterinaria , Trypanosoma brucei brucei/aislamiento & purificación , Tripanosomiasis Africana/diagnóstico , Tripanosomiasis Africana/parasitologíaRESUMEN
CATT/Trypanosoma brucei (T.b.) gambiense is an antibody detection test currently used in field surveys on Gambian sleeping sickness. The screening test is usually performed on a drop of freshly collected heparinized blood, followed by a more specific confirmation test on diluted blood, plasma or serum. This approach may be biased by the occurrence of a complement-mediated prozone phenomenon causing lower test sensitivity at lower sample dilutions. A simple remedy is by addition of a Ca2+ chelating agent such as EDTA.
Asunto(s)
Pruebas de Aglutinación , Activación de Complemento/inmunología , Trypanosoma brucei gambiense/inmunología , Tripanosomiasis Africana/diagnóstico , África Occidental , Animales , Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos , Humanos , Tamizaje Masivo , ConejosRESUMEN
A semi-quantitative ELISA, using variable surface glycoprotein of T.b. gambiense as antigen, was developed for the detection of antibodies of different immunoglobulin isotypes in serum and cerebrospinal fluid of sleeping sickness patients. Using the assay, the antibody profiles of paired serum and cerebrospinal fluid samples of 28 patients have been studied. Total concentrations of various Ig isotypes were determined as well. In serum and cerebrospinal fluid a drastic increase in IgG, basically IgG1, as well as in IgM levels was observed. The concentration of IgA remained relatively normal. The antitrypanosomal antibodies detected in serum and cerebrospinal fluid were mainly of the IgG (IgG1 and IgG3) and IgM isotypes. Measurement of immunoglobulin and trypanosome specific antibody concentrations in serum and CSF allows calculation of intrathecal antibody synthesis and is a possible tool for determining the clinical stage of sleeping sickness.
Asunto(s)
Anticuerpos Antiprotozoarios/sangre , Anticuerpos Antiprotozoarios/líquido cefalorraquídeo , Trypanosoma brucei gambiense/inmunología , Tripanosomiasis Africana/inmunología , Animales , Ensayo de Inmunoadsorción Enzimática , Guinea Ecuatorial , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina A/líquido cefalorraquídeo , Inmunoglobulina G/sangre , Inmunoglobulina G/líquido cefalorraquídeo , Isotipos de Inmunoglobulinas , Inmunoglobulina M/sangre , Inmunoglobulina M/líquido cefalorraquídeo , Sudán , Tripanosomiasis Africana/sangre , Tripanosomiasis Africana/líquido cefalorraquídeoRESUMEN
LATEX/IgM, a rapid agglutination test for the semi-quantitative detection of IgM in cerebrospinal fluid of patients with African trypanosomiasis, is described in this article. The lyophilized reagent has been designed for field use and remains stable at 45 degrees C for one year. The test has been evaluated on cerebrospinal fluid samples from trypanosome-infected and non-infected patients, by comparison with commercial latex agglutination, radial immunodiffusion, and nephelometry. All test systems yielded similar results.
Asunto(s)
Inmunoglobulina M/líquido cefalorraquídeo , Tripanosomiasis Africana/diagnóstico , Estudios de Evaluación como Asunto , Humanos , Inmunodifusión , Indicadores y Reactivos , Pruebas de Fijación de Látex , Nefelometría y Turbidimetría , Tripanosomiasis Africana/líquido cefalorraquídeoRESUMEN
In serum and in cerebrospinal fluid (CSF) from patients with human African trypanosomiasis (HAT) with central nervous system involvement, we detected autoantibodies directed to some proteins from these tissues. The characterization of antigenic proteins by Western blotting showed that the antibodies recognized the 200-kD and 160-kD proteins of neurofilament (NF). Serum anti-NF antibodies were more frequent in HAT patients than in control subjects (86% versus 24%; P < 10[-9]) and they belonged predominantly to the IgM class (anti-NF IgM = 86% versus anti-NF IgG = 4%; P < 10[-9]) in the patients with stage II (central nervous system involvement) HAT. The CSF antibodies to NF were IgM in 88% (22 of 25) of the cases and IgG in 32% (8 of 25) of the cases. Epitopes shared by NF and trypanosomes were detected by indirect immunofluorescence and this was confirmed by the disappearance of anti-NF reactivity after adsorption with trypanosome antigens (Trypanosoma brucei brucei or T. b. gambiense). Anti-NF antibodies were undetectable in the CSF from stage I HAT patients.
Asunto(s)
Autoanticuerpos/análisis , Proteínas de Neurofilamentos/inmunología , Tripanosomiasis Africana/inmunología , Animales , Antígenos de Protozoos/inmunología , Autoanticuerpos/sangre , Autoanticuerpos/líquido cefalorraquídeo , Autoanticuerpos/inmunología , Epítopos/análisis , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina G/líquido cefalorraquídeo , Inmunoglobulina M/sangre , Inmunoglobulina M/líquido cefalorraquídeo , Trypanosoma/inmunología , Trypanosoma brucei brucei/inmunologíaRESUMEN
Six goats were experimentally infected with a stock of Trypanosoma vivax. Parasitaemia was weekly monitored by buffy coat and wet blood film examination during a period of 15 weeks and another 3 weeks following drug-treatment. Dried blood samples were tested by the polymerase chain reaction (PCR), using an extraction method with Chelex 100 (BioRad). PCR proved consistently more sensitive than the parasitological techniques.
Asunto(s)
Enfermedades de las Cabras/diagnóstico , Cabras/parasitología , Reacción en Cadena de la Polimerasa , Tripanosomiasis Africana/veterinaria , Animales , Femenino , Enfermedades de las Cabras/parasitología , Reacción en Cadena de la Polimerasa/métodos , Trypanosoma vivax , Tripanosomiasis Africana/diagnósticoRESUMEN
Twelve T.b. gambiense clone populations of distinct Variable Antigen Type (VAT) were combined in immune lysis tests with 340 sera of trypanosome infected patients from 8 different African countries and 267 non trypanosomiasis control sera. The diagnostic specificity of the test was 100%. At a serum dilution of 1:4 the overall test sensitivity with single VATs varied from 39.1 to 98.2% and from 12.1 to 86.8% at 1:32. At a serum dilution of 1:32 some combination tests with 2 VATs still scored above 96%. The VAT recognition patterns were clearly correlated with the geographical origin of the sera, reflecting a diversity in variable antigen repertoires.
Asunto(s)
Trypanosoma brucei gambiense/inmunología , Tripanosomiasis Africana/diagnóstico , Animales , Cobayas , Humanos , Ratones , Conejos , Sensibilidad y Especificidad , Pruebas SerológicasRESUMEN
Le depistage systematique de la maladie du sommeil a Trypanosoma brucei gambiense dans un foyer endemique necessite la mise en oeuvre de tests serologiques detectant des anticorps specifiques. A cet egard; certains tests d'agglutination relativement simples ont l'avantage de donner une reponse rapide sur le lieu de rencensement meme
Asunto(s)
Trypanosoma brucei gambiense , Tripanosomiasis , Tripanosomiasis/diagnósticoRESUMEN
The results of a novel direct serological card agglutination test for the diagnosis of camel trypanosomosis due to Trypanosoma evansi (CATT/T. evansi) were compared with those obtained by direct detection of parasites in a study using 1,093 sera from camels raised in northern Mali. A good correlation was revealed between the percentage of positive results obtained by CATT and the presence of trypanosomes (89%), as well as a good coincidence between the percentage of positive results obtained by CATT and low haematocrit values (packed cell volume). CATT revealed a global serological prevalence of 30.6%, whereas trypanosomes were found in only 5.85% of the corresponding animals. CATT/T. evansi is a quick and easy-to-read test, which merits further evaluation in camel-rearing countries.
Asunto(s)
Pruebas de Aglutinación/veterinaria , Camelus/parasitología , Trypanosoma/aislamiento & purificación , Tripanosomiasis Africana/veterinaria , Factores de Edad , Animales , Estudios de Evaluación como Asunto , Hematócrito/veterinaria , Malí/epidemiología , Prevalencia , Reproducibilidad de los Resultados , Tripanosomiasis Africana/diagnóstico , Tripanosomiasis Africana/epidemiologíaRESUMEN
In the national park of Pendjari, situated in the North-West of Benin, 91 wild animals, belonging to seven species, were darted. Thick and thin blood smears were examined for trypanosomes and plasma for trypanolytic antibodies against 6 antigenic variants of Trypanosoma brucei gambiense. Parasites were found in 13.92% and trypanolytic antibodies in 20.88% of the samples. A total of 28.57% of animals were positive by at least one of the two test systems used. Morphologically Trypanosoma congolense, T. vivax and T. brucei were identified. Overall prevalence was 40% in Adenota kob (n: 50), 13.63% in Alcelaphus buselaphus (n: 22), 10% in Hippotragus equinus (n: 10), 33% in Kobus defassa (n: 3), 0% in Phacochoerus aethiopicus (n: 3) and in Syncerus caffer (n: 2). The only lion (Panthera leo) examined was serologically positive. The results indicate that the wild animals are reservoirs of animal trypanosomes and suggest that among them Adenota kob and Panthera leo are carriers of T. brucei gambiense, one of the etiological aspects of human trypanosomiasis.
Asunto(s)
Animales Salvajes/parasitología , Reservorios de Enfermedades , Trypanosoma brucei gambiense/aislamiento & purificación , Animales , Anticuerpos Antiprotozoarios/aislamiento & purificación , Antígenos de Protozoos/aislamiento & purificación , Benin , Trypanosoma brucei gambiense/inmunologíaAsunto(s)
Trypanosoma brucei gambiense/inmunología , Trypanosoma brucei rhodesiense/inmunología , Tripanosomiasis Africana/diagnóstico , Animales , Anticuerpos Antiprotozoarios/aislamiento & purificación , Antígenos de Protozoos/aislamiento & purificación , Humanos , Técnicas Inmunológicas , Examen Físico , Tripanosomiasis Africana/inmunologíaRESUMEN
A latex card agglutination test for detection of antibodies in human African trypanosomiasis is presented. The latex was covalently coated with semipurified surface glycoprotein of Variable Antigen Type LiTat 1.6 of Trypanosoma brucei gambiense. Sera from 100 patients infected with T.b. gambiense, 26 patients infected with T.b. rhodesiense and 707 individuals without trypanosomiasis, including 132 malaria seropositives, have been tested. At serum dilution 1:16, sensitivity of the test was 91% for the T.b. gambiense and 42.3% for the T.b. rhodesiense group. Specificity was over 99%. The reagent remained stable at +/- 6 degrees C for at least 3 months. Reagent kept at 37 degrees C for 3 months retained its sensitivity and showed a slight decrease in specificity.