Divers inquires established by chagasic patients in relation to its clinical condition, motivated to a group of parasitologists to design an assistance educative programme. 72 volunteer patients participated, 32 men and 40 women from the high and low chagasic endemic zones of Chile. The educative methodology basically consist in the application of a diagnosis and acquired knowledge tests; theorical sessions of six relationated tematics subjects, tutorial practical activities; use of audiovisual and printed material, personal diligence by a parasitological doctor (after the educative assistance and with the serological, electrocardiographical and parasitological antecedents determinated previously) and evaluation of the educative activity by the patients. A greater previous and acquired knowledge was observed in chronic chagasics patients from endemic zones. All of them demonstrated a high degree of interest and actively participated in the programmed activities. The used methodology, the tutorial work of small groups and the individual attention-orientator by the parasitological doctor, facilitated the teaching-learning process. It is concludes that the educative assistance answer many of the inquires in relation to the disease, allows the patient to recognize the role as protagonist of his own comfort and transforms him in an efficient agent to control Chagas disease

Las diversas inquietudes planteadas por pacientes chagásicos crónicos en relación a su condición clínica, motivaron a un grupo de parasitólogos a diseñar un programa de intervención educativa. Participaron en forma voluntaria 72 pacientes, 32 hombres y 40 mujeres, procedentes de zona de alta y baja endemia chagásica de Chile. La metodología docente consistió fundamentalmente en: aplicación de test diagnóstico y de conocimientos adquiridos; sesiones teóricas que abordaron seis temáticas relacionadas; actividades prácticas tutoriales; utilización de material audiovisual e impreso; atención personalizada por médico parasitólogo (posterior a la intervención educativa y con los antecedentes serológicos, electrocardiográficos y parasitológicos previamente determinados) y evaluación de la actividad educativa por parte de los pacientes. Un mayor conocimiento previo y adquirido se observó en chagásicos crónicos procedentes de zonas endémicas. Todos demos-traron un alto grado de interés y participaron activamente de las actividades programadas. La metodología utilizada, el trabajo tutorial de pequeño grupo y la atención-orientación individual por parte del médico parasitólogo, facilitaron el proceso de enseñanza-aprendizaje. Se concluye que la intervención educativa responde a muchas de las interrogantes respecto de la afección, permite al paciente reconocer el rol que le cabe como protagonista de su propio bienestar y lo transforma en un eficaz agente en el control de la enfermedad de Chagas

A familiar outbrake of strongyloidosis affected peruvian immigrants who had arrived Chile in november 2001 is reported. In march 2002, Strongyloides stercoralis infection of the index individual was confirmed by the Basic-Clinical Laboratory of Parasitology of the Faculty of Medicine of the University of Chile, in Santiago, Chile. At the Roberto del Río Pediatric Hospital, a 11 years old girl presenting juvenil rheumatoid arthritis and mild abdominal distress was studied. A serial of three stool samples was collected and procesed by ether-centrifugal concentration technique. A plentiful quantity of rhabditoid larvae of S. stercoralis was observed. To detect larvae in the faeces and specific serum antibodies against S. stercoralis by means of ELISA her parents and sister were studied. The mother of the index case and her sister were positive in both test. The father was not infected. The three positive cases were treated with Ivermectine. A control study performed one year later demonstrated a positive ELISA test only in the sister

Se presenta un brote familiar de stron-gyloidosis que afectó a inmigrantes peruanos que habían llegado a Chile en noviembre del año 2001. En marzo del 2002, se confirmó en el Laboratorio de Parasitología Básico-Clínico de la Facultad de Medicina de la Universidad de Chile que el caso índice presentaba infección por Strongyloides stercoralis. Correspondía a una menor de 11 años que estaba siendo estudiada en el Hospital Roberto del Río por artritis reumatoide juvenil. Además de esta patología la niña refería leves molestias abdominales, siendo derivada a nuestra unidad, donde se le efectuó un examen parasitológico seriado de deposiciones (EPSD), observándose abundantes larvas rabditoides de S. stercoralis, por lo cual se procedió a estudiar al grupo familiar integrado por los padres y una hermana. A todos ellos se les efectuó EPSD e inmunodiagnóstico mediante ELISA para detectar anticuerpos anti S.stercoralis. Resultaron positivos para ambos exámenes la madre y las dos hijas. El padre fue negativo. Se decidió tratar con ivermectina y controlar los resultados del tratamiento anti-parasitario al grupo familiar al cabo de un año. Después de ese periodo permanecía positiva serológicamente, solamente la hermana del caso índice debido a que no ingirió los medicamentos de la manera indicada

In may 2003 an epidemiologic-parasitological survey was carried out in 206 pre-school and school-children from San Vicente de Lo Arcaya School in Colina, a semi-rural county of the Santiago Province in the Metropolitan Region of Chile.The most frequent parasitic elements were: Blastocystis hominis - in men and women respectively - 38.8% and 44.4%, Giardia intestinalis with 9.5% and 16.2% and Enterobius vermicularis with 12.9% and 10.0%. It is notewortly that the infected children were asymptomatic Cryptosporidium parvum was not observed and an ELISA test for Strongyloides stercoralis infections was positive in one children.This study confirms that intestinal parasitic infections in children remain with a high prevalence in Chile.

En mayo de 2003 se efectuó una encuesta epidemio-parasitológica en pre-escolares y escolares de la Escuela San Vicente de Lo Arcaya de Colina, comuna semirural de la Provincia de Santiago ubicada en la Región Metropolitana de Chile. Hay que destacar que los niños estudiados eran asintomáticos. Los elementos parasitarios más frecuentemente encontrados fueron: Blastocystis hominis - en hombre y mujeres respectivamente - 38,8% y 44,4%, Giardia intestinalis con 9,5% y 16,2% y Enterobius vermicularis con 12,9% y 10,0%. Cryptosporidium parvum no fue encontrado y ELISA para Strongyloides stercoralis resultó positiva en un niño.

An indirect hemagglutination test (IHAT) and an ELISA test for trichinosis using as antigen a larvae soluble fraction from Trichinella spiralis was carried out for the detection of IgG, IgM and IgA specific antibodies in 113 serum samples from patients confirmed or suspected to have trichinosis by strong clinical and epidemiological evidences (Group I). The same tests were also performed on 110 serum samples corresponding to patients without strong evidences of having trichinosis (Group II). In Group I the corresponding sensitivities for RHAI, ELISA IgG, ELISA IgM, ELISA IgA were: 82.3-85.8-88.5 and 88.5% respectively. Seventeen patients were tested again a week after the first analysis (10 of them corresponded to negative ones), increasing the positivity: 23.5-100.0;35.3-100.0;41.2-100.0 and 41.2-100.0% for RHAI, ELISA IgG, ELISA IgM and ELISA IgA, respectively. Other two patients were followed-up for 5 years. IHAT and ELISA IgG remained positive, whereas ELISA IgM and ELISA IgA were constantly negative betweeen 17 and 32 months in one case, and between 48 and 60 months in the other (this last one had presented a severe clinic disease). In the group II, four patients were positive with IHAT, however only one for ELISA IgA, the latter also presented ELISA IgM near the cut off. The use of ELISA IgG, ELSIA IgM and ELISA IgA in the immunodiagnosis of trichinosis is discussed.

Toxoplasmosis, a world-wide zoonotic infection, is generally asymptomatic and benign in immunocompetent individuals, but it can be serious in immunodeficiencies particulary in patients with acquired immunodeficiency syndrome and in children infected in utero. So, it is important to dispose methods which permit discriminate between recent and chronic infections. In order to contribute to improve the diagnosis of toxoplasmosis ELISA IgG, IgM, IgA and ELISA IgG avidity were performed in 15 and 24 sera from patients suspected of having acute and chronic infection respectively, according dye test (DT) titres. ELISA IgG was positive in both groups, ELISA IgM was positive in 78.6 and 58.3% respectively, while ELISA IgA was positive in 85.7 and 33.3% of recent and chronic group respectively. In those sera with low IgG avidity ( 18.8%) we found specific IgM in 71.5 and 4.2% and IgA in 78.6 and 0.0% of recent and chronic groups respectively. Parallely, 208 sera samples were clasified according to the results of DT, indirect hemagglutination and complement fixation tests in the following groups: acute (97), intermediate (36), chronic (35) and negative (40). The results were: acute (96.9-64.9-55.6 and 65.9%); intermediate (97.2-63.8-44.4 and 47.2%); chronic (45.7-42.8- 5.7 and 34.3%) for IgG, IgM, IgA and low IgG avidity respectively. The use of both acute markers, IgA and low IgG avidity in the diagnosis of toxoplasmosis is discussed.

An ELISA test for trichinosis using as antigen a larvae soluble fraction from Trichinella spiralis was carried out for the detection of IgMand IgA specific antibodies in 45 serum samples from patients confirmed or suspected to have trichinosis by strong clinical and epidemiological evidences. All the patients had positive serology detected by precipitin test, bentonite floculation test, indirect hemagglutination test and ELISA IgG test. The cut-off value was determined using two criteria. Criterion A was determined in each plate, using three positive controls and two negative ones; the average of the negative controls and the weakest positive control, muliplied by a 1.2 factor was, considered the cut-off value. Criterion B was determinated using the average plus three standard deviations from 64 apparently healthy persons serum samples. In both cases, three serum dilutions (1:10, 1:100 and 1:500) were used. The sensitivity of ELISA IgM was 100.0, 93.3 and 82.2% using serum dilutions of 1:10, 1:100 and 1:500 respectively (criterion A) and 100.0, 97.8 and 95.6% for the same dilutions (criterion B), whereas the values for ELISA IgA were: 100.0, 91.1 and 86.7% (criterion A) and 100.0, 100.0 and 91.1%(criterion B). In order to find out the specificity of ELISA IgM and ELISA IgA, additional118 serum samples from individuals with other parasitoses, such as cysticercosis (18) hydatidosis (39), fascioliasis (12), toxocariasis (30), Chagas' disease(12) and individuals with non-specif eosinophilia (7), were also tested. ELISA IgM presented a specificity of 92.3, 93.4 and 97.3% (criterion A) and 96.2, 97.8 and 97.8% (criterion B) whereas the results for ELISA IgA were 97.8, 98.9 and 99.4% (criterion A) and 98.4% for the 1:10 and 1:100 dilutions and 100.0% for the 1:500 dilution (criterion B). The positive predictive values of ELISA IgM were 76.3, 77.8 and 88.1% (criterion A) and 86.5, 91.7 and 91.5% (criterion B) whereas the negative ones were 100.0, 98.3 and 95.7% (criterion A) and 100.0, 99.4 and 98.9% (criterion B). The positive predictive values of ELISA IgA were 91.8, 95.3 and 97.5% (criterion A) and 93.8, 93.8 and 100.0% (criterion B) whereas the negatives ones were: 100.0, 97.8 and 96.8% (criterion A) and 100.0, 100.0 and 97.8%(criterion B). The use of ELISA IgM and ELISA IgA in the immunodiagnosis of trichinosisis discussed.

Chile is located in the southwestern border of South America. The country is 4,329 km long and 96-342 wide. From north to south it is divided into five marked different biogeographical zones: deserts, steppes, bushes, forests (cattle raising) and austral (sheep raising). Population (June1999) 15,017,760 (14.6% rural). Human hydatidosis is endemic in Chile. According to Ministry of Health information about 320 cases are registered each year. In order to find out the likely prevalence of human hydatidosis in Chile,a series of serosurveys was carried out in 1988-1997 throughout the total country. By using the indirect hemagglutination reaction and ELISA for hydatidosis (tests with good sensibility and specificity) 60,790 unselected apparently healthy persons: 41,399 from urban areas (16,428 blood donors, from 13,894 delivering mothers and 11,077 middle grade school children) and 19,361 from rural areas - from randomly selected family groupings-were studied. A total individuals 82 (136/100,000) resulted positive: 36 (87/100,000) urban and 46 (241/100,000) rural, being the prevalence higher in rural areas, particularly in the southern austral zone (mean 1068/100,00). These figures agree with those observed in clinical epidemiological studies. In conformity with the present results, in the whole country 17,002 individuals should have hydatidosis: 10,318 urban and 6,784 rural. All these possible infected people, not necessarily should present pathology in the future, as it has been observed in autopsies from unselected individuals, performed at the Medico-Legal Service in Santiago, in whom 71.3% of diagnosed hydatosis with hydatid cysts in many different locations, was an autopsy finding

A series of already published and unpublished seroepidemiological surveys for toxoplasmosis, carried out in Chile in 1982-1994, is reviewed, expanded and analyzed. The surveys included 76,317 apparently healthy individuals of different ages (0.57% of the country's total population), from 309 urban and rural-periurban localities. Urban groups were integrated by blood donors, delivering mothers and middle grade schoolchildren, while rural-periurban individuals corresponded to unselected family groups. Blood samples were collected in filter paper. The presence of antibodies to Toxoplasma gondii was determined by the indirect hemagglutination test (IHAT), titers > 16 were considered positive. The test resulted positive in 28,124 (36.9%) of the surveyed people. Two hundred and six (0.3%) individuals presented IHAT titers > 1000, probably corresponding to acute or reactivated infections. A progressive increase of positive IHAT from northern to southern regions of the country was noted, phenomenom probably related to geographical conditions and to a higher production and consumption of different types of meat in the latter regions. It is postulated that ingestion of T. gondii cysts by humans is epidemiologically as important as ingestion of oocysts. The results presented stress the epidemiological importance of toxoplasmosis in humans, and warn about eventual implications in immunocompromised patients and in transplacental transmission, organ transplants and transfusions.

En este trabajo se revisa, se amplía y se analiza en conjunto una serie de encuestas seroepidemiológicas sobre toxoplasmosis efectuadas en Chile entre 1982 y 1994, utilizando la reacción de hemaglutinación indirecta (RHAI). El estudio incluyó 76.317 personas aparentemente sanas de diferentes edades (0,57% de la problación total del país), procedentes de 309 localidades urbanas y rural-periurbanas. Los grupos urbanos estuvieron constituídos por donantes de sangre, parturientas y escolares del nivel medio de la enseñanza básica, mientras que los habitantes rural-periurbanos correspondieron a grupos familiares no seleccionados. Las muestras de sangre fueron recolectadas en papel filtro, y fueron consideradas positivas las RHAI con títulos > 16. La RHAI resultó positiva en un total de 28.124 (36,9%) de las personas encuestadas, encontrándose títulos > 1000 en 206 (0,3%) individuos, los que probablemente correspondieron a infecciones agudas o reactivadas. Hubo un progresivo incremento de las RHAI positivas desde las regiones del extremo norte hacia las regiones del extremo sur del país, lo que podría relacionarse con una mayor humedad ambiental y con una mayor producción y consumo de diferentes tipos de carne en estas últimas. Los resultados presentados destacan la importancia de la toxoplasmosis en el hombre y alertan sobre eventuales implicancias en pacientes inmunocomprometidos, en la transmisión transplacentaria, transplantes de órganos y transfusiones.