Evaluación de una prueba rápida para el diagnóstico de la infección por Trypanosoma cruzi en suero / Evaluation of a rapid diagnosis test for trypanosoma cruzi infection in serum sample

Con el fin de evaluar la utilidad práctica, y la sensibilidad y especificidad del test rápido Dipstick test Trypanosoma cruzi Detect, (Inbios, Seattle, WA) se estudiaron 284 sueros humanos de los cuales 145 correspondieron a casos probados de infección chagásica y 139 a individuos sanos de zonas no endémicas. Todos ellos analizados previamente con las Técnicas de ELISA y de Inmunofluorescencia Indirecta para la detección de anticuerpos IgG anti T. cruzi. Además se estudiaron 56 muestras serologicamente negativas para enfermedad de Chagas pero que presentan otras patologías parasitarias y no parasitarias. El "test" rápido de INBIOS demostró una especificidad de 99,3 por ciento al igual que la sensibilidad. Y una concordancia con La ELISA y la RIFI de de 98,2 por ciento. De acuerdo a estos resultados y a la facilidad de su ejecución, Dipstick test T. cruzi Detect (INBIOS) resulta ideal como tamiz para la vigilancia y los programas de intervención de la enfermedad de Chagas.

We tested a Rapid Diagnostic Test (RDT) to detect Trypanosoma cruzi infection using a total of 284 human sera, some of them from provedcases ofChagas disease (n = 145) and healthy individuals from non-endemic areas (n = 139). Another group included was non chagasic serum samples of individuals of other parasitic and non parasitic disease (n = 56), all of them with known serological test results. The RDT had a specificity of 99,3 percent and a sensitivity of 99,3 percent. The agreement with ELISA and IFAT was 98,2 percent. According to the results and the feasibility of the RDT should be an ideal tool for screening purposes in disease surveillance and intervention programs ofChagas disease.

Aspectos parasitológicos y epidemiológicos de los donantes de sangre seropositivos para Trypanosoma cruzi, en un hospital universitario / Parasitological and epidemiological aspects of Trypanosoma cruzi seropositive blood donors

Background: After the interruption of the transmission of Chagas disease via vector insects in Chile, there is little available epidemiological information about this parasitosis in blood banks. Aim To update the rates of T cruzi positive blood donors. To measure parasitological and epidemiological parameters in blood donors with anti T cruzi antibodies. Material and Methods: An ELISA-T cruzi test was carried out in 30,309 blood donors between 2000 and 2004. In 75 blood donors with an ELISA-T cruzi positive test and 79 donors with negative ELISA (controls), a survey about personal or parental history of biting by a kissing bug (Triatomine), was performed. A blood sample was also obtained to perform Polymerase Chain Reaction (PCR) for T cruzi and a xenodiagnostic test. Results: Annual frequency of positive ELISA for T cruzi serum antibodies in blood donors varied from 0.31 percent to 0.45 percent. Twenty eight percent of subjects with positive and 6 percent of subjects with negative specific antibodies answered the survey about biting. PCR and xenodiagnostic test were positive in 52 (69 percent) and 16 (21 percent) of positive ELISA-T cruzi test blood donors, respectively. Xenodiagnostic was also positive in 5 individuals who had a negative PCR. Conclusions: Seroprevalence of T cruzi antibodies decreased from 3 percent in 1968 to 0.3 percent in 2004.

Seroprevalencia de hidatidosis humana en la Región de Coquimbo. Chile / Human hydatidic seroprevalence in Coquimbo Region, Chile

Estudio previos de seroprevalencia de hidatidosis en Chile, realizados en sectores urbanos y rurales encontraron una tasa de 135 x 105, con una estimación probable de 17.002 personas infectadas. En los últimos años la prevalencia humana y animal ha tendido a disminuir en todas las regiones del país, excepto en la IV, VI y IX. Entre ellas destaca la IV Región por mostrar las mayores alzas, tanto en el ganado ovino como en el caprino. Con el objeto de contribuir al conocimiento actual de la hidatidosis humana, se estudió la prevalencia serológica en comunidades rurales ganaderas de la IV Región de Coquimbo con el fin de que dichos resultados sirvan de base para la aplicación de programas de control en la zona. Se estudiaron 4.632 muestras de habitantes de las provincias de Elqui, Limarí y Choapa. La selección del grupo se efectuó por muestreo aleatorio sistemático representativo de la región, según localidades y equivalentes al 3 por ciento de la población rural total de la IV Región. Las muestras de sangre obtenidas del pulpejo del dedo medio, fueron colectadas en papel filtro, según las normas bioéticas, estando supeditado al consentimiento de las personas. A cada eluído se les efectuó ELISA IgG. En forma paralela en dos laboratorios de rutina de inmunodiagnóstico parasitológico. Como antígeno se usó líquido hidatídico hepático ovino, aislado en forma estéril, centrifugado a 12.000 g en un laboratorio y en el otro el antígeno estuvo constituido por la fracción B o antígeno de Oriol. La seroprevalencia de la hidatidosis encontrada en comunidades rurales ganaderas de la IV Región de Coquimbo, alcanzó a un 2,5 por ciento. La tasa global encontrada en la IV Región equivale a una prevalencia estimada de 2.500 x 105, cifra notablemente superior a la tasa de 1,65 x 105 a nivel nacional y de 6,73 x 105 para la Región de Coquimbo notificadas en el 2004. Las prevalencias encontradas para las provincias de Limarí y Choapa, fueron superiores, en forma significativa, al n.

Estudio seroepidemilógico de la hidatidosis humana en la comuna de San Juan de la Costa Osorno X Región Chile 2000 / Seroepidemiological study of human hydatidosis in San Juan de la Costa county Osorno X Región Chile 2000

San Juan de la Costa County (40 45ïSouth lat., 73 19ïWest long.) is located in the Osorno province, South of Chile. Is population is 11,445. The basic economic activities are agriculture, cattle raising, fishery, timber production and manufacture of wood and coal. According to official reports, the incidence of human hydatidosis in Chile and Osorno province, in 1999, was 1.8 and 12.5 per 100,000 respectively. In order to contribute to a better knowledge of the epidemiology of human hydatidosis, an indirect hemagglutination test (IHAT) and ELISA IgG for hydatidosis were performed to 533 randomized people. Three (0.56 percent) resulted positive. Parallelly, a socio-epidemiological survey on hydatidosis was carried out: the majority of people had some basic knowledge about some aspects of hydatidosis transmission. Some considerations on the correspondig prophy latic measures are mentioned

Evaluación de los programas de erradicación de vectores de la enfermedad de Chagas en Chile mediante estudio serológico de niños menores de 10 años / Evaluation of Chagas's disease vector erradication programs in Chile by serological study of children under 10 years old

Chagas's disease is a parasitic zoonosis with high prevalence in Chile. It is distributed in rural and periurban section in the northern most seven out of thirteen regions in which the country is divided, and affects about 142,000 individuals dispersed in most of the 165 counties sited in the chagasic zone triatoma infestans, intradomiciliary species, is the main and practically exclusive vector of trypanosoma cruzi. Diverse tools be utilized in order to interrupt the domestic cycle of transmission of T. cruzi health education, housing improvement and elimination of vectors by dwelling insecticide sprayings. This last resource has received priority in Chile in the last 12 years. To evaluate the effectivity of the programs for eliminating T. infestans a serological study for Chagas's disease, comprising 8,767 children less than 10 years old from 27 rural counties insecticide sprayed in the last 12 years, was carried out. A global total of 125 (1,4 percent) children resulted positive, figure significantly lower than 5,4 percent found in 1982-1990 in the same age group. Distribution by regions of positive individuals showed a decrease of prevalence in each of them: III Region, from 9,8 to 1,0 percent, IV Region, 7,2 to 2,0 percent, V Region, 5,2 to 1,9 percent, and Metropolitan Region, 1,4 to 0,6 percent. Even though positive children have still been found in 46,7 percent of localities of the studied counties, it is possible to affirm that the vector control programs have been effective and must be maintained, and increased in those localities with T. cruzi infection in children under 10 years of age, with the general aim of eradicate Chagas's disease transmission in Chile before 2000.

Diagnóstico de la neurocisticercosis humana mediante ELISA-IgG usando un antígeno purificado / Diagnosis of human neurocysticercosis by ELISA-IgG using a purified antigen

An analysis of inmunodiagnosis data for human neurocysticercosis (NC) by ELISA-IgG, complement fixation (CSF) from confirmed cases of different hospitals from the metrolitan area of Santiago, Chile, was performed. The cut-off value was determined by using serum samples from 60 apparently healthy persons, whose absorbance values were the mean plus three standard desviations. The sensitivity of ELISA was 97,0 percent and 100 percent for serum samples and CSF respectively. This assay was considered od statistical significance (p< 0,05) when it was compared with CFT. Specificity was stablished by testing a purified antigen over 109 different helminthiasis serum samples, 185 neurological affections other than NC and 60 control samples. A 98,3 percent of global specificity was found. The use of ELISA-IgG and a purified antigen in the approach of inmune diagnosis of NC is considered a useful assay, particularly if it is perfomed on paired serum/CSF samples.

Epidemiología de la enfermedad de Chagas en Chile: frecuencia de infección humana por trypanosoma cruzi por grupos de edad y por regiones / Epidemiology of Chagas's disease in Chile: frequency of trypanosoma cruzi human infection by age groups and regions

Chagas's disease is endemic in rural-periurban sections of the northern half of Chile which includes the first seven political-administrative regions of the country (18º30'-34º36' South lat.). Data concerning to the results of an indirect hemagglutination test for Chagas's disease performed to 15,418 rural-periurban and 45,119 urban inhabitants from the chagasic endemic regions are presented migrations from rural-periurban to urban areas have contributed to the dissemination of trypanosoma cruzi infection. General rates of infection for rural-periurban (r-p) and urban (u) sections were 16,7 for percent and 1,9 for percent respectively. The higher prevalence rates were detected in region III with 27,2 for percent (r-p) and 3,9 (u) and Region IV with 24,7 for percent (r-p) and 3,5 for percent (u), while the lower prevalence rates corresponded to Region VI with 7,0 for percent (r-p) and 0,8 for percent (u). Serological positivity increased parallelly with age in all regions

Evaluación de un programa de erradicación del triatoma infestans en viviendas rurales de la IV Región de Chile mediante serología para la enfermedad de Chagas en niños de 0 a 10 años de edad / Triatoma infestans eradication program assessment in rural dwellings from the IV Region of Chile by serology for Chagas' disease in children 0 to 10 years of age

The present study deals with the evaluation of the effectiveness of the measures employed in the control of triatoma infestans, the vector of trypanosoma cruzi infection (Chagas' disease), in the IV Region of Chile through a serological follow up program. For this reason, a serological survey has been carried out in 2,783 chidren, from 0 to 10 years, who live in rural high endemic areas of the region. The sera were tested using an indirect hemagglutination test (IHAT) and ELISA techniques with results agreeing in 99,9 for percent of the samples. In children with positive serology xenodiagnosis was perfomed and blood samples from the corresponding mothers were submitted to serology for Chagas's disease. These addicional tests should allow to distinguish between congenital infection and vectorial transmission. It was observed that vectorial transmission of T. cruzi was interrupted in some localities where entomological control has been applied for 10 years, or lowered in those which have been submitted to desinsectations in the last 5 years. On the other hand, a relatively high prevalence of the infection has been detected in some localities. These results suggest an apparent increase of vectorial transmision, indicating the need of readjusting the dwellings insecticide sprayings activities to improve the measures against the vector

Valor diagnóstico de la ELISA-IgG para triquinosis usando antígeno de Melcher / Diagnosis value of ELISA-IgG for human trichinosis by using Melcher's antigen

An enzyme-linked inmunosorbent assay (ELISA) for trichinosis using a Melcher's antigen was developed for the detection of IgG antibodies in 41 serum samples from patients confirmed or suspected to have trichinosis by strong clinical and epidemiological evidences. ELISA-IgG was compared with a precipitin test (PT), a bentonite floculation test (BFT) and an indirect hemagglutination test (IHAT). The cut-off value as determined using serum samples from 67 apparently healthy persons employing two serum dilutions (1:100 and 1:500) with three standard desviations (SD). The sensitivity of ELISA-IgG was 97,6 for percent and 95,2 for percent using serum dilutions of 1:100 and 1:500 respectively, whereas the values for the other tests were: PT (92,7 for percent), BFT (63,4 for percent) and IHAT (85,4 for percent). According to MacNemar test, Elisa-IgG did not present statistical significance (p>0.01). In order to find out the specificity of ELISA-IgG, additional 124 serum samples from individuals with other parasitoses, such as cysticercosis (31), fascioliasis (17), hydatidosis (51) and toxocariasis (25) were also tested. ELISA-IgG presented a specificity of 99,5 for percent with both serum dilutions. The positive predictive values were 97,6 and 97,5 for percent, whereas the negative one were 99,5 and 99,0 for percent for 1:100 and 1:500 serum dilutions respectively. The use of ELISA-IgG and Melcher's antigen in the diagnosis of human trichinosis is discussed

Positividad del xenodiagnóstico según edad en personas con serología positiva para enfermedad de Chagas / Positive xenodiagnosis according to age in people with seropositive Chagas's disease

An analytical study of positive xerodiagnosis (XD), according age distribution, in people with a positive indirect hemagglutination test (IHAT) for Chagas's disease has been carried out. A total of 1,137 IHAT for Chagas's disease positive persons were submitted to two wooden XD boxes containing 7 triatoma infestans nymphs III each. The positivity in percentage of XD in the different age groups was: 0-9 year old (60,8), 10-19 (35,8), 20-29 (31,5), 30-39 (28,7), 40-49 (30,0), 50-59 (34,3) and ò 60 (43,3). The 60,8 positivy of XD in children under 10 years of age is possibly due to the rather recent trypanosoma cruzi infection in this age group and to diverse inmunological mechanisms, which decrease with the age increasing

Evaluación de la técnica de ELISA con antígeno total de cysticercus cellulosae para el diagnóstico de la neurocisticercosis humana en Chile / Evaluation of ELISA technic with total antigen of cysticercus cellulosae in the diagnosis of human neurocysticercosis in Chile

La estandarización del método de ELISA con el empleo de un antígeno total de cysticercus cellulosae, se evaluó en 22 sueros de pacientes con neurocisticercosis comprobada y 106 sueros correspondientes a individuos sanos y pacientes con otras patologías parasitarias y no parasitarias. Los resultados demostraron una sensibilidad de 68,2 por ciento y una especificidad global de 92,5 por ciento. Las reactividades cruzadas se presentaron en sueros de pacientes con hidatidosis, tumor cerebral y factor reumatoide. Se concluye que se debe buscar nuevas alternativas metodológicas que permiten aumentar la sensibilidad y especificidad para el diagnóstico de la cisticercosis humana en Chile

Evaluación de la ELISA IgG, usando un antígeno purificado en el diagnóstico de la hidatidosis humana / Evaluation of ELISA IgG test using a purified antigen in the human hydatidosis diagnosis

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of IgG antibodies to purified sheep hydatic cyst fluid antigen in 56 sera of confirmed cases of hydatidosis. The cut-off value was determined using serum samples from 80 healthy persons, employing two serum dilutions (1:100 and 1:500) with two and three standard desviations (SD). This assay was compared with the indirect hemaglutination test (IHAT). The sensitivity of ELISA-IgG was 94,3 for percent, for hepatic cysts and 92,9 for percent, for pulmonary cysts, whereas the values for IHAT were 77,1 and 64,3 for percent, respcetively. According to Mac Nemar test, both thod presented statistical significance (p < 0,05). In order to find out the specificity, additional 70 serum samples from individuals with other parasitoses, such as cysticercosis (30), trichinosis (26) and fascioliasis (14) were also tested, IHAT presented a specificity of 92,7 for percent and for ELISA-IgG the specificity using a cut-off of average + 3 SD was 99,3 and 100,0 por percent with sera dilution of 1:100 and 1:500 respectively when a cut-off of average +2 SD was considered, we found a specificity of 91,3 and 97,3 por percent, for 1:100 and 1:500 dilutions. The use of ELISA-IgG and purified antigen in the diagnosis of human hydatidosis is discussed

Brote de triquinosis en la comuna de Purranque X Región, Chile: octubre/noviembre 1992 / Outbreak of trichinosis in Purranque county X Region, Chile: october/november 1992

An outbreak of trichinosis occurred in Purranque county, X Region, Chile, between october and november of 1992, which involved 36 persons. The incubation period, determinated by the clinical picture and laboratory assays, fluctuated between 10 and 12 days, myalgias (88,9 for percent) and palpebral oedema (86,1 por percent) were the most important symptoms, followed by fever (44,4 for percent) and headache (33,3 for percent). Eosinophils count ranged from two to 42 for percent the first week, and this value raised to 55 for percent the second week of the outbreak. Anti-trichinella spiralis antibodies were determinated by some serological tests such as: precipitin test (PT), bentonite flocculation test (BFT) and indirect hemagglutination test (IHAT) in sera IHAT (21,4 for percent) and BFT (3,6 for percent). After 15 days, the three tests were perfomed in sera from 12 patients. At that time, the positivity was elevated in all of them: PT (100,0 for percent), BFT (66,7 for percent) and IHAT (91,7 for percent). It is believed that the outbreak had its origin in infected pork meat that was consumed raw or insufficiently cooked without a previous veterinary inspection

Investigación seroepidemiológica de algunas helmintiasis tisulares mediante la reacción de hemaglutinación indirecta en la comuna de Lonquimay, Chile / Seroepidemiological research of some tissue helminthiasis using an indirect hemagglutination test in the Lonquimay county, Chile

In order to have a present perspective on the prevalence on the epidemiology of some tissue helminthiasis in Lonquimay county, southern Chile, in 1993 a seroepidemiological survey, by means an indirect hemagglutination test (IHAT) for hydatidosis, cysticerosis and trichinosis was undertaken. In 11 (1,2 for percent) and 6 (0,6 for percent) out of 945 examined persons, most of them from rural areas, the corresponding IHAT resulted positive. Addicionally, radigraphic and ecotomographical studies for thorax and abdomen respectively were performed to the 11 individuals with serology positive for hydatidosis: whereas all the thoraxic radiographies resulted negative, liver hydatic cysts were detected in five persons, who latter on were submitted to surgery. Prevalence rates of hydatidosis in Lonquimay are among the highest regional and national values

Quimioterapia del Cáncer Gástrico. / Gastric Cancer Chemotherapy.

Se reportan los resultados obtenidos en el tratamiento quimioterápico del cáncer gástrico avanzado.En 31 pacientes de ambos sexos,se aplicó el esquema FAM-5-Fluoruracilo,Adriamicina y Mitomicyn;los pacientes procedieron de centros hospitalarios de Lima-Perú y tuvieron diagnóstico clínico,radiológico,endoscópico e histológico y fueron tratados durante dos años.La respuesta completa y parcial a la quimioterapia fue de 64% y el tiempo libre de enfermedad fue de 9.3 meses en promedio.