Amebiasis intestinal y hepática / Intestinal and hepatic amebiasis

Amebiasis is the infection by Entamoeba histolytica, a protozoan capable of invading the colonic mucosa causing a diarrheic syndrome, although most of the time is mild, it can lead to a fulminating colitis. Sometimes it can spread to other organs; among extra-intestinal manifestations of this parasite, the most frequent is the amebic liver abscess. In the next pages, general aspects of this protozoan, its epidemiology, clinical findings, diagnosis and treatment are reviewed, emphasizing the possibilities of diagnosis and treatment available in Chile.

La amebiasis corresponde a la infección por Entamoeba histolytica, protozoo capaz de invadir la mucosa del colon provocando un cuadro diarréico que, si bien la mayoría de las veces es leve, puede llegar a una colitis fulminante. En algunas oportunidades puede diseminarse a otros órganos; dentro de las manifestaciones extra-intestinales de este parásito, la más frecuente es el absceso hepático amebiano. A continuación se revisan aspectos generales de este protozoo, su epidemiología, cuadro clínico, diagnóstico y tratamiento, destacando las posibilidades de diagnóstico y tratamiento disponibles en Chile.

Diagnóstico parasitológico e molecular de enteroparasitos entre crianças residentes e funcionários de uma institução beneficente para menores no município de Niterói-RJ, Brasil / Parasitological and molecular diagnosis of enteroparasites among resident children and employees of a child care institution at Niterói city, RJ, Brazil

Os enteroparasitos são causa importante de agravos à saúde humana e podem interferir de forma significativa no desenvolvimento infantil. Embora as formas de transmissão sejam bemdocumentadas, a desinformação e as precárias condições socioeconômicas de alguns segmentos da população ainda são fatores que contribuem para a manutenção de parasitos no País, viabilizando a transmissão. Este estudo foi realizado entre crianças residentes e funcionários de uma instituiçãofilantrópica religiosa, situada na cidade de Niterói, Rio de Janeiro, consistindo em um ciclo de palestras educativas, seguido da coleta de amostras fecais para diagnóstico coproparasitológico.Foram coletadas 68 amostras fecais frescas e encontrados enteroparasitos em 41 delas (60 por cento),sendo o Blastocystis hominis o parasito mais prevalente (44 por cento). Adicionalmente, sete amostrasforam positivas para o complexo Entamoeba histolytica/E. dispar, sendo uma confirmada como E. histolytica pelo ELISA para pesquisa de coproantígeno. Em 37 amostras de fezes foi pesquisadaa presença de E. histolytica e E. dispar pela técnica de Nested-PCR. Entre essas, 12 (32 por cento) amplificaram um fragmento de 195 pb quando utilizados primers específicos para E. dispar, não havendo amplificação de qualquer produto com os primers de E. histolytica. Estudo feito no entornoda instituição revelou acúmulo de lixo e a presença de saídas de esgoto no peridomicílio, as quais desembocavam nas proximidades da área de lazer das crianças. É possível que esses pontos sejam responsáveis pela contaminação do solo e mesmo incriminados como uma das possíveis fontes deinfestação para as crianças.

Intestinal parasites are important agents of human diseases, besides being responsible for impairingchildhood development. Although transmission is well known, lack of information and precarioussocial and economic conditions are risk factors that allow maintenance of parasite cycles, favoringtransmission. This study was carried out among resident children and employees of a Catholic Institution, located in Niterói, Rio de Janeiro, and consisted of delivering lectures and collectingfresh stool samples, which were processed through the Willis and Hoffman, Pons and Janermethods. Enteroparasites were found in 41 samples (60 percent) and Blastocystis hominis was the mostprevalent (44 percent). Additionally, in seven samples where microscopic examination was positive forthe E. histolytica/E. dispar complex an ELISA was employed to detect E. histolytica and only onereacted positively in the immunoassay. In 37 samples a Nested-PCR was carried out for detectionof E. histolytica and E. dispar and in 12 samples (32 percent) a product with 195 bp was observed usingE. dispar primers, while there was no amplification product with E. histolytica specific primers. As the Institution has a good pattern of hygiene not related with the results, a superficial analysis of its peripheral area was carried out and showed lots of garbage in the neighborhood and sewage outflowinto the play area of the Institution. We concluded that these points may be responsible for the soil contamination and could be incriminated as one of the sources of infection in the children.

Perforación intestinal secundaria a amebiasis / Amebiasis intestinal perforation secondary

La amebiasis intestinal es una enfermedad frecuente en países en desarrollo, que es común en regiones tropicales y subtropicales, así como en regiones con servicios sanitarios deficientes. Presentamos el caso de un paciente de 74 años de edad, sexo masculino, originario y residente de la ciudad de Guatemala, quién cursó una diarrea y dolor abdominal. Fue intervenido quirúrgicamente por abdomen agudo, con resección intestinal extensa por perforaciones. En el estudio de anatomía patológica se realizó el diagnóstico de colitis amebiana con perforaciones y peritonitis.

Intestinal amoebiasis is a disease common indeveloping countries, which is common in tropicaland subtropical regions, as well as in regions withpoor sanitation. We report the case of a 74-year-oldmale, resident of Guatemala City, who presented withdiarrhea and abdominal pain. He had a laparatomy foracute abdomen, undergoing wide intestinal resectiondue to perforations. The pathology diag-nosis wasamoebic colitis with perforations and peritonitis.

Nuevos métodos para el diagnóstico microbiológico de la amebiasis y de otros protozoarios intestinales / New methods for the microbiological diagnosis of amebiasis and other intestinal protozoa

La Organización Mundial de la Salud (OMS) ubica a las enfermedades diarreicas en segundo lugar como causa de morbi-mortalidad de niños en países en vías de desarrollo, siendo las infecciones por protozoarios intestinales proporcionalmente una causa trascendente en dichas regiones. La mayoría de estos parásitos se transmiten por vía fecal-oral o por contacto interpersonal y exhiben ciclosde vida que, en general se desarrollan en dos estadios: el trofozoíto que coloniza el intestino y el quiste que es excretado con las heces y cuya rígida pared protectora, le confiere resistencia en el ambiente, permitiendo de este modo la propagación de la enfermedad. Entamoeba histolytica es uno de los agentes infecciosos de mayor distribución mundial, y es aproximadamente la causa de 100.000 muertes por año, siendo responsable de uno de los problemas de salud más serios en países en vías de desarrollo. Se reconocen al menos ocho amebas que podrían colonizar el intestino del hombre: E. histolytica, E. dispar, E. moshkovskii, E. coli, E. hartmanni, E. polecki, Iodamoeba butschlii y Endolimax nana. Aunque sólo E. histolytica es considerada como el agente etiológico de la Amebiosis. Su presentación clínica va desde la colonización asintomática, la disentería amebiana, hasta la propagación extraintestinal, originando abscesos en diversos órganos y tejidos. Por este motivo, la correcta identificación de E. histolytica en heces y tejidos y diferenciándola de otras amebas comensales y de otros protozoarios representa un desafío en la práctica médica, a que de ello dependerá el tratamiento y el pronóstico de laenfermedad.

Abstract: The World Health Organization (WHO) includes diarrhea a the second leading cause of morbidity and mortality of children in developing countries. Among these causes, infections by intestinal protozoan parasites represent an important percentage in any place of the world. Most of these parasites are transmitted by the fecal-oral route or by inter personal contact and exhibit simple life cycles, consisting in the disease-causing, proliferating trophozoites and the dormant, resistant cyst responsible for the transmission of the infection among susceptible hosts. Entamoeba histolytica is one of the most frequent of those parasites, causing about 100.000 deaths per year in developing countries, being one of the major health problems in areas where basic sanitation practices are inefficient. At least eight species of Entamoeba have been reported to infect the human large intestine: E. histolytica, E. dispar, E. moshkovskii, E. coli, E. hartmanni, E. polecki, odamoeba butschlii and Endolimax nana, although E. histolytica is the only one considered to cause pathology in humans. Clinical manifestation of this infection varies from asymptomatic infection to dysentery and extraintestinal invasion, producing abscesses in many tissues. Therefore, the correct identification of E. histolytica in stool and tissue samples and its differential diagnostic is an important challenge in parasitology because treatment and prognosis depend of the valid identification of this parasite.The health issue of protozoan intestinal infections, both in developed and developing parts of the world, is of such importance that it is clearly necessary the development of novel, better, cheap, and faster diagnostic methods. The incorporation of new approaches and technology to the efficient and sensitive detection of these infections is significantly relevant.

Etiology and the role of proctosigmoidoscopy in patients with acute bloody diarrheas

To find out the etiology of acute bloody diarrheas in patients admitted to a tertiary care hospital. This descriptive study was conducted in the department of medicine, Lady Reading hospital from 2005 to 2008. A total of 50 patients were studied, comprising of 35 males and 15 females. Mean age of the sample was 32.66 +/- 15.4 years]. Patients who presented with acute bloody diarrhea of between 3-30 days duration were studied. Patients who had history of recurrent bloody diarrhea were also included. Patients below 12 years, severely dehydrated and seriously ill were excluded. All patients underwent fibreoptic proctosigmoidoscopy and rectal biopsy. Amebic colitis was confirmed on stool examination for Trophozoites of Entameoba histolytica, typical proctosigmoidoscopic findings and response to anti-amebic drugs. Thirty-two patients [64%] were having new onset bloody diarrhea, while 18 patients [36%] were giving history of recurrent bloody diarrhea. All patients had evidence of Procto-colitis on fibreoptic sigmoidoscopy. The most common conditions were ulcerative colitis in 25 [50%], bacterial dysentery in 15 [30%] and Amebic proctocolitis in 7 [14%]. Findings on proctosigmoidoscopy were mucosal hyperemia [50%], bleeding points [38%], ulcers [44%], pus [20%], pseudo polyps [4%] and mass [4%]. Fibreoptic Proctosigmoidoscopy is a simple and easier procedure to diagnose different causes of acute bloody diarrhea and should be considered in all cases except in seriously ill and dehydrated patients. The common causes of acute bloody diarrhea in our community are bacterial proctocolitis, amebiasis and ulcerative colitis

Sobrediagnóstico de amebiasis en niños con disentería / Overdiagnosis of amebiasis in children with dysentery

Existen dos amebas, morfológicamente idénticas, cuyas diferencias determinanque una de ellas, Entamoeba histolytica, pueda ser patógena. La otra, Entamoeba dispar, es inocua.Surgió la presunción de que casos tratados como amebiasis, no lo fueran. Objetivo. Identificar E. histolytica en niños con disenterías supuestamente amebianas. Métodos. Estudio transversal y observacional realizado en Santa Fe, entre marzo de 2005 y noviembre de 2007. En niños de 2 meses a 15 años con disentería y exámenes directos con E. histolytica/dispar, se realizó ELISA para detectar la adhesina de E. histolytica (adhesina Eh) en heces.Se efectuaron coloraciones para amebas, coprocultivos y se registraron datos clínicos.Resultados. De 75 casos estudiados, 35 fueron varones y 40 mujeres, con edad (mediana) de 3 años. Todos presentaron diarreas agudas con leucocitos;73 por ciento en sangre visible microcópicamente y 27 por ciento en el estudio microscópico. Tuvieron adhesina Eh positiva, 21. En 3 de ellos se detectaron trofozoítos hematófagos.Se realizaron 15 coprocultivos, en 5 desarrolló S. flexneri de tipo S2. Otros parásitos: 6 (Blastocystis homini 5).Tuvieron adhesina Eh negativa, 54. El 19 por ciento de las coloraciones demostró E. dispar.A 44 se les realizaron coprocultivos; desarrollaron bacterias invasivas 12 casos: S. flexneri de tipo S2 (13), Shigella sp (1), C. jejuni (5), otros (3). Otros parásitos: 12 (Blastocystis hominis 9).Conclusión. En este grupo de niños con disenterías amebianas, en la mitad de los casos seidentificaron bacterias invasivas y sólo en el 28 por ciento se detectó E. histolytica en heces, con lo cual cabría esperar una prevalencia de 18-38 por ciento de casos positivos en la población [IC 95 por ciento (0,179; 0,381)].

Mecanismos fisiopatogênicos e diagnóstico laboratorial da infecção causada pela Entamoeba histolytica / Physiopathogenic mechanisms and laboratorial diagnosis of Entamoeba histolytica infection

A amebíase é a segunda causa de morte entre as doenças parasitárias no mundo. Seu agente etiológico é o protozoário Entamoeba histolytica, que através da secreção de proteinases é capazes de destruir o tecido hospedeiro, matando as células-alvo por contato e fagocitando eritrócitos. Dessa forma, os trofozoítos invadem a mucosa intestinal, provocando a colite amebiana. Em alguns casos atravessam a mucosa e, através da circulação porta, chegam ao fígado, onde causam necrose constituída por poucos trofozoítos rodeados de hepatócitos mortos e debris celulares liquefeitos. Essa invasão está diretamente relacionada com a capacidade de síntese e a secreção de moléculas responsáveis pela virulência dos trofozoítos, como os amebaporos, as lectinas e as cisteína proteinases. O diagnóstico da infecção causada pelo patógeno é rotineiramente realizado através da microscopia óptica de amostras frescas ou espécimes fixados. Entretanto essa metodologia apresenta limitações, sendo incapaz de distinguir as espécies pertencentes ao complexo E. histolytica/E. dispar. A pesquisa de coproantígenos e a reação em cadeia da polimerase (PCR) têm sido utilizadas para diferenciação desses protozoários em amostras fecais. No entanto, estudos mais aprofundados são necessários para maior compreensão sobre a relação parasita/hospedeiro, a proteômica e a genômica do protozoário, o desenvolvimento de vacinas e a real prevalência dessa infecção no Brasil e no mundo.

Amebiasis is the second cause of death among parasitary diseases in the world. Its etiologic agent is the protozoan Entamoeba histolytica, which destroys the host tissue by means of the secretion of proteinases, kills the target-cells by contact and phagocytizes erythrocytes. Accordingly, the trophozoites invade the intestinal mucosa, what causes amoebaean colitis. In some cases, they pass through the mucosa and reach the liver through the portal system, where they cause necrosis, which is composed of a few trophozoites surrounded by dead hepatocytes and liquefied cellular debris. This invasion is directly related to the synthesis capacity and secretion of molecules responsible for the virulence of trophozoites such as amoebapores, lectins and cysteine proteinases. The diagnosis of infection caused by this pathogen is routinely performed through optical microscopy of fresh samples or fixed specimens. However this methodology presents limitations insofar as it is unable to distinguish the specimens belonging to the complex E. histolytica /E. dispar. The research on coproantigens and the polymerase chain reaction (PCR) method have been used to differentiate these protozoa in fecal samples. However further studies are required for a better understanding of the host-parasite relationship, the proteomics and genomics of the protozoa, the development of vaccines and the real prevalence of this infection in Brazil and worldwide.

Amebíase / Amoebiasis: an update

A amebíase é a segunda principal causa de morte por parasito em todo o mundo. O protozoário responsável, Entamoeba histolytica, apresenta elevada patogenicidade. É capaz de secretar proteases que dissolvem o tecido do hospedeiro, matar suas células por contato, fagocitar eritrócitos e invadir a mucosa intestinal causando a colite amebiana. Em alguns casos, este parasito é capaz de romper a barreira da mucosa intestinal e chegar ao fígado por meio da circulação porta, onde pode causar abscesso que cresce rapidamente e é quase sempre fatal. Evidências baseadas apenas na morfologia apontavam a existência de uma única espécie. No entanto, estudos mais modernos mostraram que, na realidade, há duas espécies geneticamente bem distintas, denominadas Entamoeba histolytica (patogênica) e Entamoeba dispar (não patogênica ou comensal).

Entamoeba histolytica and Entamoeba dispar: differentiation by Enzyme-Linked Immunosorbet Assay (ELISA) and its clinical correlation in pediatric patients

Studies were carried out at a mexican pediatric hospital to determine the ratio between the pathogenic species Entamoeba histolytica and non-pathogenic species E. dispar using an enzyme-linked immunosorbent assay (ELISA) to detect the lectin (1 galactose N-acetyl D-galactosamine) of E. histolytica in feces. A close correlation was noted between the presence of the E. histolytica lectin and clinical symptoms. In the study, amebas were detected by microscopy in 120 children (either E. histolytica or E. dispar). But while almost all (13/14) of the children with E. histolytica had clinical symptoms, dysentery-feces with mocus and blood, diarrhea, cramping abdominal pain, tenesmus rectal, flatulence, vomiting and headache, almost none (1/106) of the children infected with the non-pathogenic ameba E. dispar had signs and symptoms. This suggests that much of the amebiasis diagnoses made in Mexico are, in fact, due to non-pathogenic E. dispar.

Differentiating amoebic ulcero-haemorrhagic recto-colitis from idiopathic inflammatory bowel disease: still a diagnostic dilemma / Diferenciar la Rectocolitis Úlcero-hemorrágica Amebiana de la Enfermedad Inflamatoria Idiopática del Intestino: un Dilema Diagnóstico sin Resolver

The colon responds monomorphically to a variety of insults thus making it difficult to differentiate invasive amoebic colitis and inflammatory bowel disease (IBD). The authors present a case with chronic dysentery, haematochezia, anaemia and hypoproteinaemia. The endoscopic findings were suggestive of IBD. The stool examination was negative for trophozoites or cysts of parasites. The recto-colonic biopsy specimens showed mucosal inflammation with exudates containing amoebic trophozoites. The patient was successfully treated with metronidazole and iodoquinol. He recovered within two weeks and repeat colonoscopy four weeks after the treatment showed a normal rectum and colon. Clinicians should have a high level of suspicion for amoebic colitis in cases of colitis especially in regions where amoebiasis is still present. Efforts should be made to find the amoebic trophozoites in multiple stool and colonic biopsy specimens

El colon responde de manera monomórfica a una variedad de insultos, lo cual hace difícil distinguir entre la colitis amebiana invasiva y la enfermedad intestinal inflamatoria (EII). Los autores presentan un caso con disentería crónica, hematoquexia, anemia e hipoproteinemia. Los resultados endoscópicos apuntaban a una EII. El análisis de las heces fecales arrojó resultados negativos en cuanto a presencia de trofozoitos o quistes de parásitos. Esto condujo a un diagnóstico erróneo y el paciente fue tratado por una EII. Sin embargo, los especímenes de la biopsia rectocolónica mostraron una inflamación mucosal con exudados en los que se hallaban presentes trofozoitos amebianos. El paciente tuvo un tratamiento exitoso con metronidazol y iodoquinol. Se recuperó en dos semanas, y se le repitió la colonoscopia cuatro semanas después de que el tratamiento mostró un recto y colon normales. Los clínicos debían mostrar un alto nivel de sospecha ante la colitis amebiana, especialmente en aquellas regiones donde la amebiasis todavía está presente. Deben hacerse esfuerzos por encontrar trofozoitos amebianos en múltiples especímenes de heces fecales y biopsia colónica.

Conocimientos, creencias y prácticas de médicos de Cienfuegos en relación con la amebiasis intestinal: resultados de una intervención

Se demostró, con el empleo de herramientas inmunológicas y biomoleculares, en un estudio realizado en la provincia de Cienfuegos, que en aquella provincia la amebiasis intestinal era un problema de salud sobredimensionado. Una encuesta sobre conocimientos, percepciones y prácticas aplicada a médicos relacionados con el diagnóstico, tratamiento y control de esta parasitosis evidenció que la sobredimensión podía estar asociada a una inadecuada percepción del problema y a un marcado desconocimiento que sobre importantes aspectos de esta entidad poseían. Para contribuir a la solución de la sobredimensión, y de sus consecuencias, se ejecutó un grupo de acciones en la citada provincia. A 1 año de completada la puesta en práctica de esas medidas, una segunda aplicación de la encuesta, cuyos resultados se publican en este documento, permitió conocer de una significativa mejoría de los encuestados en la casi totalidad de los aspectos cognoscitivos (6,73 y 11,23 medias de respuestas correctas antes y después, respectivamente, de la intervención) y perceptuales evaluados.

In a study conducted in the province of Cienfuegos, it was proved by using immunological and biomolecular tools that intestina amebiasis in that province was an overdimensioned health problem. A survey on knowledge, perceptions and practices applied to those physicians related to the diagnosis, treatment and control of this parasitosis showed that the overdimensioning may be associated with an inadequate perception of the problem and with a marked lack of knowledge about important aspects of this entity. To contribute to the solution of the ovedimensioning and of its consequences, a set of actions were taken in that province. After a year, a second survey was done, whose results are published in this document, allowing to know about a significant improvement of the surveyed in almost all the evaluated cognitive and perceptual aspects (6.73 and 11.23 means of correct answers before and after. the intervention, respectively).

Characterization of entamoeba histolytica antigens in circulating immune complexes in sera of patients with amoebiasis.

Isolated circulating immune complexes (CICs) from sera of patients with amoebiasis were characterized to determine Entamoeba histolytica antigens that participate in the disease process. In total, 116 serum samples were collected before starting anti-amoebic therapy, and their CICs were isolated by differential polyethylene glycol precipitation. The presence of amoeba-specific antigens in CICs was detected by antigen capture enzyme-linked immunosorbent assay (ELISA) and by immunoblot assay. Antigen capture ELISA showed significantly higher optical density (p < 0.001) in all patients with amoebiasis than in the normal healthy controls and patients of non-amoebic hepatic disorder. Immunoblot assay detected amoeba-specific CICs in all 18 patients (100%) with confirmed amoebic liver abscess, 28 (80%) of 35 patients with clinically-suspected amoebic liver abscess, and 18 (78.26%) of 23 patients with amoebic colitis. No patients with non-amoebic hepatic disorders and healthy control subjects had any detectable level of amoebic antigens in CICs. Immunoblot assay revealed E. histolytica antigens of relative molecular masses of 35, 56, 70, and 90 kDa present in CICs of 64 of 76 patients with amoebiasis. The 35-kDa polypeptide was observed in 52 patients (81.25%). The results of the study suggest that the 35-kDa polypeptide antigen can be a diagnostic marker in active amoebiasis.

Amoeboma of ascending colon with multiple amoebic liver abscesses.

A case of amoeboma of the ascending colon with multiple amoebic liver abscess is being presented; which was mistakenly diagnosed as carcinoma of ascending colon with multiple secondaries in liver. Awareness of this previously unreported association is important because it adds to our knowledge of the spectrum of intestinal amoebiasis.

Comparison between R-phycocyanin-labeled and R-phycoerythrin-labeled monoclonal antibody (Mab) probes for the detection of Entamoeba histolytica trophozoites.

A comparison between R-phycocyanin (R-PC)-labeled monoclonal antibody (MAb) probe and R-phycoerythrin (R-PE)-labeled MAb probe for the detection of the three standard reference strains of the cultured-derived Entamoeba histolytica trophozoites, namely HK-9, HM-1:IMSS, and HTH-56:MUTM were evaluated by using direct immunofluorescence antibody (DIFA) assay five times for each strain. Under the blue irradiation of the fluorescent microscope, both R-PC-labeled and R-PE-labeled MAb probes showed consistently greenish-yellow trophozoites and golden-orange trophozoites, respectively. The R-PE-labeled MAb probe stained the trophozoites more brightly and clearly than those stained by the R-PC-labeled MAb probe of the same Eh208C2-2MAb. When observed under the green irradiation, both probes showed the same intensity of brightly red color at the trophozoites of all three strains of E. histolytica. The sensitivity of both tests was 100%. Since this Eh208C2-2MAb could recognize specifically E. histolytica pyruvate:ferredoxin oxidoreductase (PFOR) enzyme, therefore, our two antibody probes would be valuable for use as a rapid, easy and sensitive test for diagnosis of invasive amebiasis. Further applications of these two probes directly onto the fecal sample spots and to more culture-derived strains of E. histolytica/E. dispar of known zymodemes in collaboration with the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDRB), Dhaka, Bangladesh, are under investigation.

Diagnosis of intestinal amebiasis using salivary IgA antibody detection.

Attempts were made to use soluble antigen extract of strain HK-9 of Entamoeba histolytica to detect salivary IgA antibodies in intestinal amebiasis patients by using ELISA. Total salivary samples of 109 individuals were divided into four groups. Group I comprised 32 patients whose stools were positive only for E. histolytica cysts and/or trophozoites. Group II comprised 12 individuals whose stools were positive for E. histolytica and other intestinal parasites. Group III comprised 36 individuals whose stools were negative for E. histolytica but contained other intestinal parasites such as E. coli, E. nana, Blastocystis hominis, Trichomonas hominis, Giardia lamblia, Opisthorchis viverrini, and hookworm. Group IV comprised 29 healthy individuals whose stools were free from any intestinal parasitic infections. Based on the mean optical density, OD + 2SD of the results from 29 parasitologically negative healthy individuals, the cut-off OD value for salivary IgA antibodies was 1.265. Therefore, the assays were positive in 14 out of 32 (43.75%) of group I and 2 out of 12 (16.6%) of group II. The assays were positive in 16 out of 36 (44.44%) for group III whereas 2 out of 29 (6.90%) for group IV were positive. The overall sensitivity and specificity of the assays were 36% and 72%, respectively. The false positive rate was 28% and the false negative rate was 64%. The predictive values of positive and negative results were 47% and 63%, respectively. The diagnostic accuracy of ELISA for the presence of salivary IgA antibodies was 58%.

Diagnóstico de amebíase intestinal utilizando métodos coproscópicos e imunológicos em amostra da populaçäo da área metropolitana de Belém, Pará, Brasil / Diagnosis of intestinal amebiasis using coproscopic and immunological methods in a population sample in Greater Metropolitan Belém, Pará, Brazil

Expöe a comparaçäo de métodos de diagnóstico de Entamoeba histolytica em amostra da populaçäo de Belém do Pará. Foram analisadas amostras fecais de crianças e adultos (Grupo I), amostras fecais e soros de adultos (Grupo II) e material fecal de crianças (Grupo III). Nos grupos I e III foram empregados os métodos direto com lugol (MD), Faust e cols. (MFF) e ELISA (detecçäo de coproantígeno anti-GIAP de E. histolytica); no grupo II, MD, hematoxilina férrica (HF), MFF, ELISA e reaçäo de imunofluorescência indireta (RIFI) para detecçäo de anticorpos IgG. A positividade encontrada foi de 10,50 por cento, empregando (MD + MFF) e de 28,99 por cento pelo ELISA. Näo houve correlaçäo entre positividade e grupo etário. No Grupo II (n = 87), a positividade encontrada foi de 4,59 por cento pelos métodos coproscópicos (MD + MFF), 8,04 por cento por HF, 4,59 por cento pela RIFI e 21,83 por cento pelo ELISA. O teste de ELISA foi o mais sensível para todos os grupos. Conclui-se que a RIFI ainda näo é ferramenta útil para diagnóstico desta protozoose. O teste de ELISA, de fácil execuçäo, foi feito em 1/3 do tempo usado para HF e RIFI, melhorando a qualidade do diagnóstico. Recomenda-se o ELISA como método de diagnóstico nos casos suspeitos de infecçöes com E.histolytica.

Toxic amebic colitis coexisting with intestinal tuberculosis

A patient with a fulminant amebic colitis coexisting with intestinal tuberculosis had a sudden onset of crampy abdominal pain, mucoid diarrhea, anorexia, fever and vomiting with signs of positive peritoneal irritation. Fulminant amebic colitis occurring together with intestinal tuberculosis is an uncommon event and may present an interesting patho-etiological relationship. The diagnosis was proven by histopathologic examination of resected specimen. Subtotal colectomy including segmental resection of ileum, about 80 cm in length, followed by exteriorization of both ends, was performed in an emergency basis. Despite all measures, the patient died on the sixth postoperative day. The exact relationship of fulminant amebic colitis and intestinal tuberculosis is speculative but the possibility of a cause and effect relationship exists. Fulminant amebic colitis may readily be confused with other types of inflammatory bowel disease, such as idiopathic ulcerative colitis, Crohn's disease, perforated diverticulitis and appendicitis with perforation. This report draws attention to the resurgence of tuberculosis and amebiasis in Korea, and the need for the high degree of caution required to detect it.