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.

Parasitological Evaluation of Domestic Water Sources in a Rural Community in Nigeria.

Aim: To evaluate the level of safety of water sources in a rural settlement in Nigeria with reference to parasitic infections and to make appropriate recommendations to the government and the community dwellers. Study Design: Investigative study. Place and Duration of Study: Samples were collected in Heipang, Barkin Ladi Local Government Area of Plateau State, Nigeria between October-December, 2012. They were processed at the General Laboratory of National Veterinary Research Institute, Vom, Nigeria. Methodology: 100 water samples were collected from domestic water sources. 10 of the samples were from streams, 60 from ponds, 20 from wells and 10 were from bore holes. Samples were investigated for presence of parasites using standard World Health Organisation approved laboratory techniques. Each sample was subjected to macroscopy, filtration, centrifugation and microscopy. Results: It revealed that 59 out of 100 water sources investigated had parasitic infestation. Ponds had the highest degree of parasitic contamination (78.3%), streams followed closely with 50%, while wells and bore holes had 35% and 0% in that order. Helminths were the leading parasitic genera encountered with Ascaris species accounting for 33.9% of the parasites. Hookworm was the second most common helminth with the prevalence of 20.3%. Strongyloides species accounted for a paltry prevalence of 3.4%. Protozoan cysts of Balanditium coli and Entamoeba histolytica accounted for 18.6% of parasites each. Conclusion: These findings clearly show that most water sources in the study area constitute grave epidemiological threat to public health. Inhabitants of such communities should boil or treat their water before consumption while government authorities should provide safe drinking water to the rural dwellers.

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.

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.

Ausência de amebíase invasiva em aidéticos homossexuais masculinos, no Recife / Absence of invasive amoebiasis in male homosexual AIDS patients in Recife

The purpose of this paper was to determine if among male homosexual AIDS [correction of SIDA] patients, the Entamoeba histolytica was able to product invasive illness. From the 77 investigated patients only one (1.3 per cent) has cysts of E. histolytica in his stools. The electrophoresis of the only isolated strain has shown it was from zimodeme I, non pathogenic. The research of antiamebic antibodies was negative in the serum of the totality of patients. Those results showed that even in immunocompromised patients with AIDS [correction of SIDA], E. histolytica strain found in Recife was not able to produce disease. The utilization of metronidazol is not indicated in amoebic cysts carriers.

Seroepidemiología de la amebiasis / Seroepidemiological study of amebiasis

Por medio de la técnica de ELISA se estudiaron 35 sueros de personas del distrito de Sapillica (Piura) y 36 sueros de estudiantes de la Joya (Arequipa) encontrándose que el 46 por ciento de los sueros de Sapillica y el 72 por ciento de los sueros de La Joya eran positivos para anticuerpos contra Entamoeba histolytica.

Intestinal amebiasis-about 52 cases

The authors report the results of an epidemiological, clinical and therapeutical retrospective study of 52 cases of intestinalis amibiasis disease hospitalized in the infectious disease section of the hospital of sfax. This disease happens all ages and especially to the young adult of rural origin duning the summer and autumn seasons. The clinical polymorphism is notable with mainly coecoappendicular manifestations leading sometimes to diagnosis difficulties and the dysenteric syndrome is not frequent. The diagnosis is always based on the parasitologic exam of stool which requires good technical conditions and a clever technician

Ameboma de colon y recto. Experiencia clinico-patologica en tres pacientes / Colon and rectum ameboma. Clinico-pathological experience in three patients

El ameboma es una complicación rara de la ambiasis intestinal que requiere de su sospecha y diagnóstico preciso para instalar el adecuado tratamiento médico específico, que permita al paciente una mejor evolución