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PubMed1982

Spectrum of amebiasis in children.

In 11 patients with childhood amebiasis, only two had dysentery. Additional clinical findings included hematochezia without diarrhea (four patients), dysentery with appendicitis (one patient), exacerbation of ulcerative colitis (two patients), and disseminated infantile amebiasis (two patients). All patients with hematochezia examined by proctosigmoidoscopy had colitis. The diagnosis of amebiasis was confirmed by microscopic examination of fresh stool specimens, pathologic findings, and/or serologic titers. Amebiasis should be considered in the differential diagnosis of infants and children with hematochezia or hepatomegaly, especially in endemic areas.

Adolescent↗
PubMed1992

The prevalence of invasive amebiasis is not increased in patients with AIDS.

OBJECTIVE: To determine whether the frequency or severity of invasive amebiasis is increased in patients with AIDS. DESIGN: A case-control sampling approach, based on an autopsy registry. SETTING: General Hospital of Mexico City, Mexico, a large government-supported, tertiary care medical institution. PATIENTS, PARTICIPANTS: Ninety-four patients with AIDS and 335 historical and contemporary, age- and sex-matched controls who were defined as dying, but not because of AIDS. RESULTS: The odds ratio (OR) for mortality from invasive amebiasis was the same for cases and controls (0.7; 95% confidence interval, 0.07-7.2). By contrast, the OR for other diseases, such as miliary tuberculosis, cytomegalovirus infection, Pneumocystis carinii pneumonia and toxoplasmosis was greatly increased. Only one patient with AIDS had amebiasis of the common amebic ulcerative colitis type, without extraintestinal involvement. CONCLUSION: In conclusion, we show that the frequency and severity of invasive amebiasis is not increased in Mexican patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Cytopathologic and genetic diagnosis of pulmonary amebiasis: a case report.

BACKGROUND: Amebiasis is a parasitic infection with Entamoeba histolytica. Pulmonary amebiasis is rare since the infection is commonly manifested as amebic colitis or liver abscess. Most pleuropulmonary amebiasis is seen in patients with amebic liver abscesses. A pulmonary amebic lesion without either a liver abscess or amebic colitis is extremely rare. Thus, reported cases of sputum cytologic diagnosis of a pulmonary amebic lesion from a patient without a liver abscess are also very rare. CASE: A 53-year-old man presented with a dry cough and mild fever. Chest radiography revealed an abnormal solitary mass lesion in the right upper lung field. The clinical diagnosis was a bacterial lung abscess. Sputum cytologic examination demonstrated many trophozoites of E. histolytica. Following sputum cytodiagnosis, serologic tests revealed a slightly high but almost normal titer of IgG antibodies to E. histolytica, indicating the possible presence of the pathogen. Polymerase chain reaction (PCR) using E. histolytica-specific primers for DNA extracted from the sputum sample revealed specific DNA product. CONCLUSION: Pulmonary amebiasis without either a liver abscess or amebic colitis must be distinguished from bacterial abscesses and neoplastic disease. A sputum cytologic examination combined with PCR for DNA extracted from a sputum sample is a good approach to the diagnosis of a pulmonary amebic abscess.

Adult↗
PubMed1981

Assessment of the sensitivity, specificity, and reproducibility of the indirect immunofluorescent technique for the diagnosis of amebiasis.

The indirect immunofluorescence (IIF) test was used to study antibody titers to Entamoeba histolytica in various manifestations of clinical amebiasis by comparing the results with parasitological and clinical data from confirmed cases. The sensitivity, specificity, and reproducibility of this test for diagnosis were also studied. A high degree of correlation was found between reactivity in the IIF test and confirmed cases of amebic liver abscess. A positivity rate of 96% in sera of confirmed cases of amebic liver abscess in the present study compares favorably with the results of other workers. The IIF test is very useful in the diagnosis of hepatic amebiasis but is less sensitive for amebic dysentery. The test could not be used to differentiate between hepatic amebiasis and amebic dysentery. The IIF test was insensitive for amebic colitis and of no diagnostic value. Specificity and reproducibility of the test were good, as shown by results obtained with sera from patients with parasitic infections other than amebiasis.

Amebiasis↗
PubMed1987

Correlation of positive syphilis serology with invasive amebiasis in Japan.

Approximately 20% of 52 Japanese males with invasive amebiasis confirmed by gel diffusion precipitin test (GDP) were positive by both Treponema pallidum hemagglutination test (TPHA) and nontreponemal antigen tests, and an additional 20% were positive by TPHA alone. However, none of 109 GDP-negative Japanese males without invasive amebiasis were positive on these serologic tests for syphilis. At least 2 bisexuals and 4 homosexuals were among those with invasive amebiasis. All of these biased males were positive on both TPHA and nontreponemal antigen tests. Four of the biased males had liver abscess and 2 had amebic dysentery or colitis. Bisexual or homosexual males were not found in the negative GDP group. These observations suggest that sexually transmitted amebiasis due to Entamoeba histolytica occurs among sexually biased males in Japan.

Adolescent↗
PubMed1988

Invasive amebiasis in naturally infected New World and Old World monkeys with and without clinical disease.

Histopathological preparations of cecum and colon from monkeys naturally infected with invasive Entamoeba histolytica were examined to determine the distribution of amebae in the tissues and the types of lesions, if any, associated with them. Infections were studied in 3 New World species (10 Callicebus moloch, 1 C. torquatus, and 2 Aotus trivirgatus) and 3 Old World species (8 Macaca mulatta, 6 Erythrocebus patas, and 1 Cercopithecus aethiops). Amebiasis was recorded as the principal or a contributing cause of death of all of the 13 New World monkeys and in 6 of the 15 Old World monkeys; amebiasis was detected in the rest of the monkeys only after tissues were re-examined specifically for amebae. Amebae causing no apparent damage were found in the lamina propriae, mainly at the muscularis mucosae. Most frequent were colonies or aggregates of amebae in the crypts between the epithelium and basement membrane, causing either no evident necrosis or changes ranging from necrosis and disarrangement of adjacent cells to complete destruction of the epithelium and reduction of the cells to pyknotic bodies. A lesion interpreted as possibly characteristic of carrier-state invasive amebiasis was destruction of the epithelium in patches of mucosal crypts, not leading to ulceration. Uncommon but present in both New and Old World monkeys were typical areas of surface erosion and classical flask-shaped ulcers. The observations show that in some species of Old World monkeys amebiasis can be invasive without causing clinical disease.

Amebiasis↗
PubMed1975

[Clinical problems of amebiasis].

Dagnostic and therapeutic problems of amebiaiss, a disease rarely observed in this country, are discussed in the light of four own cases representing the various courses of the disease. These observations prompt the following conclusions: 1. Amebiasis should be considered in cases of unclear acute or chronic intestinal disease, even if the patient has never visited endemic regions. 2. Non-tropical forms of amebiasis may follow a severe course with complications such as liver abscess or ameboma. 3. The advice of a specialized laboratory is necessary for stool examinations on amebae. 4. Stool examinations for amebiasis should be combined with serological tests. The immunofluorescense test is of special value. False negative results are however possible, especially in cases without tissue inflitration where the infection is limited to the intestinal lumen. 5. Metronidazol (Flagyl) greatly simplifies the treatment of amebiasis as it is both efffective and better tolerated than most other antiamebic agents.

Adult↗
PubMedDate not supplied

[Amebiasis. Has its clinical expression changed?].

In Mexico, like in other countries, there is an special interest for amebiasis because it represents a Public health problem; there are about 5 million people that in some time of their lives had tissue invasion by this parasite. 1-2% of mexicanas have intestinal amebiasis and probably there are 850,000 to 1,700,000 carriers of entamoeba cysts. 6% of the general population have circulating antiameba antibodies. In 1988 we studied the amebic hepatic abscess seen in the hospitals of the Instituto Mexicano del Seguro Social in the Valley of Mexico. During that year there were 396 patients with such illness (0.19% of hospital admissions) with a 1.01% mortality. Comparing this data with reports of 1969 there was a reduction in the number of patients and deaths. Also amebiasis has decreased in autopsy studies. However, we have not found recent variations in the clinical behavior of amebiasis. Advances in diagnostic methods and more liberal use of metronidazole have reduced the number of severely ill patients.

Amebiasis↗
PubMedDate not supplied

[Amebiasis. Medical treatment. Is there anything better than metronidazole?].

Since 1961, when Cosar pointed out for the first time that metronidazol was a useful pharmacological agent against E. histolytica, several authors have demonstrated its effectiveness against invasive amebiasis in its colonic or extraintestinal variety. The obtained results with metronidazol were so far better compared with the rest of the known amebecides, that in 1974, Elsdon Dew stated that a new era in the medical treatment of the amebiasis had started with the forthcoming use of the agent. However, the frequent and important adverse collateral effects produced in a good number of patients have forced to look for other nitroimidazole derivates, hopefully more efficient and, of course, better tolerated. Thus, the tinidazole, ornidazole, flunidazole, romidazole, ornidazole, flunidazole, dimetridazole, satranidazole, nitrimidazine, panidazole, have been tried and some others are still subject to experimentation, such as the Ro 7-0207 (alpha-chlorometil-2-metil-5-nitro-1-imidazol), the phexinidazole (HOE 239) and the CG 10213-Go from CIBA-Geigy and no significant advantage has been found over the metronidazol. The phexinidazole turned out to be twice as effective as the metronidazole in the experimental hepatic amebiasis of the golden hamster. This fact must be confirmed or discarded in the human hepatic amebiasis.

Amebiasis↗
PubMedDate not supplied

Hepatopulmonary amebiasis--a review of 40 cases.

Forty cases of hepatopulmonary amebiasis secondary to hepatic amebiasis are reported. In an endemic area of amebiasis, this entity should always be borne in mind, as the frequent reports of hepatopulmonary amebiasis gives evidence of the magnitude of the problem. Diagnosis is mainly based on a palpable tender liver and/or lower intercostal tenderness, the fluoroscopic and radiological findings, and therapeutic response to dehydroemetine.

Adolescent↗
PubMed1997

In vivo and in vitro experimental intestinal amebiasis in Mongolian gerbils (Meriones unguiculatus).

One of the main drawbacks of experimental amebiasis is the lack of an adequate animal model for invasive intestinal lesions. Mongolian gerbils are useful because both intestinal and hepatic amebiasis can be produced experimentally with Entamoeba histolytica trophozoites. In this paper we show results obtained with in vivo and in vitro models of intestinal amebiasis in gerbils. We inoculated gerbils intracecally with monoxenic cultures of a highly virulent E. histolytica HM1:IMSS substrain. In the in vivo model an increase in mucus production was observed during the first 6 h of interaction. Microulcerative mucosal lesions appeared at 24-72 h postinoculation. Inflammatory infiltrate and edema of the lamina propria were associated with superficial foci of necrosis. At 96 h the cecal mucosa had an almost normal appearance and live amebas were no longer detected. In the in vitro model, early damage was detected in cecal strips mounted in Ussing chambers as a rapid fall in potential difference, short-circuit current, and transepithelial resistance that correlated with the extent of the microscopic lesions produced. The latter consisted of cellular edema and the appearance of small, translucent vacuoles at the base of epithelial cells. Further damage led to loss of intercellular junctions, destruction of interglandular epithelial cells, and edema of the lamina propria. The present results demonstrate that the gerbil is useful as an experimental model for the analysis of early stages of invasive intestinal amebiasis both in vivo and in vitro.

Animals↗
PubMed2004

[Isolated pleural amebiasis: about one case in France].

INTRODUCTION: Isolated pleural amebiasis is exceptional in the world and specially in France. CASE REPORT: We report a case of acute isolated pleural amebiasis in a 56 year old man who did not travelled in endemic countries for the 20 past years. Chocolate-colored pus from the pleural puncture suggested the diagnosis. Positive amebic serology and above all, trophozoites (Entamoeba histolytica) in the pleural liquid confirmed the diagnosis of pleural amebiasis. Drainage was required and metronidazole was introduced. Other antibiotics were necessary to treat bacterial co-infection, which is frequent. Of interest, a nurse developed an acute intestinal amebiasis probably infected by pleural pus, an indirect confirmation of diagnosis. CONCLUSION: This diagnosis should be suspected even in low endemic areas in case of infectious pleurisy resistant to traditional antimicrobial regimens.

Entamoebiasis↗
PubMed2001

Protective immunity to amebiasis: new insights and new challenges.

Amebiasis, infection with the protozoan parasite Entamoeba histolytica, is the third leading cause of death from parasitic diseases. Despite its importance, we know little about protective immunity to amebiasis. Now, studies from a cohort of children in Bangladesh have provided some critical insights into immunity to intestinal amebiasis. Children with mucosal IgA antibodies to the amebic adherence lectin were found to be resistant to reinfection with E. histolytica. However, immunity was short-lived, and approximately 20% of children in the cohort had a second episode of E. histolytica infection during the study period. Theses findings indicate that immunity to amebiasis can develop in some children after intestinal infection, but protective immunity may be transient, and its importance in preventing disease remains to be established.

Animals↗
PubMedDate not supplied

Identification of immunogenic epitopes of the 170-kDa subunit adhesin of Entamoeba histolytica in patients with invasive amebiasis.

Entamoeba histolytica causes amebic dysentery (AD) and liver abscess (ALA). Little is known about protective immunity to amebiasis, and studies in this area have been complicated by the paucity of defined ameba antigens. We examined the proliferative responses of peripheral blood mononuclear cells (PBMC) from patients with AD and ALA to a recombinant protein containing a portion of the 170 kDa adhesin of E. histolytica (170CR), and to two synthetic peptides (1 and 2) derived from the 170 kDa sequence that were predicted to contain T cell epitopes. A significant number of patients with AD and ALA had PBMC that proliferated to 170CR molecule, and several individuals with ALA and AD had T cells that recognized one or both peptides. Contrarily, individuals from a non-endemic region for amebiasis did not respond to 170CR protein, or to both peptides. In regard to antibody response, nine of fifteen patients with ALA showed antibodies to 170CR protein. These same patients had antibodies to peptide 2. We identified peptides from 170-kDa adhesin that may contain both T and B cell epitopes recognized by some patients with invasive amebiasis. These peptides may be valuable reagents in studies of the immune response to amebiasis.

Adolescent↗
PubMed1996

Recombinant antigen-based avidin-biotin microtiter enzyme-linked immunosorbent assay for serodiagnosis of invasive amebiasis.

An immunoscreening approach was used to isolate a strongly positive cDNA clone from an Entamoeba histolytica HK-9 cDNA expression library in the phage vector lambda ZAP-II. The 1.85-kb cDNA insert was found to be truncated and encoded the cysteine-rich, immunodominant domain of the antigenic 170-kDa subunit of the amebal galactose-N-acetylgalactosamine binding lectin. This domain was expressed as a glutathione S-transferase fusion protein in Escherichia coli. Inclusion bodies of the recombinant protein were solubilized with Sarkosyl, and the protein was enriched from the crude bacterial extract by thiol-affinity chromatography. The recombinant protein was used to develop a rapid, sensitive, and specific avidin-biotin microtiter enzyme-linked immunosorbent assay (ELISA) for invasive amebiasis. Sera from 38 individuals suffering from invasive amebiasis, 12 individuals with noninvasive amebiasis, 44 individuals with other infections, and 27 healthy subjects were screened by the recombinant antigen-based ELISA. The sensitivity and specificity of the assay were 90.4 and 94.3%, respectively, which correlated well with those of an ELISA developed with crude amebal antigen (r = 0.94; P < 0.0001), as well as with those of a commercially available serodiagnostic ELISA (r = 0.92; P < 0.0001). Thus, the bacterially expressed recombinant lectin can replace the crude amebal extract as an antigen in the serodiagnosis of invasive amebiasis by using avidin-biotin microtiter ELISA.

Animals↗
PubMed1989

[Invasive amebiasis as a public health problem].

Amebiasis, an infection of humans with the protozoan Entamoeba histolytica, has a wide distribution in Mexico. The lumenal, asymptomatic infection, as measured by the presence of cysts in stools has been recorded from 2.4% at Ometepec, Guerrero to over 55% at Mixquic, D.F., but only a small percentage of those having intestinal infection will develop invasive amebiasis, the main clinical forms being dysentery and liver abscess. In Mexico City, from 0.8 up to 14% of cases of acute diarrhoea in children requiring hospitalization were found to be associated with E. histolytica. Serological surveys for antibodies, suggest that approximately 5.98% of people had intestinal mucosal or liver invasion, but amebic dysentery may be five to 50 times more frequent than liver abscess, namely in children. Amebiasis may cause death when it manifests itself as fulminating colitis or liver abscess. Lethality in adults has been estimated to be around 0.2 to 2%, but in children with liver abscess it may be 1.1 to 26%. In addition to being a potentially lethal disease, it has important socioeconomic consequences, because incapacitating infections are rather frequent in wage-earning adult males requiring several weeks of hospitalization and from two to three months for full recovery. In Mexico, amebiasis has been more closely associated with poverty and low levels of sanitation than to climate, and in view of the high rates of morbidity and mortality caused by E. histolytica, more research into better and cheaper methods of diagnosis, treatment and prevention is clearly necessary plus a substantial improvement in control strategies.

Adolescent↗
PubMed1979

[Chronic recurrent intestinal amebiasis in Israel (author's transl)].

Abdominal pain, nausea, flatulence and diarrhea are the main clinical symptoms in chronic amebiasis; diarrhea and constipation may alternate in many cases, whereas constipation alone does occur only rarely. These symptoms may persist over years, with long asymptomatic intervals. In most cases cysts of entameba histolytica can be demonstrated in the feces, accompanied rather often by dientameba fragilis in Israel. 835 carriers of entameba histolytica were found among our patients between 1968 and 1974. Patients exhibiting 3 of the above mentioned clinical symptoms and having entameba histolytica in the stools are defined to be suffering from chronic recurrent amebiasis; 371 (= 44%) of our patients could be classified in this group. In spite of the fact, that the number of cases of acute amebiasis and its complications in Israel has been reduced considerably in the past, chronic amebiasis continues to be a clinical and epidemiological problem, its incidence being scarcely diminished.

Chronic Disease↗
PubMedDate not supplied

[Hepatic amebiasis in French Polynesia. 16 cases in 2 years].

Asymptomatic amebiasis in known for long ago in French Polynesia; the presence of Entamoeba histolytica cyst carriers have been shown by several parasitological investigations. But, until now, no hepatic amebiasis case has been reported in this geographical area. An homogeneous series of 16 cases of hepatic amebiasis is reported here. The diagnosis was made by hepatic ultrasonography and confirmed by immunology (Indirect immunofluorescent tests gave always a positive reaction for a dilution of 1/512 or more). Clinical, biological and radiological signs are well known in tropical pathology. Therapy was always conducted with metronidazol by the authors. From the epidemiological point of view, 14 out of 16 cases come from Tuamotu Archipelago. This epidemiological fact appears important enough to carry out systematically hepatic ultrasonography and amebic++ serology for every patient evacuated from this Archipelago to Tahiti. Hence it must be kept in mind the possibility of hepatic amebiasis not only in people living in French Polynesia but also, for the ones coming from over there but living in France.

Adolescent↗