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Invasive amebiasis in a spider monkey (Ateles geoffroyi). Case report and a short review of the literature of amebiasis in non-human primates.

A spider monkey (Ateles geoffroyi) studied at the San Juan de Aragon Zoo died with symptoms of amoebic dysentery verified by coprologic investigation of the parasite, his female partner was cured with conventional antiamoebic treatment. At autopsy widespread ulcerations in the colon and multiple liver abscesses were found, containing trophozoites of Entamoeba histolytica. Both lesions were identical to those observed in human amoebiasis. A short review of the literature in nonhuman primates infections points out that the so-called spontaneous amoebiasis seen in colonies of captive monkeys, and transmission to their newborns within the same species of monkeys, have been in contact with humans. It is proposed that amoebiasis in monkeys should be considered as an excellent model for experimental studies on amoebiasis because other phylogenetically distant species have shown different pathology or are resistant to the infection. Also, it should raise concern that monkeys may become carriers of cysts and trophozoites of virulent strains of E. histolytica. Entamoeba histolytica DNA hybridization techniques should be considered for comparing genomic similarities with other protozoa, including the genera Amoeba to establish its pattern of evolution.

Animals↗
PubMed1977

Experimental amebiasis. II. Hepatic amebiasis in the newborn hamster.

Newborn hamsters inoculated intrahepatically were highly susceptible to infection by axenically cultured Entamoeba histolytica. Inoculations were performed through the abdominal wall, and lesions could be observed through the skin as early as 4 days after inoculation. The most virulent amebal strain, HM-1:IMSS, produced liver lesions in 19% of newborn animals inoculated with 20 amebae, and in about 90% receiving 2,000 amebae. Eleven other strains similarly tested either produced no lesions with 20,000 amebae or were of intermediate virulence. Two hamster strains did not show appreciable differences in susceptibility to the HM-1:IMSS amebal strain. Newborn hamsters were more susceptible to HM-1:IMSS amebae than animals which were 2, 4, or 7 days old at the time of inoculation. Three-week-old animals were resistant to doses below 20,000 virulent amebae.

Animals↗
PubMed1978

Amebiasis: epidemiologic studies in the United States, 1971-1974.

Seven investigations of suspected foci of amebiasis between October 1971 and June 1974 lead to three conclusions. (1) A number of laboratories have vastly overdiagnosed amebiasis and have reported leukocytes in stools as Entamoeba histolytica. Two laboratories found to be in error were in community hospitals, and one was at a teaching hospital associated with a medical school and a school of public health. These three laboratories had been diagnosing more than 1200 cases of amebiasis a year for 20 years. (2) When amebiasis does occur, it is likely to be misdiagnosed. In one outbreak with four cases and three deaths, amebiasis was not diagnosed until two patients had died and another was critically ill. Sporadic cases may be mistakenly diagnosed as ulcerative colitis and inappropriately treated with steroids. (3) Foci of endemic amebiasis continue to exist in the United States, both in institutions and in noninstitutional settings.

Amebiasis↗
PubMed1991

Serodiagnosis of invasive amebiasis using a recombinant Entamoeba histolytica protein.

One hundred eight serum samples from 106 patients were examined by Western blot analysis for the presence of antibodies to a recombinant fusion protein containing the sequence of the newly described serine-rich Entamoeba histolytica protein (SREHP). Among patients with invasive amebiasis from Durban, Republic of South Africa; San Diego, Calif; Mexico City, Mexico; and St Louis, Mo, 53 (82%) of 65 had antibodies to SREHP. In contrast, only one patient (2%) of 43 without acute invasive amebiasis had antibodies to SREHP. The predictive value of a positive test for anti-SREHP antibodies in the detection of acute invasive amebiasis was most marked when analyzed in the patients from Durban, where 11 (92%) of 12 patients who were seropositive for SREHP had acute invasive amebiasis vs 17 (65%) of 26 patients who had a positive serologic diagnosis as determined by agar gel diffusion. The use of a serologic test based on the recombinant SREHP fusion protein may be a useful adjunct to the diagnosis of acute invasive amebiasis in endemic regions.

Amebiasis↗
PubMed1978

Serology of amebiasis using the FIAX-TM system.

A new fluorescent immunoassay system (FIAX TM) has permitted development of a promising serologic test for amebiasis. The test is similar but far superior to the soluble antigen fluorescent antibody test. The main differences are the unique StiQ TM sampler and the flourometer itself. Quantitative results can be obtained from a single standard dilution of serum. The procedure is simple to perform, gives objective readings, and uses the proven principle of immunofluorescence. It is possible to test for different immunoglobulin classes and to use purified antigen prepared from axenically cultured Entamoeba histolytica. Conservation of reagents is comparable to microplate systems, and results are available in less than two hours. FIAX TM for amebiasis has demonstrated excellent discriminating power between amebic and nonamebic sera. Sensitivity is 100 percent for extra-intestinal amebiasis (33 sera), 90 percent for symptomatic intestinal amebiasis (20 sera), and 43 percent for asymptomatic amebiasis (seven sera). Specificity is 97 percent (158 sera).

Amebiasis↗
PubMed1992

Amebiasis complicating carcinomas: a diagnostic dilemma.

Two black African women and one black American man had carcinomas of cervix, perineum, and sigmoid colon, respectively. In each of these patients, trophozoites of Entamoeba histolytica had invaded the surface of the tumor, and in some areas had invaded more deeply into the stroma between the tumor cells. Although it is well known that cutaneous amebiasis of anus, penis, vulva, and cervix can mimic squamous cell carcinoma, it may be, perhaps, less well known that carcinomas at these sites may be colonized by trophozoites of E. histolytica. In patients with amebiasis but without an associated carcinoma, a correct diagnosis of amebiasis spares the patient unnecessary and sometimes mutilating surgery. But a diagnosis of amebiasis, when there is an unrecognized underlying carcinoma, delays effective treatment of the carcinoma. A smear that establishes a diagnosis of cutaneous amebiasis, therefore, should be followed by biopsy to exclude or confirm an underlying carcinoma.

Adenocarcinoma↗
PubMed1990

Amebiasis at an evacuation site on the Thai-Cambodian border.

Symptomatic intestinal amebiasis was highly endemic among the Cambodians living at Green Hill, an evacuation site on the Thai-Cambodian border between June 1987 through May 1989. Monthly incidence rates of intestinal amebiasis were determined to be inversely proportional to cumulative monthly rainfall. The highest incidence of amebic dysentery was 63/1000 in children 12-23 months old. Behavioral risk factors were investigated by conducting a case-control study. A questionnaire was administered to 73 families, each having at least one member with confirmed intestinal amebiasis within the past 3 months, and to 95 randomly selected control families having no individual with diarrhea for at least 3 months. Individuals from families with greater than 4 members were at higher risk for acquiring intestinal amebiasis. No significant differences in behavioral risk factors were identified between case and control families. Eighty-six percent of 51 water samples drawn from wells where amebiasis patients obtained their drinking water had greater than 10 coliforms/100 ml. The main route of transmission of E. histolytica was not identified, but was most likely via the fecal-oral route.

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↗
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↗
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↗
PubMed1992

Use of a recombinant 170-kilodalton surface antigen of Entamoeba histolytica for serodiagnosis of amebiasis and identification of immunodominant domains of the native molecule.

We expressed the gene that encodes one of the major surface antigens of Entamoeba histolytica, the 170-kDa protein (1,270 amino acids), as a glutathione S-transferase fusion protein containing amino acids 1 to 1202 (lacking the putative transmembrane and cytoplasmic regions) and as separate fusion proteins containing each of three major domains of the 170-kDa molecule. Lysates from bacteria induced to express one of these proteins were used as the target antigens in a Western blot (immunoblot) analysis to determine whether a recombinant 170-kDa antigen could serve as the basis for a serologic test used to detect invasive amebiasis and whether there are differences in humoral immunogenicity among the three major domains of the 170-kDa antigen. Among patients with invasive amebiasis from three major areas where the disease is endemic and two sites in the United States, 54 (90%) of 60 had antibodies to the recombinant 170-kDa protein. Among 37 patients from regions where the disease is endemic and 20 patients from the United States without amebic disease, 1 (2%) of 57 had antibodies to the recombinant 170-kDa protein. We found significant differences in seroreactivity to each of three major domains of the molecule among patients seropositive for the complete construct, ranging from 100% seroreactivity with the fusion protein containing the domain designated cysteine rich and 89% seropositivity with the fusion protein incorporating a portion of the region designated cysteine poor to only 9% seropositivity for the fusion protein containing the pseudorepeat domain. Our study indicates that a serologic test based on the recombinant 170-kDA antigen could serve as a highly sensitive and specific test for acute invasive amebiasis.

Animals↗
PubMed1992

Sensitive and specific serodiagnosis of invasive amebiasis by using a recombinant surface protein of pathogenic Entamoeba histolytica.

A recombinantly expressed protein, recEh-P1, representing part of an immunodominant surface antigen of pathogenic Entamoeba histolytica, was used for serodiagnosis of invasive amebiasis. Expression was performed under the control of a T7-RNA promoter by using a modified procaryotic expression vector, designated pHisT7. This vector allowed high-yield expression of recEh-P1 fused to a stretch of sequence containing eight histidine residues, which facilitated purification by metal chelate affinity chromatography on Ni2+ columns under highly denatured conditions. Purified recEh-P1 was found to be water soluble after prolonged dialysis and was used as the antigen for the detection of antiamebic serum antibodies by immunoblotting and enzyme-linked immunosorbent assay. In both tests all sera of patients with invasive amebiasis reacted to recEh-P1 whereas none of those collected from healthy controls, including individuals with noninvasive amebiasis, or from patients suffering from bacterial or protozoan infections unrelated to E. histolytica did so.

Amino Acid Sequence↗
PubMed1992

Extraintestinal amebiasis.

Extraintestinal involvement is a dreaded complication of amebiasis, with a reported mortality rate of 7%-14%. The authors retrospectively studied 188 patients with extraintestinal amebiasis confirmed by means of clinical, surgical, and radiologic criteria over a 45-month period. Ultrasonography (US) was the mainstay of radiologic investigation. Liver abscess was present in 183 patients (97%); five patients (3%) had other organ involvement but a normal liver. The majority of liver abscesses were in the right lobe. US is recommended for the diagnosis and follow-up of patients with extraintestinal amebiasis. It is noninvasive, simple, easily reproducible, and less expensive than computed tomography. Portable models can be taken into remote areas of the less-developed world.

Adult↗
PubMed1977

Endemic amebiasis in an extended family.

Two cousins from a large Spanish-American family were simultaneously diagnosed as having amebic liver abscesses. Survey of 183 extended-family members revealed that 45.7% of 162 had a positive amebiasis indirect hemagglutination test and 12.6% of 111 had cysts or trophozoites of Entamoeba histolytica demonstrated in a single stool examination. A total of five family members had had liver abscesses; two deaths had occurred. In a random sample survey of the remainder of the community, only one person (0.3%) had a positive serologic test. Within the extended family, person-to-person appeared to be the predominant mode of transmission. Water supplies were not contaminated. Both community and extended family homes had the same source of water. Type and source of food supply were not correlated with infection and there was no evidence to implicate an infected food handler. Clustering of seropositivity occurred in homes without indoor toilets. Homes of the extended family were more crowded and significantly fewer of them had indoor toilets. Endemic foci of amebiasis continue to exist in the United States. Follow-up family and other close contacts of persons with amebiasis will frequently identify other cases.

Feces↗