Entamoeba sp. (Sarcomastigophora: Endamoebidae) from ostriches (Struthio camelus) (Aves: Struthionidae)

The first case of Entamoeba of the 1-nucleate mature cyst group in birds is described. Trophozoites and cysts of Entamoeba have been found in ostriches (Struthio camelus) from farms located all over Spain. The cysts are large (13.47microm mean diameter); they possess one nucleus when mature, with a large endosome and peripheral chromatine arranged in small granules; chromatoid bodies, when present, are large and elongated. Trophozoites are large (19. 88microm mean diameter), with a clear differentiation between ecto- and endoplasm, this containing numerous vacuoles; the nucleus is large and diffuse. The characteristics of this amoeba resembles but do not completely fulfill those of E. suis and E. chattoni; also, these species are from mammals.

Screening of the municipal water system of La Plata, Argentina, for human intestinal parasites

The La Plata River, though severely contaminated by intestinal parasites through the discharge of tons of crude fecal material from a main sewage channel, nevertheless provides drinking water to two-thirds of La Plata, Argentina, after conventional purification at a processing plant. With intestinal parasitosis being endemic here, we investigated the importance of this water in transmitting such pathogens to the city's populace by means of standard methodology for sample acquisition and processing involving filter-concentration of waterborne particulates. Of 14 tap-water samples collected from the distribution network, 12 pertained to four zones (A-D) within the city center; while the remaining 2 were obtained near the processing plant, 15 kilometers outside the city. Although parasites were found within the samples derived from the four urban zones, none were detected in the specimens obtained near the plant. The four downtown areas differed from each other as to the quantity and nature of the parasites present in their water: whereas zones A and B registered similar lower levels of contaminants, C and D exhibited higher values significantly different from the former two and from each other. Given an average parasite count/l citywide of 0.38 and a probability of encountering a parasite within 11 of water of 0.32, the municipal network is seen to contribute to the transmission of intestinal parasites. A routine system of water-quality control is therefore needed throughout the city along with the establishment of infrastructures for locating and eliminating peripheral sources of contamination.

Detection of Giardia lamblia, Entamoeba histolytica/Entamoeba dispar, and Cryptosporidium parvum antigens in human fecal specimens using the triage parasite panel enzyme immunoassay

The Triage parasite panel (BIOSITE Diagnostics, San Diego, Calif.) is a new qualitative enzyme immunoassay (EIA) panel for the detection of Giardia lamblia, Entamoeba histolytica/E. dispar, and Cryptosporidium parvum in fresh or fresh, frozen, unfixed human fecal specimens. By using specific antibodies, antigens specific for these organisms are captured and immobilized on a membrane. Panel performance was evaluated with known positive and negative stool specimens (a total of 444 specimens) that were tested by the standard ova and parasite (O&P) examination as the "gold standard," including staining with both trichrome and modified acid-fast stains. Specimens with discrepant results between the reference and Triage methods were retested by a different method, either EIA or immunofluorescence. A number of samples with discrepant results with the Triage device were confirmed to be true positives. After resolution of discrepant results, the number of positive specimens and the sensitivity and specificity results were as follows: for G. lamblia, 170, 95.9%, and 97.4%, respectively; for E. histolytica/E. dispar, 99, 96.0%, and 99.1%, respectively; and for C. parvum, 60, 98.3%, and 99.7%, respectively. There was no cross-reactivity with other parasites found in stool specimens, including eight different protozoa (128 challenges) and three different helminths (83 challenges). The ability to perform the complete O&P examination should remain an option for those patients with negative parasite panel results but who are still symptomatic.

Gastrointestinal parasites of mountain gorillas (Gorilla gorilla beringei) in the Parc National des Volcans, Rwanda

Ninety-eight fecal samples were collected from 74 free-living mountain gorillas (Gorilla gorilla beringei) from the Parc National des Volcans, Rwanda, between July 1995 and January 1997 and examined for parasites by Sheather's sugar and zinc sulfate flotation methods, trichrome staining, and larval cultures. All samples contained at least one parasite. Seventeen endoparasites were identified, including eight protozoa, seven nematodes, one cestode, and one trematode. Two species of arthropod mite were also recovered from the fecal samples. Parasites observed on fecal examinations included strongyle/trichostrongyle-type eggs (72/74) (representing Oesphagostomum sp., Trichostrongylus sp., Hyostrongylus spp., and possibly Murshidia sp.), Strongyloides sp. (1/74), Trichuris trichiura (2/74), Probstmayria sp. (7/74), Anoplocephala sp. (63/74), Entamoeba hartmanni cysts and trophozoites (19/70), Endolimax nana cysts (31/70), Iodamoeba buetschlii cysts (11/70), Endolimax nana or Iodamoeba buetschlii trophozoites (63/70). Entamoeba coli cysts and trophozoites (14/70), Entamoeba histolytica trophozoite (1/70), Chilomastix sp. cysts and trophozoites (31/70), and Giardia sp. cysts (2/70). In addition, one ascarid and one trematode egg were seen. There were no significant differences in the prevalence of parasites between males and females and between age groups: however, infants and juveniles appeared to have a lower prevalence of Anoplocephala gorillae, and the silverbacked males appeared to have a higher prevalence of Probstmayria sp. Parasite prevalence was consistent among the five social groups studied except Susa group had a significantly lower prevalence of Anoplocephala gorillae. Trichuris trichiura, Strongyloides sp., Chilomastix sp., and Endolimax nana were identified for the first time in this population, and it is possible that these parasites were of human origin. Although there were no obvious clinical effects due to the presence of these parasites, six parasites identified (Trichuris trichiura, Strongyloides sp., Oesphagostomum sp., Trichostrongylus sp., Entamoeba histolytica, and Giardia sp.) could potentially be pathogenic. Some of the parasite products and cultured larvae could not be speciated.

Entamoeba histolytica/Entamoeba dispar infections in human immunodeficiency virus-infected patients in the United States

We describe the incidence of and laboratory and clinical characteristics associated with Entamoeba histolytica/Entamoeba dispar infection diagnosed in human immunodeficiency virus (HIV)-infected persons enrolled in the Adult and Adolescent Spectrum of HIV Disease Project. From 1 January 1990 to 1 January 1998 (82, 518 person-years of follow-up), 111 patients (98% men) were diagnosed with E. histolytica/E. dispar infection. Among HIV-infected patients in the United States, the incidence of diagnosed E. histolytica disease is low (13.5 cases per 10,000 person-years [95% confidence interval, 7.7-22.2], with diagnosis most common in those patients exposed to HIV through male-male sex.

Differentiation of Entamoeba histolytica and Entamoeba dispar cysts using polymerase chain reaction on DNA isolated from faeces with spin columns

Since Entamoeba histolytica and Entamoeba dispar were formally recognized as two different species at the World Health Organization (WHO)/Pan American Health Organization (PAHO)/United Nations Educational, Scientific and Cultural Organization (UNESCO) meeting in Mexico City in 1997, the specific differentiation of the two morphologically identical species would seem relevant in clinical diagnosis. Several polymerase chain reaction (PCR)-based methods have been described and used successfully, but methods for DNA isolation from cysts in stool samples are time-consuming and problematic due to inhibitory factors in faeces. The use of the slightly modified QIAamp tissue method (Qiagen, Germany) for DNA isolation was evaluated in 657 unpreserved faecal samples from cases of suspected Entamoeba histolytica/Entamoeba dispar infection. In only 1.7% of the cases was PCR hampered by inhibitors present in the faeces. The DNA isolation procedure was found to be rapid, simple and one that could easily be implemented in a routine diagnostic setting. In 98.8% of Entamoeba histolytica/Entamoeba dispar cyst-positive faecal samples, the true identity of the cysts could be determined using PCR specific for Entamoeba histolytica and Entamoeba dispar, respectively.

Comparison of antigen-capture ELISA to stool-culture methods for the detection of asymptomatic Entamoeba species infection in Kafer Daoud, Egypt

We performed a prospective field study in the village of Kafer Daoud in Menofia, Egypt to compare the fecal culture method with enzyme linked immuno assay (ELISA) for detection of 170 kDa lectin antigen in feces for diagnosis of asymptomatic Entamoeba histolytica and Entamoeba dispar infection. All subjects with E. histolytica or E. dispar infection detected by culture also had positive ELISA for amebic antigen in their feces and an additional 57 Entameoba infections missed by culture were detected by ELISA (P < 0.001 compared to culture). The presence of fecal anti-lectin IgA antibodies and serum anti-LC3 (recombinant cysteine-rich lectin protein) IgG antibodies were positive predictors for E. histolytica infection (P < 0.03). Of interest, infection with Trichomonas hominis but not Blastocystis hominis was positively associated with E. histolytica infection (P < 0.05). In conclusion, ELISA for detection of fecal lectin antigen is a more sensitive method than fecal culture for detecting asymptomatic E. histolytica infection.

A nested, multiplex, PCR assay for the simultaneous detection and differentiation of Entamoeba histolytica and Entamoeba dispar in faeces

The detection of and differentiation between Entamoeba histolytica and Entamoeba dispar are of great importance, both for diagnosis and for epidemiological studies. Most PCR-based methods for the discrimination of these two species employ complex procedures for DNA extraction and require different protocols for E. histolytica and E. dispar, leading to relatively high expenditure, labour costs and turnaround times. A simple, rapid, cost-effective and yet sensitive and specific multiplex PCR technique has now been developed for the simultaneous detection and differentiation of E. histolytica and E. dispar in faecal samples. The detection limit is 200 trophozoites of E. dispar or 1000 trophozoites of E. histolytica/g stool sample. The sensitivity of the assay remains practically unchanged, even in the presence of 20,000 trophozoites of the other species/g stool sample. Thus, this technique may also easily reveal mixed infections, without the danger of misdiagnosis caused by one strain displacing the other in culture.

Entamoeba histolytica and Entamoeba dispar: epidemiology and comparison of diagnostic methods in a setting of nonendemicity

Recent studies suggest that stool antigen assays are more sensitive and specific than microscopy for the diagnosis of Entamoeba histolytica infection. One hundred twelve patients presenting at 3 centers with symptoms or risk factors of E. histolytica infection were prospectively enrolled in this study to evaluate new diagnostic tests for infections with E. histolytica and Entamoeba dispar. Four ELISA-based stool antigen kits for detecting E. histolytica or E. dispar were blindly compared with stool microscopy. Amebic serology was assessed by indirect hemagglutination. When antigen assays were used as the reference standard, microscopy performed at referral centers was more specific (68.4% vs. 9.5%) but less sensitive (70.4% vs. 92.1%) than microscopy performed in community laboratories. Diagnosis with the E. histolytica test and Merlin Optimun S ELISA indicated that only 3 (4.2%) of 72 coproantigen-positive stools were positive for E. histolytica. Indirect hemagglutination was a good predictor of E. histolytica infection when titers of antibody to ameba were >/=1:512.

Intestinal parasite carriage in workers exposed to sewage

The presence of protozoan cysts and helminth eggs in sewage and the very low minimal infective doses of parasites suggest an occupational risk for workers exposed to sewage. The objective of this study was to assess this risk in a group of raw sewage-exposed workers. The relationship between sewage exposure and intestinal parasite carriage was estimated by a multiple cross-sectional survey comparing yearly prevalence rates in 126 employees working in sewers in Paris, France, with the prevalence rate in 363 food-handlers employed between 1988 and 1993. The incidence of intestinal parasitic infestation was estimated among sewage-exposed workers. Four parasite species were identified among sewage-exposed workers: whipworm, Giardia lamblia, Entamoeba coli and Endolimax nanus. The prevalence mean of intestinal parasite carriage was 11.8% (57/480), related to the presence of protozoa in 91% of samples. G. lamblia was present in 3.5% (17/480) of samples. The incidence of positive parasitological stool examination was 5.9/100 person-years. The incidence of G. lamblia in stool examinations was 1.7/100 person-years. Age-adjusted odds ratios were significantly higher in exposed workers in 1988 (OR: 6.5; 95% CI: 2.0-14.5), 1990 (OR: 4.4; 95% CI: 1.2-10.1) and 1991 (OR: 3.4; 95% CI: 1.0-8.2), but not during the other three years. The results of this study emphasize an occupational risk of intestinal protozoan infestation in workers exposed to sewage. The decrease of adjusted OR with time reflects the efficacy of compliance with rules of hygiene.

[incidence of intestinal parasites in pediatric patients with hematologic neoplasms from 1 to 15 years of age]

INTRODUCTION

Reference is made to the most frequent intestinal parasites in the hematologic patients and the association with malnutrition.

MATERIAL AND METHOD

In the Unit of Pediatrics of Hospital General de Mexico, it was studied in prospective, observational and descriptive form to a group of 85 patient hematoncologic, coming from the external consultation, with or without parasitic symptoms. The patients were assisted between June and December of 1994. To all they were carried out studies coproparasitoscopic in series of three, for the method of Faust.

RESULTS

A total of 85 children was studied from 1 to 15 years of age; 59 were parasitaded (69.5%) and 26 (30.5%) free of parasites.

CONCLUSIONS

The most frequent affections in the patients pediatric hematoncologic were: leukemia, tumors of the central nervous system and lymphomas. The most frequent parasites were: Giardia lamblia, 28.7%, Entamoeba histolytica 26%, Ascaris lumbricoides 12.3%. Of the 59 patients with some parasite, 54 (91.4%) they studied with some degree of malnutrition.

Isoenzyme and molecular characterization of Entamoeba histolytica and Entamoeba dispar isolates from symptomatic and asymptomatic subjects

AIM

To correlate the clinical features of amebic infections with the characteristics of Entamoeba culture isolates of stools.

METHODS

Isolates from seven irritable bowel syndrome (IBS) patients, four asymptomatic cyst passers (ACP) and five patients with invasive amebic disease were subjected to hexokinase polyacrylamide electrophoresis (HK-PAGE) and their DNA subjected to restriction fragment (RF) analysis of amplified polymerase chain reaction (PCR) products. These findings were correlated with anti-amebic serology. Two axenic pathogenic strains (HM1:IMSS, NIH:200) and one xenic nonpathogenic strain (SAW1734) were used as standards.

RESULTS

All isolates from IBS patients as well as ACP had slow-moving (nonpathogenic) band pattern, whereas those from patients with invasive disease had fast-moving (pathogenic) band pattern on HK-PAGE. Serological data using EIA and RF patterns of PCR-amplified genome corroborated these results.

CONCLUSIONS

Our results support the view that there are two species of Entamoeba infecting humans--E. histolytica(pathogenic) and E. dispar (nonpathogenic), and HK-PAGE of culture isolates can differentiate between them.

[Selected parasitic and infectious diseases in persons returning from the tropics]

Due to dramatic development of modern means of transport, exotic countries located on distant continents are today within a few-hour reach by a jet. Every year several million people travelled by air in business or as a tourists. This results in easy transmission of parasitic and infectious factors from continent to continent or from country to country. Plasmodium vivax infection: diagnosis concerned 6 men who had returned from Thailand, India, Senegal and Zaire. The parasitosis was detected as a result of thin smear of periferal blond tests - there were found P. vivax trophozoites an shizontes in erythrocytes. In the patients we found haematologic and termoregulation disturbances as well as hapepatosplenomegaly. Halfan was applied in therapy. Plasmodium falciparum infection: the infection was found in a man and a women after return from Kenya and Sudan. The parasitosis was detected as a result of thin smear of peripheral blond test - there found trophozoites of the parasite in erthorocytes. The course of malaria in the woman was very severe with cerebral malaria, DIC syndrome and blond circulation disturbances, hepatocellular and nephrocellular damage. Entamoeba histolytica, HAV and Candida albicans mixed infections: found in men who had returned from India. Severe E. histolytica infection: diagnosed in a women after return from Greece. There were found massive lesion of large intestine mucosa and high-degree disturbances. Leptospirosis icterohaemorrhagiae infection: found in a man after return from Belarus. Haematologic disturbance and hepatocellular and nephrocellular damage were observed.

Application of the polymerase chain reaction (PCR) in the epidemiology of Entamoeba histolytica and Entamoeba dispar infections

In this paper, we briefly summarize the latest information on the polymerase chain reaction (PCR) as an epidemiologic tool for Entamoeba histolytica and Entamoeba dispar infections. This method which employs DNA template directly extracted from formalin fixed stool specimens offers a good promise for an accurate and reliable epidemiology of the two species. The assay is, sensitive enough to detect as few as five cysts in the stool sample, rapid and selectively differentiates E. histolytica from E. dispar DNA from stool specimens without the need for prior cultivation.

Field study on the distribution of Entamoeba histolytica and Entamoeba dispar in the northern Philippines as detected by the polymerase chain reaction

We used the polymerase chain reaction (PCR) to study the distribution of Entamoeba histolytica and E. dispar in 1,872 individuals in 14 communities in the northern Philippines. Here we report a field study using a DNA extraction protocol from formalin-fixed stool specimens as previously reported. This assay detected 137 stools (7.318%) containing E. dispar and 18 stools (0.961%) containing E. histolytica. The most affected age group for E. histolytica/E. dispar infections were those 5-14 years of age. There was no significant difference in the sex distribution of E. histolytica, while in the case of E. dispar, a higher prevalence was observed in females (9.186%) than in males (5.731%) (P < 0.01). An apparent clustering of stool-positive cases of E. histolytica and E. dispar was also observed in the northern part of the study area. The results of this survey demonstrate that E. dispar is highly prevalent in the communities studied. Moreover, it offers promise for the PCR using DNA extracted from formalin-fixed stools as a sensitive epidemiologic tool for detecting E. histolytica and E. dispar infections.

[Morphology and diagnosis of the oral protozoans Trichomonas tenax and Entamoeba gingivalis using the Giemsa-Romanovsky stain]

In the microscopic diagnosis of Trichomonas tenax and Entamoeba gingivalis is the technically and time not demanding native preparation of a culture, in which both protozoans can be detected according to their typical motility, determining. In the permanent preparation of the culture stained according to Giemsa-Romanovsky, which has also documentary character, are all of the characteristic cell organelles stainable, enabling so their detection without their typical motility. Staining according to Giemsa-Romanovsky is technically simple and not time consuming, not very laborious, low cost and the coloration is permanent, that means optimal for the diagnostic of oral protozoans in permanent preparations. (Fig. 5, Ref. 4.)

Seropositivity for and intestinal colonization with Entamoeba histolytica and entamoeba dispar in individuals in northeastern Brazil

In a slum community in northeastern Brazil 20% of a sample population was colonized with Entamoeba histolytica or Entamoeba dispar and 10.6% was colonized with E. histolytica alone. No correlation between seropositivity for anti-Ga1NAc lectin antibody and colonization was found. These results suggest that colonization does not necessarily produce immunity to reinfection.