Experimental production of new zymodemes of Entamoeba histolytica supports the hypothesis of genetic exchange

By mixing in culture zymodemes of Entamoeba histolytica, clones showing a different pattern from the 2 parents have been obtained on 3 occasions. Two new zymodemes (XI alpha- and XXI) have thus been produced, which belong to the third generation of a family of E. histolytica zymodemes apparently obtained by genetic exchange. A hypothesis for the molecular basis of those exchanges is discussed. We report also the observation of probable mutation.

Clinical survey of Entamoeba gingivalis by multiple sampling in patients with advanced periodontal disease

A clinical survey of Entamoeba gingivalis was conducted in patients with advanced periodontal disease. A total of 100 specimens were taken from 10 patients (four females and six males) who were each sampled at 10 disto-facial random sites. The oral hygiene of the persons scored from good to fair to poor and very poor. The age of the test persons ranged from 20 to 68 years. All persons examined harbored E. gingivalis: the minimum prevalence was four sites positive out of 10 and the maximum prevalence was 10 sites positive out of 10 for the protozoan. It is recommended that for reliable testing of the presence of E. gingivalis at least five-10 different sites should be examined within the periodontium of each patient. Data reported earlier in the literature on the incidence of E. gingivalis--obtained after a single sampling per individual--are believed to be on average too low and, therefore, should be interpreted with caution.

Entamoeba polecki infection in a Southeast Asian refugee in Japan

We report the first human case of Entamoeba polecki infection found in Japan. Cysts of E. histolytica-like amoeba were detected in a stool sample from a female Cambodian refugee. The cysts were morphologically investigated after stained by the modified Kohn's method. The amoeba was identified as E. polecki by the findings that the cyst had frequently an inclusion mass, usually one or very rarely two nuclei, frequently a darkly stained nucleus, and some other characteristics. This protozoan parasite is essentially non-pathogenic to humans, but it is morphologically similar to and often confused with E. histolytica, a pathogenic species. Therefore, it is very important in laboratory diagnosis to differentiate the former from the latter.

Coincidence of deficient delayed hypersensitivity and intestinal protozoa in homosexual men

Stool samples of 134 subjectively and apparently healthy male homosexual volunteers were studied, and in 86 men (64.2%) 190 parasite infestations, up to 6 per host, were identified. The most frequent species were Endolimax nana (40), Entamoeba coli (38), Entamoeba histolytica (34), Entamoeba hartmanni (32), and Iodamoeba bütschlii (22); Cryptosporidium was not found. All 11 isolates of Entamoeba histolytica analysed belonged to a noninvasive zymodeme: 10 were of zymodeme I and I of zymodeme III. In 172 healthy control adults 6 parasite infestations were found. In the homosexual men, a negative tuberculin test was more frequent in the presence than in the absence of parasites. Entamoeba histolytica (p = 0.005) Entamoeba coli (p = 0.013) and Iodamoeba bütschlii (p = 0.004) were associated with the anergy.

PEHPS medium: an alternative for axenic cultivation of Entamoeba histolytica and E. invadens

Knowledge of Entamoeba histolytica biology in the last 17 years has been acquired largely as a consequence of this parasite's axenic cultivation in TPS-1 or TYI-S-33 media. Unfortunately, there are often low yields in these media, due to variability of their main components, Panmede and yeast extract. We describe a medium, PEHPS, of which the main components are extracts of ox liver, and ox and swine pancreas (EHP). 5 strains of E. histolytica and 2 of E. invadens were quickly and easily adapted to PEHPS and serially cultivated for 3 years. Yields progressively rose initially, and then became stable. Depending on the strain, average yields in the last 6 months of this study were 1.3 to 3.1 x 10(5) amoebae/ml for E. histolytica and 5.5 to 5.7 x 10(5) for E. invadens. All the 18 EHP batches tested supported vigorous amoebal growth. PEHPS had 2 additional advantages: (a) it was stable at 4 degrees C or 25 degrees C for 9 months, and at -10 degrees C for at least 2 years, and (b) it supported amoebal growth with inocula as low as one trophozoite/ml. PEHPS avoids the variability shown by TPS-1 and TYI-S-33, and could therefore be a good alternative for axenic amoebal cultivation.

Simple and rapid staining for detection of Entamoeba cysts and other protozoans with fluorochromes

Three fluorochromes were applied to stain various parasitic protozoans. By double staining with 4',6-diamidino-2-phenylindole and propidium iodide, differentiation of the nuclei from the cytoplasm can easily be achieved within several seconds. The chromatoid bodies in Entamoeba cysts were stained bright red. Plasmodium yoelii at all stages except late trophozoites and young gametocytes was easily identified. In the oocysts of Cryptosporidium sp., the nuclei and cytoplasm of the sporozoites fluoresced bluish white and red, respectively, whereas the residual body appeared blue or green. The third fluorochrome, Calcofluor white M2R, was suitable for detecting the cysts of Entamoeba spp. and Chilomastix mesnili.

Entamoeba polecki and other intestinal protozoa in Papua New Guinea Highland children

Relatively few cases of humans infected with Entamoeba polecki have been reported world-wide. Where man and pig live in close association and where sanitation is poor, pig to man transmission is considered to be the most likely source of human infection. In our survey of 184 children only fresh faeces were used, thus allowing the identification of trophozoites as well as cysts. Thirty-five children (19%) were found positive for E. polecki, although in one community ten of 23 (43.4%) over five-year olds were infected. Sera from 20 positive children were tested against E. histolytica antigen, but no positive reactions were observed. We propose the possibility of man to man transmission of E. polecki where the prevalence rate and intensity of infection are high.

Entamoeba polecki infection in Southeast Asian refugees: multiple cases of a rarely reported parasite

Recently, Entamoeba polecki was identified for the first time in our parasitology laboratory in stool specimens from eight Southeast Asian refugees. This ameba has been reported infrequently in the Western world; most reported cases have been from the New Guinea region. In most previously described patients and in our patients, no definite gastrointestinal symptoms could be directly attributed to E. polecki infection. Morphologically, E. polecki may mimic the pathogen E. histolytica and also nonpathogens such as E. coli. These species are most readily distinguished by studying encysted forms. In contrast to E. histolytica and E. coli, E. polecki characteristically has uninucleate cysts. Both pigs and monkeys naturally harbor E. polecki, but four of the patients in this series had no apparent contact with these animals. Other modes of infection may be human-to-human transmission or acquisition from other domestic animals. Six of our eight patients were treated successfully with one course of metronidazole in a regimen similar to that used for E. histolytica infection. In the two other patients, repeated courses of therapy eradicated the infection. Because of the recent increase in number of Southeast Asian immigrants to the United States, E. polecki may be identified more frequently than in the past. Physicians and laboratory personnel should be familiar with this organism, because it may be confused with E. histolytica or may act as a pathogen.

Entamoeba gingivalis: prevalence amongst inhabitants of the Niger Delta

A survey based on microscopic examination of scrapping taken from the gum-line was conducted on the prevalence of Entamoeba gingivalis amongst inhabitants of the Niger Delta area of Nigeria. An overall prevalence of 6.9% was recorded. Infection was highest among the 5-10 year age group (22.9%) and dropped progressively with increase in age of the subjects such that by the age of 29 years it had fallen to 5.7%. No significant difference (p less than 0.005) could be detected regarding infection amongst smokers (4.1%) and non-smokers (4.3%) or between male (6.8%) and female subjects (7.0%).

Carriage of intestinal protozoal cysts in homosexuals

A total of 83 male homosexuals were studied to ascertain the carriage of intestinal protozoal cysts. The homosexual group had a significantly (p less than 0.0005) higher prevalence than a control group. One or more types of protozoa were found in 33 homosexuals. The carriage of intestinal protozoal cysts was associated with particular sexual practices and promiscuity, but not with symptomatic bowel disorders. The possible implications of the carriage of these cysts are discussed.

[A copro-parasitological study on the wrestlers of the national team]

This copro-parasitological research was made on the 18 wrestlers of the national team in the Talas training camp in Kayseri, The majority of them came to our laboratory with gastro-intestinal complaint such as nausea colicky pains anorexia and dyspepsia and other complaints such as exhaustion and fatigue and 16 of them were found infested with one or more than one parasites. As a result of our coprologic examination finding parasites and their infection rate were: Entamoeba histolytica (50%), Entamoeba coli (16,6%), iodamoeba bütschlii (16,6%), Endolimax nana (11,1%), Giardia lamblia (11,1%), Enteromonas hominis (11,1%) Ascaris lumbricoides (5,5%) and Hymenolepis nana (5,5%). It has been indicated that, 11 of total wrestlers were found infected with one kind, 4 of them were found infected with two kinds and 1 was found infested with three kinds parasites.

Enteric pathogenic protozoa in homosexual men from San Francisco

The prevalence of enteric protozoa was studied in a survey conducted among 150 male homosexual patients in San Francisco. All patients were from a private practice in internal medicine. Each was asked to complete a questionnaire and to submit multiple stool specimens for examination. Of this group, 47% were positive for one or more potentially pathogenic intestinal protozoa; Entamoeba histolytica was found in 36%, Entamoeba hartmanni in 35%, Giardia lamblia in 5%, and Dientamoeba fragilis in 1.3%. Symptoms were unreliable as a diagnostic index of intestinal protozoan infection. Colonization rates could not be correlated with any specific sexual technique. The large number of homosexuals at risk, combined with the potential for difficulties in diagnosis and contact-tracing, indicate the possibility that enteric pathogenic protozoa will cause future health problems in this population.

Amebiasis presenting as multiple apple core lesions

An unusual manifestation of amebiasis is presented to demonstrate its ability to masquerade as carcinoma or a variety of colitides. The importance of actively considering Entamoeba histolytica-induced disease in a differential diagnosis of bloody diarrhea is emphasized.

Frequency of Entamoeba gingivalis in human gingival scrapings

A survey was made of gingival scrapings stained by the Papanicolaou method to assess the occurrence of Entamoeba gingivalis, a nonpathogenic-oral amoeba. Positive findings were recorded in 59% of 113 dental patients, and 32% of 96 healthy controls. These figures showed no significant changes during the last 20 years when compared with data published in 1960 and 1963. The existence of E. gingivalis and its rare appearance in the sputum should be known to cytologists because of the morphologic resemblance to Entamoeba histolytica, a pathogenic amoeba. Morphologic features are described to differentiate E. gingivalis from similar structures found in sputum.

Entamoeba invadens and E. histolytica: separation and purification of precysts and cysts by centrifugation on discontinuous density gradients of Percoll

The different cell forms in the life cycle of Entamoeba invadens (trophozoites, precysts, and cysts) were rapidly and quantitatively separated on density step gradients of polyvinylpyrolidone-coated colloidal silica particles (Percoll). With this method, the gradual process of encystation by E. invadens trophozoites could be monitored. Percoll gradients were also efficient in separating trophozoites of Entamoeba histolytica and bacteria. After purification on Percoll, trophozoites display no evidence of damage when examined by light microscopy and no loss in viability as judged by their ability to multiply.

Entamoeba moshkovskii (Tshalaia, 1941): morpho-biological characterization of new strains isolated from the environment, and a review of the literature

After an investigation carried out with samples from several sewage sludges from the town of Pavia (Italy) the AA. report the isolation of two new strains of Entamoeba moshkovskii. The usefulness and reliability of two methods, i.e. growth in hypotonic media and the thermoresistance tests in vitro for the biological typing of this species are analyzed and discussed. Both methods had already proven useful to characterize the Laredo-type strains of E. histolytica too, as reported by other AA.