Entamoeba dispar in a terminal case of acquired immune deficiency syndrome compared with Brumpt's (1925) original cat material.

A rectal biopsy from a terminal case of acquired immune deficiency syndrome is compared with a similar biopsy taken by Brumpt in 1925 from a cat which he had infected with what he named Entamoeba dispar.

A survey of Entamoeba histolytica and Entamoeba dispar (Brumpt) infections on Mahé, the Seychelles.

E. histolytica, pathogenic, and E. dispar, non-pathogenic, being morphologically identical are, when recovered as cysts in feces, diagnosed as E. histolytica. A survey on The Seychelles demonstrated that when culture and zymodeme characterization was used to compare against microscopy alone, the risk of overdiagnosis of E. histolytica infections was drastically reduced. From a total of 313 subjects tested 21 cultures grew amebas. By zymodeme analysis eight were E. histolytica, 40 were E. dispar and the remainder were various species of non-pathogenic intestinal amebas. Two further small comparative surveys confirmed these findings.

Autochthonous amoebiasis in institutionalized mentally-retarded patients: preliminary evaluation of isoenzyme patterns in three isolates.

Three autochthonous cases of Entamoeba histolytica infection in institutionalized mentally-retarded patients are reported. Isoenzyme analysis by starch-gel electrophoresis shows the pathogenicity of the three isolates: two belong to zymodeme II, and one to zymodeme XIX. The study shows that invasive E. histolytica strains occur in Italy and can be isolated from institutionalized oligophrenic patients.

Entamoeba histolytica zymodemes: exhibition of gamma and delta bands only of glucose phosphate isomerase and phosphoglucomutase may be influenced by starch content in the medium.

Entamoeba histolytica isolated from human can be associated with either symptomatic disease or with asymptomatic carriers. Pathogenic and nonpathogenic strains can be distinguished on the basis of differences in the electrophoretic patterns of four isoenzymes (zymodeme). With glucose phosphate isomerase and phosphoglucomutase, we observed variation of the expression of their gamma bands as a function of starch volume in culture. We cultured E. histolytica strains from different zymodemes in Robinson medium using both a low (2-4 mg/bottle) and a high (12-15 mg/bottle) content of rice starch as supplement. These cultures were monitored by electrophoresis of glucose phosphate isomerase and phosphoglucomutase. Strains having gamma or delta bands exhibited those bands when a high content of starch was used in culture, but did not do so with a low content. Contrarily, strains that never exhibited those bands did not express them when the amount of starch in the culture was increased. However, alpha and beta bands of the same isoenzymes were always present and never showed any variation. The results suggest that expression of gamma and delta bands of glucose phosphate isomerase and phosphoglucomutase are subject to culture conditions and that genes coding for those isoenzymes may be different from those coding for the alpha and beta bands.

Entamoeba histolytica infections in flight personnel of an international airline.

A cohort of 99 subjects, members of the flight staff of Lufthansa German airlines, all infected with Entamoeba histolytica, were followed over a period of 2.5 years to monitor their clinical and parasitological status. All but 4 of the subjects were infected with non-pathogenic zymodemes of E. histolytica and had negative amoebic serology, and most were clinically well. One male heterosexual carrying a pathogenic zymodeme was found, despite massive treatment regimes, to carry the infection persistently for 12 months. Most non-pathogenic infections were left untreated.

An immunogenic 30-kDa surface antigen of pathogenic clinical isolates of Entamoeba histolytica.

A 30-kDa surface antigen was identified by Western blots with human immune sera in all 15 isolates of E. histolytica from patients with invasive amebiasis (pathogenic) but not in 15 strains from asymptomatic patients (nonpathogenic). This antigen is highly immunogenic in naturally infected humans and was recognized by sera from 22 patients with invasive disease but not by sera from 13 patients harboring nonpathogenic strains. Its surface location is supported by its differential extraction in the detergent phase of Triton X-114 and by surface immunofluorescence of live trophozoites. Unlike previously described amebic surface antigens, this 30-kDa antigen is undetectable in axenic strains that were originally isolated from patients with invasive disease but have been adapted to grow without bacteria. Affinity-purified antibody to the 30-kDa antigen did not promote lysis of complement-resistant pathogenic strains. This surface antigen may be diagnostically important in the identification of pathogenic clinical isolates.

Entamoeba histolytica: naturally occurring infections in baboons.

Entamoeba chattoni frequently occurs as an intestinal infection in non-human primates. It has been isolated from both wild and captive animals. Morphologically this amoeba resembles E. histolytica. E. histolytica has also been isolated from non-human primates on a number of occasions but these isolations have been from captive animals. In recent years identification of E. histolytica has been enhanced by the introduction of iso-enzyme electrophoresis methods. This technology has been widely applied to amoebae isolated from humans from many parts of the world. Limited work using iso-enzyme electrophoresis on non-human primates in captivity has confirmed the earlier parasitological studies mentioned above as both E. histolytica and E. chattoni were isolated; furthermore zymodeme (strain or species based on the characteristic iso-enzyme electrophoretic pattern) analysis demonstrated that these two organisms could be readily distinguished by this method. The importance of establishing whether E. histolytica occurs in wild primates as a true zoonosis was emphasised by these studies, particularly from the point of view of potential disease transmission. A study of baboons (Papio ursinus) in South African game reserves has been initiated and three surveys have been conducted in the Kruger National Park; these baboons are considered to live in isolation from humans. Of the 210 isolations attempted 65-75% yielded E. chattoni while E. histolytica were cultured from the faeces of 1-3% of the baboons. Although the prevalence rates varied in each of the 3 study locations both species of amoeba were found in baboons from all of them. All the E. histolytica isolated thus far have been non-pathogenic zymodemes.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

Biological evidence of genetic exchange in Entamoeba histolytica.

The demonstration of a new zymodeme of Entamoeba histolytica produced in culture from cloned isolates suggested possible genetic exchange in this parasite. We have attempted to substantiate that finding by using rats as biological hosts. Clones were made from 3 separate isolates of E. histolytica, each established in culture from liver pus or faeces. After enzyme characterization these clones, of zymodemes II, XIV and XIX, were paired in each of the 3 possible combinations and the mixtures injected into the caecum of rats. Clones of new or hybrid zymodemes were produced as well as the original parents, with one exception, the mixture of XIV and XIX, from which only one of the parents was recovered. The hybrids produced included zymodeme XX, observed previously, and zymodeme XI, a naturally occurring zymodeme that has in the past been recovered only from subjects with invasive amoebiasis.

Amebic liver abscess in a European patient: zymodeme classification of Entamoeba histolytica.

This is a case report of a 36-year-old patient who developed an amebic liver abscess after a stay in the Sudan. He was first misdiagnosed as having pneumonia of the right lower lobe. Following establishment of the correct diagnosis, the patient recovered fully after metronidazole treatment. The fecal culture in Robinson's medium yielded extensive growth of Entamoeba histolytica. Electrophoretic characterization proved it to be a zymodeme XIX, which is one of the zymodemes associated with pathogenicity in the host. This first report of a zymodeme classification of E. histolytica in Germany should initiate further epidemiological studies.