Endoparasites of western lowland gorillas (Gorilla gorilla gorilla) at Bai Hokou, Central African Republic

A coprologic study of free-ranging western lowland gorillas (Gorilla gorilla gorilla) at Bai Hokou, Dzangha-Ndoki National Park, Central African Republic (2 degrees 51'34''N, 16 degrees 28'03''E) was conducted from October 1999 to November 2000. All 75 fecal samples examined were positive for endoparasites, and each contained at least two species. Parasites present included two genera of amoebae, entodiniomorph ciliates, including Prototapirella gorillae, Troglodytella spp., and Gorillophilus thoracatus, a Balantidium-like organism, strongyle/trichostrongyle eggs (including a presumptive Mammomonogamus sp. and several other genera), Strongyloides sp., Probstmayria sp., a spirurid, a trichuroid, and several unidentified trematodes. Flagellates and cestodes were not found. Despite the presence of a variety of parasite genera, in general, levels of parasitism were low. These data provide baseline parasitologic data for this population as part of a comprehensive health-monitoring program. With the advent of ecotourism in this study area, continued monitoring is indicated for insuring the health of both gorillas and humans in the Bai Hokou study area.

[Amebic lung abscess: an unexpected diagnosis]

Pleuropulmonary amebiasis is a very rare complication of amebiasis infection and direct pulmonary involvement is exceptional. The clinical diagnosis is difficult without any intestinal or extraintestinal manifestations. A percutaneous drainage is necessary to aspirate pus. We report herein the case of a 56-year-old man presenting with an amebic lung abscess in his right lower lung and pleural effusion. The diagnosis was suspected by our laboratory from a serological assay (antiamebic antibodies reaching 320 by IHA) and established from a direct examination of the pus in which rare trophozoites of Entamoeba were detected. We pointed out the importance of the communication between the clinician and the biologist. Protozoan infection should be suspected in pleuropulmonary infection when antibiotics failed even in France. This patient left endemic area a long time ago and the way of his amebiasis contamination is unknown: recurrence of amebic infection is rare and prevalence in industrialized countries reaches only 1%. Several hypothesis are exposed.

Entamoeba histolytica and Entamoeba dispar: prevalence infection in a rural Mexican community

The frequency of Entamoeba histolytica and Entamoeba dispar infection was analyzed in a rural community in the state of Morelos, Mexico, through PCR technique by using specie specific primer. The E. histolytica specie was detected in 33 of 290 analyzed stool samples (11.4%), E. dispar specie was observed in 21 samples (7.2%) and both species of Entamoeba were detected in seven samples (2.4%). So a higher E. histolytica than E. dispar frequency infection was detected (13.8 versus 9.6%). Even though in our design we did not considered the follow-up of included individuals, the absence of invasive amebiasis cases in the studied population during our stay in town was unexpected.

Species- and strain-specific probes derived from repetitive DNA for distinguishing Entamoeba histolytica and Entamoeba dispar

Entamoeba histolytica and Entamoeba dispar are two morphologically indistinguishable species that are found in the human gut. Of the two, E. histolytica is considered to be pathogenic while E. dispar is nonpathogenic. To generate molecular probes to detect and distinguish between the two species, we utilized repeat sequences present in Entamoeba genome. We have developed probes and primers from rDNA episomes, and unidentified Entamoeba EST1 repeat for this purpose, and used them for dot blot hybridization and PCR amplification. To investigate the possible existence of invasive and noninvasive strains of E. histolytica, the ability to differentiate individual isolates is necessary. For this purpose, we have utilized a modification of the AFLP procedure called 'Transposon display,' which generates and displays large number of genomic bands associated with a transposon. We have used the abundant retrotransposon, EhSINE1, for this purpose,and demonstrated its potential as a marker to study strain variation in E. histolytica. This technique could suitably be employed in carrying out significant molecular epidemiological studies and large-scale typing of this parasite.

Entamoeba histolytica or Entamoeba dispar among children in Gaza, Gaza Strip?

Most physicians in Gaza prescribe medicaments for patient's suffering from Entamoeba histolytica/dispar without parasitologic diagnosis. Additionally, stool analysis performed by the routine methods usually reports the species as E. histolytica without con-firmation. In this study, 92 stool specimens were collected and analyzed by wet mount, iron haematoxylin staining, antigen detection of E. histolytica and polymerase chain reaction (PCR). The total number of E. histolytica identified by PCR was 64 (69.6%) that of E. dispar was 21 (22.8%). Mixed infection with both E. histolytica and E. dispar was evident in 7 specimens (7.6%). In the light of these results approximately 30% of suspected clinical amoebiasis cases were negative for E. histolytica. It is recommended to use PCR for diagnosis of stool specimens from patients with E. histolytica/dispar and that treatment should be prescribed for only patients positive for E.

Genetic characterization of Entamoeba dispar isolates in Northeast Brazil

The genetic variability of Entamoeba dispar strains was investigated in 39 positive isolates on a survey of 1783 individuals from two different cities of Northeast Brazil (Recife and Macaparana) using two polymorphic species-specific loci (loci 1-2 and 5-6). A combinatory clustering analysis revealed no geographical correlation and remarkable genetic polymorphism among all the isolates examined. Nevertheless, a comparison of the frequency of eight individual PCR products, shared by both Recife and Macaparana populations, for the two loci, showed that only one product of locus 5-6 was significantly different between the two cities. These results suggested that the Macaparana population is infected by similar strains and that locus 5-6 shows potential in assaying questions related to the molecular epidemiology of this region.

E. dispar strain: analysis of polymorphism as a tool for study of geographic distribution

The intra-species polymorphism of E. histolytica and E. dispar species in endemic area is an important tool for geographic distribution and spread mechanism studies. Since E. dispar and E. histolytica shears ecological niche, cell cycle, and transmission mechanism for human host, we studied the intra-specie variation and distribution of E. dispar strains obtained from cyst passers, in two neighbor rural communities in Morelos Mexico. We analyzed the polymorphic region of the quitinase protein gene in isolates of E. dispar. In 45 isolates from one community we identified 12 different CHI patterns while in 15 isolates from the other community we identified 5 different patterns. However both communities share 4 patterns. This finding suggests the presence of strains with different geographic mobility.

The distribution of Entamoeba histolytica and Entamoeba dispar in northern, central, and southern Iran

The present study was carried out from August 1999 through February 2002 in order to determine the prevalence of Entamoeba histolytica and Entamoeba dispar in three different climatic regions of Iran by using a PCR-RFLP method. A total of 16,592 stool samples were randomly collected from different age-groups in central, northern, and southern Iran in both urban and rural areas. The samples were examined by direct and formalin-ether concentration methods. A total of 226 samples were positive for E. histolytica/E. dispar cysts. Of these, 101 isolates were cultured and maintained successfully in Robinson's medium and were identified by the PCR-RFLP method. The study showed that 92.1% of isolates were E. dispar and 7.9% were E. histolytica or mixed infections. The ratio of E. histolytica to E. dispar was higher in southern regions (tropical and subtropical) than in the other two regions. This study demonstrated that E. dispar is the predominant species found among "cyst passers" in Iran.

Parasitological analyses of the male chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda

Numerous intestinal parasites identified in populations of wild nonhuman primates can be pathogenic to humans. Furthermore, nonhuman primates are susceptible to a variety of human pathogens. Because of increasing human encroachment into previously nonimpacted forests, and the potential for disease transmission between human and nonhuman primate populations, further detailed investigations of primate ecological parasitology are warranted. For meaningful comparisons to be made, it is important for methods to be standardized across study sites. One aspect of methodological standardization is providing reliable estimates of parasite prevalence and knowing how many samples are needed to adequately estimate an individual's parasite prevalence. In this study the parasitic fauna of 37 adult, adolescent, and juvenile male chimpanzees from the Ngogo group, Kibale National Park, Uganda, were assessed from 121 fecal samples collected over a 3-month period. Twelve taxa of intestinal species (five helminth and seven protozoan) were recovered from the samples. The four most prevalent species were Troglodytella abrassarti (97.3%), Oesophagostomum sp. (81.1%), Strongyloides sp. (83.8%), and Entamoeba chattoni (70.3%). No one species was found in all samples from any one animal, and Troglodytella abrassarti, the most common intestinal organism, was found in all of the serial samples of only 69.4% of the chimpanzees. The cumulative species richness for individuals significantly increased for every sequential sample (up to three to four samples) taken per animal during this study. The results indicate that to accurately diagnose total intestinal infection and evaluate group prevalence, three to four sequential samples from each individual must be collected on nonconsecutive days. This conclusion applies only to short study periods in which possible seasonal effects are not taken into consideration. Validation of these results at different study sites in different regions with different climatic patterns is needed.

[Transmission of enteropasitosis through currency notes]

PURPOSE

There are several ways to propagation of parasitary diseases and how there aren't many bibliographic work about this theme, it was realized a study near to the Natal-RN population, to verify the enteroparasites transmission through the paper money.

METHODS

In the Laboratório Parasitologia Clínica was analysed 500 bills of several worths gotten in shops and, concomitantly it was examined samples of a water got from the washed hands of the people who held the money. The methods to realize the parasitologic exams were: Ritchie and Faust et al.

RESULTS

It was observed the following parasites prevalent in 48 (9.6%) examined bills: Endolimax nana 31 (6.2%), Entamoeba coli 06 (1.2%), Entamoeba histolytica 01 (0.2%), Ascaris lumbricoides 10 (2.0%). In the water, it vas observed that 40 (40.0%) of them had the same kinds of parasites in their hands.

CONCLUSIONS

Finally, it is postulated that the paper money is important to the enteroparasites transmission and it is suggested that new researches must be done in this area.

Detection of Entamoeba histolytica/Entamoeba dispar in stool specimens by using enzyme-linked immunosorbent assay

Entamoeba histolytica actually comprises two genetically distinct but morphologically indistinguishable species. E. histolytica can cause invasive intestinal and extra intestinal disease, while E. dispar cannot. Identification and differentiation of E. dispar and E. histolytica in stool sample by microscopy is imprecise. Several weeks of culture and isoenzyme analysis are required to differentiate E. histolytica from E. dispar. In this study, we have used an enzyme-linked immunosorbent assay (ELISA) for detection of E. histolytica/E.dispar and compared it with microscopy. Eighty-eight samples were evaluated, trichrome staining was positive in 20.4% (18) and ELISA was positive in 29.5% (26). Both tests were positive in 14 (15.9%) samples, 4 (4.5%) only with direct microscopy, and 12 (13.6%) only with ELISA. Both tests were negative in 58 (65.9%) samples. Microscopy has low sensitivity and high specificity, low negative predictive value and high positive predictive value in comparison with ELISA. E. histolytica/E. dispar antigen detection ELISA tests are inexpensive compared to the specific tests, yield objective results and do not require experienced microscopists and can therefore be recommended for screening of stools worldwide and the results can be taken for treatment that are fitting with its clinic.

An improved PCR-based method for detection and differentiation of Entamoeba histolytica and Entamoeba dispar in formalin-fixed stools

Detection of infectious agents in faecal samples by polymerase chain reaction (PCR) can be limited by the presence of substances which inhibit DNA amplification. Here, an improved protocol is reported for directly isolating DNA from fresh and aged formalin-fixed stools, after concentration by formalin-ethyl acetate (FEA). The protocol was successfully applied to detect DNA of Entamoeba histolytica/Entamoeba dispar complex in stools by nested PCR, showing high specificity and low detection limit. Extended time of specimen storage in formalin had no influence on PCR yields. This PCR-based method offers technical advantages for routine detection and discrimination of invasive E. histolytica and non-invasive E. dispar.

Detection and genotyping of Entamoeba histolytica, Entamoeba dispar, Giardia lamblia, and Cryptosporidium parvum by oligonucleotide microarray

Entamoeba histolytica, Giardia lamblia, and Cryptosporidium parvum are the most frequently identified protozoan parasites causing waterborne disease outbreaks. The morbidity and mortality associated with these intestinal parasitic infections warrant the development of rapid and accurate detection and genotyping methods to aid public health efforts aimed at preventing and controlling outbreaks. In this study, we describe the development of an oligonucleotide microarray capable of detecting and discriminating between E. histolytica, Entamoeba dispar, G. lamblia assemblages A and B, and C. parvum types 1 and 2 in a single assay. Unique hybridization patterns for each selected protozoan were generated by amplifying six to eight diagnostic sequences/organism by multiplex PCR; fluorescent labeling of the amplicons via primer extension; and subsequent hybridization to a set of genus-, species-, and subtype-specific covalently immobilized oligonucleotide probes. The profile-based specificity of this methodology not only permitted for the unequivocal identification of the six targeted species and subtypes, but also demonstrated its potential in identifying related species such as Cryptosporidium meleagridis and Cryptosporidium muris. In addition, sensitivity assays demonstrated lower detection limits of five trophozoites of G. lamblia. Taken together, the specificity and sensitivity of the microarray-based approach suggest that this methodology may provide a promising tool to detect and genotype protozoa from clinical and environmental samples.

Entamoeba struthionis n.sp. (Sarcomastigophora: Endamoebidae) from ostriches (Struthio camelus)

In the present work we identify the species of Entamoeba from ostriches (Struthio camelus). The complete sequence of the small subunit ribosomal RNA gene from this organism has been compared with those published for other species of the genus and clear differences have been found. These results confirm previous data which showed differences on parasite morphology and class of host with the other Entamoeba species. Taking all these data together, it can be concluded that the organism from ostriches is a new species whose proposed name is Entamoeba struthionis n.sp. This species probably infects rheas (Rhea americana), but genetic analysis of isolates from this host should be performed to confirm morphological data. Also, comparison of gene sequences with data from other authors on cysts recovered from human stool samples showed the possibility that this amoeba may affect humans. Further studies are needed to determine the risk of transmission of this new species to humans.

The use of real-time PCR to identify Entamoeba histolytica and E. dispar infections in prisoners and primary-school children in Ethiopia

In Ethiopia, it is generally unknown what proportion of the amoebic infections commonly found, by microscopy, in humans are caused by non-invasive Entamoeba dispar rather than the potentially invasive E. histolytica. Faecal samples were therefore collected from 363 primary-school students and 409 prisoners from various regions of Ethiopia. Each of these samples was checked for Entamoeba infection by the microscopical examination of formol-ether concentrates. DNA was then extracted from the 213 samples (27.6%) found Entamoeba-positive, and run in a real-time PCR with primers, based on the SSU-rRNA gene sequences of E. histolytica and E. dispar, that allow DNA from the two species to be distinguished. Although E. dispar DNA was identified in 195 (91.5%) of the 213 samples checked by PCR, no E. histolytica DNA was detected. This finding is consistent with the conclusion of a previous, smaller investigation: that many amoebic infections in Ethiopia are incorrectly attributed to E. histolytica and then treated, unnecessarily, with amoebicidal drugs.

Short communication: Prevalence of Entamoeba histolytica and Entamoeba dispar in northern Ghana

Since the redescription of the potentially invasive Entamoeba histolytica, separating it from the morphologically identical non-invasive Entamoeba dispar, there is a need for the reassessment of epidemiological data on amoebiasis. In this context we conducted a descriptive survey on the presence of E. histolytica and E. dispar in a rural area in northern Ghana. We found a high prevalence (39.8%) of the E. histolytica/E. dispar complex with microscopy, but E. histolytica and E. dispar-specific DNA amplification using real-time polymerase chain reaction identified only one E. histolytica case and revealed a considerably higher prevalence of E. dispar (82.8%).

Determination of the prevalence of Entamoeba histolytica and E. dispar in the pernambuco state of northeastern Brazil by a polymerase chain reaction

Previous studies using methods varying from traditional serologic tests to molecular biology techniques have shown that in northeastern Brazil, Entamoeba dispar was more prevalent than E. histolytica. In this study, the prevalence was established by using E. histolytica stool antigen detection kits and a polymerase chain reaction (PCR) with genomic DNA extracted from cultured trophozoites in all four-nuclei, amoeba-positive samples from a population living in Macaparana in northeastern Brazil. Among 1,437 stool samples analyzed, only 59 (4.1%) were positive for four nuclei amoeba. However, all of these samples were negative in an immunoenzymatic assay for the presence of E. histolytica-specific galactose adhesin. Of 59 cultivated samples, only 31 showed trophozoites. Extraction of DNA from these 31 samples, followed by the PCR, showed that 23 samples (74.19%) were positive for E. dispar and no amplification was observed for pathogenic E. histolytica. The remaining eight samples were negative for both species. These findings are consistent with those previously reported.

Laboratory diagnosis of amebiasis

The detection of Entamoeba histolytica, the causative agent of amebiasis, is an important goal of the clinical microbiology laboratory. To assess the scope of E. histolytica infection, it is necessary to utilize accurate diagnostic tools. As more is discovered about the molecular and cell biology of E. histolytica, there is great potential for further understanding the pathogenesis of amebiasis. Molecular biology-based diagnosis may become the technique of choice in the future because establishment of these protozoa in culture is still not a routine clinical laboratory process. In all cases, combination of serologic tests with detection of the parasite (by antigen detection or PCR) offers the best approach to diagnosis, while PCR techniques remain impractical in many developing country settings. The detection of amebic markers in serum in patients with amebic colitis and liver abscess appears promising but is still only a research tool. On the other hand, stool antigen detection tests offer a practical, sensitive, and specific way for the clinical laboratory to detect intestinal E. histolytica. All the current tests suffer from the fact that the antigens detected are denatured by fixation of the stool specimen, limiting testing to fresh or frozen samples.

[Frequency of intestinal parasites in samples of lettuce (Lactuca sativa) commercialized in Lavras, Minas Gerais State]

The aim of this study was to evaluate the parasitological contamination in samples of lettuce (Lactuca sativa) commercialized in Lavras city, Minas Gerais. The samples of lettuce showed low hygienic conditions, indicated by the presence of parasites of animal or human origin and high concentration of fecal coliforms.

[Microbiological and parasitological contamination of lettuce (Lactuca sativa) from self service restaurants of Niterói city, RJ]

Thirty samples of lettuces from self service restaurants of Niterói were analyzed to detect bacteriological and parasitological contamination. Sixteen samples presented fecal coliform, 16 mesophilic aerobic microorganisms greater than 10(7) UFC/g and 3 cysts of Entamoeba coli. These data suggest the need of better orientation for food handlers regarding the hygiene of processed vegetables.

Detection of Cryptosporidium amongst diarrhoeic and asymptomatic children in Jeddah, Saudi Arabia

Between the March and May of 2000, stool specimens were collected from children aged <5 in six pre-school crèches and clinics in the Jeddah area of Saudi Arabia. Sixty-three (25%) of the children had diarrhoeal disease but the other 190 were asymptomatic. When the stool samples were stained and examined for the oocysts of Cryptosporidium spp. and other enteric protozoa, 20 (32%) of the symptomatic children but only nine (4.7%) of the asymptomatic were found to be excreting Cryptosporidium oocysts. Similarly, Cyclospora cayetanensis was found, always as a co-infection with Cryptosporidium sp., in seven (11%) of the children with diarrhoeal disease but only eight (4.2%) of the asymptomatics. One asymptomatic child was found to be co-infected with Isospora belli and Cryptosporidium. Giardia intestinalis and cysts of Entamoeba histolytica/dispar were detected in 18 (29%) and nine (14%) of the children with diarrhoeal disease and in eight (4.2%) and 13 (6.8%) of the asymptomatic children, respectively. This appears to be the first report of Cy. cayetanensis from Saudi Arabia and the highest prevalence of Cryptosporidium infection ever described.

Genotyping of Entamoeba species in South Africa: diversity, stability, and transmission patterns within families

Using a recently described polymerase chain reaction-based DNA typing method for Entamoeba histolytica and E. dispar, we investigated the genetic diversity of these species in a geographically restricted region of South Africa. Patterns were stable over time in the same infection, and, with few exceptions, infected family members carried the same strain. However, both species exhibited remarkable variation, with no 2 family groups being infected with the same strain of E. histolytica. Mixed infections were rare. The results indicate that this typing method will be useful in identifying epidemiological linkage between infections.

Entamoeba histolytica infections in captive primates

A group based survey on the presence of Entamoeba histolytica and Entamoeba dispar using real-time PCR among 20 species of captive non-human primates was performed after diagnosis of E. histolytica dysentery in a spider monkey ( Ateles belzebuth hybridus). E. histolytica DNA was detected in three species of New World primates and in three species of Old World primates. In five of six E. histolytica isolates, it was possible to amplify the SREHP gene. They all revealed the same pattern after AluI digestion, indicating a common source of infection. E. dispar DNA was detected in two species of New World monkeys and three species of Old World monkeys. The results demonstrate that E. histolytica is capable of causing symptomatic and non-symptomatic infections in Old World and New World non-human primates. To our knowledge, this is the first report of E. histolytica sensu stricto in non-human primates after the redescription separating it from E. dispar in 1993.

Induction of permeability changes and death of vertebrate cells is modulated by the virulence of Entamoeba spp. isolates

Although Entamoeba histolytica is capable of inducing an apoptotic response in vertebrate cells in vitro (Cell. Microbiol. 2 (2000) 617), it is not known whether vertebrate cell death requires direct amoeba-vertebrate cell contact or simply the presence of amoebae in the area of the vertebrate cells. In addition, Entamoeba spp. vary in their virulence and pathogenicity. The potential effects of these critical parameters also have not been elucidated. We tested the virulent HM-1:IMSS isolate and the non-virulent Rahman isolate of E. histolytica, and the non-virulent E. dispar CYNO16:TPC isolate against two vertebrate cell lines, HeLa and Chinese hamster ovary cells in vitro using ethidium homodimer as a fluorescent indicator of changes in vertebrate cell permeability. Fluorescence appeared in vertebrate cell nuclei within approximately 2-3 min of contact between HM-1 amoebae and vertebrate cells independent of vertebrate cell type. However, vertebrate cells in the immediate vicinity of but not contacted by HM-1 amoebae were not affected. In contrast, although both E. histolytica Rahman and E. dispar CYNO16 amoebae moved freely among and contacted vertebrate cells, the nuclei of the vertebrate cells never fluoresced implying that the cells remained alive and impermeant to the ethidium homodimer. This is the first demonstration that direct contact between virulent amoebae and vertebrate cells is required to kill vertebrate cells and that the process is restricted to virulent Entamoeba isolates. An understanding at the molecular level of the processes involved could help to reduce the pathology associated with this parasite.

Gene discovery in the Entamoeba invadens genome

Entamoeba invadens, a parasite of reptiles, is a model for the study of encystation by the human enteric pathogen Entamoeba histolytica, because E. invadens form cysts in axenic culture. With approximately 0.5-fold sequence coverage of the genome, we were able to get insights into E. invadens gene and genome features. Overall, the E. invadens genome displays many of the features that are emerging from ongoing genome sequencing efforts in E. histolytica. At the nucleotide level the E. invadens genome has on average 60% sequence identity with that of E. histolytica. The presence of introns in E. invadens was predicted with similar consensus (GTTTGT em leader A/TAG) sequences to those identified in E. histolytica and Entamoeba dispar. Sequences highly repeated in the genome of E. histolytica (rRNAs, tRNAs, CXXC-rich proteins, and Leu-rich repeat proteins) were found to be highly repeated in the E. invadens genome. Numerous proteins homologous to those implicated in amoebic virulence, (Gal/GalNAc lectins, amoebapores, and cysteine proteinases) and drug resistance (p-glycoproteins) were identified. Homologs of proteins involved in cell cycle, vesicular trafficking and signal transduction were identified, which may be involved in en/excystation and cell growth of E. invadens. Finally, multiple copies of a number of E. invadens genes coding for predicted enzymes involved in core metabolism and the targets of anti-amoebic drugs were identified.