Dispar Species Research Articles

Genetic Patterns of Oral Cavity Microbiome in Patients with Sickle Cell Disease.

The Middle Eastern prevalence of sickle cell anemia, a genetic disorder that affects red blood cells, necessitates additional research. On a molecular level, we sought to identify and sort the oral microbiota of healthy individuals and those with sickle cell anemia. Furthermore, it is crucial to comprehend how changes in the genetic makeup of the oral microbiota impact the state of sickle cell anemia. Using next-generation sequencing, the 16S rRNA amplicon was examined using saliva samples from 36 individuals with sickle cell anemia and healthy individuals. These samples were obtained from sickle cell anemia patients (18 samples) and healthy control participants (controls, 18 samples). Various analyses are conducted using bioinformatic techniques to identify distinct species and their relative abundance. Streptococcus, followed by Fusobacterium nucleatum, Prevotella, and Veillonella were the most prevalent genera of bacteria in the saliva of the SCA and non-SCA individuals according to our findings. Rothia mucilaginosa, Prevotella scoposa, and Veillonella dispar species were the dominant species in both sickle cell anemia and non-sickle cell anemia subjects. Streptococcus salivarius, Actinomyces graevenitzii, Actinomyces odontolyticus, and Actinomyces georgiae spp. were the most prevalent bacterial spp. in the studied SCA cases. The sequencing of the 16S rRNA gene yielded relative abundance values that were visualized through a heatmap analysis. Alterations in the oral microflora's constitution can significantly affect the susceptibility of sickle cell anemia patients to develop more severe health complications. Salivary diagnosis is a potential tool for predicting and preventing oral microbiome-related diseases in the future.

Evaluation of the Use of Singleplex and Duplex CerTest VIASURE Real-Time PCR Assays to Detect Common Intestinal Protist Parasites

Cryptosporidium spp., Giardia duodenalis and Entamoeba histolytica are species of protozoa- causing diarrhoea that are common worldwide, while Entamoeba dispar, Dientamoeba fragilis and Blastocystis sp. appear to be commensal parasites whose role in pathogenicity remains controversial. We conducted the clinical evaluation of five singleplex and one duplex CerTest VIASURE Real-Time PCR Assays against a large panel of positive DNA samples (n = 358), and specifically to Cryptosporidium spp. (n = 96), G. duodenalis (n = 115), E. histolytica (n = 25) E. dispar (n = 11), Blastocystis sp. (n = 42), D. fragilis (n = 37), and related parasitic phylum species such as Apicomplexa, Euglenozoa, Microsporidia and Nematoda. DNA samples were obtained from clinical stool specimens or cultured isolates in a national reference centre. Estimated diagnostic sensitivity and specificity values were 0.94–1 for Cryptosporidium spp., 0.96–0.99 for G. duodenalis, 0.96–1 for E. histolytica, 1–1 for E. dispar, and 1–0.99 for D. fragilis in the evaluated singleplex assays. In the duplex assay for the simultaneous detection of Blastocystis sp. and D. fragilis these values were 1–0.98 and 1–0.99, respectively. Measures of diagnostic precision for repeatability and reproducibility were found to be under acceptable ranges. The assays identified six Cryptosporidium species (C. hominis, C. parvum, C. canis, C. felis, C. scrofarum, and C. ryanae), four G. duodenalis assemblages (A, B, C, and F), and six Blastocystis subtypes (ST1-ST5, and ST8). The evaluated singleplex and duplex VIASURE Real-Time PCR assays provide sensitive, practical, and cost-effective choices to the molecular diagnosis of the main diarrhoea-causing intestinal protists in clinical microbiology and research laboratories.

Pathogenic infection characteristics and risk factors for bovine respiratory disease complex based on the detection of lung pathogens in dead cattle in Northeast China.

Bovine respiratory disease complex (BRDC) involves multiple pathogens, shows diverse lung lesions, and is a major concern in calves. Pathogens from 160 lung samples of dead cattle from 81 cattle farms in Northeast China from 2016 to 2021 were collected to characterize the molecular epidemiology and risk factors of BRDC and to assess the major pathogens involved in bovine suppurative or caseous necrotizing pneumonia. The BRDC was diagnosed by autopsy, pathogen isolation, PCR, or reverse transcription-PCR detection, and gene sequencing. More than 18 species of pathogens, including 491 strains of respiratory pathogens, were detected. The positivity rate of bacteria in the 160 lung samples was 31.77%, including Trueperella pyogenes (9.37%), Pasteurella multocida (8.35%), Histophilus somni (4.48%), Mannheimia haemolytica (2.44%), and other bacteria (7.13%). The positivity rate of Mycoplasma spp. was 38.9%, including M. bovis (7.74%), M. dispar (11.61%), M. bovirhinis (7.94%), M. alkalescens (6.11%), M. arginini (0.81%), and undetermined species (4.68%). Six species of viruses were detected with a positivity rate of 29.33%, including bovine herpesvirus-1 (BoHV-1; 13.25%), bovine respiratory syncytial virus (BRSV; 5.50%), bovine viral diarrhea virus (BVDV; 4.89%), bovine parainfluenza virus type-3 (BPIV-3; 4.28%), bovine parainfluenza virus type-5 (1.22%), and bovine coronavirus (2.24%). Mixed infections among bacteria (73.75%), viruses (50%), and M. bovis (23.75%) were the major features of BRDC in these cattle herds. The risk analysis for multi-pathogen co-infection indicated that BoHV-1 and H. somni; BVDV and M. bovis, P. multocida, T. pyogenes, or Mann. haemolytica; BPIV-3 and M. bovis; BRSV and M. bovis, P. multocida, or T. pyogenes; P. multocida and T. pyogenes; and M. bovis and T. pyogenes or H. somni showed co-infection trends. A survey on molecular epidemiology indicated that the occurrence rate of currently prevalent pathogens in BRDC was 46.15% (6/13) for BoHV-1.2b and 53.85% (7/13) for BoHV-1.2c, 53.3% (8/15) for BVDV-1b and 46.7% (7/15) for BVDV-1d, 29.41% (5/17) for BPIV-3a and 70.59% (12/17) for BPIV-3c, 100% (2/2) for BRSV gene subgroup IX, 91.67% (33/36) for P. multocida serotype A, and 8.33% (3/36) for P. multocida serotype D. Our research discovered new subgenotypes for BoHV-1.2c, BRSV gene subgroup IX, and P. multocida serotype D in China's cattle herds. In the BRDC cases, bovine suppurative or caseous necrotizing pneumonia was highly related to BVDV [odds ratio (OR) = 4.18; 95% confidence interval (95% CI): 1.6-10.7], M. bovis (OR = 2.35; 95% CI: 1.1-4.9), H. somni (OR = 8.2; 95% CI: 2.6-25.5), and T. pyogenes (OR = 13.92; 95% CI: 5.8-33.3). The risk factor analysis found that dairy calves <3 mo and beef calves >3 mo (OR = 5.39; 95% CI: 2.7-10.7) were more susceptible to BRDC. Beef cattle were more susceptible to bovine suppurative or caseous necrotizing pneumonia than dairy cattle (OR = 2.32; 95% CI: 1.2-4.4). These epidemiological data and the new pathogen subgenotypes will be helpful in formulating strategies of control and prevention, developing new vaccines, improving clinical differential diagnosis by necropsy, predicting the most likely pathogen, and justifying antimicrobial use.

A Comparative Study and Quantitative Characterization of Hydrachna globosa, Hydryphantes dispar and Limnesia fulgida (Acari, Hydrachnidia) Species through Spectrophotometric Techniques

A Comparative Study and Quantitative Characterization of Hydrachna globosa, Hydryphantes dispar and Limnesia fulgida (Acari, Hydrachnidia) Species through Spectrophotometric Techniques

A Comparative Study and Quantitative Characterization of Hydrachna Globosa, Hydryphantes Dispar and Limnesia Fulgida (Acari, Hydrachnidia) Species through Spectrophotometric Techniques

This study has been so far the first attempt of biomolecular investigation on three water mite species, namely, Hydrachna globosa, Hydryphantes dispar and Limnesia fulgida. UV-Vis spectroscopy was used to determine vibration frequencies of different biomolecules, and FTIR spectrum ranges were used to characterize the functional groups of different biochemical substances. A comparative study was performed to understand similarities and/or differences between these three species, based on the qualitative and quantitative analyses of various biocompounds. Despite having similar functional groups in all of them, significant similarities between H. dispar and L. fulgida were found in terms of UV–Vis absorbance peaks, IR graphical patterns and absorption percentage (%). On the other hand, although these three species comprise distinctive morphological features, H. dispar and L. fulgida were observed to be closer considering their body lengths, whereas H. globosa was identified to be the largest among these mites. In addition to the noble findings, this investigation will contribute to the identification and characterization of other water mites too

Sex-Based Diverse Plaque Microbiota in Children with Severe Caries

Severe early childhood caries (S-ECC) is a multifactorial disease that can lead to suffering and reduced oral health–related quality of life in young children. The bacterial and fungal composition of dental plaque and how children’s sex is associated with S-ECC are largely unknown. In this study, V4-16S rRNA and ITS1 rRNA gene amplicon sequencing was used to compare the plaque bacteriome and mycobiome of children <72 mo of age: 40 with S-ECC (15 males, 25 females) and 40 caries-free (19 males, 21 females). Health- and nutrition-related questionnaire data were also investigated. This study aimed to analyze potential sex-based differences in the supragingival plaque microbiota of young children with S-ECC and those caries-free. Behavioral and nutritional habit differences were observed between children with S-ECC and those caries-free and between male and female children. Overall, higher levels of Veillonella dispar, Streptococcus mutans, and other bacterial species were found in the S-ECC group as compared with caries-free controls (P < 0.05). A significant difference in the abundance of Neisseria was observed between males and females with S-ECC (P < .05). Fungal taxonomic analysis showed significantly higher levels of Candida dubliniensis in the plaque of children with S-ECC as compared with those caries-free (P < 0.05), but no differences were observed with Candida albicans (P > 0.05). Significant differences in the relative abundance of Mycosphaerella, Cyberlindnera, and Trichosporon fungal species were also observed between the caries-free and S-ECC groups (P < 0.05). Machine learning analysis revealed the most important bacterial and fungal species for classifying S-ECC versus caries-free. Different patterns of crosstalk between microbial species were observed between male and female children. Our work demonstrates that plaque microbiota and sex may be important determinants for S-ECC and could be factors to consider for inclusion in caries risk assessment tools.

Morphometric characteristics of embryonic development Heterakis dispar isolated from geese

Knowledge of the biological properties and ecological environment of the development of helminths, especially those that cause invasive diseases of animals and humans, is extremely important for understanding the epizootic aspects and clinical manifestations of invasions. Among the domestic and wild birds, one of the dominant ones is the group of parasitic nematodes of the genus Heterakis Dujardin, 1845. The aim of this study was to study the peculiarities of the embryonic development of Heterakis dispar, isolated from domestic geese, taking into account their morphological and metrical changes. Experimental cultivation of eggs isolated from gonads of H. dispar females to their invasive stage in the laboratory. Morphological and metric changes in the process of their embryogenesis were established. The picking of nematodes was performed by the method of complete helminthological opening of the caecum of dead or forcedly killed geese. It has been determined that the eggs of nematodes of domestic geese of H. dispar species under the temperature regime of 22 ºС undergo 4 stages of exogenous development: protoplast, crushing of blastomeres, formation of the larva of the first stage, formation of the larva of the second stage. At this temperature, the development of the parasites ended in 8 days, and the viability of the embryonic stages of the development of heteroxides was 79.33 ± 0.88%. In this case, developmental stoppage and death were observed in 20.67 ± 0.88% of eggs. The protoplast stage occurred within 1–18 days, the formation of two blastomeres – 2–4 days, the formation of the first stage larvae – 2–6 days, the formation of the second stage larvae – 4–8 days. In the process of exogenous development, the metric parameters of eggs of heterakises isolated from domestic geese change. Their sizes for cultivation from the stage of the protoplast to the larvae of the second stage are characterized by a significant decrease in width by 1.2 times and a simultaneous thinning of the shell by 1.1 times. Obtained data on the timing of the formation of invasive H. dispar eggs parasite in domestic geese, as well as their viability in the process of embryonic development can be used to improve the efficiency of species identification of isolated parasites by the results of scatoscopic studies of the bird.

Recently diverged killifishes: Morphometry and caudal skeleton osteology of two members of the Aphanius dispar species group (Aphaniidae, Teleostei)

Recently diverged killifishes: Morphometry and caudal skeleton osteology of two members of the Aphanius dispar species group (Aphaniidae, Teleostei)

Systematics and historical biogeography of theAphanius disparspecies group (Teleostei: Aphaniidae) and description of a new species from Southern Iran

Among the species of Aphanius Nardo, 1827, Aphanius dispar (Ruppell, 1828) is the most common taxon and has long been viewed as representing a species group rather than a single species. This study provides comprehensive data on the phylogenetic relationships, morphology, and otoliths within the A. dispar species group, including the description of a new species. Our data demonstrate that the true A. dispar is restricted to the Sea drainages and that all other populations hitherto identified as A. dispar actually represent separate species. Four main clades are defined and named for the geographic areas in which the respective species of Aphanius occur. The oldest one is the Red Sea clade, it comprises A. dispar. The Dead Sea clade is represented by A. richardsoni (Boulenger, 1907). It is sister to both the Hormuzgan clade in S Iran (containing A. hormuzensis sp. nov. and A. ginaonis (Holly, 1929)) and the Persian Gulf & Gulf of Oman clade (comprising A. stoliczkanus (Day, 1872)). The species separation within the A. dispar group is confirmed by the distinctive otolith morphology of each species. Moreover, we present a time-calibrated phylogeny (chronogram) for the A. dispar species group using dagger A. princeps (16-17 Mya) as a minimum age and the first appearance of dagger Prolebias (33-34 Mya) as a maximum age for the genus Aphanius. The evolution and historical biogeography routes are discussed based on the outcome of the chronogram and in the context of the geological and climatic history of the Near East in Pliocene-Pleistocene times.

Aphanius kruppi, a new killifish from Oman with comments on the A. dispar species group (Cyprinodontiformes: Aphaniidae).

Eight species are recognised in the Aphanius dispar group. Aphanius dispar from the Red and Mediterranean Sea basins, A. stoliczkanus from coastal areas of the Arabian/Persian Gulf, the northern Arabian Sea east to Gujarat in India, the Gulf of Oman and some endorheic basins in Iran and Pakistan, A. richardsoni from springs in the Dead Sea basin in Jordan and Israel, A. sirhani from the Azraq Oasis in Jordan, A. ginaonis from one spring in Iran, A. furcatus from few streams and springs in Iran and A. stiassnyae from one lake in Ethiopia. Aphanius kruppi, new species, from the Wadi al Batha drainage in northern Oman, is distinguished from adjacent A. stoliczkanus by having 9-14 brown or grey lateral bars on the flank in the male, a roundish, diamond-shaped or somewhat vertically-elongate blotch centred on the caudal-fin base in the female and 2-3 scale rows on the caudal-fin base. The available molecular genetic data for A. dispar reject the hypothesis of the presence of a single widespread coastal species in the Middle East and make it likely that two additional unidentified species occur in the Red Sea basin.

Entamoeba histolytica and E. dispar Calreticulin: inhibition of classical complement pathway and differences in the level of expression in amoebic liver abscess.

The role of calreticulin (CRT) in host-parasite interactions has recently become an important area of research. Information about the functions of calreticulin and its relevance to the physiology of Entamoeba parasites is limited. The present work demonstrates that CRT of both pathogenic E. histolytica and nonpathogenic E. dispar species specifically interacted with human C1q inhibiting the activation of the classical complement pathway. Using recombinant EhCRT protein, we demonstrate that CRT interaction site and human C1q is located at the N-terminal region of EhCRT. The immunofluorescence and confocal microscopy experiments show that CRT and human C1q colocalize in the cytoplasmic vesicles and near to the surface membrane of previously permeabilized trophozoites or are incubated with normal human serum which is known to destroy trophozoites. In the presence of peripheral mononuclear blood cells, the distribution of EhCRT and C1q is clearly over the surface membrane of trophozoites. Nevertheless, the level of expression of CRT in situ in lesions of amoebic liver abscess (ALA) in the hamster model is different in both Entamoeba species; this molecule is expressed in higher levels in E. histolytica than in E. dispar. This result suggests that EhCRT may modulate some functions during the early moments of the host-parasite relationship.

Prevalence of Intestinal Parasitic Infection among HIV Positive Persons Who Are Naive and on Antiretroviral Treatment in Hiwot Fana Specialized University Hospital, Eastern Ethiopia

Background. Intestinal parasitic infection affects the health and quality of life of people living with HIV. This study was aimed to determine the prevalence of intestinal parasites among HIV positive individuals who are naive and who are on antiretroviral treatment (ART) in Hiwot Fana Specialized University Hospital, Eastern Ethiopia. Methods. A comparative cross-sectional study was conducted on 371 (112 ART-naive group and 259 on ART) HIV positive individuals. Stool specimens were collected and examined by direct wet mount, formol ether concentration technique, and modified ziehl-Neelsen methods. Results. The overall prevalence of intestinal parasitic infections was 33.7%; it was significantly higher among the study participants who were ART-naive group (45.5%) (AOR: 2.60(1.56,4.34)) and diarrheic (53.3%) (AOR: 2.30(1.34,3.96)) and with CD4 count <200 cells/μL (46%) (AOR: 2.07(1.06,4.04)). The most commonly identified parasites were Entamoeba histolytica/E. dispar (13.5%), Giardia lamblia (8.1%), Strongyloides stercoralis (4.0%), and Cryptosporidium species (2.2%). Conclusion. HIV positive individuals with diarrhea and low CD4 count and ART naive groups were more infected with intestinal parasites than their counterparts. Early stool examination and treatment of intestinal parasites for HIV/AIDS patients is essential.

Factors affecting proliferation and differentiation of lepidopteran midgut stem cells

Midgut stem cells of last instar larvae and pupae of Heliothis virescens, Lymantria dispar and several other Lepidopteran species have been cultured in vitro and have been induced to proliferate using low titers of ecdysteroids and the 77-Kda peptide fragment, alpha-arylphorin, isolated and identified from pupal fat body tissue. The insulin-related hormone, Bombyxin, also induced mitosis in cultured midgut stem cells; it appeared to be fast-acting and quickly inactivated, while alpha-arylphorin was slower to act and had a longer lasting effect in vitro, indicating different functions for these proliferation agents. Changes in Calcium ion concentration within or outside the cells discretely affected stem cell differentiation, indicating a role for second messenger participation in peptide regulation of this process. Four different peptides (MDFs 1-4) that induced midgut stem cells to differentiate to mature midgut cell types in vitro were isolated and characterized from conditioned media and hemolymph of H. virescens and L. dispar. However, platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and all-trans retinoic acid (RA) from vertebrate sources induced differentiation to non-midgut cell types as well. MDF1 was located in basal areas of columnar cells of midgut epithelium, although MDF2 was observed in all of the cytoplasm of columnar cells and in droplets of antibody positive material in the midgut lumen, suggesting a digestive function as well for this peptide. Anti-MDF-3 stained the central areas of cultured midgut columnar cells and the bases of columnar cells of midgut epithelium in vivo. Midgut secretory cells stained with anti-MDF-4; streams of MFD-4-positive material were observed extending from secretory cells facing the epithelial lumen, and as a layer on the hemolymph-facing side, suggesting an endocrine or paracrine function for this or an immunologically similar peptide.

Human amebiasis: breaking the paradigm?

For over 30 years it has been established that the Entamoeba histolytica protozoan included two biologically and genetically different species, one with a pathogenic phenotype called E. histolytica and the other with a non-pathogenic phenotype called Entamoeba dispar. Both of these amoebae species can infect humans. E. histolytica has been considered as a potential pathogen that can cause serious damage to the large intestine (colitis, dysentery) and other extraintestinal organs, mainly the liver (amebic liver abscess), whereas E. dispar is a species that interacts with humans in a commensal relationship, causing no symptoms or any tissue damage. This paradigm, however, should be reconsidered or re-evaluated. In the present work, we report the detection and genotyping of E. dispar sequences of DNA obtained from patients with amebic liver abscesses, including the genotyping of an isolate obtained from a Brazilian patient with a clinical diagnosis of intestinal amebiasis that was previously characterized as an E. dispar species. The genetic diversity and phylogenetic analysis performed by our group has shown the existence of several different genotypes of E. dispar that can be associated to, or be potentiality responsible for intestinal or liver tissue damage, similar to that observed with E. histolytica.

Reassessment of the epidemiology of amebiasis: State of the art

The epidemiology of amebiasis has dramatically changed since the separation of Entamoeba histolytica and Entamoeba dispar species, and the worldwide prevalence of these species has not been estimated until recently. The most cited data regarding prevalence, morbidity, or mortality due to amebiasis is the 1986 Walsh report, in which 100,000 deaths are reported to occur worldwide each year due to medical complications of invasive amebiasis. However, the prevalence values of Entamoeba histolytica infection could be completely erroneous since the estimations were performed prior to the molecular characterization of E. histolytica and E. dispar species. Moreover, Entamoeba moshkovskii, another morphologically indistinguishable human parasitic Entamoeba, was not mentioned or considered as a contributor to the prevalence figures in endemic areas. However, recent available prevalence and morbidity data obtained through molecular techniques allow the construction of a more reliable map of endemic regions of amebiasis all over the world [the Asian subcontinent (India, Bangladesh), Africa, Asian Pacific Countries (Thailand, Japan), South and Central America (Mexico, Colombia)]. The epidemiology of infectious diseases focuses on identification of factors that determine disease distribution in time and space, transmission factors responsible for the disease, clinical manifestations, and progression in the host, with the goal being the design of realistic intervention and prevention strategies in a reasonable period of time. In the present review, we will describe how molecular tools have made actual knowledge regarding the epidemiology of amebiasis possible. We will also analyze the most relevant available data on prevalence, morbidity, geographic distribution, patterns of transmission, exposure, and risk factors for infection in the human host. Our intention is to emphasize the recent molecular typing methods applied in genotyping Entamoeba species and strains, and to assess their value and limitations. Finally, we will discuss those areas of the host–parasite relationship that are still not fully understood, and the scientific challenges to approach this important public health problem in the future.

Taxonomic review of the Australian Drosophila setifemur species group, a new name for the D. dispar species group (Diptera: Drosophilidae)

Examination of the holotype and a paratype of Drosophila setifemur Malloch, 1924 in the Australian Museum has resulted in the discovery that it is not a synonym of D. sulfurigaster as had previously been assumed. Instead, D. setifemur is a senior synonym of the widespread eastern Australian species D. dispar Mather, 1955. The so-called Drosophila dispar species group is renamed the Drosophila setifemur species group and Drosophila unguicula is removed from it. An illustrated key to Australian drosophilids with spinescent fore-femora is provided. Mcevey, Shane F., 2009. Taxonomic review of the Australian Drosophila setifemur species group, a new name for the D. dispar species group (Diptera: Drosophilidae). Records of the Australian Museum 61(1): 31–38. The genus Drosophila accommodates a great range of drosophilids, with numerous aggregations at various levels between genus and species (viz. subgenus, species group, subgroup, complex, etc.). A rapidly growing body of knowledge is allowing us to know with ever increasing certainty the true genetic relationship between species. But ultimately, even when the tree that relates every lab strain and every field-sampled specimen is known with a high level of confidence, there will remain the task of affixing the taxonomically valid names to each of those samples and to biological species. Drosophila currently has c. 1,600 described species; c. 350 are classified with D. melanogaster in the subgenus Sophophora, and another c. 730 species are treated as Drosophila s.str. Nearly all are attracted to fruit baits and can be established as cultures in the laboratory. The following synonymy involves Drosophila dispar Mather, 1955: 570 (a species in the dispar species group of the Drosophila subgenus Sophophora) and D. setifemur Malloch, 1924: 351 (a species incorrectly classified as synonymous with D. sulfurigaster (Duda, 1923: 48) in the nasuta subgroup, immigrans species group of Drosophila s.str.). Removing D. setifemur from synonymy with D. sulfuri­ gaster and placing it in synonymy with D. dispar leads to a need to rename the Drosophila dispar species group (established by Mather,1955).

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.

Differences in morphology of phagosomes and kinetics of acidification and degradation in phagosomes between the pathogenicEntamoeba histolytica and the non-pathogenicEntamoeba dispar

Phagocytosis plays an important role in the pathogenicity of the intestinal protozoan parasite Entamoeba histolytica. We compared the morphology of phagosomes and the kinetics of phagosome maturation using conventional light and electron microscopy and live imaging with video microscopy between the virulent E. histolytica and the closely-related, but non-virulent E. dispar species. Electron micrographs showed that axenically cultivated trophozoites of the two Entamoeba species revealed morphological differences in the number of bacteria contained in a single phagosome and the size of phagosomes. Video microscopy using pH-sensitive fluorescein isothiocynate-conjugated yeasts showed that phagosome acidification occurs within 2 min and persists for >12 h in both species. The acidity of phagosomes significantly differed between two species (4.58 +/- 0.36 or 5.83 +/- 0.38 in E. histolytica or E. dispar, respectively), which correlated well with the differences in the kinetics of degradation of promastigotes of GFP-expressing Leishmania amazonensis. The acidification of phagosomes was significantly inhibited by a myosin inhibitor, whereas it was only marginally inhibited by microtubules or actin inhibitors. A specific inhibitor of vacuolar ATPase, concanamycin A, interrupted both the acidification and degradation in phagosomes in both species, suggesting the ubiquitous role of vacuolar ATPase in the acidification and degradation in Entamoeba. In contrast, inhibitors against microtubules or cysteine proteases (CP) showed distinct effects on degradation in phagosomes between these two species. Although depolymerization of microtubules severely inhibited degradation in phagosomes of E. histolytica, it did not affect degradation in E. dispar. Similarly, the inhibition of CP significantly reduced degradation in phagosomes of E. histolytica, but not in E. dispar. These data suggest the presence of biochemical or functional differences in the involvement of microtubules and proteases in phagosome maturation and degradation between the two species.

Species-specific field testing of Entamoeba spp. in an area of high endemicity

Entamoeba histolytica has been separated in recent years into 2 morphologically identical species: the apathogenic E. dispar and the pathogenic E. histolytica, only the latter being pathogenic. Although various laboratory techniques allow discrimination between the 2 species there is a lack of field data about the suitability of available diagnostic tests for use in epidemiological studies and few epidemiological studies using species-specific diagnosis have been performed at community level in endemic areas, especially in sub-Saharan Africa. We conducted a repeated cross-sectional study of 967 schoolchildren in central Côte d'Ivoire to compare and evaluate light microscopy, 2 different antigen detection assays, and one polymerase chain reaction (PCR) assay. Microscopy and a non-specific antigen capture Entamoeba enzyme-linked immunosorbent assay (ELISA) were used for the primary screening of all children (time t 0). The prevalence of the E. histolytica/E. dispar species complex at t 0 was 18 · 8% by single microscopical examination and 31 · 4% using the non-specific ELISA. Approximately 2 months after the initial screening, fresh stool specimens were collected on 2 consecutive days ( t 1, and t 2) from (i) all the children who were positive by microscopy at t 0 ( n = 182) and (ii) 155 randomly selected children who were negative at the primary screening. These samples were tested with a second antigen detection ELISA specific for E. histolytica ( n = 238) and with a species-specific PCR assay ( n = 193). The second and third examinations ( t 1, and t 2) revealed an additional 43 infections with the species complex E. histolytica/E. dispar, so that the cumulative microscopical prevalence for t 1 and t 2 was 27 · 7%. The overall prevalence of E. histolytica by species-specific ELISA antigen detection was low (0 · 83%), while the prevalence of E. dispar was 15%. When analysing only microscopically positive samples by PCR ( n = 129), the ratio E. histolytica: E. dispar was very low (1:46), suggesting that the vast majority of Entamoeba infections in this area were apathogenic. Both species-specific tests performed well but the ELISA was easier to use for large-scale field screening.

Diferenciación de Entamoeba histolytica y Entamoeba dispar en muestras de materia fecal por detección de adhesina de E. histolytica mediante ELlSA

lnfections caused by the Entamoeba histolytica/Entamoeba dispar species complex have a worldwide distribution. E. histolytica is the only pathogenic species. but the differentiation with E. dispar can only be done by biochemical methods. The aim of this work was to detect the E. histolytica specific adhesin molecule to differentiate this parasite from E. dispar in faeces samples, as well as to determine the prevalence of infection by the E. histolytica/E. disparcomplex in a rural population from Cundinamarca, Colombia. One hundred and foity fecal samples were collected at the health center of La Virgen, Quipile, Cundinamarca. They were examined by formalin-ether concentration method to determine the prevalence of E. histolytica/E. dispar Twenty three positive samples (1 6.42%) were submitted to an ELlSA test for detection of E. histolytca specific adhesin, out of which only 2 (8.69%) were found to be positive for E. histolytica. Serum samples from 19 patients infected with E. histolytica/E. disparwere submitted to an ELlSA test for antibodies against E. histolytica; all of them were negative. If the prevalence of specific adhesin test had been applied to al1 the people included in the study, the estimated prevalence of E. histolytica infection would be 1.42% (2/140).The advantage of the ELlSA test for specific detection of the E. histolytica adhesion molecule is its easiness, which allows a rapid diagnosis in order to provide adequate treatment. This methodology could be recommended for nationwide epidemiological studies to determine the prevalence of E. histolytica infection.