Genetic characterization of the Entamoeba moshkovskii population based on different potential genetic markers.

Entamoeba moshkovskii, according to recent studies, appears to exert a more significant impact on diarrhoeal infections than previously believed. The efficient identification and genetic characterization of E. moshkovskii isolates from endemic areas worldwide are crucial for understanding the impact of parasite genomes on amoebic infections. In this study, we employed a multilocus sequence typing system to characterize E. moshkovskii isolates, with the aim of assessing the role of genetic variation in the pathogenic potential of E. moshkovskii. We incorporated 3 potential genetic markers: KERP1, a protein rich in lysine and glutamic acid; amoebapore C (apc) and chitinase. Sequencing was attempted for all target loci in 68 positive E. moshkovskii samples, and successfully sequenced a total of 33 samples for all 3 loci. The analysis revealed 17 distinct genotypes, labelled M1­M17, across the tested samples when combining all loci. Notably, genotype M1 demonstrated a statistically significant association with diarrhoeal incidence within E. moshkovskii infection (P = 0.0394). This suggests that M1 may represent a pathogenic strain with the highest potential for causing diarrhoeal symptoms. Additionally, we have identified a few single-nucleotide polymorphisms in the studied loci that can be utilized as genetic markers for recognizing the most potentially pathogenic E. moshkovskii isolates. In our genetic diversity study, the apc locus demonstrated the highest Hd value and π value, indicating its pivotal role in reflecting the evolutionary history and adaptation of the E. moshkovskii population. Furthermore, analyses of linkage disequilibrium and recombination within the E. moshkovskii population suggested that the apc locus could play a crucial role in determining the virulence of E. moshkovskii.

Molecular Detection of a Pathogenic Entamoeba among Symptomatic Children in Eastern Kurdistan of Iraq.

Entamoeba histolytica infects the large intestine of humans, causing a spectrum of clinical appearances ranging from asymptomatic colonization to severe intestinal and extra-intestinal disease. The parasite is identical microscopically to commensal nonpathogenic amoeba. To detect the pathogenic Entamoeba and estimate the precise prevalence of the parasite among the symptomatic pediatric population using molecular techniques. 323 fecal samples were collected from symptomatic children admitted to Sulaimani Pediatric Teaching Hospital, Sulaimaniyah Province, Iraq, from June to October 2021. A structured, validated questionnaire was prepared and used to report participants' gender, residency, and drinking water source. Then, stool samples were microscopically examined, and the positive samples were submitted to molecular analysis by amplifying the 18s rRNA gene using nested PCR to differentiate E. histolytica from other nonpathogenic Entamoeba. Finally, gene sequences were done to confirm the species. Microscopically, 58 positive samples represented Entamoeba species infection rate of 18% among symptomatic patients. However, only 18 samples were positive for E. histolytica based on molecular methods, which accounts for 31% of the positive by microscopy and 5.6% among the 323 symptomatic populations. NCBI, available in their database, gives the gene sequence and accession number. Patients' sociodemographic data and water sources were directly related to the infection rate. Classical microscopic examination provides a misleading profile about the prevalence of E. histolytica in an endemic region that might lead to unnecessary treatments and a lack of appropriate management for patients.

Multi-locus sequence analysis reveals phylogenetically segregated Entamoeba histolytica population.

Amoebiasis, caused by the enteric parasite, Entamoeba histolytica, is one of the major food- and water-borne parasitic diseases in developing countries with improper sanitation and poor hygiene. Infection with E. histolytica has diverse disease outcomes, which are determined by the genetic diversity of the infecting strains. Comparative genetic analysis of infecting E. histolytica strains associated with differential disease outcomes from different geographical regions of the world is important to identify the specific genetic patterns of the pathogen that trigger certain disease outcomes of Amoebiasis. The strategy is able to elucidate the genealogical relation and population structure of infecting E. histolytica strains from different geographical regions. In the present study, we have performed a comparative genetic analysis of circulating E. histolytica strains identified from different parts of the world, including our study region, based on five tRNA-linked short tandem repeat (STR) loci (i.e., D-A, NK2, R-R, STGA-D and A-L) and evaluated their potential associations with differential disease outcomes of Amoebiasis. A number of regional-specific, emerging haplotypes of E. histolytica, significantly associated with specific disease outcomes have been identified. Haplotypes, which have a significant positive association with asymptomatic and amoebic liver abscess outcomes, showed a significant negative association with diarrheal outcome, or vice versa. Comparative multi-locus analysis revealed that E. histolytica isolates from our study region are phylogenetically segregated from the isolates of other geographical regions. This study provides a crucial overview of the population structure and emerging pattern of the enteric parasite, E. histolytica.

Differential diagnosis of human Entamoeba infections: Morphological and molecular characterization of new isolates in Argentina.

Entamoeba infections occur worldwide, with higher frequency in countries of low socioeconomic status and poor public health. Since Entamoeba histolytica has long been recognized as the only pathogenic species, making a differential diagnosis of other morphologically identical Entamoeba is important. This study aimed to determine the prevalence of Entamoeba species in two populations from Argentina, make a differential diagnosis by PCR and characterize Entamoeba isolates at the SSU rRNA gene. A total of 493 serial fecal samples were obtained from individuals in the provinces of Buenos Aires (n=210) and Misiones (n=283). Samples were examined by conventional methods (formalin-ethyl acetate and Willis flotation) and specific PCRs to differentiate Entamoeba species. Entamoeba isolates were characterized by sequencing a fragment of the SSU rRNA gene. The overall prevalence of Entamoeba infection was 12.4%, being more prevalent in Buenos Aires than in Misiones (14.8% vs. 10.6%). A case of E. histolytica confirmed by PCR and sequence analysis was reported for the first time in Buenos Aires. Moreover, new genetic data on Entamoeba coli and Entamoeba dispar were recorded. The phylogenetic analysis revealed a congruence between morphological characteristics and SSU rRNA gene sequences. This study increases the amount of information on the distribution of these species in Argentina and the region of the Americas.

Evaluation of a rapid immunochromatographic test for the diagnosis of intestinal protozoan infections among patients attending a rural outreach outpatient department in Northern India.

Despite great efforts, intestinal protozoan infections remain a significant healthcare concern worldwide. Although many point-of-care (POC) tests are increasingly being used, microscopic examination of stool specimens remains the mainstay for their diagnosis, especially in resource-limited settings. We assessed the utility of rapid POC tests based on immunochromatography among patients from rural Northern India. A total of 78 patients were enrolled in the study. Out of nine specimens that tested positive for Giardia duodenalis on microscopy, an immunochromatographic test (ICT) could detect only five (55.55%). Entamoeba histolytica/dispar was demonstrated in two specimens on microscopy, both of which were missed by ICT. Its overall sensitivity, specificity, and positive and negative predictive value were 50%, 98.5%, 83.3%, and 93%, respectively. Its performance was considered unsatisfactory. Although ICT-based tests provide a relatively rapid and less labor-intensive alternative, they should be used to supplement and not replace stool microscopy.

Short tandem repeat (STR) based sequence typing of Entamoeba histolytica identifies STGA-D locus as a genetic marker, associated with disease outcomes.

Amoebiasis, caused by the enteric parasite Entamoeba histolytica has differential disease outcomes. The association of parasite genotypes with outcomes of amoebic infection is still a paradox and requires to be explored. The genetic information of infecting strains from endemic settings of different geographical regions is essential to evaluate the relation. Comparative genetics of E. histolytica clinical isolates from different disease outcomes have been explored based on two tRNA-linked STR loci (STGA-D and A-L). All of the repeat patterns in the A-L locus were newly identified and unique to Indian isolates. The majority of newly identified repeat patterns in STGA-D locus have outcome-specific distributions, predicting the emergence of disease-specific mutations in this target locus. Statistical analysis further reinforces this observation, as identified repeat patterns only from STGA-D but not A-L locus were significantly associated with disease outcomes. Phylogenetic analysis indicates independent segregation and divergence of tRNA-linked STR arrays for each STR locus.

Prevalence and risk factors for infection with Entamoeba histolytica/dispar/ moshkovskii complex in people living in the slightest and outermost islands of Indonesia.

Entamoeba histolytica (E. histolytica), the causative agent of amoebiasis, is still a global public health problem that cannot be controlled, especially in tropical and subtropical countries. This study was conducted to obtain information about the incidence of Entamoeba histolytica/dispar/ moshkovskii complex infection and the factors that influence it. The prevalence of infection with the Entamoeba histolytica/dispar/moshkovskii complex and the factors that influence it in people living on the smallest and outermost island of Indonesia, Sabang Island, Aceh Province. This study involved 335 respondents aged >= 10 years. Respondents were selected by non-probability sampling technique. Interviews and observations were conducted to identify risk factors. The Entamoeba histolytica/dispar/ moshkovskii complex was identified by direct examination, concentration, and Whitley's trichrome staining techniques. A Chi-Square test was performed to analyze the correlation of risk factors with the incidence of infection. The prevalence of infection with the Entamoeba histolytica/dispar/ moshkovskii complex in the people of Sabang Island was 26.6% (89/335). Source and adequacy of clean water correlated with the incidence of Entamoeba histolytica/dispar/moshkovskii complex infection. Demographic variables are not correlated with the incidence of infection. However, the group of women aged > 61 years, unemployed, unmarried, and earning less than the regional minimum wage tend to be more likely to be found with Entamoeba histolytica/dispar/moshkovskii complex infections. Thus it can be concluded that the prevalence of infection with the Entamoeba histolytica/dispar/moshkovskii complex on Sabang Island is in the high category. The prevalence of E. histolytica as the causative agent of amoebiasis cannot be explained with certainty because the two identical non-pathogenic Entamoeba species cannot be distinguished by microscopic identification. Sources and adequacy of clean water correlate with the incidence of Entamoeba histolytica/dispar/moshkovskii complex infection in the people of Sabang Island.

Prevalence and molecular characterization of Entamoeba moshkovskii in diarrheal patients from Eastern India.

BACKGROUND: Importance of the amphizoic amoeba Entamoeba moshkovskii is increasing in the study of amoebiasis as a common human pathogen in some settings. Limited studies are found on the genetic and phylogenetic characterization of E. moshkovskii from India; hence remain largely unknown. In this study, we determined the prevalence and characterized the E. moshkovskii isolates in eastern India. METHODS: A three-year systemic surveillance study among a total of 6051 diarrhoeal patients from ID Hospital and BC Roy Hospital, Kolkata was conducted for E. moshkovskii detection via a nested PCR system targeting 18S rRNA locus. The outer primer set detected the genus Entamoeba and the inner primer pair identified the E. moshkovskii species. The 18S rRNA locus of the positive samples was sequenced. Genetic and phylogenetic structures were determined using DnaSP.v5 and MEGA-X. GraphPad Prism (v.8.4.2), CA, USA was used to analyze the statistical data. RESULT: 4.84% (95%CI = 0.0433-0.0541) samples were positive for Entamoeba spp and 3.12% (95%CI = 0.027-0.036) were infected with E. moshkovskii. E. moshkovskii infection was significantly associated with age groups (X2 = 26.01, P<0.0001) but not with gender (Fisher's exact test = 0.2548, P<0.05). A unique seasonal pattern was found for E. moshkovskii infection. Additionally, 46.56% (95%CI = 0.396-0.537) were sole E. moshkovskii infections and significantly associated with diarrheal incidence (X2 = 335.5,df = 9; P<0.0001). Sequencing revealed that the local E. moshkovskii strains were 99.59%-100% identical to the prototype (GenBank: KP722605.1). The study found certain SNPs that showed a correlation with clinical features, but it is not necessarily indicative of direct control over pathogenicity. However, SNPs in the 18S rRNA gene could impact the biology of the amoeba and serve as a useful phylogenetic marker for identifying pathogenic E. moshkovskii isolates. Neutrality tests of different coinfected subgroups indicated deviations from neutrality and implied population expansion after a bottleneck event or a selective sweep and/or purifying selection in co-infected subgroups. The majority of FST values of different coinfected subgroups were <0.25, indicating low to moderate genetic differentiation within the subgroups of this geographical area. CONCLUSION: The findings reveal the epidemiological significance of E. moshkovskii infection in Eastern India as the first report in this geographical area and expose this species as a possible emerging enteric pathogen in India. Our findings provide useful knowledge for further research and the development of future control strategies against E. moshkovskii.

Entamoeba histolytica induced NETosis and the dual role of NETs in amoebiasis.

Entamoeba histolytica (Eh), a microaerophilic parasite, causes deadly enteric infections that result in Amoebiasis. Every year, the count of invasive infections reaches 50 million approximately and 40,000 to 1,00,000 deaths occurring due to amoebiasis are reported globally. Profound inflammation is the hallmark of severe amoebiasis which is facilitated by immune first defenders, neutrophils. Due to size incompatibility, neutrophils are unable to phagocytose Eh and thus, came up with the miraculous antiparasitic mechanism of neutrophil extracellular traps (NETs). This review provides an in-depth analysis of NETosis induced by Eh including the antigens involved in the recognition of Eh and the biochemistry of NET formation. Additionally, it underscores its novelty by describing the dual role of NETs in amoebiasis where it acts as a double-edged sword in terms of both clearing and exacerbating amoebiasis. It also provides a comprehensive account of the virulence factors discovered to date that are implicated directly and indirectly in the pathophysiology of Eh infections through the lens of NETs and can be interesting drug targets.

Intestinal parasitic infections and risk factors for infection in Kenyan children with and without HIV infection.

It has been reported that HIV infection is not a risk factor for Entamoeba species infection but is for Giardia intestinalis assemblage B in children living in Western Kenya. This study aimed to investigate the prevalence of and the risk factors for Entamoeba spp. and G. intestinalis infection in children living in Nairobi, Kenya. This cross-sectional study included 87 children with HIV [HIV(+)] and 85 without HIV [HIV(-)]. Stool and blood samples were collected for the detection of the parasites by PCR and immunological analyses using flow cytometry. Sociobehavioral and hygienic data were collected using questionnaires and analyzed statistically. The prevalence of Entamoeba spp. infection was significantly lower in the HIV(+) than in the HIV(-) children (63.2% vs. 78.8%, P = 0.024), whereas the prevalence of G. intestinalis infection was not (27.6% vs. 32.9%, P = 0.445). "Not boiling drinking water" (adjusted odds ratio [aOR]: 3.8, P = 0.044) and "helping in nursery care" (aOR: 2.8, P = 0.009) were related to G. intestinalis assemblage B infection, and "CD4/CD8 ratio ≥1" was related to Entamoeba spp. infection (aOR: 3.3, P = 0.005). In stratified regression analyses, HIV infection was negatively associated with G. intestinalis assemblage B infection in females (aOR: 0.3, P = 0.022), but positively associated in males (aOR 3.8, P = 0.04). These results suggest that G. intestinalis assemblage B infection is related to hygienic conditions, while Entamoeba spp. infection is an indicator of better immunological status, and that the role of HIV infection in Giardia infection may differ between Kenyan boys and girls.

Assessing the prevalence and risk factors associated with Entamoeba complex infection among the Orang Asli school children in Perak, Malaysia through molecular approach.

This study performed a cross-sectional investigation on the prevalence of Entamoeba complex infection comprising Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii and their associated risk factors among the Orang Asli school children in three districts in Perak, Malaysia. Stool samples collected from 544 school children aged between 7 and 12 years old were examined through the nested multiplex PCR assay. The univariate and multivariate regression analyses were then carried out to determine the risk factor associated with Entamoeba complex infection. The overall prevalence of Entamoeba complex infections (E. histolytica, E. dispar and E. moshkovskii) was 21.3% (116/544). Most positive school children were infected with E. moshkovskii (10.7%; 58/544), followed by E. dispar (9.0%; 49/544) and E. histolytica (5.0%; 27/544). Not washing their hands after using the toilet was identified as the only significant risk factor for E. histolytica. The significant risk factors associated with E. moshkovskii infection included children within the age of 10-12 years old, with high BMI, living with working and non-educated mothers, no toilet in the house, not washing their hands after using the toilet, and fever. On the other hand, drinking water from the river, well, and rain was associated with a decreased risk of E. dispar infection. In conclusion, this study showed a high prevalence of Entamoeba spp. infections among the Orang Asli school children in Perak, Malaysia. Addressing the identified risk factors coupled with a holistic approach in breaking the transmission of Entamoeba complex can help improve their quality of life.

The Epidemiology of Entamoeba histolytica Infection and Its Associated Risk Factors among Domestic and Imported Patients in Taiwan during the 2011-2020 Period.

Background and Objectives: Amebiasis remains an important public health problem worldwide, and immigration and increased international travel have affected incident disease cases. This study assesses the prevalence of Entamoeba histolytica in Taiwan between 2011 and 2020 by analyzing data from surveillance programs conducted by the Centers for Disease Control of Taiwan (TCDC) on laboratory-confirmed cases. Materials and Methods: The E. histolytica infection-related data reported to the National Infectious Diseases Statistics System at the TCDC from 1 January 2011 to 31 December 2020 were collected, including age, gender, place of residence, and the geographic season of exposure for each case. Results: In total, 3066 cases with E. histolytica infections were included in our analysis. Among them, 1735 (57%) cases were imported, and 1331 (43%) were locally acquired. The average annual incidence rate of E. histolytica infections in Taiwan between 2011 and 2020 was 10.6 and 16.1 per 1,000,000 patients. There were statistical differences in gender, age group, and place of residence (p < 0.001) by the source distribution of cases. Also, these differences were found every year (p < 0.05). There were statistical differences in gender and age group (p < 0.001) by place of residence (p < 0.001). The only difference between the distribution of cases and age group was in gender (p < 0.001). Eight patients with amebiasis died, and the fatality rate was 0.3% (8/3066), of whom 75% (6/8) were male, and 75% (6/8) were over 45 years old. This study demonstrates that multiple linear regression analysis shows positive associations between NO2 concentration and amebiasis cases (B value = 2.569, p = 0.019), O3 concentration and amebiasis cases (B value = 0.294, p = 0.008), and temperature and amebiasis cases (B value = 1.096, p = 0.046). Conclusions: This study is the first report of confirmed E. histolytica cases from TCDC surveillance data between 2011 and 2020. This study showed the importance of long periods, air pollutants, and geographically comprehensive analysis for estimating the effect of amebiasis transmission in Taiwan's populations.

Molecular evidence suggests the occurrence of Entamoeba moshkovskii in pigs with zoonotic potential from eastern India.

Entamoeba moshkovskii Tshalaia, 1941 is prevalent in developing countries and it is considered to be primarily a free-living amoeba, which is morphologically indistinguishable, but biochemically and genetically different from the human infecting, pathogenic Entamoeba histolytica Schaudinn, 1903. The pathogenic potential of this organism is still under discussion. Entamoeba moshkovskii in human stool samples has been reported in different countries such as the United States, Italy, Australia, Iran, Turkey, Bangladesh, India (Pondicherry), Indonesia, Colombia, Malaysia, Tunisia, Tanzania and Brazil, but no data are available about the occurrence of E. moshkovskii in farm animals. This study provides data on the occurrence of E. moshkovskii in pigs in a total of 294 fresh faecal samples collected from five different regions in Kolkata, West Bengal, India. Stool samples were tested by nested PCR using primers targeting SSU rDNA of E. moshkovskii. The amplified PCR products were further confirmed by RFLP technique. Purified nested PCR products were also sequenced and identified via BLAST program run on the NCBI website to confirm species along with their genetic characteristics of the E. moshkovskii isolates. Overall 5.4 % samples were identified as E. moshkovskii positive. Results of this study demonstrate that swine can host E. moshkovskii and should be considered as a potential natural reservoir for E. moshkovskii. However, the occurrence of E. moshkovskii infection in pigs was not statistically associated with their faecal consistency, sex and developmental stage.

Identification of asymptomatic Entamoeba histolytica infection by a serological screening test: A cross-sectional study of an HIV-negative men who have sex with men cohort in Japan.

BACKGROUND: Amebiasis, caused by Entamoeba histolytica, is spreading in developing countries and in many developed countries as a sexually transmitted infection. Here, we evaluated the efficacy of serological screening to identify asymptomatic E. histolytica infection as a potential epidemiological control measure to limit its spread. METHODOLOGY/PRINCIPAL FINDINGS: This cross-sectional study was carried out between January and March 2021 in an HIV-negative men who have sex with men (MSM) cohort at the National Center for Global Health and Medicine. Serological screening was performed using a commercially available ELISA kit. For seropositive individuals, we performed stool polymerase chain reaction (PCR) to determine current E. histolytica infection. We performed E. histolytica serological screening of 312 participants. None had a history of E. histolytica infection prior to the study. The overall E. histolytica seropositivity was 6.7% (21/312), which was similar to that found by the rapid plasma reagin test (17/312). We identified current infection in 8 of 20 seropositive participants (40.0%) by stool PCR. CONCLUSIONS/SIGNIFICANCE: Our serological screening approach constitutes a potentially practical epidemiological strategy. Active epidemiological surveys, in combination with an effective screening strategy for asymptomatically infected individuals, should be applied to help reduce sexually transmitted E. histolytica infections.

A Case Of Entamoeba Histolytica Infection Among Men Who Have Sex With Men.

Entamoeba histolytica is a parasite responsible for intestinal amebiasis and possible extraintestinal manifestations, such as liver abscesses. India, Africa, Mexico, and Central and South America have some of the highest rates of infection due to poor socioeconomic and environmental conditions. The infection has become more common in the United States due to an increase in emigration. There has been a rising incidence of sexual transmission of the infection, most commonly seen in men who have sex with men. Here, we present a case of a symptomatic extraintestinal E histolytica infection in a young Hispanic bisexual man.

Molecular diagnosis of amoebiasis.

Amoebiasis is an intestinal parasitosis caused by the protozoan Entamoeba histolytica that represents the third leading cause of mortality due to parasitosis. It is a prevalent disease in tropical climate regions with poor or absent sanitary services. Microscopy and antigen detection techniques are routinely used to diagnose amoebiasis because of their low cost and ease of application. However, these techniques do not differentiate E. histolytica infections and other potentially pathogenic species such as Entamoeba moshkovskii or Entamoeba bangladeshi. Therefore, in the last decades, molecular tests that allow correct identification of the causal agent of amoebiasis and the establishment of the prevalence of the infecting species have been developed. Techniques based on nucleic acids, such as conventional, multiplex, or real-time polymerase chain reaction (PCR), are being seriously considered in clinical laboratories, because they detect the etiologic agent directly from the sample without the need for previous prolonged culture, thus reducing diagnostic time. Also, the nested PCR test and the sequencing of ribosomal markers have allowed the identification of new parasitic species in humans, such as E. moshkovskii and E. bangladeshi, and an improved characterization of the known infecting species. The application of multiplex platforms allows the simultaneous identification of infecting species, increasing the sensitivity and specificity of these techniques. Therefore, the molecular diagnosis of amoebiasis is projected as an innovative tool in the fight against this parasitosis.

La amebiasis es una parasitosis intestinal causada por el protozoario Entamoeba histolytica y representa la tercera causa de mortalidad por parasitosis. Es una enfermedad prevalente en regiones de clima tropical con deficientes o nulos servicios sanitarios. Las técnicas de microscopía y detección de antígenos se emplean sistemáticamente para el diagnóstico de la amebiasis por su bajo costo y fácil aplicación. Sin embargo, no permiten diferenciar entre infecciones por E. histolytica y otras especies de potencial patogenicidad como Entamoeba moshkovskii o Entamoeba bangladeshi. Ante ello, en las últimas décadas se han desarrollado pruebas moleculares que permiten una correcta identificación del agente causal de la amebiasis y el establecimiento de la prevalencia de la especie infectante. Las técnicas basadas en ácidos nucleicos, como la reacción en cadena de la polimerasa (PCR) convencional, múltiple o en tiempo real, están siendo seriamente consideradas en los laboratorios clínicos, porque detectan al agente etiológico de manera directa en la muestra sin necesidad de cultivo prolongado previo, disminuyendo de esta forma el tiempo del diagnóstico. Asimismo, la PCR anidada sumada a la secuenciación de marcadores ribosomales ha permitido la identificación de nuevas especies parasitarias, como E. moshkovskii y E. bangladeshi en humanos, y una mejor caracterización de las especies infectantes ya conocidas. La aplicación de las plataformas multiplex permite la identificación simultánea de especies infectantes, aumentando la sensibilidad y la especificidad de estas técnicas. Por esto, el diagnóstico molecular de la amebiasis se proyecta como una verdadera herramienta innovadora en la lucha contra las parasitosis.

Prevalence of intestinal parasites and molecular characterization of Giardia intestinalis, Blastocystis spp. and Entamoeba histolytica in the village of Fortín Mbororé (Puerto Iguazú, Misiones, Argentina).

BACKGROUND: Intestinal parasites (IPs) are widely distributed worldwide and are one of the major contributors to gastrointestinal disease. Their prevalence is associated with poor access to water, sanitation and hygiene (WASH). The objective of this study was to identify the prevalence of IPs, including soil-transmitted helminths (STH), and their relation to socioeconomic characteristics, as well as a first approach to molecularly characterize the types of Giardia intestinalis, Blastocystis spp. and Entamoeba histolytica present in an indigenous community from Puerto Iguazú, Misiones, Argentina. METHODS: A cross-sectional study was conducted in the rural settlement of Fortin Mbororé between January and March 2018. Socioeconomic variables, household characteristics, and stool and blood samples were collected. Standard coprological techniques were used to analyze stool samples, and a complete hemogram was performed on the blood samples. Giardia intestinalis microscopy-positive samples were genetically typed by the ß-giardin (bg) gene. Molecular identification of Blastocystis spp. subtypes and E. histolytica were carried out by amplification and sequencing of a partial fragment of the small subunit ribosomal RNA gene (SSU rDNA). RESULTS: The overall prevalence of IPs was 92.7%, with 72.0% specifically for hookworm. IPs were significantly more prevalent in preschool- and school-age children (P < 0.05). No formal education (P = 0.035), the presence of unimproved floors (P = 0.001) and overcrowding (P = 0.005) were significantly associated with IP infection. Hookworm was associated with anemia (P = 0.019). Molecular characterization revealed the presence of E. histolytica sub-assemblages AII (12.5%), AIII (87.5%) and BIV (100%); one case of sub-assemblage D for G. intestinalis; and the presence of subtypes ST1 (14.8%), ST2 (14.8%) and ST3 (70.4%) of Blastocystis spp. CONCLUSIONS: Protozoans detected in this study are transmitted mainly through water contaminated with fecal matter, evidencing the need to improve the quality of water and sanitation for the inhabitants of Fortín Mbororé. Molecular characterization showed that domestic animals can be implicated in the zoonotic transmission of G. intestinalis and Blastocystis spp. to humans. A hyperendemic area for STH was found, with hookworm prevalence greater than 50%. Therefore, improvements in WASH as well as mass deworming programs need to be implemented in this area to control and decrease the prevalence of IPs in general and STH in particular.

Epidemiology of clinically relevant Entamoeba spp. (E. histolytica/dispar/moshkovskii/bangladeshi): A cross sectional study from North India.

BACKGROUND: Entamoeba infections have major impact on millions of the people worldwide. Entamoeba histolytica has long been accepted as the only pathogenic species. However, recent reports of other Entamoeba spp. in symptomatic cases have raised questions on their pathogenicity. METHODOLOGY/PRINCIPAL FINDINGS: Total 474 stool samples and 125 liver aspirates from patients with intestinal and extra intestinal manifestations and from community were included. Sewage samples from the hospital and the city were also included. Microscopic examination and molecular detection were performed to detect presence of E. histolytica/ dispar/ moshkovskii/ bangladeshi. The associated demographic and socioeconomic factors were statistically analyzed with the presence of Entamoeba. Microscopy detected Entamoeba spp. in 5.4% stool and 6.4% liver aspirate samples. Through nested multiplex PCR, prevalence of Entamoeba spp. in intestinal and extra-intestinal cases was 6.6% (20/301) and 86.4% (108/125) respectively and in asymptomatic population was 10.5% (13/123). Sewage samples did not show presence of any Entamoeba spp. Uneducated subjects, low economic conditions, untreated drinking water, consumption of raw vegetables and habit of not washing hands before meals were significantly associated with presence of Entamoeba spp. CONCLUSIONS: E. histolytica still remains the only Entamoeba spp. in invasive extra intestinal infections. E. dispar was detected in both asymptomatic and symptomatic intestinal infections. Routine identification of Entamoeba spp. should incorporate PCR based detection methods.

South American Entamoeba dispar strains produce amoebic liver abscesses with different pathogenicities and evolutionary kinetics.

Amoebiasis is a protozoan disease caused by Entamoeba histolytica, and presents a geographic distribution of worldwide amplitude, high incidence, sometimes accompanied by severe clinical manifestations such as amoebic colitis and Amoebic Liver Abscess (ALA), remaining as a public health problem in developing countries. Entamoeba dispar is another species of amoeba that infects approximately 12% of the world's population, and it has previously been classified as noninvasive. However, E. dispar has already been isolated from patients with symptomatic non-dysenteric colitis, as well as its DNA sequences were detected and genotyped in samples from patients with dysenteric colitis, and patients with ALA, suggesting that this species could also be involved in the development of lesions in the large intestine and liver of human beings. In this context, this study aims to evaluate the ability of isolated strains of Entamoeba dispar in South America to cause liver damage, and to better characterize histopathological findings in 3, 8, 12 and 16 days after infection (DAI). Firstly, we assessed whether trophozoites from MCR, ACFN, ICS, ADO and VEJ E. dispar strains, and EGG Entamoeba histolytica strain differed in their in vitro phagocytosis ability, being related to greater ability to phagocyte with greater virulence. Then, we investigate and characterize histopathological changes present in the liver of mice induced by different strains of E. dispar. Our results demonstrated that trophozoites from E. dispar strains are capable of phagocyting human erythrocytes, but in lower amounts than Entamoeba histolytica. In addition, we described and characterized the lesions in different periods after infection by different E. dispar strains, and identified ACFN as the most pathogenic strain, followed by MCR. The large areas of necrosis produced by the ACFN strain as the eighth DAI, which also show high parasitism, led to 100% mortality. On the other hand, the ICS, ADO and VEJ strains did not produce mortality, and this was correlated with the presence of well-developed chronic granulomatous inflammation, necrosis absorption throughout the infection, and regeneration of the liver parenchyma. The greater pathogenicity of the ACFN strain strongly suggests that this strain could be producing higher levels of virulence factors. As the experimental infection, the heterogeneity of biological behavior of different Entamoeba dispar strains could be involved in the development of undiagnosed human clinical conditions.

Precision of Serologic Testing from Dried Blood Spots Using a Multiplex Bead Assay.

Multiplex bead assays (MBAs) for serologic testing have become more prevalent in public health surveys, but few studies have assessed their test performance. As part of a trachoma study conducted in a rural part of Ethiopia in 2016, dried blood spots (DBS) were collected from a random sample of 393 children aged 0 to 9 years, with at least two separate 6-mm DBS collected on a filter card. Samples eluted from DBS were processed using an MBA on the Luminex platform for antibodies against 13 antigens of nine infectious organisms: Chlamydia trachomatis, Vibrio cholera, enterotoxigenic Escherichia coli, Cryptosporidium parvum, Entamoeba histolytica, Camplyobacter jejuni, Salmonella typhimurium Group B, Salmonella enteritidis Group D, and Giardia lamblia. Two separate DBS from each child were processed. The first DBS was run a single time, with the MBA set to read 100 beads per well. The second DBS was run twice, first at 100 beads per well and then at 50 beads per well. Results were expressed as the median fluorescence intensity minus background (MFI-BG), and classified as seropositive or seronegative according to external standards. Agreement between the three runs was high, with intraclass correlation coefficients of > 0.85 for the two Salmonella antibody responses and > 0.95 for the other 11 antibody responses. Agreement was also high for the dichotomous seropositivity indicators, with Cohen's kappa statistics exceeding 0.87 for each antibody assay. These results suggest that serologic testing on the Luminex platform had strong test performance characteristics for analyzing antibodies using DBS.