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The intestinal parasites Giardia lamblia and Entamoeba histolytica are major causes of morbidity and mortality associated with diarrheal diseases. Metronidazole is the most common drug used to treat giardiasis and amebiasis. Despite its efficacy, treatment failures in giardiasis occur in up to 5%-40% of cases. Potential resistance of E. histolytica to metronidazole is an increasing concern. Therefore, it is critical to search for more effective drugs to treat giardiasis and amebiasis. We identified antigiardial and antiamebic activities of the rediscovered nitroimidazole compound, fexinidazole, and its sulfone and sulfoxide metabolites. Fexinidazole is equally active against E. histolytica and G. lamblia trophozoites, and both metabolites were 3- to 18-fold more active than the parent drug. Fexinidazole and its metabolites were also active against a metronidazole-resistant strain of G. lamblia. G. lamblia and E. histolytica cell extracts exhibited decreased residual nitroreductase activity when metabolites were used as substrates, indicating nitroreductase may be central to the mechanism of action of fexinidazole. In a cell invasion model, fexinidazole and its metabolites significantly reduced the invasiveness of E. histolytica trophozoites through basement membrane matrix. A q.d. oral dose of fexinidazole and its metabolites at 10 mg/kg for 3 days reduced G. lamblia infection significantly in mice compared to control. The newly discovered antigiardial and antiamebic activities of fexinidazole, combined with its FDA-approval and inclusion in the WHO Model List of Essential Medicines for the treatment of human African trypanosomiasis, offer decreased risk and a shortened development timeline toward clinical use of fexinidazole for treatment of giardiasis or amebiasis.

Here we describe a case of fatal amebic gastritis associated with Naegleria australiensis infection in an 11-mo-old Linnaeus's two-toed sloth (Choloepus didactylus). The sloth had a history of weight loss and intermittent diarrhea for 18 d, and subsequently died despite empirical treatment. Postmortem findings included emaciation, gastric dilation with fluid content, and fibrinonecrotic gastritis with intralesional amebic trophozoites and cysts in the glandular region of the fundus. Transmission electron microscopy ruled out Amoebozoa of the family Entamoebidae based on the presence of mitochondria in the amoeboid organisms. PCR for pan–free-living amebae followed by next-generation sequencing of the PCR product revealed 99% identity with Naegleria australiensis. Gastric amebiasis has been reported sporadically in macropods and in leaf-eating monkeys with a sacculated stomach. To our knowledge, gastric amebiasis has not been reported previously in a sloth, which also has a sacculated and multi-chambered stomach. [ABSTRACT FROM AUTHOR]

Free-living amoebae (FLA) are prevalent in diverse environments, representing various genera and species with different pathogenicity. FLA-induced infections, such as the highly fatal amoebic encephalitis, with a mortality rate of 99%, primarily affect immunocompromised individuals while others such as Acanthamoeba keratitis (AK) and cutaneous amebiasis may affect immunocompetent individuals. Despite the prevalence of FLA, there is a lack of standardized guidelines for their detection near human habitats. To date, no studies on the isolation and identification of FLA in environmental soil samples in Warsaw have been published. The aim of this study was to determine the presence of amoebae in soil samples collected from Warsaw parks and squares frequented by humans. The isolated protozoa were genotyped. Additionally, their pathogenic potential was determined through thermophilicity tests. A total of 23 soil samples were seeded on non-nutrient agar plates (NNA) at 26 °C and monitored daily for FLA presence. From the total of 23 samples, 18 were positive for FLA growth in NNA and PCR (78.2%). Acanthamoeba spp. was the most frequently isolated genus, with a total of 13 positive samples (13/18; 72.2%), and the T4 genotype being the most common. Moreover, Platyamoeba placida (3/18; 16.7%), Stenamoeba berchidia (1/18; 5.6%) and Allovahlkampfia sp. (1/18; 5.6%), also potentially pathogenic amoebae, were isolated. To our knowledge, this is the first report of FLA presence and characterization in the Warsaw area. [ABSTRACT FROM AUTHOR]

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Amebic liver abscesses should be considered in adult males with a liver abscess and a history of travel to endemic areas. Effective treatment includes metronidazole, followed by paromomycin.

Entamoeba histolytica is a protozoan parasite belonging to the phylum Amoebozoa that causes amebiasis, a global public health problem. E. histolytica alternates its form between a proliferative trophozoite and a dormant cyst. Trophozoite proliferation is closely associated with amebiasis symptoms and pathogenesis whereas cysts transmit the disease. Drugs are available for clinical use; however, they have issues of adverse effects and dual targeting of disease symptoms and transmission remains to be improved. Development of new drugs is therefore urgently needed. An untargeted lipidomics analysis recently revealed structural uniqueness of the Entamoeba lipidome at different stages of the parasite's life cycle involving very long (26–30 carbons) and/or medium (8–12 carbons) acyl chains linked to glycerophospholipids and sphingolipids. Here, we investigated the physiology of this unique acyl chain diversity in Entamoeba, a non-photosynthetic protist. We characterized E. histolytica fatty acid elongases (EhFAEs), which are typically components of the fatty acid elongation cycle of photosynthetic protists and plants. An approach combining genetics and lipidomics revealed that EhFAEs are involved in the production of medium and very long acyl chains in E. histolytica. This approach also showed that the K3 group herbicides, flufenacet, cafenstrole, and fenoxasulfone, inhibited the production of very long acyl chains, thereby impairing Entamoeba trophozoite proliferation and cyst formation. Importantly, none of these three compounds showed toxicity to a human cell line; therefore, EhFAEs are reasonable targets for developing new anti-amebiasis drugs and these compounds are promising leads for such drugs. Interestingly, in the Amoebazoan lineage, gain and loss of the genes encoding two different types of fatty acid elongase have occurred during evolution, which may be relevant to parasite adaptation. Acyl chain diversity in lipids is therefore a unique and indispensable feature for parasitic adaptation of Entamoeba. Author summary: Entamoeba, a protozoan parasite, thrives in its niche by alternating its form between a proliferative trophozoite and a dormant cyst. Entamoeba parasites were recently shown to generate lipid acyl chain diversity throughout their life cycle. Here, we provide insight into the mechanism generating this acyl chain diversity and its importance in maintaining the parasite's life cycle. We also show that the E. histolytica isozymes responsible for generating this diversity are reasonable targets for developing new anti-amebiasis drugs, and that the herbicides, flufenacet, cafenstrole, and fenoxasulfone, are promising leads for such drugs. Interestingly, gain and loss of the two genes encoding the isozymes controlling acyl chain diversity is plausibly related to E. histolytica host adaptation. [ABSTRACT FROM AUTHOR]

Objective: In this study; it is aimed to evaluate E. histolytica-specific ELISA adhesin antigen test results in stool samples sent to the medical microbiology laboratory with suspicion of amebiasis. Material and Methods: ELISA (Cellabs, Entamoeba Celisa Path, Brookvale, NSW Australia) adhesin antigen test results, examined on stool samples sent to the medical microbiology laboratory with suspicion of amebiasis in a two-year period between January 2022 and December 2023 were evaluated retrospectively. The data including the test results, gender, age, date and clinical information of the cases of the examined sample were obtained from our hospital’s laboratory data software system. Fisher’s exact chi-square test was used in statistical analyses. Results: Of the 1120 samples in the study, 578 (51.6%) belong to male patients and 542 (48.4%) belong to female patients. The ages of the patients ranged from 0 to 94 years, and the average age was 33.92 (standard deviation: ±24.33). There were 335 (30%) samples from pediatric patients, and the mean age was determined as 4.48 ±4.78. One hundred and sixty-one (14.3%) samples were found positive with the ELISA adhesin antigen test specific to E. histolytica. Of patients with positive test results, 77 (47.8%) were male and 84 (52.2%) were female. Among the positive samples, there were 55 (34.1%) samples from pediatric patients. While there was no statistically significant difference between the positivity status and age and gender of the patients (p>0.05), the seasonal difference was considered significant (p<0.05). Conclusion: In our study, E. histolytica specific ELISA adhesin antigen test positivity was determined as 14.3%, and this rate was found close to the country’s literature data. It has been determined that amoebiasis is more common in tropical and subtropical climates. With the use of ELISA adhesin antigen test specific to E. histolytica, which is cheap, fast and does not require experienced personnel, the rate of misdiagnosis can be reduced and unnecessary treatment applications can be reduced. [ABSTRACT FROM AUTHOR]

The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis, with clinical outcomes ranging from asymptomatic infections to severe invasive diseases. The innate immune system, particularly macrophages, is of paramount importance in resisting the invasion of host tissues and organs by the trophozoites of E. histolytica. Parasite-derived pathogenic factors, such as lectins, play a pivotal role in the promotion of macrophage polarization phenotypes that have undergone alteration. Nevertheless, the precise mechanisms by which E. histolytica modulates immune polarization remain largely unknown. The current study focused on the immunomodulatory effects of the Igl-C fragment of E. histolytica Gal/GalNAc lectin on macrophage polarization. These results demonstrated that Igl-C could induce the secretion of IL-1b, IL-6, and other cytokines, activating a mixed M1/M2 polarization state. M1 polarization of macrophages occurs in the early stages and gradually transitions to M2 polarization in the later stages, which may contribute to the persistence of the infection. Igl-C induces the macrophage M1 phenotype and causes the release of immune effector molecules, including iNOS and cytokines, by activating the NF-kB p65 and JAK-STAT1 transcription factor signaling pathways. Furthermore, Igl-C supports the macrophage M2 phenotype via JAK-STAT3 and IL-4-STAT6 pathways, which activate arginase expression in later stages, contributing to the tissue regeneration and persistence of the parasite. The involvement of distinct signaling pathways in mediating this response highlights the complex interplay between the parasite and the host immune system. These findings enhance our understanding of the Igl-Cmediated pathogenic mechanisms during E. histolytica infection. [ABSTRACT FROM AUTHOR]

The need for new drugs to treat human infections is a global health concern. Diseases like tuberculosis, trypanosomiasis, amoebiasis, and AIDS remain significant problems, especially in developing countries like Mexico. Despite existing treatments, issues such as resistance and adverse effects drive the search for new alternatives. Herein, we introduce the NUATEI research consortium, made up of experts from the Institute of Biomedical Research at UNAM, who identify and obtain natural and synthetic compounds and test their effects against human pathogens using in vitro and in vivo models. The consortium has evaluated hundreds of natural extracts and compounds against the pathogens causing tuberculosis, trypanosomiasis, amoebiasis, and AIDS, rendering promising results, including a patent with potential for preclinical studies. This paper presents the rationale behind the formation of this consortium, as well as its objectives and strategies, emphasizing the importance of natural and synthetic products as sources of antimicrobial compounds and the relevance of the diseases studied. Finally, we briefly describe the methods of the evaluation of the compounds in each biological model and the main achievements. The potential of the consortium to screen numerous compounds and identify new therapeutic agents is highlighted, demonstrating its significant contribution to addressing these infectious diseases. [ABSTRACT FROM AUTHOR]

Background: Enterocolitis and gastroenteritis remain major health problems, particularly in children living in developing countries. Intestinal protozoa, such as Entamoeba histolytica, Blastocystis, and Cyclospora, are frequently associated with these conditions. Amebic colitis can cause serious complications, including fulminant necrotizing colitis, toxic megacolon, extraintestinal amebiasis, and stunting in children. The diagnosis of amoebiasis is challenging, relying on microscopic examination, which cannot distinguish E. histolytica from the nonpathogenic E. dispar and E. moshkovskii. Therefore, this study aimed to identify intestinal parasites, particularly Entamoeba, their prevalence, and the clinical characteristics of patients admitted for enterocolitis and gastroenteritis at a tertiary-referral hospital. Material and Methods: A cross-sectional, retrospective study was conducted at a national, tertiary-referral government hospital, in Jakarta. Of the 111 retrieved medical records from hospitalized patients with enterocolitis and gastroenteritis, for which parasitology feces were examined, 54 fecal samples (48.6%) were still available in the parasitology laboratory storage. All fecal samples underwent the following tests: 1) direct stool examination, after staining with 1% Lugol’s solution, and using the water–ether concentration method; 2) modified acid-fast staining for coccidian parasites; 3) Jones’ culture medium to detect Blastocystis; 4) copro-antigen assay to detect Cryptosporidium and Giardia; and 5) a polymerase chain reaction (PCR) assay to identify Entamoeba. Clinical and demographic data were obtained from the medical records. Results: Largely, patients (44.1%) were from the cohort of young children ≤5 years old, followed by adults aged 19–60 years old (24.3%). Both cohorts exhibited polyparasitism. Intestinal parasites were detected in 17 out of the 54 samples (31.4%). These included 6 (11.1%), 2 (3.7%),5 (9.2%), 3 (5.5%), 2 (3.7%), and 1 (1.8%) samples that were positive for Blastocystis, E dispar, E. histolytica, E. moshkovskii, Cryptosporidium, and Dientamoeba fragilis, respectively. PCR analysis revealed that 10 samples were positive for Entamoeba infection, eight of which originated from pediatric patients. Conclusion: At a national tertiary-referral hospital in Indonesia, Entamoeba infection was the most prevalent parasite among pediatric patients with enterocolitis. E. histolytica and E. moshkovskii were the two main species identified by PCR. Therefore, PCR assays and fecal occult–blood tests are recommended in cases of enterocolitis and gastroenteritis. [ABSTRACT FROM AUTHOR]

Digestive health is an overlooked but vital component of the success of Western honey bee (Apis mellifera) colonies. Viral, bacterial, fungal, and protozoal infections can inhibit nutrient uptake and waste elimination by the honey bee digestive tract. Active management requires monitoring honey bee health on an individual and colony basis, providing adequate nutrition, and controlling for other pests and diseases. One organism that has gained recent attention is Malpighamoeba mellificae. This publication describes how to detect M. mellificae in A. mellifera colonies.

Key points Dupilumab targets Th2‐associated inflammatory mediators to reduce disease burden in CRSwNP. While rare, potential sequelae include viral, helminth, and potentially amebic infections. [ABSTRACT FROM AUTHOR]

Free-living amoebae are rare causes of morbidity and mortality in humans and animals around the globe. Because the route of exposure and clinical progression of disease caused by different species of amoebae may vary in people and animals, determining the species of amoeba present is important. We describe here a fatal infection by the free-living amoeba Balamuthia mandrillaris in a Siberian tiger (Panthera tigris altaica). The 17-y-old patient had a rapid clinical decline after a peracute onset of severe lethargy, dull mentation, and anorexia. Autopsy did not identify a cause of death. Histology revealed inflammation associated with amoebic trophozoites in the brain, lungs, and iris of one eye. These amoebae were confirmed to be B. mandrillaris based on a PCR assay and sequencing. Although there are subtle morphologic differences between cyst stages of Acanthamoeba spp., B. mandrillaris, and Naegleria fowleri when present and identified on routine staining, other modalities, including PCR, immunofluorescence, electron microscopy, and immunohistochemistry, are typically utilized to confirm the pathogen involved in these cases. We review the reports of balamuthosis in animals.

Entamoeba histolytica, the causative agent of amebiasis, is one of the top three parasitic causes of mortality worldwide. However, no vaccine exists against amebiasis. Using a lead candidate vaccine containing the LecA fragment of Gal-lectin and GLA-3M-052 liposome adjuvant, we immunized rhesus macaques via intranasal or intramuscular routes. The vaccine elicited high-avidity functional humoral responses as seen by the inhibition of amebic attachment to mammalian target cells by plasma and stool antibodies. Importantly, antigen-specific IFN-γ-secreting peripheral blood mononuclear cells (PBMCs) and IgG/IgA memory B cells (BMEM) were detected in immunized animals. Furthermore, antigen-specific antibody and cellular responses were maintained for at least 8 months after the final immunization as observed by robust LecA-specific BMEM as well as IFN-γ+ PBMC responses. Overall, both intranasal and intramuscular immunizations elicited a durable and functional response in systemic and mucosal compartments, which supports advancing the LecA+GLA-3M-052 liposome vaccine candidate to clinical testing.

Entamoeba histolytica is a disease-causing parasitic amoeba which affects an estimated 50 million people worldwide, particularly in socioeconomically vulnerable populations experiencing water sanitation issues. Infection with E. histolytica is referred to as amoebiasis, and can cause symptoms such as colitis, dysentery, and even death in extreme cases. Drugs exist that are capable of killing this parasite, but they are hampered by downsides such as significant adverse effects at therapeutic concentrations, issues with patient compliance, the need for additional drugs to kill the transmissible cyst stage, and potential development of resistance. Past screens of small and medium sized chemical libraries have yielded anti-amoebic candidates, thus rendering high-throughput screening a promising direction for new drug discovery in this area. In this study, we screened a curated 81,664 compound library from Janssen pharmaceuticals against E. histolytica trophozoites in vitro, and from it identified a highly potent new inhibitor compound. The best compound in this series, JNJ001, showed excellent inhibition activity against E. histolytica trophozoites with EC50 values at 0.29 μM, which is better than the current approved treatment, metronidazole. Further experimentation confirmed the activity of this compound, as well as that of several structurally related compounds, originating from both the Janssen Jump-stARter library, and from chemical vendors, thus highlighting a new structure-activity relationship (SAR). In addition, we confirmed that the compound inhibited E. histolytica survival as rapidly as the current standard of care and inhibited transmissible cysts of the related model organism Entamoeba invadens. Together these results constitute the discovery of a novel class of chemicals with favorable in vitro pharmacological properties. The discovery may lead to an improved therapy against this parasite and in all of its life stages.

A patient in California, USA, with rare and usually fatal Balamuthia mandrillaris granulomatous amebic encephalitis survived after receiving treatment with a regimen that included the repurposed drug nitroxoline. Nitroxoline, which is a quinolone typically used to treat urinary tract infections, was identified in a screen for drugs with amebicidal activity against Balamuthia.

Currently, one of most severe environmental problems is the high levels of pollution of many of drinking water bodies in India. The present research is focuses on the relationship between total coliform bacteria levels and the increase of human digestive tract diseases in the highly polluted water in the various drinking water source of Bhopal. Aim of the studied to find out what is the connection between gastrointestinal diseases and water bodies of Bhopal by conducting an online survey with questions related to the topic. This survey was particularly based for the residents in Bhopal where a total of 333 respondents were surveyed. Most of the respondents were aged 18-25 years old. Out of all the respondents, majority were the females. Around 68.5 % respondents were the local residents of Bhopal who have been there in Bhopal for around 1-5 years. A majority of people were from the western part of the Bhopal and were also aware about the gastrointestinal diseases. The results presented here are the first of their kind of this water bodies and will serve as basis for future research exploring other similarly contaminated riparian communities. As the causes of pollution are directly related to the economic development and population growth of the region, further research should be conducted for prevention of diseases, educational programs, water remediation and conservation programs that will have a positive impact on the quality of life of the population presently at risk. [ABSTRACT FROM AUTHOR]

Introduction: Intestinal infections are a significant health issue; antibiotics are essential in treating acute intestinal infections. However, evidence in the literature shows that the excessive use of antibiotics has created many threats to human health. This work aimed to study the impact of apple pectin in combination with antibiotics on treating patients with amebiasis and dysentery. Methodology: Patients suffering from acute intestinal diseases (amebiasis and dysentery) were treated with traditional antibiotic therapy and a new formula containing antibiotics with low and high methoxylated apple pectin in a randomized block design. Four clinical trials were performed at the Infection Disease Hospital from 1998 until 2013. Results: The study demonstrated that the antibiotic-pectin formulae (APF) significantly reduced the severity of acute intestinal infection diseases and allowed patients to recover faster than conventional treatment. APF reduced the patient's stay in the hospital by 3.0 ± 1.0 days. The clinical trial findings demonstrated that applying APF in intestinal infection diseases helped maintain a constant concentration of the antibiotic in the blood and accelerated the clinical recovery of the patients. Conclusions: It was concluded that using pectin with antibiotics could improve clinical outcomes in patients with acute infectious diseases. Research on elucidating the mechanisms of pectin digestion in the colon, polyphenol content, and its role in dysbiosis recovery, etc., is also considered. [ABSTRACT FROM AUTHOR]

Amoebic liver abscess is caused by Entamoeba histolytica infection, which manifests as invasive extraintestinal amoebiasis and is often found in tropical countries including Indonesia. Amoebic liver abscess contributes to 50,000 deaths globally. Establishing the diagnosis requires liver imaging and serological tests. The detection of Entamoeba histolytica parasite is crucial in determining the etiology of amoebic liver abscess. The aim of this study is to report a case of a 20-year-old male with symptoms of right upper abdominal pain, fever, nausea, and anorexia, and to evaluate the effectiveness of laparoscopic abscess drainage as a treatment method. The method used is clinical data analysis and therapy outcome evaluation. The results show that the patient experienced clinical improvement after treatment with metronidazole and laparoscopic abscess drainage, with no additional physical complications. Entamoeba histolytica is an amoeba transmitted through the fecaloral route and enters the bloodstream, subsequently forming abscesses in the liver. The patient presented with a large liver abscess and required operative drainage. Amoebic liver abscess generally responds well to medical treatment. However, in certain cases such as large abscess sizes, percutaneous drainage is needed to prevent abscess rupture. The patient was managed with laparoscopic drainage, which resulted in fewer physical injuries. Proper management can prevent complications from liver abscess rupture. [ABSTRACT FROM AUTHOR]

ABSTRACT Diarrheal diseases with infectious etiology remain a major cause of death globally, particularly in low-income countries. Entamoeba histolytica is a pathogenic protozoan parasite that is the causative agent of amebiasis. Amebiasis has a wide presentation in clinical severity with many factors, including the bacterial microbiota, contributing to this variation. The innate immune response also plays a critical role in regulating the severity of E. histolytica infection, with neutrophils reported to have a protective role. Despite this, the precise mechanism of how neutrophils mediate amebic killing is poorly understood. Thus, modern platforms that allow for inquiry of granulocyte–ameba interactions will increase our understanding of this disease. Herein, we describe an assay for neutrophil killing of E. histolytica by utilizing high-dimensional spectral flow cytometry. Neutrophils were isolated from wild-type 5-week-old C57BL/6 mice and co-cultured with E. histolytica at various multiplicity of infections (MOIs). After co-culture, neutrophils and E. histolytica were stained for spectral flow cytometry. Cell populations were identified using surface markers and fluorescence minus one (FMO) controls. We have previously shown that animals colonized with a component of the human microbiota, Clostridium scindens, were protected from E. histolytica. This protection was associated with elevated neutrophil count. Here, we explored amebic killing capacity and observed that neutrophils from animals with C. scindens possessed heightened amebic killing compared with controls. Thus, this study establishes a novel platform that can provide an in-depth analysis of granulocyte–parasite interactions in various contexts, including during alteration of the intestinal microbiota.IMPORTANCEThe tools for studying host immune cell–E. histolytica interactions are limited. Factors, such as parasite heterogeneity, infectivity, and difficulties with culture systems and animal models, make interrogation of these interactions challenging. Thus, Entamoeba researchers can benefit from next-generation models that allow for the analysis of both host and parasite cells. Here, we demonstrate the use of a novel platform that allows for the determination of parasite–host cell interactions and customizable high-dimensional phenotyping of both populations. Indeed, spectral flow cytometry can approach >40 markers on a single panel and can be paired with custom-developed parasite antibodies that can be conjugated to fluorochromes via commercially available kits. This platform affords researchers the capability to test highly precise hypotheses regarding host–parasite interactions.

A fluorescence immunochromatography (FIC) kit was developed recently using fluorescent silica nanoparticles coated with a recombinant C-terminal fragment of the surface lectin intermediate subunit (C-Igl) of Entamoeba histolytica to establish rapid serodiagnosis of amebiasis. We further evaluated the system using serum samples from 52 Thai patients with amebiasis. Of the patients, 50 (96%) tested positive using FIC. The samples were also tested using enzyme-linked immunosorbent assay (ELISA) with C-Igl as the antigen. Two samples were negative on ELISA but positive on FIC. The correlation coefficient between the fluorescence intensity using FIC and the optical density value using ELISA was 0.5390, indicating a moderate correlation between the two tests. Serum samples from 20 patients with malaria and 22 patients with Clostridioides difficile infection were also tested using FIC. The false-positive rates were 4/20 (20%) and 1/22 (4%) in patients with malaria and C. difficile infection, respectively. Combining the data from the present study with our previous study, the sensitivity and specificity of FIC were determined to be 98.5% and 95.2%, respectively. The results of the 50 samples were studied using a fluorescence scope and a fluorescence intensity reader, and the findings were compared. Disagreements were found in only two samples showing near-borderline fluorescence intensity, indicating that the use of scope was adequate for judging the results. These results demonstrate that FIC is a simple and rapid test for the serodiagnosis of amebiasis. [ABSTRACT FROM AUTHOR]

Background: Parasitic infections in children are one of the most important health and health problems worldwide, especially in developing countries. Diarrheal diseases such as those caused by Entamoeba histolytica are among the causes of death in children, so the purpose of this systematic review and meta-analysis is to determine the prevalence of Entamoeba histolytica in Iranian children. Materials and Methods: This study is a systematic review and meta-analysis by examining the Scientific Information Database (SID), Medline (PubMed), Scopus and Google Scholar until March 2023. Results: In a review of 12 studies with a sample size of 10,982 Iranian children, the prevalence of Entamoeba Histolytica in Iranian children was reported to be 1% (95% CI 0.6-1.7%). The meta-regression results showed that in examining the factors influencing the heterogeneity of studies and examining the effect of sample size on this heterogeneity, it was reported that with increasing sample size, the prevalence of Entamoeba histolytica in Iranian children decreased (P<0.05) and also with the increase in the year of conducting studies, the prevalence decreases in Iranian children (P=0.289). Conclusion: The results of the present study show that the prevalence of Entamoeba histolytica in Iranian children is not at a very high level, but to continue preventive measures and reach lower levels, it still requires the attention of health policymakers in this area to carry out extensive information and screening to prevent the effects of this parasitic disease on children. [ABSTRACT FROM AUTHOR]

In order to accurately diagnose Entamoeba spp., this study's major goal was to develop a proof-of-concept method for simultaneously detecting pathogenic and nonpathogenic amoebae using DNA. During amoebiasis, two diagnostic techniques (microscopic inspection and PCR techniques with particular primers) were evaluated. About 100 feces samples from Fallujah individuals who had clinical symptoms were taken. The outcome reveals that only 20 samples have Entamoeba spp. infections. According to this study, the two species had distinct infection percentages. Entamoeba histolytica was the most prevalent infection, at 85%, followed by Entamoeba dispar, which was 15% of all the Entamoeba-positive samples. In addition to studying the morphology and genes of the positive samples, the residential environment, age, and gender were also taken into consideration. It showed the infective patients in the rural area had a higher rate of infection, which was 18%, while the infection in the urban area was less, which was represented by 2%. As for the effect of the age factor, the highest percentage was from children who did not exceed ten years old, which was 10%. The lowest percentage was 2% for people over the age of sixteen (16). According to the gender factor, a different percentage appeared in males than females. The result showed a high infection rate for males, which was estimated at about 16%, but for females it was much less, at only 4%. [ABSTRACT FROM AUTHOR]

Amoebiasis is still of serious concern for public health in developing countries. The main issue in diagnosing amoebiasis infection through stool samples is the inability to differentiate the morphologically indistinguishable Entamoeba histolytica from the nonpathogenic Amoeba. This study aimed at detecting Entamoeba species (E. histolytica / dispar) among the microscopically diagnosed amoebiasis infections in the Nablus district using nonconventional immunoassay methods. The study utilized 101 Amoeba-positive stool samples based on the microscope examination. The stool specimens were collected from patients who sought medical investigation and diagnosis regardless of age or gender. The consented patients answered questionnaires. The immunoassay method detected E. histolytica / E. dispar in 36.2% of stool specimens out of the tested samples. There was a variation in the prevalence of amoebiasis among the different age groups. Noteworthy, infants positive, 9.9 % and 20.6 % microscopically and using the immunoassay, respectively. In conclusion, this study stressed the urgent need to revise the conventional technique used to diagnose amoebiasis for its serious impact on health. The immunoassay kits could be a good and fast screening technique. [ABSTRACT FROM AUTHOR]

The impact of the COVID-19 pandemic was very broad and substantial, affecting a variety of fields worldwide. In Japan, the infection began spreading in March 2020. At that time, the government alerted people to cancel overseas travel, and encouraged wearing of masks, handwashing, sanitizing and keeping social distance. We sought to determine how COVID-19 infections affected other infectious diseases by investigating the trends in seven gastrointestinal infections that are listed among the 77 important infectious diseases designated by the National Institute of Infectious Diseases. We compared seven gastrointestinal infectious diseases, namely cholera, bacterial dysentery, enterohemorrhagic Escherichia coli, typhoid fever, paratyphoid fever, amoebic dysentery, and giardiasis, in terms of numbers of new cases before the COVID-19 pandemic (2012–2019) and during the pandemic (2020–2022). During the COVID-19 pandemic period (2020–2022), the incidence of the seven infections decreased significantly (p < 0.05) compared with before the pandemic (2012–2019). The sharp and significant decline in incidence of these seven infections in Japan during the COVID-19 pandemic period (2020–2022) appears to be due to restrictions on overseas travel and strict anti-infection measures, such as self-quarantine and encouragement of handwashing and sanitizing. The number of new cases of gastrointestinal infections in Japan is expected to increase in 2024 as these measures lapse. It is important for physicians to continue to monitor trends in gastrointestinal infections and educate people about proper infection prevention. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 43-year-old man, a lung transplant candidate, who underwent screening colonoscopy, revealing a sessile and ulcerated non-obstructing cecal mass, prompting the question of diagnosis. Topics include the patient's medical history, examination findings, and the histological features of the colonic mucosa obtained from a biopsy of the identified mass.

determine the prevalence of the Amoebic dysentery among children under the The present study aims to age of five years in Thi-Qar province during the period from October 2022 to August 2023 and to study the effects of some factors such as sex, age, location, source of drinking water and others on the prevalence of the disease. Study was carried out at the Bint Al-Huda Educational Hospital for Women and Children and Mohammed al-Musawi Hospital in Thi-Qar Province, 697 samples of feces were collected from children with diarrhea and examined by direct microscopic examination. The results showed that 100 out of 697 and %14.34 % of children were infected with Entamoeba spp. No significant differences (p>0.05) were recorded in prevalence of Entamoeba spp. according to sex and the infected males %7.46% more than infected females 6.88%. A significant differences (p≤0.05) were observed in the prevalence of Entamoeba spp. according to age groups, the highest infection percent on the age group (48-60 months) 5% and the lowest infection percent on the age group (<12 months) 1.43 %. No significant differences (p>0.05) were recorded in prevalence of Entamoeba spp. according to months of the year, the high percent 23.33% in June and the lowest percent 10.67% in November. The study recorded significant differences (p≤0.05) in infection percent according to the location, the percent of infected children living in rural 9.75% more than infected children living in the urban 4.59%. The study recorded significant differences in prevalence of Entamoeba spp. according parent educational level. The high percent of infection was recorded in children belonging to parents without educational attainment 6.89%. The results showed that there were no differences (p>0.05) in prevalence of Entamoeba spp. according to source of drinking water. [ABSTRACT FROM AUTHOR]

Background: Amoebiasis, an infectious disease caused by the parasitic protozoan E. histolytica, is easily misdiagnosed due to its declining incidence and atypical symptoms.Case Presentation: A 31-year-old male presented to the hospital with dyspnea and inability to lie flat. Imaging studies indicated a large amount of pleural effusion on the right side and multiple huge cysts in the liver. The patient underwent liver tumor resection surgery at another hospital due to suspected malignancy, but no evidence of relevant malignant tumors was found in the pathological examination. Subsequently, we performed metagenomic next-generation sequencing on the liver drainage fluid and obtained liver pathology slides from the hospital where the surgery was performed at that time. Both of them confirmed the diagnosis of amoebic infection. Empirical treatment with metronidazole was initiated before the diagnosis was confirmed, along with symptomatic treatments such as thoracic drainage and liver drainage. Eventually, the patient's condition improved and he was discharged smoothly.Conclusion: In order to avoid misdiagnosis of amoebiasis, thoroughly inquiring about the patient's medical history, shifting perspectives and continuing investigating are necessary when one diagnostic approach proves ineffective. Besides, interdisciplinary collaboration and persistent efforts are crucial for accurate diagnosis. [ABSTRACT FROM AUTHOR]

Entamoeba histolytica is the cause of amoebiasis. The trophozoite (amoeba) form of this parasite is capable of invading the intestine and can disseminate through the bloodstream to other organs. The mechanisms that allow amoebae to evade complement deposition during dissemination have not been well characterized. We previously discovered a novel complement-evasion mechanism employed by E. histolytica. E. histolytica ingests small bites of living human cells in a process termed trogocytosis. We demonstrated that amoebae were protected from lysis by human serum following trogocytosis of human cells and that amoebae acquired and displayed human membrane proteins from the cells they ingested. Here, we aimed to define how amoebae are protected from complement lysis after performing trogocytosis. We found that amoebae were protected from complement lysis after ingestion of both human Jurkat T cells and red blood cells and that the level of protection correlated with the amount of material ingested. Trogocytosis of human cells led to a reduction in deposition of C3b on the surface of amoebae. We asked whether display of human complement regulators is involved in amoebic protection, and found that CD59 was displayed by amoebae after trogocytosis. Deletion of a single complement-regulatory protein, CD59 or CD46, from Jurkat cells was not sufficient to alter amoebic protection from lysis, suggesting that multiple, redundant complement regulators mediate amoebic protection. However, exogeneous expression of CD46 or CD55 in amoebae was sufficient to confer protection from lysis. These studies shed light on a novel strategy for immune evasion by a pathogen. IMPORTANCE Entamoeba histolytica is the cause of amoebiasis, a diarrheal disease of global importance. While infection is often asymptomatic, the trophozoite (amoeba) form of this parasite is capable of invading and ulcerating the intestine and can disseminate through the bloodstream to other organs. Understanding how E. histolytica evades the complement system during dissemination is of great interest. Here, we demonstrate for the first time that amoebae that have performed trogocytosis (nibbling of human cells) resist deposition of the complement protein C3b. Amoebae that have performed trogocytosis display the complement-regulatory protein CD59. Overall, our studies suggest that acquisition and display of multiple, redundant complement regulators is involved in amoebic protection from complement lysis. These findings shed light on a novel strategy for immune evasion by a pathogen. Since other parasites use trogocytosis for cell killing, our findings may apply to the pathogenesis of other infections.

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Significant and composite indices for infectious disease can have implications for developing interventions and public health. This paper presents an investment for developing access to further analysis of the incidence of individual and multiple diseases. This research mainly comprises two steps: first, an automatic and reproducible procedure based on functional data analysis techniques was proposed for analyzing the dynamic properties of each disease; second, orthogonal transformation was adopted for the development of composite indices. Between 2000 and 2019, nineteen class B notifiable diseases in China were collected for this study from the National Bureau of Statistics of China. The study facilitates the probing of underlying information about the dynamics from discrete incidence rates of each disease through the procedure, and it is also possible to obtain similarities and differences about diseases in detail by combining the derivative features. There has been great success in intervening in the majority of notifiable diseases in China, like bacterial or amebic dysentery and epidemic cerebrospinal meningitis, while more efforts are required for some diseases, like AIDS and virus hepatitis. The composite indices were able to reflect a more complex concept by combining individual incidences into a single value, providing a simultaneous reflection for multiple objects, and facilitating disease comparisons accordingly. For the notifiable diseases included in this study, there was superior management of gastro-intestinal infectious diseases and respiratory infectious diseases from the perspective of composite indices. This study developed a methodology for exploring the prevalent properties of infectious diseases. The development of effective and reliable analytical methods provides special insight into infectious diseases' common dynamics and properties and has implications for the effective intervention of infectious diseases. [ABSTRACT FROM AUTHOR]

Copyright of Gaceta Médica de Caracas is the property of Academia Nacional de Medicina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Multinucleated Giant Cells (MGCs) are specialized cells that develop from the fusion of multiple cells, and their presence is commonly observed in human cells during various infections. However, MGC formation is not restricted to infections alone but can also occur through different mechanisms, such as endoreplication and abortive cell cycle. These processes lead to the formation of polyploid cells, eventually resulting in the formation of MGCs. In Entamoeba, a protozoan parasite that causes amoebic dysentery and liver abscesses in humans, the formation of MGCs is a unique phenomenon and not been reported in any other protozoa. This organism is exposed to various hostile environmental conditions, including changes in temperature, pH, and nutrient availability, which can lead to stress and damage to its cells. The formation of MGCs in Entamoeba is thought to be a survival strategy to cope with these adverse conditions. This organism forms MGCs through cell aggregation and fusion in response to osmotic and heat stress. The MGCs in Entamoeba are thought to have increased resistance to various stresses and can survive longer than normal cells under adverse conditions. This increased survival could be due to the presence of multiple nuclei, which could provide redundancy in case of DNA damage or mutations. Additionally, MGCs may play a role in the virulence of Entamoeba as they are found in the inflammatory foci of amoebic liver abscesses and other infections caused by Entamoeba. The presence of MGCs in these infections suggests that they may contribute to the pathogenesis of the disease. Overall, this article offers valuable insights into the intriguing phenomenon of MGC formation in Entamoeba. By unraveling the mechanisms behind this process and examining its implications, researchers can gain a deeper understanding of the complex biology of Entamoeba and potentially identify new targets for therapeutic interventions. The study of MGCs in Entamoeba serves as a gateway to exploring the broader field of cell fusion in various organisms, providing a foundation for future investigations into related cellular processes and their significance in health and disease. [ABSTRACT FROM AUTHOR]

Amebiasis is caused by the protozoan parasite Entamoeba histolytica. Treatment options other than metronidazole and its derivatives are few, and their low efficacy against asymptomatic cyst carriers, and experimental evidence of resistance in vitro justify the discovery/repurposing campaign for new drugs against amebiasis. Global metabolic responses to oxidative stress and cysteine deprivation by E. histolytica revealed glycerol metabolism may represent a rational target for drug development. In this study using 14C-labelled glucose, only 11% of the total glucose taken up by E. histolytica trophozoites is incorporated to lipids. To better understand the role of glycerol metabolism in this parasite, we focused on characterizing two important enzymes, glycerol kinase (GK) and glycerol 3-phosphate dehydrogenase (G3PDH). Recombinant GK was biochemically characterized in detail, while G3PDH was not due to failure of protein expression and purification. GK revealed novel characteristics and unprecedented kinetic properties in reverse reaction. Gene silencing revealed that GK is essential for optimum growth, whereas G3PDH is not. Gene silencing of G3PDH caused upregulated GK expression, while that of GK resulted in upregulation of antioxidant enzymes as shown by RNA-seq analysis. Although the precise molecular link between GK and the upregulation of antioxidant enzymes was not demonstrated, the observed increase in antioxidant enzyme expression upon GK gene silencing suggests a potential connection between GK and the cellular response to oxidative stress. Together, these results provide the first direct evidence of the biological importance and coordinated regulation of the glycerol metabolic pathways for proliferation and antioxidative defense in E. histolytica, justifying the exploitation of these enzymes as future drug targets. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the effective‑ ness of a health education program on mothers' knowledge and practices related to amebiasis. Pre‑ and post‑I and II‑tests were used, along with a two‑group quasi‑experimental design. The study included a convenience sample of 120 mothers, including 60 from the study and 60 from the control group. Out of the entire number of PHCs in Wasit Governorate, seven were used for the study. A three‑part structured questionnaire tests mothers' knowledge of the illness and attitudes about it. The results of this study indicated that there is statistically significant difference between the study and control groups during the post‑test I and post‑test II periods (t=14.968, P=.000 and t=13.731, P=.000, respectively). Data from the study group during the pre‑test period of 31.17(9.14) revealed that (70%) of mothers had bad practices connected to Entameba Histolytica among children. According to the post‑test I results, 47.4 (9.48) respondents, or 70%, identified good practices. The main finding showed that, after the educational program was implemented, mothers' knowledge and practice of amebiasis dramatically increased, with pre‑post implementation differ‑ ences that are statistically significan [ABSTRACT FROM AUTHOR]

Les abcès hépatiques à Entamoeba histolytica représentent la quatrième cause de mortalité par maladie parasitaire dans le monde. Cette étude visait à préciser les caractéristiques cliniques, d'imagerie et la prise en charge thérapeutique des patients atteints d'un abcès hépatique amibien comparativement aux abcès à pyogènes au sein d'un centre hospitalier tertiaire spécialisé dans les pathologies hépatobiliaires. Les dossiers des patients hospitalisés entre 2010 et 2020 pour un abcès hépatique étaient examinés puis séparés en deux groupes : abcès hépatiques amibiens et abcès à pyogènes de porte d'entrée portale. Les données cliniques et radiologiques étaient examinées pour comparaison en analyse univariée. Vingt et un patients ont été hospitalisés pour un abcès hépatique amibien, et vingt et un patients pour un abcès à pyogènes de porte d'entrée portale. Tous les patients hospitalisés pour abcès amibien étaient originaires d'une zone d'endémie et/ou y avaient voyagé récemment. Comparativement aux patients hospitalisés pour abcès à pyogènes, les patients admis pour abcès amibien étaient plus jeunes (44 ans vs 63 ans, p < 0,001), avaient moins de comorbidités (5 % contre 43 %, p < 0,01), présentaient une durée médiane des symptômes avant diagnostic plus importante (10 jours vs 3 jours, p = 0,015) avec une fréquence plus importante de douleurs abdominales (86 % contre 52 %, p = 0,019), ainsi qu'une hyperleucocytose modérée (9600 G/L contre 15 500 G/L, p = 0,041). Sur le plan radiologique, les abcès amibiens présentaient une densité plus élevée (34 vs 25 UH, p < 0,01), et moins d'aspect multiloculé. La prise en charge diagnostique et thérapeutique spécifique des abcès amibiens ne doit pas être sous-estimée. La présence d'un abcès unique peu hypodense chez un patient originaire ou revenant de zone d'endémie doit suggérer ce diagnostic en priorité. Amoebic liver abscess (ALA) is the fourth cause of mortality by parasitic infection. This study aimed to assess clinical, radiological and therapeutic characteristics of patients admitted for amoebic liver abscess compared to pyogenic abscess in a French digestive tertiary care-centre. The charts of patients hospitalized for a liver abscess between 2010 and 2020 were retrospectively assessed then separated in two groups: amoebic liver abscess and pyogenic liver abscess from portal underlying cause. Clinical and radiological data were collected for univariate comparison. Twenty-one patients were hospitalized during the time of the study for ALA, and 21 patients for pyogenic liver abscess with a portal mechanism. All patients hospitalized for ALA lived in and/or had travelled recently in an endemic area. In comparison with patients hospitalized for pyogenic abscess, patients admitted for ALA were younger (44 years old vs. 63 years old, P < 0.001), had less comorbidities (5% vs. 43% of patients with at least one comorbidity, P < 0.01), a longer median duration of symptoms (10 days vs. 3 days, P = 0.015), abdominal pain (86% vs. 52%, P = 0.019), and a slighter leucocytosis (9600 G/L vs. 15,500 G/L, P = 0.041) were more frequent. On the abdominal tomodensitometry, density of ALA was higher (34 vs. 25 UH, P < 0.01), associated with a focal intra-hepatic biliary dilatation and less often multiloculated. While rare in western countries, amoebic liver abscess care should not be underestimated. The presence of a solitary liver abscess of intermediate density on computed tomography, occurring on a patient returning from an endemic zone should lead the physician to a possible diagnosis of ALA. [ABSTRACT FROM AUTHOR]

This article discusses the evaluation of intestinal parasites as a cause of diarrhea in children and the treatments used in Babylon Governorate. The study collected stool samples from children with diarrhea and found that the most prevalent parasites were Giardia lamblia and Entamoeba histolytica. The study also examined the effectiveness of different drugs in treating these parasites, with metronidazole and albendazole being highly effective. The study suggests that urban inhabitants are more likely to suffer from parasitic diarrhea. [Extracted from the article]

Background & Objective: Conventional treatment of Acanthamoeba typically involves a combination drug strategy, but its efficacy in clinical settings remains incomplete. Evaluating the therapeutic potential of existing drugs is a way used to introduce effective treatments for infectious agents. This study aimed to assess the in vitro anti-Acanthamoeba effect of valproate (VPA). Materials & Methods: An experimental study was conducted using Acanthamoeba cysts belonging to the T4 and T5 genotypes. Cysts collected from the culture medium were exposed to gentamicin, polymyxin, and three different concentrations of VPA for varying durations (1, 4, 6, and 24 hours). The treated cysts were stained with trypan blue, and the percentage of growth inhibition was calculated. Additionally, the viability of treated cysts was assessed by culturing them on non-nutrient agar plates for one month. Results: The Acanthamoeba cysts of T4 and T5 genotypes showed susceptibility to VPA. The minimal cysticidal concentration (MCC) of VPA for maximum growth inhibition in both single and combination drug assays were 100 and 3 mg/ml, for durations of 24 and 4 hours, respectively. The growth inhibition observed in the groups exposed to gentamicin and polymyxin differed significantly from the growth inhibition in the group treated with ≥100 mg/ml VPA (P< 0.05). Conclusion: VPA enhances the effects of gentamicin and polymyxin on Acanthamoeba. Combining a low concentration of VPA (≥3 mg/ml) with gentamicin and polymyxin increases the potency and speed of action of these antibiotics. [ABSTRACT FROM AUTHOR]

Cytochromes P450 (P450, CYP) metabolize a wide variety of endogenous and exogenous lipophilic molecules, including most drugs. Sterol 14α-demethylase (CYP51) is a target for antifungal drugs known as conazoles. Using X-ray crystallography, we have discovered a domain-swap homodimerization mode in CYP51 from a human pathogen, Acanthamoeba castellanii CYP51 (AcCYP51). Recombinant AcCYP51 with a truncated transmembrane helix was purified as a heterogeneous mixture corresponding to the dimer and monomer units. Spectral analyses of these two populations have shown that the CO-bound ferrous form of the dimeric protein absorbed at 448 nm (catalytically competent form), whereas the monomeric form absorbed at 420 nm (catalytically incompetent form). AcCYP51 dimerized head-to-head via N-termini swapping, resulting in formation of a nonplanar protein-protein interface exceeding 2000 Å2 with a total solvation energy gain of -35.4 kcal/mol. In the dimer, the protomers faced each other through the F and G α-helices, thus blocking the substrate access channel. In the presence of the drugs clotrimazole and isavuconazole, the AcCYP51 drug complexes crystallized as monomers. Although clotrimazole-bound AcCYP51 adopted a typical CYP monomer structure, isavuconazole-bound AcCYP51 failed to refold 74 N-terminal residues. The failure of AcCYP51 to fully refold upon inhibitor binding in vivo would cause an irreversible loss of a structurally aberrant enzyme through proteolytic degradation. This assumption explains the superior potency of isavuconazole against A. castellanii The dimerization mode observed in this work is compatible with membrane association and may be relevant to other members of the CYP family of biologic, medical, and pharmacological importance. SIGNIFICANCE STATEMENT: We investigated the mechanism of action of antifungal drugs in the human pathogen Acanthamoeba castellanii. We discovered that the enzyme target [Acanthamoeba castellanii sterol 14α-demethylase (AcCYP51)] formed a dimer via an N-termini swap, whereas drug-bound AcCYP51 was monomeric. In the AcCYP51-isavuconazole complex, the protein target failed to refold 74 N-terminal residues, suggesting a fundamentally different mechanism of AcCYP51 inactivation than only blocking the active site. Proteolytic degradation of a structurally aberrant enzyme would explain the superior potency of isavuconazole against A. castellanii.

Key Clinical Message Amebic liver abscesses should be considered in adult males with a liver abscess and a history of travel to endemic areas. Effective treatment includes metronidazole, followed by paromomycin.

This study was conducted to assess the effectiveness of a health education program on mothers' knowledge and practices related to amebiasis. Pre‑ and post‑I and II‑tests were used, along with a two‑group quasi‑experimental design. The study included a convenience sample of 120 mothers, including 60 from the study and 60 from the control group. Out of the entire number of PHCs in Wasit Governorate, seven were used for the study. A three‑part structured questionnaire tests mothers' knowledge of the illness and attitudes about it. The results of this study indicated that there is statistically significant difference between the study and control groups during the post‑test I and post‑test II periods (t=14.968, P=.000 and t=13.731, P=.000, respectively). Data from the study group during the pre‑test period of 31.17(9.14) revealed that (70%) of mothers had bad practices connected to Entameba Histolytica among children. According to the post‑test I results, 47.4 (9.48) respondents, or 70%, identified good practices. The main finding showed that, after the educational program was implemented, mothers' knowledge and practice of amebiasis dramatically increased, with pre‑post implementation differences that are statistically significant.

Background: Despite significant progress in sanitation status and public health awareness, intestinal infectious diseases (IID) have caused a serious disease burden in China. Little was known about the spatio-temporal pattern of IID at the county level in Zhejiang. Therefore, a spatio-temporal modelling study to identify high-risk regions of IID incidence and potential risk factors was conducted. Methods: Reported cases of notifiable IID from 2008 to 2021 were obtained from the China Information System for Disease Control and Prevention. Moran's I index and the local indicators of spatial association (LISA) were calculated using Geoda software to identify the spatial autocorrelation and high-risk areas of IID incidence. Bayesian hierarchical model was used to explore socioeconomic and climate factors affecting IID incidence inequities from spatial and temporal perspectives. Results: From 2008 to 2021, a total of 101 cholera, 55,298 bacterial dysentery, 131 amoebic dysentery, 5297 typhoid, 2102 paratyphoid, 27,947 HEV, 1,695,925 hand, foot and mouth disease (HFMD), and 1,505,797 other infectious diarrhea (OID) cases were reported in Zhejiang Province. The hot spots for bacterial dysentery, OID, and HEV incidence were found mainly in Hangzhou, while high-high cluster regions for incidence of enteric fever and HFMD were mainly located in Ningbo. The Bayesian model showed that Areas with a high proportion of males had a lower risk of BD and enteric fever. People under the age of 18 may have a higher risk of IID. High urbanization rate was a protective factor against HFMD (RR = 0.91, 95% CI: 0.88, 0.94), but was a risk factor for HEV (RR = 1.06, 95% CI: 1.01–1.10). BD risk (RR = 1.14, 95% CI: 1.10–1.18) and enteric fever risk (RR = 1.18, 95% CI:1.10–1.27) seemed higher in areas with high GDP per capita. The greater the population density, the higher the risk of BD (RR = 1.29, 95% CI: 1.23–1.36), enteric fever (RR = 1.12, 95% CI: 1.00–1.25), and HEV (RR = 1.15, 95% CI: 1.09–1.21). Among climate variables, higher temperature was associated with a higher risk of BD (RR = 1.32, 95% CI: 1.23–1.41), enteric fever (RR = 1.41, 95% CI: 1.33–1.50), and HFMD (RR = 1.22, 95% CI: 1.08–1.38), and with lower risk of HEV (RR = 0.83, 95% CI: 0.78–0.89). Precipitation was positively correlated with enteric fever (RR = 1.04, 95% CI: 1.00–1.08), HFMD (RR = 1.03, 95% CI: 1.00–1.06), and HEV (RR = 1.05, 95% CI: 1.03–1.08). Higher HFMD risk was also associated with increasing relative humidity (RR = 1.20, 95% CI: 1.16–1.24) and lower wind velocity (RR = 0.88, 95% CI: 0.84–0.92). Conclusions: There was significant spatial clustering of IID incidence in Zhejiang Province from 2008 to 2021. Spatio-temporal patterns of IID risk could be largely explained by socioeconomic and meteorological factors. Preventive measures and enhanced monitoring should be taken in some high-risk counties in Hangzhou city and Ningbo city. [ABSTRACT FROM AUTHOR]

In the human host, the protozoan parasite Entamoeba histolytica is adapted to a non-invasive lifestyle in the colon as well as to an invasive lifestyle in the mesenterial blood vessels and the liver. This means to cope with bacteria and human cells as well as various metabolic challenges. Galactose and N-acetylgalactosamine (GalNAc) are sugars of great importance for the amoebae, they attach to the host mucus and enterocytes via their well-studied Gal/GalNAc specific lectin, they carry galactose residues in their surface glycans, and they cleave GalNAc from host mucins. The enzyme UDP-glucose 4-epimerase (GalE) works as a bridge between the galactose and glucose worlds, it can help to generate glucose for glycolysis from phagocytosis products containing galactose as well as providing UDP-galactose necessary for the biosynthesis of galactose-containing surface components. E. histolytica contains a single galE gene. We recombinantly expressed the enzyme in Escherichia coli and used a spectrophotometric assay to determine its temperature and pH dependency (37°C, pH 8.5), its kinetics for UDP-glucose (Km = 31.82 μM, Vmax = 4.31 U/mg) and substrate spectrum. As observed via RP-HPLC, the enzyme acts on UDP-Glc/Gal as well as UDP-GlcNAc/GalNAc. Previously, Trypanosoma brucei GalE and the bloodstream form of the parasite were shown to be susceptible to the three compounds ebselen, a selenoorganic drug with antioxidant properties, diethylstilbestrol, a mimic of oestrogen with anti-inflammatory properties, and ethacrynic acid, a loop diuretic used to treat oedema. In this study, the three compounds had cytotoxic activity against E. histolytica, but only ebselen inhibited the recombinant GalE with an IC50 of 1.79 μM (UDP-Gal) and 1.2 μM (UDP-GalNAc), suggesting that the two other compounds are active against other targets in the parasite. The importance of the ability of GalE to interconvert UDP-GalNAc and UDP-GlcNAc may be that the trophozoites can generate precursors for their own cyst wall from the sugar subunits cleaved from host mucins. This finding advances our understanding of the biochemical interactions of E. histolytica in its colonic environment. Author summary: Entamoeba histolytica is a unicellular parasite causing amoebic dysentery and liver abscess. The trophozoites live in the human colon where they feed on bacteria and simple sugars, e.g. glucose, which is essential for their fermentative energy metabolism, moreover, glucose and galactose appear in large amounts on their surface molecules. We characterised the enzyme UDP-glucose 4-epimerase (GalE). The enzyme converts UDP-galactose (UDP-Gal) to UDP-glucose (UDP-Glc), and in addition UDP N-acetylgalactosamine (UDP-GalNAc) to UDP-N-acetylglucosamine (UDP-GlcNAc). As E. histolytica possesses a β-N-acetylhexosaminidase, which potentially releases GalNAc and GlcNAc from human intestinal mucins; via the action of GalE, these building blocks can be utilised to generate UDP-GlcNAc, the precursor for the chitin of the amoebic cyst wall. The compounds ebselen, diethylstilbestrol and ethacrynic acid had been reported as inhibitors of Trypanosoma brucei GalE and were also active against the parasite. When we tested the compounds against E. histolytica and its GalE, all three compounds led to amoebic death, but only one of them, ebselen, inhibited GalE activity. Considering its bifunctionality, GalE is not only key to the synthesis of trophozoite glycans, but probably is essential for the generation of chitin for the emerging cyst wall from sugars cleaved from the host intestinal mucin. [ABSTRACT FROM AUTHOR]

Amoebiasis is the second leading cause of death worldwide associated with parasitic disease and is becoming a critical health problem in low-income countries, urging new treatment alternatives. One of the most promising strategies is enhancing the redox imbalance within these susceptible parasites related to their limited antioxidant defense system. Metal-based drugs represent a perfect option due to their extraordinary capacity to stabilize different oxidation states and adopt diverse geometries, allowing their interaction with several molecular targets. This work describes the amoebicidal activity of five 2-(Z-2,3-diferrocenylvinyl)-4X-4,5-dihydrooxazole derivatives (X = H (3a), Me (3b), iPr (3c), Ph (3d), and benzyl (3e)) on Entamoeba histolytica trophozoites and the physicochemical, experimental, and theoretical properties that can be used to describe the antiproliferative activity. The growth inhibition capacity of these organometallic compounds is strongly related to a fine balance between the compounds' redox potential and hydrophilic character. The antiproliferative activity of diferrocenyl derivatives studied herein could be described either with the redox potential, the energy of electronic transitions, logP, or the calculated HOMO–LUMO values. Compound 3d presents the highest antiproliferative activity of the series with an IC50 of 23 µM. However, the results of this work provide a pipeline to improve the amoebicidal activity of these compounds through the directed modification of their electronic environment. [ABSTRACT FROM AUTHOR]

In current research work, pH responsive pectin-co-poly(MAA) hydrogels containing diloxanide furoate were developed by graft polymerization of pectin and methacrylic acid, for the treatment of amebiasis. Developed hydrogels were evaluated for drug loading efficiency, swelling behavior, porosity, sol–gel fraction and drug release kinetics. Ex vivo mucoadhesion, X-ray and acute oral toxicity studies were also conducted. Structural entanglement was revealed by FTIR spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) evaluation exhibited better thermal stability of developed hydrogel. The optimized hydrogel (PM6) showed pH responsiveness by providing maximum swelling of 95.16 ± 0.054% in alkaline media (pH 7.4), and 91.37 ± 0.53% drug release occurs in pH 7.4 up to 24 h. Scanning electron microscopy (SEM) revealed the presence of tiny channels in the network which significantly promote swelling of developed hydrogel. In vivo gastrointestinal transit behavior of optimized formulation (PM-6) was evaluated by X-ray imaging on albino rabbits. Acute oral toxicity studies after administered of developed hydrogel indicated no signs of histopathology or any dermal toxicity. Hence, current investigation suggests that PM6 could be a promising approach for colon delivery. Thus, the proposed work would be helpful for the treatment of amebiasis. [ABSTRACT FROM AUTHOR]

Amoebiasis is the most common protozoan disease caused by Entamoeba histolytica. The second most frequent extraintestinal infection, behind amoebic liver abscess, is pulmonary amoebiasis. We present the case of an immunocompromised 40‐year‐old man. He complained of cough for 1 month, shortness of breath, and fever. Chest x‐ray demonstrated left paracardial consolidation, possibly pneumonia or a mass. Chest CT scans with contrast revealed the presence of an abscess‐mimicking tumour. CT‐guided TTB and histology examinations indicated the presence of trophozoites of E. histolytica. This patient was diagnosed with pulmonary amoebiasis. Diagnostic criteria for pulmonary amoebiasis include clinical manifestations, radiography, and microscopic examination. There was an improvement in clinical response after a 10‐day course of antibiotics. Amoebiasis of the lungs is treatable with medicines and drainage when necessary. Early diagnosis and treatment are imperative to decrease mortality and morbidity. [ABSTRACT FROM AUTHOR]