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All living organisms are destined to die. Cells, the core of those living creatures, move toward the irresistible direction of death. The question of how to die is critical and is very interesting. There are various types of death in life, including natural death, accidental death, questionable death, suicide, and homicide. The mechanisms and molecules involved in cell death also differ depending on the type of death. The dysenteric amoeba, E. histolytica, designated by the German zoologist Fritz Schaudinn in 1903, has the meaning of tissue lysis; i.e., tissue destroying, in its name. It was initially thought that the amoebae lyse tissue very quickly leading to cell death called necrosis. However, advances in measuring cell death have allowed us to more clearly investigate the various forms of cell death induced by amoeba. Increasing evidence has shown that E. histolytica can cause host cell death through induction of various intracellular signaling pathways. Understanding of the mechanisms and signaling molecules involved in host cell death induced by amoeba can provide new insights on the tissue pathology and parasitism in human amoebiasis. In this review, we emphasized on the signaling role of NADPH oxidases in reactive oxygen species (ROS)-dependent cell death by pathogenic E. histolytica.

Entamoeba histolytica virulence results from complex host–parasite interactions implicating multiple amoebic components (e.g., Gal/GalNAc lectin, cysteine proteinases, and amoebapores) and host factors (microbiota and immune response). UG10 is a strain derived from E. histolytica virulent HM-1:IMSS strain that has lost its virulence in vitro and in vivo as determined by a decrease of hemolytic, cytopathic, and cytotoxic activities, increased susceptibility to human complement, and its inability to form liver abscesses in hamsters. We compared the transcriptome of nonvirulent UG10 and its parental HM-1:IMSS strain. No differences in gene expression of the classical virulence factors were observed. Genes downregulated in the UG10 trophozoites encode for proteins that belong to small GTPases, such as Rab and AIG1. Several protein-coding genes, including iron-sulfur flavoproteins and heat shock protein 70, were also upregulated in UG10. Overexpression of the EhAIG1 gene (EHI_180390) in nonvirulent UG10 trophozoites resulted in augmented virulence in vitro and in vivo. Cocultivation of HM-1:IMSS with E. coli O55 bacteria cells reduced virulence in vitro, and the EhAIG1 gene expression was downregulated. In contrast, virulence was increased in the monoxenic strain UG10, and the EhAIG1 gene expression was upregulated. Therefore, the EhAIG1 gene (EHI_180390) represents a novel virulence determinant in E. histolytica.

The infection caused by Entamoeba histolytica is still a serious public health problem, especially in developing countries. The goal of this study was to evaluate the effect of terfenadine against Entamoeba histolytica. The trophozoites were exposed to 1, 2, 3, and 4 μM of terfenadine, for 24 and 48 h. Consequently, the viability of cells was determined by trypan blue exclusion test. The effect of terfenadine on adhesion of Entamoeba histolytica was evaluated in Caco-2 cells. In addition, the effect of terfenadine on the erythrophagocytic capacity of the parasite was investigated. The results show that terfenadine affects the growth and cell viability in a time- and dose-dependent manner. The higher inhibitory effects were observed with 4 µM at 48 h; 91.6% of growth inhibition and only 22.5% of trophozoites were viable. Additionally, we demonstrate that terfenadine is highly selective for the parasite and has low toxicity on Caco-2 cells. Furthermore, adhesion to Caco-2 cells and erythrophagocytic capacity were significantly inhibited. These findings demonstrate that terfenadine exerts significant effects on the virulence of Entamoeba histolytica. This is the first study demonstrating the amoebicidal activity of terfenadine and the results suggest it may be effective in the treatment of amoebiasis.

Many HIV/AIDS patients still present with low CD4 count and other complications even when placed on highly active antiretroviral therapy (HAART). Prevalence of intestinal parasitoses and their influence on CD4 levels of HIV/AIDS patients attending a Hospital in Nigeria was studied to determine their role in low CD4 levels during treatment. Two hundred and fifty HIV sero-positive and 100 sero-negative subjects were recruited for the study. HIV screening was done using Determine and confirmed with Unigold with Start Park as tie breaker. Questionnaires were used to obtain subject’s bio-data, Partec Cyflow counter (GEM Laboratories, Germany) was used for estimation and differentiation of CD4 cells while parasites were detected using direct stool microscopy, formal ether and modified Ziehl Neelson techniques. Prevalence of parasites was 25 (7.1%) with test subjects being more infected (7.6%) than controls (6.0%) (P < 0.001). The parasites detected were Entamoeba histolytica/dispar (7.8%), Ascaris lumbricoides (4.2%), Gairdia intestinalis (1.2%), Cryptosporidium parvum (0.6%), and Hookworm (0.4%). Parasite positive subjects had significantly lower mean CD4 count (373.3±275.6 c/μl) than their parasite negative counterpart (626.7±337.6 c/μl), P = 0.028, and likewise in the control group. HIV/parasite infected subjects on ART had significantly lower mean CD4 count (391.8±270 c/μl) than HIV/parasite negative subjects on ART (659.8±331.1), P = 0.01. Intestinal parasitoses may aggravate CD4 reduction in HIV/AIDS patients even when on HAART, hence undermine the potency of ART and hinder their successful management. Screening tests before baseline treatment for HIV/AIDS patients should include parasitological diagnosis.

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 β-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 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. Graphical Abstract

Background In Ghana, Balantidium coli (B. coli) has been identified in vegetables and in pigs, although there is a paucity of data regarding human balantidiosis. This study sought to assess human B. coli infection in Ghana, factors associated with the infection as well as its association with haematological and biochemical parameters. Methods Two pig rearing communities in the Ga West Municipality, Ghana, were involved in this study. Stool and blood samples were collected from pig farmers and their exposed household members as well as relevant information on potential associated factors. Eosin-saline wet preparation was done on the same day of stool samples were collected while formol ether concentration technique was performed later. Haematological, biochemical parameters and serum electrolytes were determined using Celltac MEK-6500 K, PKL-125 biochemical analyser, and FT-320 electrolyte analyser, respectively. Results The overall prevalence of balantidiosis was 10.4 %, significantly higher among farmers (21.7 %) than in exposed household members (5.8 %) (x2 = 17.8, p = 0.000025). Of the 43 infected individuals, 20.9 % were co-infected with either Entamoeba histolytica, Giardia lamblia, or Schistosoma mansoni. In B. coli infection, mild to moderate anaemia together with a reduction in levels of platelet, albumin and, sodium, chloride, and bicarbonate ions were observed. However, white blood cells were significantly elevated in infected states. Poor farming practices such as free-range systems, improper disposal of pig faeces, lack of use of protective farming clothing, and unavailability of dedicated farming clothing were found to be associated with B. coli infection status. Finally, frequent diarrhea (OR = 12.30, p = 0.006) with occult blood (OR = 25.94, p B. coli infection. Conclusions Human balantidiosis is endemic in Ga West Municipality, Ghana. Individuals living closed to pig rearing communities presenting with frequent diarrhea with occult blood in stool should be screened and treated for balantidiosis to mitigate the clinical consequences of the infection.

Infections by the parasite E. histolytica are increasing in HIV-infected individuals. Interleukin (IL-10) plays an important role in maintaining the mucosal barrier. Therefore, the seroprevalence of E. histolytica was investigated in relation to the IL-10 serum concentration among HIV- infected patients. A total of 647 blood samples were collected from asymptomatic HIV-infected patients. The Entamoeba histolytica antigen (GALNAC lectin) and serum antibodies were assessed using specific ELISAs (TECHLAB, Virginia, USA). IL10 blood levels were measured using a commercial ELISA test, and the results were analyzed using parametric and non-parametric statistical tests. The Gal/GALNAC lectin was detected in only 0.5% (3/647) of individuals, and the antibodies against E. histolytica were detected in 65.2% (422/647) of the samples. A significant increase in IL-10 levels was found in 68.1% of patients who were sero-negative for E. histolytica antibodies compared to patients who were sero-positive. There is a high level of exposure to E. histolytica among HIV patients in South Africa, although the prevalence of amoebic liver abscesses might be low. This study revealed that elevated levels of IL-10 might be associated with a reduced risk of amebiasis.

Entamoeba histolytica, the causative agent of human amoebiasis, exhibits a continuous membrane remodelling to exert its virulence properties. During this dynamic process, the Endosomal Sorting Complexes Required for Transport (ESCRT) machinery is a key player, particularly in phagocytosis, a virulence hallmark of this parasite. In addition to ESCRT, other molecules contribute to membrane remodelling, including the EhADH adhesin, EhRabs, actin, and the lysobisphosphatidic acid (LBPA). The endocytosis of a prey or molecules induces membrane invaginations, resulting in endosome and multivesicular bodies (MVBs) formation for cargo delivery into lysosomes. Alternatively, some proteins are recycled or secreted. Most of these pathways have been broadly characterized in other biological systems, but poorly described in protozoan parasites. Here, we encompass 10 years of ESCRT research in E. histolytica, highlighting the role of the ESCRT-I and ESCRT-III components and the EhADH and EhVps4-ATPase accessory proteins during phagocytosis. In particular, EhADH exhibits a multifunctional role along the endocytic pathway, from cargo recognition to endosome maturation and lysosomal degradation. Interestingly, the interaction of EhADH with EhVps32 seems to shape a concurrent route to the conventional one for MVBs biogenesis, that could optimize their formation. Furthermore, this adhesin is secreted, but its role in this event remains under study. Other components from the endosomal pathway, such as EhVps23 and LBPA, are also secreted. A proteomic approach performed here, using an anti-LBPA antibody, revealed that some proteins related to membrane trafficking, cellular transport, cytoskeleton dynamics, and transcriptional and translational functions are secreted and associated to LBPA. Altogether, the accumulated knowledge around the ESCRT machinery in E. histolytica, points it out as a dynamic platform facilitating the interaction of molecules participating in different cellular events. Seen as an integrated system, ESCRTs lead to a better understanding of E. histolytica phagocytosis.

In regions where sanitary conditions are poor, prophylactic administration of antiparasitic drugs is common and affects the prevalence of intestinal parasites, in spite of the environmental maintenance of their life cycle. The purpose of this study was to evaluate the prevalence of parasitic infections, patient lifestyles, health conditions and environmental sources of contamination. One hundred seventy two children and adolescents, 5 to 15 years of age of both sexes were analyzed. Data were obtained through epidemiological questionnaires, parasitological examinations using Paratest®, IgG testing for Entamoeba histolytica, and analysis of sources of contamination in living areas. The study detected a prevalence of 45.9% (79/172) parasitic infections, of which 62.0% (49/79) Entamoeba histolytica/E. dispar complex; 46.8% (37/79) Entamoeba coli; 27.8% (22/79) Giardia intestinalis; 12.7% (10/79) Endolimax nana; 10.1% (8/79) Hymenolepis nana; 8.9% (7/79) Ascaris lumbricoides and 2.5% (2/79) Trichuris trichiura. Out of the 49 samples positive for Entamoeba histolytica complex, there was only one case of antibodies to E. histolytica. The children’s life habits demonstrated inadequate food hygiene practices. These insufficient sanitary parameters revealed a general lack of information in face of an alarming situation regarding sewage and other sources of environmental contamination in 20% of the areas. The high prevalence of protozoan infections despite chemoprophylaxis, with environmental sources of contamination/risk, inadequate health conditions and the general apathy of the population suggest the ineffectiveness of current preventive practices. Thus, it is advisable that control actions include protozoa as therapeutic targets and, above all, health education as a routine practice to prevent the long-term continuance of this vicious cycle. KEY WORDS: Parasitic infections; chemoprophylaxis; environmental sources.

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.

Amebic dysentery caused by Entamoeba histolytica accounts for significant morbidity in the non-human primates (NHP) at the Singapore Zoo. This includes the animals in the collection as well as a sizeable free-roaming wild crab-eating macaque (Macaca fascicularis) population. The disease is of great concern because of its zoonotic potential. Passive surveillance, both ante and post-mortem, of NHP displaying clinical symptoms and active surveillance of NHP assessed to be at a higher risk of infection were carried out via fecal real-time polymerase chain reaction (PCR) testing for 4 years. Treatment of the disease with 25 mg/kg metronidazole BID for 10 days followed by 15 mg/kg paromomycin BID for 7 days achieved good clinical resolution in most cases that tested positive. Three diseased NHP with severe clinical signs of weight loss, lethargy, and diarrhea were anesthetized for veterinary diagnostic investigation. Mesenteric lymphadenopathy was consistently seen on ultrasound examination in these severe cases of entamoebiasis. Two animals eventually died of severe chronic enteritis due to the disease. The eradication of entamoebiasis in the NHP at the Singapore Zoo may be complicated by the maintenance of a disease reservoir in wildlife, but a combination of timely treatment and efforts at maintaining biosecurity can help manage the disease in the collection.

Background Intestinal parasitic infections are amongst the most common infections worldwide and have been identified as one of the most significant causes of morbidity and mortality among disadvantaged populations. This comparative cross-sectional study was conducted to assess the prevalence of intestinal protozoan infections and to identify the significant risk factors associated with intestinal parasitic infections in Laghouat province, Southern Algeria. Methods A comparative cross-sectional study was conducted, involving 623 symptomatic and 1654 asymptomatic subjects. Structured questionnaires were used to identify environmental, socio demographic and behavioral factors. Stool specimens were collected and examined using direct wet mount, formalin-ether concentration, xenic in vitro culture and staining methods. Results A highly significant difference of prevalence was found between symptomatic (82.3%) and asymptomatic subjects (14.9%), with the majority attributable to protozoan infection. The most common species in the symptomatic subjects were Blastocystis spp. (43.8%), E. histolytica/dispar (25.4%) and Giardia intestinalis (14.6%) and more rarely Enterobius vermicularis (02.1%), Teania spp. (0.6%) and Trichuris trichiura (0.2%), while in asymptomatic population Blastocystis spp. (8%), Entamoeba coli (3.3%) and Entamoeba histolytica/dispar (2.5%) were the most common parasites detected with no case of helminth infection. Multivariate log-linear analysis showed that contact with animals was the main risk factor for transmission of these protozoa in both populations. Furthermore, living in rural areas was significantly associated with combined protozoan infection in the asymptomatic population, whereas, in the symptomatic population an increasing trend of protozoan infection was detected in the hot season. In addition, Blastocystis spp. and G. intestinalis infection were found to be associated with host sex and contact with animals across the study period. Conclusions Based on these results, several strategies are recommended in order to effectively reduce these infections including good animal husbandry practices, health education focused on good personal hygiene practices and adequate sanitation.

The consumption of fresh vegetables serves as source of important nutrients in the body; however, parasitic infection from the consumption of raw fruits and vegetables is on the increase. This study aimed at identifying the parasitic contamination of Vegetables sold at Masaka market New Karu, Nasarawa State. A total of 240 samples of vegetables were examined by sedimentation concentration after washing using normal saline. The overall prevalence of parasitic contamination was 52.5%. Fluted pumpkin (93.3%) was the most contaminated vegetable while cucumber and apple (16.7%) were the least contaminated vegetables (P>0.05). Strongyloides stercoralis(28.9%) was the most frequently detected parasite followed by Taenia spp (18.8%), Entamoeba coli (17.2%), Hookworm (13.3%), Entamoeba histolytica (8.6%), Ascaris lumbricoides (7.8%) and Toxocara spp (5.5%) was the least detected parasite. The parasitic contamination of different vegetables shows that Tomatoes and Lettuce had the highest poly-parasitic contamination of four species of parasites, whereas Apple and Cucumber had the least poly-parasitic contamination of one parasite. Strongyloides stercoralis had the highest infestation (37.5%) of the water samples used to refresh the vegetables. Vegetables that were washed before display for selling was significantly associated with reduced parasitic contamination (P>0.05). Vegetables are potential sources of transmission for intestinal parasites in the study area, hence, proper washing of fruits and cooking of vegetables is required to reduce parasitic infections. Keywords: Vegetables, Parasitic contamination, Masaka, Karu, Nasarawa

Recurrence of amebic liver abscess (ALA), once considered unusual, is increasingly being reported, despite proper management. Realizing the endemicity of ALA in the study setup, this 2-year follow-up study was conducted to investigate the recurrent cases and study the associated factors. A total of 101 confirmed cases of ALA were followed up for a period of 2 years. Recurrent cases were studied for associated bacterial flora, presence of resistance genes (nim), level of matrix metalloproteinase 3 and MMP-9, and genotypes of Entamoeba histolytica and statistically compared with the nonrecurrent cases as controls. Recurrence rates of 8.9% (nine patients) were detected. The presence of Prevotella along with an increased level of MMP-9 in abscess fluid and large size of abscesses (11 × 10.8 cm) was found to be significantly associated with recurrence in ALA. Among the nine cases, the presence of nimE gene was detected in two (22.2%) patients. The genotyping of E. histolytica strains showed that in seven (77.7%) cases, the genotype of E. histolytica was the same in the primary and recurrent samples. This study reports a high rate of recurrence in the cases of ALA, hinting toward the gradual development of clinical resistance toward the commonly used drug. The presence of nim gene and Prevotella in abscess fluid along with increased MMP-9 levels and large abscess size could be important predictors of recurrent ALA.

Trichomonas vaginalis is a neglected urogenital parasitic protist that causes 170 million cases of trichomoniasis annually, making it the most prevalent non-viral, sexually transmitted disease. Trichomoniasis treatment relies on nitroheterocyclics, such as metronidazole. However, with increasing drug-resistance, there is an urgent need for novel anti-trichomonals. Little progress has been made to translate anti-trichomonal research into commercialised therapeutics, and the absence of a standardised compound-screening platform is the immediate stumbling block for drug-discovery. Herein, we describe a simple, cost-effective growth assay for T. vaginalis and the related Tritrichomonas foetus. Tracking changes in pH were a valid indicator of trichomonad growth (T. vaginalis and T. foetus), allowing development of a miniaturised, chromogenic growth assay based on the phenol red indicator in 96- and 384-well microtiter plate formats. The outputs of this assay can be quantitatively and qualitatively assessed, with consistent dynamic ranges based on Z′ values of 0.741 and 0.870 across medium- and high-throughput formats, respectively. We applied this high-throughput format within the largest pure-compound microbial metabolite screen (812 compounds) for T. vaginalis and identified 43 hit compounds. We compared these identified compounds to mammalian cell lines, and highlighted extensive overlaps between anti-trichomonal and anti-tumour activity. Lastly, observing nanomolar inhibition of T. vaginalis by fumagillin, and noting this compound has reported activity in other protists, we performed in silico analyses of the interaction of fumagillin with its molecular target methionine aminopeptidase 2 for T. vaginalis, Giardia lamblia and Entamoeba histolytica, highlighting potential for fumagillin as a broad-spectrum anti-protistal against microaerophilic protists. Together, this new platform will accelerate drug-discovery efforts, underpin drug-resistance screening in trichomonads, and contributing to a growing body of evidence highlighting the potential of microbial natural products as novel anti-protistals., Graphical abstract Image 1

Parasites release extracellular vesicles (EVs) which, in some cases, modulate the host’s immune response contributing to the establishment of the infection. In this work we have isolated and characterized the EVs released by trophozoites of the human protozoan parasite Entamoeba histolytica, the causal agent of amoebiasis, when alone or in coculture with human neutrophils, and determined their effect on neutrophil NETs and ROS production. Nanoparticle tracking analysis showed that amoebic EVs are variable in size, ranging from less than 50 nm to nearly 600 nm in diameter (average of 167 nm), whereas neutrophil EVs are more uniform in size, with an average of 136 nm. In cocultures amoeba:neutrophil (1:100) most EVs are 98 nm in size, which is the typical size of exosomes. EVs from amoebae and neutrophils showed almost equal levels of ROS, which were considerably increased in EVs from cocultures. Uptake of amoebic EVs by neutrophils was demonstrated by fluorescence and resulted in a significant reduction in the oxidative burst and NET release triggered by PMA, ionophore A23187, or the amoebae itself used as stimuli. Interestingly, uptake of EVs from cocultures did not affect ROS production, but instead caused a greater delay in the onset of NETs release and in their quantity. A comparative proteomic analysis between the EVs of amoebae and neutrophils separately vs the cocultures showed a similar distribution of protein categories in the GO analysis, but differences in the expression and abundance of proteins such as the N-acetyl-D-galactosamine (GalNAc) inhibitable surface lectin and calreticulin in amoeba EVs, and various antimicrobial molecules in neutrophil EVs, such as lactoferrin and myeloperoxidase. These results highlight the importance of EVs in the immunomodulatory effects exerted by amoeba on human neutrophils.

The epidemiological behaviour of the main extraintestinal complication due to E. histolytica (amoebic liver abscess, ALA) has been little explored in developing countries. Since Mexico meets the characteristics to be considered as endemic, the aim of this work was to analyze the national surveillance data (seven years) of ALA issued by the General Directorate of Epidemiology. An analysis of cases and incidence of ALA (2014-2020) was performed in the annual reports issued by the GDE in Mexico. Cases and incidence of ALA were classified by year, incidence, age group, sex and seasons. Geographical distribution map for the whole country of ALA was constructed. The cases and mean incidence of ALA did not shown significant variation during the study period. Of the total cases accumulated, Sonora, Sinaloa, Nayarit, Colima and Zacatecas states showed the most incidence by ALA. Male sex of 24-44 years old showed higher ALA cases. No temporal behaviour was identified between the ALA cases. In Mexico, the incidence of ALA remains unchanged, however, it should not be underestimated since the monitoring programs for the search for new cases have not yet been implemented mainly in endemic states. These results summarize the priority in the national ALA report.

Entamoeba histolytica, an anaerobic protozoan, is an important global health problem. This parasite has a biphasic life cycle consisting of a dormant cyst stage which is environmentally resistant and transmits the infection, and the proliferative trophozoite stage which is motile and causes invasive disease. The stage conversion process remains poorly understood despite being central to amoebic biology. In this review, we will highlight recent progress in our understanding of Entamoeba stage conversion including dissecting transcriptome analysis in development, characterization of transcriptional networks, demonstration of epigenetic regulation, and role of small molecules that regulate Entamoeba development.

Background Amebiasis has been defined by World Health Organization (WHO) and Pan American Health Organization (PAHO) as the infection with Entamoeba histolytica regardless of symptoms. Necrotizing amoebic colitis is a rare clinical form of amebosis that is associated with high morbidity and mortality. Case report We present a 68-years-old-female patient with necrotizing amoebic colitis with multiple perforations who survived after right hemicolectomy with ileus-transverse anastomosis. Conclusions Effective interventions to prevent amebic colitis, and additional therapies to treat fulminant amebic colitis are needed to improve outcomes.

The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis, an infection that manifests as colitis and, in some cases, liver abscess. A better understanding of host protective factors is key to developing an effective remedy. Recently, significant advances have been made in understanding the mechanisms of MUC2 production by goblet cells upon amebic infection, regulation of antimicrobial peptide production by Paneth cells, the interaction of commensal microbiota with immune stimulation, and host genetics in conferring protection from amebiasis. In addition to host pathways that may serve as potential therapeutic targets, significant progress has also been made with respect to development of a vaccine against amebiasis. Here, we aim to highlight the current understanding and knowledge gaps critically.

This epidemiological study assesses the occurrence of enteric parasites in 4303 patients attended at two public hospitals in Ankara (Turkey) during 2018–2019. Microscopy was used as a screening test. Giardia duodenalis was also identified using a commercial ELISA for the detection of parasite-specific coproantigens. Giardia-positive samples by microscopy/ELISA were confirmed by real-time PCR and characterized using a multilocus genotyping scheme. Blastocystis sp. was genotyped in a sample subset. Blastocystis sp. (11.1%, 95% CI 11.4‒14.8%) and G. duodenalis (1.56%, 95% CI 1.22‒1.96) were the most prevalent pathogens found. Cryptosporidium spp., Entamoeba histolytica and intestinal helminths were only sporadically (G. duodenalis, sequence (n = 30) analyses revealed the presence of sub-assemblages AII (23.3%), discordant AII/AIII (23.3%) and mixed AII + AIII (6.7%) within assemblage A, and BIII (10.0%), BIV (3.3%) and discordant BIII/BIV (23.3%) within assemblage B. Two additional sequences (6.7%) were assigned to the latter assemblage but sub-assemblage information was unknown. No associations between G. duodenalis assemblages/sub-assemblages and sociodemographic and clinical variables could be demonstrated. For Blastocystis sp., sequence (n = 6) analyses identified subtypes ST1, ST2 and ST3 at equal proportions. This is the first molecular characterization of G. duodenalis based on MLG conducted in Turkey to date.

Hepatic amebiasis, predominantly occurring in men, is a focal destruction of the liver due to the invading protozoan Entamoeba histolytica. Classical monocytes as well as testosterone are identified to have important functions for the development of hepatic amebiasis in mice, but a link between testosterone and monocytes has not been identified. Here we show that testosterone treatment induces proinflammatory responses in human and mouse classical monocytes. When treated with 5α-dihydrotestosterone, a strong androgen receptor ligand, human classical monocytes increase CXCL1 production in the presence of Entamoeba histolytica antigens. Moreover, plasma testosterone levels of individuals undergoing transgender procedure correlate positively with the TNF and CXCL1 secretion from their cultured peripheral blood mononuclear cells following lipopolysaccharide stimulation. Finally, testosterone substitution of castrated male mice increases the frequency of TNF/CXCL1-producing classical monocytes during hepatic amebiasis, supporting the hypothesis that the effects of androgens may contribute to an increased risk of developing monocyte-mediated pathologies., Altered monocyte responses and testosterone levels correlate, individually, with the pathogenesis of hepatic amebiasis in mice. Here the authors show that testosterone induces enhanced TNF/CXCL1 expression and stronger proinflammatory responses in both human and mouse monocytes to support an androgen-monocyte axis of inflammation regulation.

In acute gastroenteritis (GE), identification of the infectious agent is important for patient management and surveillance. The prevalence of GE caused by protozoa may be underestimated in Swedish patients. The purpose was to compare the prevalence of E. histolytica, Cryptosporidium spp., G. intestinalis, and C. cayetanensis in samples from patients where the clinician had requested testing for gastrointestinal parasites only (n = 758) to where testing for bacterial GE only (n = 803) or where both parasite and bacterial testing (n = 1259) was requested and a healthy control group (n = 197). This prospective cohort study was conducted in Region Jönköping County, Sweden (October 2018–March 2019). Fecal samples were analyzed with microscopy and real-time PCR. Cryptosporidium spp. was detected in 16 patients in the bacterial GE group and in 13 in the both bacterial and parasite group; no cases were detected in the group were only parasite infection was suspected. C. cayetanensis was detected in two patients in the bacterial GE group. One case of E. histolytica was detected in the bacterial group and one in the both bacterial and parasite group. G. intestinalis was detected in 14 patients in the parasite only group, 12 in the both parasite and bacterial group, three in the bacterial GE group, and one in the control group. Diarrhea caused by protozoa, especially Cryptosporidium was under–recognized by clinicians and is likely more common than hitherto estimated in Sweden. A more symptom-based diagnostic algorithm may increase detection and knowledge about protozoan infections.

Correctional inmates are among the vulnerable groups to intestinal parasitic infections due to deprived situations characterized by inadequate facilities, malnutrition, scarce potable water, over-crowding, and poor hygiene. Two hundred and fifty faeces of inmates of Jos Correctional Facility were investigated for the prevalence of intestinal parasites between May and June 2019, using the wet mount and formol-ether concentration techniques. Results obtained showed that from the 250 faecal samples examined, 57(22.8%) were infected with various intestinal parasites. Nine (9) different intestinal parasites identified were Entamoeba histolytica 38.60%), Entamoeba coli (15.78%), Ancylostoma duodenale (4.04%), Ascaris lumbricoides (0.53%), Taeniasp (8.77%), Schistosoma mansoni (3.51%), Giardia lamblia (3.51%), Enterobius vermicularis (3.51%) and Trichuris trichuria (1.75%). The 9 different intestinal parasites were grouped into helminthes (42.1%) and protozoa (57.9%). Higher infection rate of 45.6% was recorded among those within age ranges 21-30 years. Inmates who were in prison for

In most developing countries, Dientamoeba fragilis infection is an obscure protozoan infection. We aimed to determine a frequency and clinical importance of D. fragilis infection in Taif, Saudi Arabia. A 1-year case control study included patients with gastrointestinal (cases, n=114) or non-gastrointestinal symptoms (controls, n=90). The fecal samples were examined with the classical parasitological methods for intestinal protozoa, and by real time PCR for D. fragilis. The infection by D. fragilis was detected in 5.8% by PCR and in 4.4% patients by microscopy. The infection was identified more in control group (n=9) than in cases (n=3); a sole infection in 11 patients and mixed with Giardia in 1 patient. The other enteric parasites detected were Blastocystis sp. (8.3%), Giardia sp. (5.3%), Cryptosporidium sp. (2.9%), Entamoeba histolytica (1.4%), Entamoeba coli (0.9%) and Hymenolepis nana (0.4%). Our results tend to reinforce the need to increase awareness of D. fragilis infection in Saudi Arabia.

Rodent species, such as Rattus rattus diardii and Rattus norvegicus are invasive species of wild rats that serve as potential reservoirs of important human's pathogens. Parasitic zoonosis accounts for over 60% of all human infectious diseases worldwide. This situation arises from the recent changes in the global climate and ecosystem composition, which led to the spread of rodents and rodent-borne pathogens globally. The aim of this study was to determine the occurrence of rodent's parasites and their zoonotic potentials in some selected areas in UPM. Rodents were captured using live-traps and euthanised for helminths and protozoan recovery. Intestinal parasites were detected and identified from stool samples using formalin ethyl-acetate concentration technique (FECT), while tissue parasites were identified by histopathological examination of selected tissue sections of the liver, brain, lungs, and muscle. In this study, a total of 89 wild rats were captured. Twelve species of intestinal and tissue parasites were recorded, of which, Taenia taeniaeformis accounts for the highest infection recorded (28%) followed by Hymenolepis nana (19.5%) and Capillaria hepatica (19.1%), while Toxoplasma gondii was the least parasite (6.7%) identified. Furthermore, other parasites species observed include, Cryptosporidium spp. (21.3%), Entamoeba histolytica/Entamoeba dispar and Moniliformis moniliformis (17.9%), Angiostrongylus cantonensis (16.8%), Hymenolepis diminuta (16.1%), Giardia spp. (14.6%), Trichuris spp. (12.3%), and Sarcocystis spp. (6.74). Based on the results obtained in the present study, 17.1% and 15.4% of the rodents captured were confirmed positive for at least one species of intestinal or tissue parasites, respectively. The presence of these zoonotic parasites in the wild rats suggests the potential risk of rodent-borne zoonotic disease transmission to humans. Hence, the need to improved rats control intervention and public health awareness among the populace., Graphical abstract Image 1, Highlights • This is the first report of endoparasitic infection of wild rats in Serdang, Selangor, Malaysia. • 17.1% of the rodents are positive for intestinal parasites, and 15.4% positive for tissue parasites. • Zoonotic parasites from intestine and tissue parasites were identified. • The likelihood of transmission of zoonotic parasites between wild rats and humans was suggested.