Association of Entamoeba gingivalis with Periodontal Disease-Systematic Review and Meta-Analysis

The oral cavity is a habitat to a diverse range of organisms that make up an essential element of the human microbiota. There are up to 1000 species of micro-organisms capable of colonizing the mouth. Thirty percent of them are uncultivable. The genus Entamoeba includes several species, out of which at least seven of them are able to inhabit the human body (Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba coli, Entamoeba polecki, Entamoeba hartmann, Entamoeba gingivalis). It was shown that only E. gingivalis is able to colonize the oral cavity. The aim of this study was to evaluate the association and prevalence of E. gingivalis in periodontal disease using two electronic database search engines. In order to have a broader view of the subject, a comprehensive manual search was conducted between 15th February 2023 and 1 April 2023 on these content aggregators and the initial search resulted in 277 articles using the keywords "E. gingivalis", "periodontitis", "E. gingivalis", "periodontal disease", "prevalence", and "incidence", in different combinations. The results showed that 755 patients were infected with E. gingivalis out of a total number of 1729 patients diagnosed with periodontal disease, indicating a global prevalence of 43% in the set of patients analyzed. E. gingivalis was prevalent in 58% of the patients that had gingivitis and in 44% of the patients with periodontitis. Prevalence of E. gingivalis based on gender was 43% in female patients and 47% in male patients. The results indicate that the higher incidence of E. gingivalis in people with periodontal disease compared to healthy people is more than just a sign of the disease; it could also be linked to the severity of the condition and the disease propensity to progress.

Comparative prevalence of oral bacteria and protozoa in patients with periodontitis in Taiwan

OBJECTIVES

Periodontitis is an inflammatory disease caused by bacteria present in the dental biofilm. However, the presence of two oral protozoans, Entamoeba gingivalis and Trichomonas tenax, in patients with the periodontal disease remains largely unknown in Taiwan. Therefore, we investigated the prevalence of oral microbial infections between the sites with mild gingivitis and chronic periodontitis in patients.

MATERIALS AND METHODS

We collected 60 dental biofilm samples from sites with mild gingivitis (probing depth <5 mm) and chronic periodontitis (probing depth ≥5 mm) from 30 patients at the National Cheng Kung University Hospital. The samples were analyzed via polymerase chain reaction and gel electrophoresis.

RESULTS

Among oral protozoans, E. gingivalis and T. tenax were detected in 44 (74.07%) and 14 (23.33%) of all samples, respectively. Among oral bacteria, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia were detected in 50 (83.33%), 47 (78.33%), and 48 (80.0%) samples, respectively.

CONCLUSIONS

This study, which is the first to analyze E. gingivalis and T. tenax presence among patients with periodontitis in Taiwan, revealed an association between periodontitis and oral microbes.

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

Entamoeba moshkovskii, according to recent studies, appears to exert a more significant impact on diarrhoeal infections than previously believed. The efficient identification and genetic characterization of E. moshkovskii isolates from endemic areas worldwide are crucial for understanding the impact of parasite genomes on amoebic infections. In this study, we employed a multilocus sequence typing system to characterize E. moshkovskii isolates, with the aim of assessing the role of genetic variation in the pathogenic potential of E. moshkovskii. We incorporated 3 potential genetic markers: KERP1, a protein rich in lysine and glutamic acid; amoebapore C (apc) and chitinase. Sequencing was attempted for all target loci in 68 positive E. moshkovskii samples, and successfully sequenced a total of 33 samples for all 3 loci. The analysis revealed 17 distinct genotypes, labelled M1–M17, across the tested samples when combining all loci. Notably, genotype M1 demonstrated a statistically significant association with diarrhoeal incidence within E. moshkovskii infection (P = 0.0394). This suggests that M1 may represent a pathogenic strain with the highest potential for causing diarrhoeal symptoms. Additionally, we have identified a few single-nucleotide polymorphisms in the studied loci that can be utilized as genetic markers for recognizing the most potentially pathogenic E. moshkovskii isolates. In our genetic diversity study, the apc locus demonstrated the highest Hd value and π value, indicating its pivotal role in reflecting the evolutionary history and adaptation of the E. moshkovskii population. Furthermore, analyses of linkage disequilibrium and recombination within the E. moshkovskii population suggested that the apc locus could play a crucial role in determining the virulence of E. moshkovskii.

Prevalence of intestinal protozoan parasites among school children in africa: A systematic review and meta-analysis

Introduction

Parasitic infections, especially intestinal protozoan parasites (IPPs) remain a significant public health issue in Africa, where many conditions favour the transmission and children are the primary victims. This systematic review and meta-analysis was carried out with the objective of assessing the prevalence of IPPs among school children in Africa.

Methods

Relevant studies published between January 2000 and December 2020 were identified by systematic online search on PubMed, Web of Science, Embase and Scopus databases without language restriction. Pooled prevalence was estimated using a random-effects model. Heterogeneity of studies were assessed using Cochrane Q test and I² test, while publication bias was evaluated using Egger’s test.

Results

Of the 1,645 articles identified through our searches, 46 cross-sectional studies matched our inclusion criteria, reported data from 29,968 school children of Africa. The pooled prevalence of intestinal protozoan parasites amongst African school children was 25.8% (95% CI: 21.2%-30.3%) with E. histolytica/ dispar (13.3%; 95% CI: 10.9%-15.9%) and Giardia spp. (12%; 95% CI: 9.8%-14.3%) were the most predominant pathogenic parasites amongst the study participants. While E. coli was the most common non-pathogenic protozoa (17.1%; 95% CI: 10.9%-23.2%).

Conclusions

This study revealed a relatively high prevalence of IPPs in school children, especially in northern and western Africa. Thus, poverty reduction, improvement of sanitation and hygiene and attention to preventive control measures will be the key to reducing protozoan parasite transmission.

Pathogenic intestinal protozoan parasites (IPPs) remain a major public health concern. Studies have documented that, the prevalence rates of protozoan infections are quite high in developing regions, particularly Africa and children are the primary victims. Despite numerous studies have been conducted on IPPs in school children in African countries, data on the burden of these infections in African school children have not yet been synthesised. This systematic review and meta-analysis was conducted to provide continent-wide prevalence of IPPs amongst African school children. Our study found that about 25.8% of the children had one or more species of intestinal protozoan parasites in their faecal specimens. E. histolytica/ dispar and Giardia spp. were the most predominant parasites amongst the study participants. The relatively high prevalence estimate of IPPs amongst African children and the considerable variation in the disease prevalence over the years, between and within countries and regions clearly indicates the needs to improve sanitation and hygiene, paying more attention to preventive control measures as well as poverty reduction which are the key to reducing protozoan parasite transmission.

The epidemiology of amoebiasis in Thi-Qar Province, Iraq (2015-2020): differentiation of Entamoeba histolytica and Entamoeba dispar using nested and real-time polymerase chain reaction

OBJECTIVES

The objective of this study was to evaluate the present status of amoebiasis in Thi-Qar Province in southern Iraq, and to determine the presence of Entamoeba histolytica and Entamoeba dispar with nested and real-time polymerase chain reaction (PCR).

METHODS

Epidemiological data were obtained from the public health department of the Thi-Qar Health Office (2015-2020). Eighty stool samples were also randomly collected from patients ≤12 year of age with diarrhea at 2 hospitals between the beginning of February 2020 and the end of October 2020. These samples were selected after microscopy to identify the 18S rRNA gene in Entamoeba DNA.

RESULTS

Of the 341,554 cases of intestinal parasitic infections, 38,004 (11.1%) individuals were recorded as having amoebiasis, which accounted for the highest proportion of infections in 2015 (26.1%) and the lowest in 2020 (8.1%). Amoebiasis was distributed among all age groups, with the age group of 5-14 years accounting for the highest proportion (27.3%). In molecular testing, 42 (52.5%) out of 80 samples were positive for the 18S rRNA gene (888 bp). Using nested PCR, E. histolytica (439 bp) was detected in 25 (31.3%) samples and E. dispar (174 bp) in 14 (17.5%), while using real-time PCR, E. histolytica and E. dispar were detected in 28 (35.0%) and 15 (18.8%) samples, respectively.

CONCLUSIONS

Epidemiological data confirmed that amoebiasis is endemic in this province, and is not limited to certain months. Our study confirms the applicability of molecular identification to detect pathogenic and non-pathogenic Entamoeba to prescribe the appropriate drug.

Intestinal protozoan infections shape fecal bacterial microbiota in children from Guinea-Bissau

Intestinal parasitic infections, caused by helminths and protozoa, are globally distributed and major causes of worldwide morbidity. The gut microbiota may modulate parasite virulence and host response upon infection. The complex interplay between parasites and the gut microbiota is poorly understood, partly due to sampling difficulties in remote areas with high parasite burden. In a large study of children in Guinea-Bissau, we found high prevalence of intestinal parasites. By sequencing of the 16S rRNA genes of fecal samples stored on filter paper from a total of 1,204 children, we demonstrate that the bacterial microbiota is not significantly altered by helminth infections, whereas it is shaped by the presence of both pathogenic and nonpathogenic protozoa, including Entamoeba (E.) spp. and Giardia (G.) lamblia. Within-sample diversity remains largely unaffected, whereas overall community composition is significantly affected by infection with both nonpathogenic E. coli (R2 = 0.0131, P = 0.0001) and Endolimax nana (R2 = 0.00902, P = 0.0001), and by pathogenic E. histolytica (R2 = 0.0164, P = 0.0001) and G. lamblia (R2 = 0.00676, P = 0.0001). Infections with multiple parasite species induces more pronounced shifts in microbiota community than mild ones. A total of 31 bacterial genera across all four major bacterial phyla were differentially abundant in protozoan infection as compared to noninfected individuals, including increased abundance of Prevotella, Campylobacter and two Clostridium clades, and decreased abundance of Collinsella, Lactobacillus, Ruminococcus, Veillonella and one Clostridium clade. In the present study, we demonstrate that the fecal bacterial microbiota is shaped by intestinal parasitic infection, with most pronounced associations for protozoan species. Our results provide insights into the interplay between the microbiota and intestinal parasites, which are valuable to understand infection biology and design further studies aimed at optimizing treatment strategies.

Analysis of D-A locus of tRNA-linked short tandem repeats reveals transmission of Entamoeba histolytica and E. dispar among students in the Thai-Myanmar border region of northwest Thailand

Intestinal parasitic infections, including those caused by Entamoeba species, are a persistent problem in rural areas of Thailand. The aims of this study were to identify pathogenic Entamoeba species and to analyze their genotypic diversity. Stool samples were collected from 1,233 students of three schools located in the Thai-Myanmar border region of Tak Province, Thailand. The prevalence of Entamoeba infection was measured by polymerase chain reaction (PCR) using species-specific primers. Thirty-one (2.5%) positive cases were detected for E. histolytica, 55 (4.5%) for E. dispar, and 271 (22.0%) for E. coli. Positive samples for E. histolytica and E. dispar were exclusively obtained from a few school classes, whereas E. coli was detected in all grades. No infections caused by E. moshkovskii, E. nuttalli, E. chattoni, and E. polecki were detected in the students studied. The D-A locus of tRNA-linked short tandem repeats was analyzed in samples of E. histolytica (n = 13) and E. dispar (n = 47) to investigate their diversity and potential modes of transmission. Five genotypes of E. histolytica and 13 genotypes of E. dispar were identified. Sequences of the D-A were divergent, but several unique genotypes were significantly prevalent in limited classes, indicating that intra-classroom transmission has occurred. As it was unlikely that infection would have been limited within school classes if the mode of transmission of E. histolytica and E. dispar had been through the intake of contaminated drinking water or food, these results suggest a direct or indirect person-to-person transmission mode within school classes. Positive rates for three Entamoeba species were 2-fold higher in students who had siblings in the schools than in those without siblings, suggesting that transmission occurred even at home due to heavy contacts among siblings.

Transmissions in endemic areas of the pathogen Entamoeba histolytica and other non-pathogenic Entamoeba species such as E. dispar and E. coli are caused by ingestion of drinking water and foods contaminated with cysts of the parasites. Cases of Entamoeba infections among school-aged children have been reported in several countries. However, it has not been demonstrated that transmission of protozoa of the Entamoeba genus occurs within school facilities. In addition, genetic information on E. histolytica and other morphologically indistinguishable species, including E. dispar and E. moshkovskii, in Thailand remains scarce. In the present study, we demonstrated that E. histolytica and/or E. dispar are prevalent among school-aged children, but limited to few classes in three rural schools in the Thai-Myanmar border region of northwest Thailand. Although various genotypes of these Entamoeba species were identified, identical genotypes were significantly more prevalent in certain school classes and also among siblings, suggesting that transmission occurred within the classrooms and at home. The possibility of person-to-person transmission among these students via direct or indirect contact during daily activities in classrooms and home is proposed.

The first study to detect co-infection of Entamoeba gingivalis and periodontitis-associated bacteria in dental patients in Taiwan

Periodontitis, an inflammatory disease of the oral cavity, was caused by microbes from bacteria to protozoa. In this study, we detected protozoa, Entamoeba gingivalis and other three common pathogenic bacteria, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia by the Polymerase chain reaction (PCR) on patients.

Detection of human intestinal protozoan parasites in vegetables and fruits: a review

Diarrheal diseases caused by intestinal protozoan parasites are a major food-borne public health problem across the world. Vegetables and fruits provide important nutrients and minerals, but are also common sources of some food-borne human pathogenic microorganisms. The contamination of raw vegetables and fruits with human pathogenic parasites are now a global public health threat, despite the health benefits of these foods in non-pharmacological prophylaxes against diseases. A large number of reports have documented the contamination of vegetables or fruits with human pathogenic microorganisms. In this paper, we reviewed the contamination and detection methods of human pathogenic intestinal protozoans that are frequently recovered from raw vegetables and fruits. The protozoan parasites include Cryptosporidium spp., Giardia duodenalis, Cyclospora cayetanensis, Entamoeba spp., Toxoplasma gondii, Balantioides coli, Blastocystis sp., Cystoisospora belli and Enterocytozoon bieneusi. The risk factors involved in the contamination of vegetables and fruits with parasites are also assessed.

Occurrence and genetic identifications of porcine Entamoeba, E. suis and E. polecki, at Tangerang in West Java, Indonesia

Entamoeba suis and E. polecki subtype (ST) 1 and ST3 recently have been inferred to be virulent in pigs. However, because relevant molecular epidemiological surveys have been limited, the prevalences of these species remain unknown and their pathogenicities are still controversial. We surveyed 196 fecal samples of pigs (118 of adults, 78 of piglets) at Tangerang in West Java, Indonesia, in 2017, employing PCR using porcine Entamoeba-specific primers. E. suis was the more frequently detected species, observed in 81.1% of samples, while E. polecki ST1 and ST3 were detected in 18.4% and 17.3% of samples, respectively; mixed infections (harboring 2-3 species or subtypes of Entamoeba) were confirmed in 29.3% of positive samples. Statistically significant differences in the positive rates were not seen between adult pigs and piglets, except for those of E. polecki ST3. The prevalences of Eimeria spp. and/or Cystoisospora suis (79.1%), strongyles (55.6%), and Strongyloides spp. (6.1%) were also observed morphologically in the samples. Further chronological or seasonal investigations of pigs and humans in these high-prevalence areas are needed to assess the virulence of the Entamoeba parasites, including the effects on pig productivity, and to evaluate the zoonotic impacts of these organisms.

Prevalence, molecular epidemiology and zoonotic risk of Entamoeba spp. from experimental macaques in Yunnan Province, southwestern China

Amebiasis is a worldwide parasitic zoonosis, with symptoms of abdominal discomfort, indigestion, diarrhea, and even death. However, limited information about the prevalence of Entamoeba spp. in experimental nonhuman primates (NHPs) in southwestern China is available. The objective of the current study was to investigate the frequency and species identity of Entamoeba to evaluate potential zoonotic risk factors for Entamoeba spp. infection in experimental NHPs. A total of 505 fecal samples were collected from NHPs (macaques) and analyzed by PCR analysis the small subunit rRNA (SSU rRNA) gene of Entamoeba spp. Forty-seven specimens were positive for Entamoeba spp., and the prevalence of Entamoeba spp. was 9.31% (47/505). Significant differences in the prevalence rates among the three breeds (P = 0.002 < 0.01, df = 2, χ² = 12.33) and feed types (P = 0.001 < 0.01, df = 1, χ² = 10.12) were observed. Altogether, four Entamoeba species, including E. dispar (57.44%), E. chattoni (29.78%), E. histolytica (6.38%), and E. coli (6.38%), were identified by DNA sequence analysis. The results suggested a low prevalence but high diversity of Entamoeba species in experimental NHPs in Yunnan Province, southwestern China. Results of this study contribute to the knowledge of the genetic characteristics of Entamoeba spp. in NHPs.

Entamoeba infections and associated risk factors among migrant workers in Peninsular Malaysia

The influx of low skilled migrant workers to Malaysia from low socio-economic countries where gastrointestinal parasitic infections are prevalent has raised concerns about transmission to the local population. Three methods for detection (serology, microscopy and molecular techniques) were utilized to identify Entamoeba infections amongst the targeted cohort and determine risk factors associated with infection. Serological screening of 484 migrant workers from five working sectors in Peninsular Malaysia using IgG4 ELISA based on the rPPDK antigen showed an overall seroprevalence of 7.4% (n = 36; CL95 = 5.3-10.1%) with only one factor statistically associated with seropositivity of anti-amoebic antibodies, i.e. years of residence in Malaysia (χ² 1 = 4.007, p = 0.045). Microscopic examination of 388 faecal samples for protozoan cysts and trophozoites showed a slightly higher prevalence (11.6%; n=45; CL95: 8.4-14.8%). Meanwhile, amplification of the 16S rDNA gene detected two species i.e. Entamoeba dispar (23/388; 5.9%; CL95: 3.6-8.3%) and E. histolytica (11/388; 2.8%; CL95: 1.2-4.5%) and mixed infections with both parasites in only three samples (3/388; 0.8%; CL95: 0.2-2.2%). Entamoeba dispar infection was significantly associated with those employed in food and domestic services (χ² ₄ = 12.879, p = 0.012). However, none of the factors affected the prevalence of E. histolytica infection. Despite the low prevalence of E. histolytica in faecal samples of the study cohort, the presence of this pathogenic parasite still poses potential public health risks and calls for tighter control strategies based on better availability of chemotherapeutic treatment and accessibility to appropriate health education.

Intestinal parasitic infections and associated factors in children of three rural schools in Colombia. A cross-sectional study

Rural children are one of the populations that are most vulnerable to gastrointestinal parasite infections. Such diseases decrease the quality of life and result in growth and cognitive delays in the long term. This cross-sectional study was conducted to determine the frequency of intestinal parasite infections among rural schoolchildren in the municipality of Apulo, Colombia. A total of 97 stool samples from children aged between 5 and 15 years were collected and examined via direct light microscopy. Microscopic examination was repeated with sediments obtained using a fecal parasite concentrator, and the Kato–Katz test was performed. Frequency of intestinal parasite infection was 100%. Endolimax nana (77.35%), Blastocystis sp. (71.1%), Giardia intestinalis (39.1%), Entamoeba coli (25.7%), and the Entamoeba histolytica/dispar/moshkovskii complex (9.2%) were the most prevalent protozoa. Trichuris trichiura was the most prevalent helminth (12.3%), followed by Enterobius vermicularis (6.15%) and Ascaris lumbricoides (5.1%). Among the analyzed associated factors, consumption of untreated water increased the risk of acquiring pathogenic intestinal parasites. Finally, because G. intestinalis was the most prevalent pathogenic protozoan, molecular analysis was conducted to establish genetic assemblages and subassemblages of Giardia through sequence-based genotyping of the glutamate dehydrogenase, triose phosphate isomerase, and beta-giardin genes. A total of 14 G. intestinalis-positive samples were genotyped, which revealed the presence of subassemblages AI (n = 1), AII (n = 7), BIII (n = 2), BIV (n = 2), and BIII/BIV (n = 1) as well as a mixed subassemblage AII + BIII (n = 1). Our results indicate that gastrointestinal parasite infections in the tested population were mainly caused by suboptimal water quality. Moreover, molecular typing of G. intestinalis suggested contamination of water by animal- and human-derived cysts.

An Additional Asset for the FLOTAC Technique: Detection of Gastrointestinal Parasites in Vegetables

INTRODUCTION

Gastrointestinal parasites are considered amongst the most important threats to veterinary and human health worldwide. The transmission of these parasitic diseases usually involves the accidental ingestion of oocysts, cysts, eggs, and larvae, whose detection is generally achieved by classical coproparasitological methods, based on sedimentation and/or flotation techniques. These procedures might be inefficient or display a low sensitivity when performed on food matrices. This study aimed to assess the value of the FLOTAC technique for the detection of different parasitic stages of gastrointestinal parasites of domestic animals in fresh lettuce.

MATERIAL AND METHODS

Samples (n = 100) were purchased from public markets located in the metropolitan region of Recife (Brazil).

RESULTS

A total of 79% scored positive for eggs and/or cysts of gastrointestinal parasites. Protozoa and nematodes were detected in 32% (32/100) and 64% (64/100) of samples, respectively, with cysts of the genus Entamoeba (32%) and eggs of nematodes of the order Strongylida (30%) being the most frequently diagnosed.

CONCLUSIONS

The findings herein reported demonstrate that the FLOTAC technique can be successfully applied for recovering food-borne parasites of medical and veterinary concern in food matrices.

Evaluation of a Flotation Adapted Parasep® for Stool Ova and Parasite Examination

Stool ova and parasite examination using concentration methods remains the gold standard for the investigation of digestive parasitosis. Recently, single-use filtration devices have been marketed for stool concentration sedimentation methods such as MIF or Bailenger, which improve the analytical quality by avoiding contact with feces. In this study, the Parasep® device was adapted to the Faust technique flotation method. In addition, the performance between conventional techniques (MIF concentration and Faust) and techniques using this device was evaluated on 25 formalin-preserved stools and 3 fresh stools. With the Parasep device, the main parasites (protozoa or helminths) were isolated, and the technical requirements such as hygiene control for the operator and realization according to good laboratory practice were improved due to the filtration device.

Parasitic contamination of vegetables marketed in Arba Minch town, southern Ethiopia

BACKGROUND

Consumption of unwashed, raw or unhygienically prepared fruits and vegetables act as potential source for the spread of various parasitic diseases. Moreover, the level of contamination and species of contaminant parasites vary from place to place because of variations in environmental and human factors. Therefore local determination of the level of contamination and associated factors is important for efficient intervention of infections acquired via those food items.

METHODS

A Cross-sectional study was conducted among purchased vegetables in selected markets of Arba Minch town from January to March, 2018. A structured questionnaire was used to capture data about factors associated with parasitic contamination of vegetables in the marketing phase. Selected vegetables were purchased and processed for examination of parasitic contamination using direct wet mount, iodine wet mount and modified zeihl Neelson staining following standard protocols. All data were analyzed using SPSS version 20.0.

RESULTS

Among 347 vegetable samples examined, 87(25.1%) were contaminated with at least one parasite species. Tomato (35.0%) was the most commonly contaminated vegetable while green pepper (10.6%) was the least contaminated one. Entameoba histolytica/dispar (29, 8.4%) was the commonest parasitic contaminant detected followed by Giardia lamblia (24, 6.9%) and oocyst of Cryptosporidium species (5.8%). Vegetable type (X2 = 13.5; p = 0.009) and source of vegetables (X2 = 24.1; p < 0.001) were significantly associated with parasitic contamination of vegetables.

CONCLUSION

Parasitic contamination rate among marketed vegetables in the present study is significantly considerable. Entameoba histolytica /dispar was the most frequently detected parasite. We recommend to the local public health sector to establish a system for continuous monitoring of contamination of vegetables sold at local markets.

Parasite fauna of wild Antillean manatees (Trichechus manatus manatus) of the Andean Region, Colombia

BACKGROUND

Antillean manatees (Trichechus manatus manatus) are large herbivorous aquatic mammals living in limited areas of South, Central and North America. As with other aquatic mammals, Antillean manatees can be infected by a variety of protozoan and metazoan parasites, some of them with zoonotic potential, which affect not only their welfare but also population health status. Therefore, we conducted the first epidemiological survey in Colombian free-ranging Antillean manatees to estimate their actual gastrointestinal parasite status.

RESULTS

In total, 69 faecal samples were collected from free-ranging individual manatees during ecology field studies in the rivers Carare and San Juan and in two associated wetlands in the Andean region of Colombia. Parasite diversity encompassed six different endoparasite species. The highest prevalence was found for protozoan infections with Eimeria nodulosa (47.8%) and Eimeria manatus-like species (type A, B; 43.4%), followed by Entamoeba sp. (14.49%) and Giardia sp. (1.4%) infections. In addition, infections with the trematode Chiorchis fabaceus were detected at a high prevalence (33.3%). Molecular characterization of sirenian Eimeria species led to the distinction of three species, E. nodulosa and two E. manatus-like species (type A, B). Phylogenetic analyses indicated a host-specific adaptation of sirenian Eimeria species as previously reported for Eimeria species from other mammalian hosts.

CONCLUSIONS

This study provides the first record of Antillean manatee infection with Giardia and Entamoeba species in Colombia, representing two important anthropozoonotic parasite genera. This survey should serve as a baseline investigation for future monitoring on parasitic zoonoses in this mammal and encourage for investigations on their impact on both public health and wild manatee welfare.

Invasive Colonic Entamoebiasis in Wild Cane Toads, Australia

We detected a disease syndrome in free-ranging Australian cane toads involving atypical behavior and emaciation that is associated with a previously undescribed Entamoeba sp. that infiltrates the colonic lining, causing it to slough. The organism may become seasonally pathogenic when toads are under hydric and nutritional stress.

Use of shotgun metagenomics for the identification of protozoa in the gut microbiota of healthy individuals from worldwide populations with various industrialization levels

Protozoa have long been considered undesirable residents of the human gut, but recent findings suggest that some of them may positively affect the gut ecosystem. To better understand the role and ecological dynamics of these commensal and potentially beneficial protozoan symbionts, we need efficient methods to detect them, as well as accurate estimates of their prevalence across human populations. Metagenomics provides such an opportunity, allowing simultaneous detection of multiple symbionts in a single analytical procedure. In this study, we collected fecal samples of 68 individuals from three Cameroonian populations with different subsistence modes and compared metagenomics-based and targeted methods of detection for two common protozoan genera: Blastocystis and Entamoeba. In addition, we analyzed our data along with publicly available fecal metagenomes from various worldwide populations to explore the prevalence and association patterns of ten protozoan genera. Regarding the detection method, microscopy was much less sensitive than metagenomics for Entamoeba, whereas qPCR was at least as sensitive as metagenomics for Blastocystis sp. However, metagenomics was more likely to detect co-colonizations by multiple subtypes. Out of the ten examined genera in 127 individuals from Cameroon, Tanzania, Peru, Italy or USA, only three (Blastocystis, Entamoeba and Enteromonas) had an overall prevalence exceeding 10%. All three genera were more common in less industrialized populations and their prevalence differed between continents and subsistence modes, albeit not in a straightforward manner. The majority (72.5%) of colonized individuals carried at least two protozoan species, indicating that mixed-species colonizations are common. In addition, we detected only positive and no negative association patterns between different protozoa. Despite the pitfalls of the metagenomic approach, ranging from the availability of good-quality sequencing data to the lack of standard analytical procedures, we demonstrated its utility in simultaneous detection of multiple protozoan genera, and especially its ability to efficiently detect mixed-species colonizations. Our study corroborates and expands prevalence results previously obtained for Blastocystis sp. and provides novel data for Entamoeba spp. and several other protozoan genera. Furthermore, it indicates that multiple protozoa are common residents of the healthy human gut worldwide.

Prevalence of non-pathogenic types of gastrointestinal protozoa in population in Slovakia and their potential importance in the aspect of public health

The aim of the research was to determine the prevalence of non-pathogenic protozoa circulating in the human population of Slovakia. We particularly focused on the socially deprived areas with poor sanitation conditions, as they are one of the factors affecting the transmission of these infections. Within this study, 2760 people were coprologically screened for the presence of protozoan cysts. The analyzed group comprised 1173 men and 1587 women from different regions of Slovakia. The total prevalence (2.03%) of non-pathogenic protozoa species was determined. The prevalence of Entamoeba coli was 0.80%, the prevalence of Endolimax nana 0.58%, and the prevalence of Blastocystis hominis was 0.65%. The presence of non-pathogenic protozoa was more frequent in women than that in men, in all age groups. The highest incidence of Entamoeba coli was found in children aged one month - seven years (0.79%), the lowest in the age group of 19-88 years (0.66%). Endolimax nana was most frequent in 8-18 year-olds (0.95%), where the statistical significance was found (p<0.05). The prevalence of Blastocystis hominis by the age group ranged from 0.39 to 0.95%. We did not find any statistical significance (p>0.05) for Entamoeba coli, and similarly for Blastocystis hominis associated with the sex and age. Although the circulation of non-pathogenic protozoa in the human population is far from being limited to the developing countries, their occurrence is also frequent in the population of developed countries. Despite their controversial pathogenicity, they should not be neglected, particularly in the patients with gastrointestinal symptoms.

Clinical and microscopic predictors of Entamoeba histolytica intestinal infection in travelers and migrants diagnosed with Entamoeba histolytica/dispar infection

Background

Amebiasis is a protozoal infection caused by Entamoeba histolytica, while the morphologically indistinguishable E. dispar is considered as non-pathogenic. Polymerase chain reaction (PCR) assays are necessary to differentiate both species. The most common clinical presentations of E. histolytica disease are amebic colitis and amebic liver abscess, but asymptomatic infection is also possible. We assessed the frequency and pattern of clinical symptoms and microscopic features in travelers/migrants associated with E. histolytica intestinal infection and compared them to those found in individuals with E. dispar infection.

Methods

We conducted a retrospective study at the travel clinic of the Institute of Tropical Medicine, Antwerp, Belgium on travelers/migrants found from 2006 to 2016 positive for Entamoeba histolytica/dispar through antigen detection and/or through microscopy confirmed by PCR. All files of individuals with a positive PCR for E. histolytica (= cases) and a random selection of an equal number of Entamoeba dispar carriers (= controls) were reviewed. We calculated the sensitivity, specificity and likelihood ratios (LRs) of clinical symptoms (blood in stool, mucus in stool, watery diarrhea, abdominal cramps, fever or any of these 5 symptoms) and of microscopic features (presence of trophozoites in direct and in sodium acetate-acetic acid-formalin (SAF)-fixed stool smears) to discriminate between E. histolytica and E. dispar infection.

Results

Of all stool samples positive for Entamoeba histolytica/dispar for which PCR was performed (n = 810), 30 (3.7%) were true E. histolytica infections, of which 39% were asymptomatic. Sensitivity, specificity and positive LRs were 30%, 100% and 300 (p 0.007) for presence of blood in stool; 22%, 100% and 222 (p 0.03) for mucus in stool; 44%, 90% and 4.7 (p 0.009) for cramps and 14%, 97% and 4.8 (p = 0.02) for trophozoites in direct smears. For watery diarrhea, fever and for trophozoites in SAF fixated smears results were non-significant.

Conclusions

E. histolytica infection was demonstrated in a small proportion of travelers/migrants with evidence of Entamoeba histolytica/dispar infection. In this group, history of blood and mucus in stool and cramps had good to strong confirming power (LR+) for actual E. histolytica infection. Trophozoites were also predictive for true E. histolytica infection but in direct smears only.

In the present work, we found that E. histolytica intestinal infections are rarely diagnosed among travelers and migrants presenting in a national reference travel clinic in Europe. Microscopic finding of cysts or trophozoites and antigen testing cannot discriminate between Entamoeba histolytica/dispar infection, which leads to overdiagnosis of E. histolytica infections in low resource settings where PCR is not available. We found visualization of trophozoites under the microscope helpful in discriminating between E. histolytica and E. dispar infection in direct smears. Hematophagy is a very rare finding but in our experience was always associated with E. histolytica infection. In a context where only microscopy is available, a patient presenting with blood or mucus in stool or cramps should anyhow be treated as amoebiasis if Entamoeba histolytica/dispar cysts/trophozoites are found. Nevertheless it is worth noting that a sizeable proportion of E. histolytica cases were asymptomatic. Last, our study suggests that E. dispar might be pathogenic but symptoms in E. histolytica infected patients were clearly more often suggestive of intestinal tissue invasion.

Bacterial and parasitic contaminants of salad vegetables sold in markets in Fako Division, Cameroon and evaluation of hygiene and handling practices of vendors

OBJECTIVE

Increase in awareness of the health benefits of vegetables has resulted in an increase in consumption. Many vegetables are consumed raw to retain the natural taste and heat labile nutrients. The safety of raw vegetables is a great concern. We investigated the bacteriological and parasitological quality of salad vegetables sold in three major markets in Fako Division Cameroon, the hygiene and preservation practices of vendors and determined the antimicrobial sensitivity of bacterial isolates, to provide data that could be used to improve food safety and safeguard public health.

RESULTS

Bacterial contamination was high. Mean aerobic bacteria counts ranged from 2.5 × 106 to 15 × 106 cfu/g, total coliform counts from 4 to >  2400/g and fecal coliforms < 3 to 1100/g. Six bacterial species were isolated among which Staphylococcus aureus (35.4%) predominated while Serratia marcescens (8.5%) was the least. Bacteria showed high resistance to erythromycin (87.6%). Ten parasitic organisms were detected. Balantidium coli (25.6%) and Entamoeba spp. (21.7%) predominated. Contamination was highest in lettuce and lowest in green pepper. Hygiene and vegetable preservation practices of vendors were poor and could aggravate contamination. Contamination of fresh salad vegetables with pathogenic bacteria and parasites could be a food safety concern in study area.

Occurrence and removal efficiency of parasitic protozoa in Swedish wastewater treatment plants

Giardia intestinalis, Cryptosporidium spp., Entamoeba histolytica and Dientamoeba fragilis are parasitic protozoa and causative agents of gastroenteritis in humans. G. intestinalis and Cryptosporidium spp. in particular are the most common protozoa associated with waterborne outbreaks in high-income countries. Surveillance of protozoan prevalence in wastewater and evaluation of wastewater treatment removal efficiencies of protozoan pathogens is therefore imperative for assessment of human health risk. In this study, influent and effluent wastewater samples from three wastewater treatment plants in Sweden were collected over nearly one year and assessed for prevalence of parasitic protozoa. Quantitative real-time PCR using primers specific for the selected protozoa Cryptosporidium spp., G. intestinalis, E. histolytica, Entamoeba dispar and D. fragilis was used for protozoan DNA detection and assessment of wastewater treatment removal efficiencies. Occurrence of G. intestinalis, E. dispar and D. fragilis DNA was assessed in both influent (44, 30 and 39 out of 51 samples respectively) and effluent wastewater (14, 9 and 33 out of 51 samples respectively) in all three wastewater treatment plants. Mean removal efficiencies of G. intestinalis, E. dispar and D. fragilis DNA quantities, based on all three wastewater treatment plants studied varied between 67 and 87%, 37-75% and 20-34% respectively. Neither E. histolytica nor Cryptosporidium spp. were detected in any samples. Overall, higher quantities of protozoan DNA were observed from February to June 2012. The high prevalence of protozoa in influent wastewater indicates the need for continued monitoring of these pathogens in wastewater-associated aquatic environments to minimise the potential risk for human infection.

Morphological and molecular characterization of an uninucleated cyst-producing Entamoeba spp. in captured Rangeland goats in Western Australia

Uninucleated Entamoeba cysts measuring 7.3×7.7μm were detected in faecal samples collected from wild Rangeland goats (Capra hircus) after arrival at a commercial goat depot near Geraldton, Western Australia at a prevalence of 6.4% (8/125). Sequences were obtained at the 18S rRNA (n=8) and actin (n=5) loci following PCR amplification. At the 18S locus, phylogenetic analysis grouped the isolates closest with an E. bovis isolate (FN666250) from a sheep from Sweden with 99% similarity. At the actin locus, no E. bovis sequences were available, and the isolates shared 94.0% genetic similarity with E. suis from a pig in Western Japan. This is the first report to describe the morphology and molecular characterisation of Entamoeba from Rangeland goats in Western Australia and the first study to produce actin sequences from E. bovis-like Entamoeba sp.

Intestinal parasites in stool samples and perianal swabs examined by The Voivodeship Sanitary-Epidemiological Station in Bydgoszcz between 2000-2014

INTRODUCTION

Epidemiological conditions are changing due to the modifications in human behavior and environment. Parasitic diseases are most often caused by intestinal parasites. The frequency of Echinococcus multilocularis and tropical diseases increases in Poland.

AIM OF STUDY

Analysis of intestinal parasites’ occurrence in stool samples and perianal swabs tested in Medical Diagnostics Department of The Voivodeship Sanitary-Epidemiological Station in Bydgoszcz between 2000-2014.

MATERIAL AND METHODS

24 609 fecal samples and perianal swabs were tested using microscopic method for intestinal parasites’ presence and immunoenzymatic method (ELISA) for Giardia intestinalis presence. The study population was sorted into four groups according to age.

RESULTS

Prevalence of intestinal parasites in persons tested over 2000-2014 period ranged between 2.15% - 7.04%. The most common invasive parasite was Enterobius vermicularis, especially among children between 3-7 years (64.58%). In the same time period the most prevalent pathogenic intestinal parasite in adults (>16 years) was Giardia intestinalis (65.81%).

CONCLUSIONS

1. The prevalence of intestinal parasites infection changes depending on the number of tests carried out. The number of infections may be underestimated given that the testing encompassed only a part of population. A need for more thorough examination exists. 2. Enterobius vermicularis infection was most often found in children between 3-7 years, mainly from specific communities (kindergartens, orphanages).

Diagnostics of intestinal parasites in light microscopy among the population of children in eastern Afghanistan

OBJECTIVES

The Afghans, living in poor socioeconomic conditions, are estimated to be a community with a high rate of intestinal parasitic infections. The aim of the study was to estimate the prevalence and species of intestinal parasites among children's population in eastern Afghanistan and to present the methods of optimizing the techniques for identification of pathogens in light microscopy. The research was carried out as a part of humanitarian project Capacity building of health care system in Ghazni Province.

MATERIALS AND METHOD

The study involved 500 children aged 7-18 attending the Share Kona and the Khuija Ali High Schools in Ghazni, eastern Afghanistan in the period November 2013-April 2014. Three stool samples were collected from each patient at 2-day intervals, the samples were fixed in 10% formalin, transported to the Military Institute of Medicine in Poland, where they were pooled and examined using five different diagnostic methods in light microscopy (direct smear in Lugol's solution, Fülleborne's flotation, decantation in distilled water, Kato-Miura thick smear, and DiaSys/PARASYS sedimentation system).

RESULTS

Pathogenic intestinal parasites were detected in 217 patients (43.4%), with the most common Ascaris lumbricoides (35.3%), Giardia intestinalis (31.1%), and Hymenolepis nana (15.7%). The use of direct smear method allowed for the detection of intestinal parasites in 161 individuals. The application of four following testing methods has improved the detection rates of infected patients by 11.2%.

CONCLUSIONS

The variety of detected intestinal pathogens in examined children's population has required the use of combination of multiple diagnostic methods in light microscopy, and finally improved the detection rates of intestinal parasites and helped eliminate infections with nematodes, cestodes, trematodes, and protozoa using appropriate treatment in the study population.

First report of mixed Entamoeba polecki (ST 1) and E. suis infection in piglets shedding abnormalfeces by histopathological and molecular surveys

Of the three species of Entamoeba found in swine, namely E. histolytica, E. polecki and E. suis, E. histolytica can also infect humans, producing colitis or abscesses of liver and leading to death. However, the pathogenicity of other species of Entamoeba has not been fully characterized. Here, we conducted histopathology and molecular surveys on a pig farm where piglets had blackish feces or muddy diarrhea. Histopathological examination of two piglets showed necrosis of the mucous surface at the ileum, cecum, or colon, infiltration of neutrophils, and formation of ulcers. Based on morphological characteristics, E. polecki and E. suis trophozoites were mainly detected at lamina propria and surface of the lesion, respectively, and Lawsonia intracellularis, a bacterial pathogen, was also detected. Molecular analysis using the small subunit ribosomal RNA gene on other piglets and a sow revealed infection with both E. polecki and E. suis. These findings corroborate our previous reports that the two Entamoeba spp. are pathogenic in pigs as aggravations of symptoms with L. intracellularis. This is the first report about mixed infection with E. polecki and E. suis.

Simultaneous detection and differentiation of Entamoeba histolytica, E. dispar, E. moshkovskii, Giardia lamblia and Cryptosporidium spp. in human fecal samples using multiplex PCR and qPCR-MCA

Entamoeba histolytica, Giardia lamblia and Cryptosporidium spp. are common causes of diarrheal and intestinal diseases all over the world. Microscopic methods are useful in the diagnosis of intestinal parasites (IPs), but their sensitivity was assessed approximately 60 percent. Recently, molecular techniques have been used increasingly for the identification and characterization of the parasites. Among those, in this study we have used multiplex PCR and Real-time PCR with melting curve analysis (qPCR-MCA) for simultaneous detection and differentiation of E. histolytica, E. dispar, E. moshkovskii, G. lamblia and Cryptosporidium spp. in human fecal samples. Twenty DNA samples from 12 E. histolytica and 8 E. dispar samples and twenty stool samples confirmed positive for G. lamblia and Cryptosporidium spp. were analyzed. After DNA extraction from the samples, multiplex PCR was done for detection and differentiation of above mentioned parasites. QPCR-MCA was also performed for the detection and differentiation of 11 isolates of above mentioned parasite in a cycle with a time and temperature. Multiplex PCR was able to simultaneous detect and differentiate of above mentioned parasite in a single reaction. QPCR-MCA was able to differentiate genus and species those five protozoa using melting temperature simultaneously at the same time and temperature programs. In total, qPCR-MCA diagnosed 7/11 isolation of E. histolytica, 6/8 isolation of E. dispar, 1/1 E. moshkovskii Laredo, 10/11 G. Lamblia and 6/11 Cryptosporidium spp. Application of multiplex PCR for detection of more than one species in a test in developing countries, at least in reference laboratories has accurate diagnosis and plays a critical role in differentiation of protozoan species. Multiplex PCR assay with a template and multi template had different results and it seems that using a set of primers with one template has higher diagnostic capability in compare with multi template. The results of this study showed that the use of the qPCR-MCA can be an effective method to simultaneous distinguish of the above mentioned parasites.

Investigation of Entamoeba gingivalis and Trichomonas tenax in Periodontitis or Gingivitis Patients in Kayseri

OBJECTIVE

The aim of this study was to determine the prevalence of Entamoeba gingivalis and Trichomonas tenax in periodontitis and gingivitis patients.

METHODS

The study consisted of 107 periodontitis patients and 68 gingivitis patients. Bacterial plaque samples were collected with a curette from the deepest pocket in each quadrant and placed into separate tubes containing sterile 0.9% saline solution. Samples were examined at a magnification of ×400 by light microscopy. Cultivation for T. tenax was performed using the same samples, and the cultures were examined after 48 hours.

RESULTS

E. gingivalis was present in the samples from 38 periodontitis patients, whereas T. tenax was present in samples from only 3 periodontitis patients. Both E. gingivalis and T. tenax were found together in the samples from 2 periodontitis patients. In total, 22 and 2 gingivitis patients were found to be infected with E. gingivalis and with T. tenax, respectively. Only 1 gingivitis patient was found to be infected with both E. gingivalis and T. tenax.

CONCLUSION

In our study, oral protozoa were found in a high percentage in periodontitis and gingivitis patients. We believe that the prevalence of E. gingivalis and T. tenax should be determined via new studies and, in particular, the protection principles should be complied with.

Identification of Entamoeba moshkovskii in Treated Waste Water Used for Agriculture

We conducted an observational study to determine the prevalence of Entamoeba spp., in samples collected in a waste water treatment plant that provides water for agricultural irrigation. Samples were collected weekly over a period of 10 weeks at representative contamination stages from within the treatment plant. Protozoan identification was performed via light microscopy and culture. PCR amplification of small subunit rRNA gene sequences of E. histolytica/dispar/moshkovskii was performed in culture positive samples. Light microscopy revealed the presence of Entamoeba spp., in 70% (14/20) of the raw waste water samples and in 80% (8/10) of the treated water samples. PCR amplification after culture at both 24 and 37°C revealed that 100% (29/29) of the raw waste water samples and 78.6% (11/14) of the treated waste water were positive for E. moshkovskii. We report the first isolation of E. moshkovskii in Colombia, confirmed by PCR. Recent reports of E. moshkovskii pathogenic potential suggest this finding could constitute a public health risk for people exposed to this water.

Variation in Rural African Gut Microbiota Is Strongly Correlated with Colonization by Entamoeba and Subsistence

The human gut microbiota is impacted by host nutrition and health status and therefore represents a potentially adaptive phenotype influenced by metabolic and immune constraints. Previous studies contrasting rural populations in developing countries to urban industrialized ones have shown that industrialization is strongly correlated with patterns in human gut microbiota; however, we know little about the relative contribution of factors such as climate, diet, medicine, hygiene practices, host genetics, and parasitism. Here, we focus on fine-scale comparisons of African rural populations in order to (i) contrast the gut microbiota of populations inhabiting similar environments but having different traditional subsistence modes and either shared or distinct genetic ancestry, and (ii) examine the relationship between gut parasites and bacterial communities. Characterizing the fecal microbiota of Pygmy hunter-gatherers as well as Bantu individuals from both farming and fishing populations in Southwest Cameroon, we found that the gut parasite Entamoeba is significantly correlated with microbiome composition and diversity. We show that across populations, colonization by this protozoa can be predicted with 79% accuracy based on the composition of an individual's gut microbiota, and that several of the taxa most important for distinguishing Entamoeba absence or presence are signature taxa for autoimmune disorders. We also found gut communities to vary significantly with subsistence mode, notably with some taxa previously shown to be enriched in other hunter-gatherers groups (in Tanzania and Peru) also discriminating hunter-gatherers from neighboring farming or fishing populations in Cameroon.

Genotyping of Giardia lamblia and Entamoeba spp from river waters in Iran

In this study, DNA from 55 surface and river water samples, which were collected from some water sources of Tehran and the Guilan Province, Iran, were extracted and examined for Entamoeba spp. and Giardia lamblia by PCR and genotyping. Twenty-seven samples, which were concentrated using the immunomagnetic separation technology (IMS) method, were examined for Giardia alone. Twenty-eight samples, which were concentrated using the sucrose flotation (SF) method, were examined for both Giardia and Entamoeba species. The results showed that 27/55 (17/27 and 10/28) (49 %), 4 /28 (14.28 %) and 3/28 (10.7 %) of the samples were positive for Giardia lamblia, Entamoeba spp and mixed infections (Entamoeba spp. and Giardia spp.), respectively. Sixteen out of 55 samples were negative. Entamoeba genus-specific PCR primers in single-round PCR were used to differentiate between the Entamoeba spp. (E. histolytica, E. dispar and E. moshkovskii). With respect to the 7 samples that were positive for Entamoeba, (14.28 %) 4 out of 28 were positive for E. moshkovskii, (7.14 %), 2 out of 28 were positive for E. histolytica and (3.57 %) 1 out of 28 was positive for E. dispar. Genus-specific PCR primers in a semi-nested PCR assay was performed to genotype Giardia species. Of the 27 samples that were positive for Giardia, 10 samples were sequences. All 10 successfully sequenced samples contained assemblage B of Giardia lamblia.This is first study to investigate the G. lamblia genotypes in the water supply of the Tehran and Guilan provinces, and it is the first study to investigate Entamoeba species in the water supplies of Iran. The investigated river water supplies, which are used for agriculture, camping and animal farming, were heavily contaminated by the human pathogenic Entamoeba and Giardia parasites. There is a potential risk of waterborne outbreaks in humans and animals.

Molecular Detection of the Carriage Rate of Four Intestinal Protozoa with Real-Time Polymerase Chain Reaction: Possible Overdiagnosis of Entamoeba histolytica in Nigeria

Diarrhea remains the second largest killer of children worldwide, and Nigeria ranks number two on the list of global deaths attributable to diarrhea. Meanwhile, prevalence studies on potentially diarrheagenic protozoa in asymptomatic carriers using molecular detection methods remain scarce in sub-Saharan countries. To overcome sensitivity issues related to microscopic detection and identification of cysts in stool concentrates, real-time polymerase chain reaction (PCR) was used to analyze genomic DNAs extracted from stool samples from 199 healthy school children for Entamoeba histolytica, E. dispar, Giardia intestinalis, and Cryptosporidium. Questionnaires were administered for epidemiological data collection. E. histolytica was not detected in any of the samples, whereas Giardia (37.2%), E. dispar (18.6%), and Cryptosporidium (1%) were found. Most of the children sourced their drinking water from community wells (91%), while the majority disposed of feces in the bush (81.9%). Our study is the first to use real-time PCR to evaluate the epidemiology of E. histolytica, Giardia, and Cryptosporidium in Nigeria where previous studies using traditional diagnostic techniques have suggested higher and lower carriage rates of E. histolytica and Giardia, respectively. It is also the first study to accurately identify the prevalence of common potentially diarrheagenic protozoa in asymptomatic carriers in sub-Saharan Africa.

Evaluation of factors affecting real-time PCR performance for diagnosis of Entamoeba histolytica and Entamoeba dispar in clinical stool samples

Although PCR offers the potential for sensitive detection of parasites there are several pitfalls for optimal performance, especially when DNA is extracted from a complex sample material such as stool. With the aid of a sensitive inhibitor control in a duplex real-time PCR (qPCR) for identification of Entamoeba histolytica and Entamoeba dispar we have evaluated factors that influenced the performance of the qPCR and have suggested a rationale to be used in the analysis of clinical samples. Pre-PCR processing was found to be of outmost importance for an optimal amplification since inhibitors caused false-negative results when higher amounts of sample were used. Stool sampling with a flocked swab (ESwab, Copan), yielding on average 173 mg, gave positive qPCR results in samples with cysts of E. dispar that were negative in serially diluted stool samples. The degree of inhibition found varied between samples and was not an on-off phenomenon. Even low-grade inhibition, shown as an increase of two cycles in the qPCR for the inhibitor control, could lead to false negativity in samples with low amounts of parasites. Lack of amplification in the qPCR due to inhibition could be overcome by dilution of the extracted DNA by 1/10-1/20. We also describe the use of guanidinium thiocyanate buffer for transport and storage of samples as well as a time-saving semi-automated DNA extraction method in an Arrow instrument (Nordiag) preceded by bead beating.

[Environmental conditions and prevalence of parasitic infection in Xukuru-Kariri indigenous people, Caldas, Brazil]

OBJECTIVE

To describe the environmental conditions and the parasitic infection status of Xukuru-Kariri individuals living in the municipality of Caldas, state of Minas Gerais, Brazil.

METHODS

A cross-sectional study was carried out in March 2009. Sociodemographic and environmental data were collected through interviews. Water and fecal samples were collected for determination of environmental contamination and parasitic infection status.

RESULTS

The Xukuru-Kariri population living in Caldas included 86 people divided into 22 families. Of 22 heads of household, 81.8% had low schooling (not higher than elementary education). Of 26 water samples collected for microbiological analysis, 77.0% were positive for total coliforms and 4.0% for Escherichia coli. Residents of 27.3% of households defecated in the open. Trash was scattered in the yard of 54.5% of households. Fecal samples were collected from 60 individuals, with parasitic infection in 66.6%. The following prevalence rates were recorded: Entamoeba histolytica/dispar, 6.7%; Entamoeba coli, 60.0%; Endolimax nana, 1.8%; and Giardia duodenalis, 6.6%.

CONCLUSIONS

The people included in this study faced environmental characteristics that contributed to their health vulnerability. Health actions as well as the implementation of public policies to provide sanitation, with quality water and adequate collection and treatment of human and household waste, are essential to prevent environmental degradation and improve the quality of life of these individuals.

Outbreak of acute gastroenteritis caused by contamination of drinking water in a factory, the Basque Country

On 18 September 2013, the Gipuzkoa Epidemiology Unit was notified of an outbreak of acute gastroenteritis (AGE) among employees at a domestic appliance factory. The first signs of the outbreak had emerged at the end of June and at the time of the notification 30 workers were on sick leave for gastroenteritis. Some employees had had more than one episode and the main symptoms were diarrhoea and vomiting. An investigation began to identify the causative agent, assess exposure and determine the route of transmission. Data collected by a questionnaire identified 302 episodes of AGE among 238 people affected between June and September 2013. The source of water consumed was found to be a risk factor associated with the appearance of symptoms both in the crude and the adjusted analysis: odds ratio 1.8 (0.8-4.2) and 6.4 (4.2-9.8), respectively. Microbiological analysis of stool samples and of water confirmed the presence of norovirus and rotavirus. The environmental study detected a connection between an industrial use water system and drinking water at the factory. It was concluded that the outbreak was caused by mixed viral infections, due to contamination of drinking water.

Molecular detection of Entamoeba histolytica and Entamoeba dispar infection among wild rats in Kuala Lumpur, Malaysia

Entamoeba histolytica infection is the third-greatest parasitic disease responsible for death in the world. Wild rats harbouring E. histolytica can be the possible reservoir hosts for human amoebiasis. There were numerous studies on prevalence of intestinal parasites among wild rats in Malaysia but none has reported E. histolytica. Rats were captured from Sentul and Chow Kit areas, Kuala Lumpur, Malaysia. The preserved stool samples were used for microscopy examination and molecular analysis. Out of 137 samples collected, 12 were positive for E. histolytica / E. dispar / E. moshkovskii microscopically. Two E. histolytica (1.4%), 1 E. dispar (0.7%) and 6 mixed infections of E. histolytica and E. dispar (4.3%) were detected using PCR. This is the first report of molecular detection of E. histolytica/dispar infection among wild rats in Malaysia. This study provides useful information about the potential risks of zoonotic agents and the importance of developing control measures to prevent zoonotic transmission.

First evidence of genetic intraspecific variability and occurrence of Entamoeba gingivalis in HIV(+)/AIDS

Entamoeba gingivalis is considered an oral commensal but demonstrates a pathogenic potential associated with periodontal disease in immunocompromised individuals. Therefore, this study evaluated the occurrence, opportunistic conditions, and intraspecific genetic variability of E. gingivalis in HIV(+)/AIDS patients. Entamoeba gingivalis was studied using fresh examination (FE), culture, and PCR from bacterial plaque samples collected from 82 HIV(+)/AIDS patients. Genetic characterization of the lower ribosomal subunit of region 18S (18S-SSU rRNA) was conducted in 9 positive samples using low-stringency single specific primer PCR (LSSP-PCR) and sequencing analysis. Entamoeba gingivalis was detected in 63.4% (52/82) of the samples. No association was detected between the presence of E. gingivalis and the CD4⁺ lymphocyte count (≤200 cells/mm³ (p = 0.912) or viral load (p = 0.429). The LSSP-PCR results helped group E. gingivalis populations into 2 polymorphic groups (68.3% similarity): group I, associated with 63.6% (7/11) of the samples, and group II, associated with 36.4% (4/11) of the samples, which shared 74% and 83.7% similarity and association with C and E isolates from HIV(−) individuals, respectively. Sequencing of 4 samples demonstrated 99% identity with the reference strain ATCC 30927 and also showed 2 divergent clusters, similar to those detected by LSSP-PCR. Opportunistic behavior of E. gingivalis was not detected, which may be related to the use of highly active antiretroviral therapy by all HIV(+)/AIDS patients. The high occurrence of E. gingivalis in these patients can be influenced by multifactorial components not directly related to the CD4⁺ lymphocyte counts, such as cholesterol and the oral microbiota host, which could mask the potential opportunistic ability of E. gingivalis. The identification of the 18S SSU-rRNA polymorphism by LSSP-PCR and sequencing analysis provides the first evidence of genetic variability in E. gingivalis isolated from HIV patients.

Molecular epidemiology and genetic diversity of Entamoeba species in a chelonian collection

Veterinary medicine has focused recently on reptiles, due to the existence of captive collections in zoos and an increase in the acquisition of reptiles as pets. The protozoan parasite, Entamoeba can cause amoebiasis in various animal species and humans. Although amoebiasis disease is remarkably rare in most species of chelonians and crocodiles, these species may serve as Entamoeba species carriers that transmit parasites to susceptible reptile species, such as snakes and lizards, which can become sick and die. In this study, we identified the Entamoeba species in a population of healthy (disease-free) chelonians, and evaluated their diversity through the amplification and sequencing of a small subunit rDNA region. Using this procedure, three Entamoeba species were identified: Entamoeba invadens in 4.76 % of chelonians, Entamoeba moshkovskii in 3.96 % and Entamoeba terrapinae in 50 %. We did not detect mixed Entamoeba infections. Comparative analysis of the amplified region allowed us to determine the intra-species variations. The E. invadens and E. moshkovskii strains isolated in this study did not exhibit marked differences with respect to the sequences reported in GenBank. The analysis of the E. terrapinae isolates revealed three different subgroups (A, B and C). Although subgroups A and C were very similar, subgroup B showed a relatively marked difference with respect to subgroups A and C (Fst = 0.984 and Fst = 1.000, respectively; 10-14 % nucleotide variation, as determined by blast) and with respect to the sequences reported in GenBank. These results suggested that E. terrapinae subgroup B may be either in a process of speciation or belong to a different lineage. However, additional research is necessary to support this statement conclusively.

Entamoeba dispar strains: analysis of polymorphism in Tunisian isolates

The ability to detect intra-species polymorphism in Entamoeba histolytica and Entamoeba dispar is an important tool for studying geographic distribution and transmission mechanisms. E. dispar and E. histolytica share the same mechanism for transmission among human hosts, and so after differentiation between these species. We studied the intra-species variation and distribution of E. dispar strains obtained from cyst passers, specifically from African students and Tunisian food handlers. We analyzed the polymorphic region of the chitinase protein gene in 13 individuals infected with E. dispar, of which 9 were from Tunisia and 4 from other African countries. We identified 7 different chitinase patterns in Tunisians while the 4 isolates from other countries each had a distinct pattern. Two of the patterns we found have been reported in studies from Mexico and India, possibly indicating worldwide spread of certain strains.

Determining the prevalence of intestinal parasites in three Orang Asli (Aborigines) communities in Perak, Malaysia

This study was conducted to determine the prevalence of intestinal parasites among children and adult Orang Aslis (Aborigines) from different locations in Perak. Faecal samples were collected and analyzed using the direct smear and formal ether sedimentation technique. Some of the faecal samples were stained using the Modified Acid fast stain for Cryptosporidium. Nail clippings of the respondents and the soil around their habitat were also analyzed. Of the 77 stool samples examined, 39 (50.6%) were positive for at least one intestinal parasite. The most common parasite detected was Trichuris trichiura (39.0%) followed by Ascaris lumbricoides (26.9%), Entamoeba coli (5.2%), Giardia lamblia (5.2%), Blastocystis hominis (3.9%), hookworm (3.9%), Entamoeba histolytica (1.3%), Iodamoeba butschlii (1.3%) and Cryptosporidium sp. (1.3%) respectively. Some respondents had single parasites (24.7%), some with two parasites (18.2%). Some with three parasites (6.5%) and one had four parasites species (1.3%). The parasites were slightly more common in females (54.7%) than males ((41.7%). The parasites were more common in the 13-20 year age group (90.9%) followed by 1-12 years (69.6%), 21-40 year age group (34.8%) and least in the 41-60 year age group (27.8%). Nail examinations of the respondents did not show any evidence of parasites. One had a mite, three had pollen grains and one had yeast cells isolated from the finger nails. Soil samples taken around their houses showed only one sample with a nematode ova and one with oocyst which was of a non human origin.

Albendazole therapy and enteric parasites in United States-bound refugees

BACKGROUND

Beginning on May 1, 1999, the Centers for Disease Control and Prevention (CDC) recommended presumptive treatment of refugees for intestinal parasites with a single dose of albendazole (600 mg), administered overseas before departure for the United States.

METHODS

We conducted a retrospective cohort study involving 26,956 African and Southeast Asian refugees who were screened by means of microscopical examination of stool specimens for intestinal parasites on resettlement in Minnesota between 1993 and 2007. Adjusted prevalence ratios for intestinal nematodes, schistosoma species, giardia, and entamoeba were calculated among refugees who migrated before versus those who migrated after the CDC recommendation of presumptive predeparture albendazole treatment.

RESULTS

Among 4370 untreated refugees, 20.8% had at least one stool nematode, most commonly hookworm (in 9.2%). Among 22,586 albendazole-treated refugees, only 4.7% had one or more nematodes, most commonly trichuris (in 3.9%). After adjustment for sex, age, and region, albendazole-treated refugees were less likely than untreated refugees to have any nematodes (prevalence ratio, 0.19), ascaris (prevalence ratio, 0.06), hookworm (prevalence ratio, 0.07), or trichuris (prevalence ratio, 0.27) but were not less likely to have giardia or entamoeba. Schistosoma ova were identified exclusively among African refugees and were less prevalent among those treated with albendazole (prevalence ratio, 0.60). After implementation of the albendazole protocol, the most common pathogens among 17,011 African refugees were giardia (in 5.7%), trichuris (in 5.0%), and schistosoma (in 1.8%); among 5575 Southeast Asian refugees, only giardia remained highly prevalent (present in 17.2%). No serious adverse events associated with albendazole use were reported.

CONCLUSIONS

Presumptive albendazole therapy administered overseas before departure for the United States was associated with a decrease in the prevalence of intestinal nematodes among newly arrived African and Southeast Asian refugees.

Comparative study of entero-parasitic infections among HIV sero-positive and sero-negative patients in Lagos, Nigeria

BACKGROUND

Intestinal parasites are endemic in many parts of the world where HIV infection is also widespread. Previous studies had shown that the spectrum of opportunistic and common endemic parasitic infections with HIV vary in different regions and usually reflect the infections prevalent in these regions. This present study was aimed at comparing the prevalence and types of intestinal parasitic infections in HIV sero-positive and sero-negative patients in Lagos.

MATERIALS AND METHODS

Venous blood and stool samples of 1080 patients, recruited from three health care institutions were screened for HIV infection and intestinal parasites using HIV-1, HIV-2 rapid tests, direct wet mount with saline/iodine and formol-ether technique, respectively.

RESULTS

Results showed that 6% (65/1080) of patients were sero-positive for HIV infection. In addition, 23.3% (252/1080) patients were infected with intestinal parasites and 33.8% (22/65) of patients with HIV had intestinal parasites co-infections. The prevalence of Entamoeba histolytica/Entamoeba dispar, Entamoeba coli, Iodamoeba butschilii, Giardia intestinalis, and Hookworm were statistically significantly higher among HIV sero-positive patients as compared to the HIV sero-negative patients. In addition, HIV sero-positive patients had higher odds of mixed intestinal parasites than the HIV sero-negative patients (9.1% versus 3.9%; adjusted OR 2.05, 95% CI, 1.14-3.72, P=0.021).

CONCLUSION

In this study population, HIV sero-positive patients were more likely to have intestinal parasitic infections. The study underscores the public health significance of intestinal parasitic infections in HIV infected individuals.

[Microscopic diagnosis of amebiasis: an obsolete method but necessary in the developing world]

Molecular biology-based diagnosis offers the best approach to detect amebiasis, but remains impractical in the clinical laboratories from the developing world. In these areas, the microscopic diagnosis remains the routine method. It is imperative that a series of fresh stool specimens be examined. The use of a concentration method should become a routine procedure. Permanent stained smears is the most critical and reliable diagnostic method for the microscopic detection of intestinal protozoa. If the direct or concentrate wet mounts were considered as a preliminary examination; and the use of iron-hematoxylin stained smears become a routine procedure, many of the misdiagnosis that frequently occur could be avoided. The iron-hematoxylin stained preparation is the method of choice for the microscopic detection of E. histolytica/E. dispar and other intestinal protozoa.

Public health and clinical importance of amoebiasis in Malaysia: a review

Entamoeba histolytica, the causative agent of human amoebiasis remains a significant cause of morbidity and mortality in developing countries and is responsible for up to 100,000 deaths worldwide each year. Entamoeba dispar, morphologically indistinguishable from E. histolytica is more common in humans in many parts of the world. Similarly Entamoeba moshkovskii, which was long considered to be a free-living amoeba is also morphologically identical to E. histolytica and E. dispar, and is highly prevalent in some E. histolytica endemic countries. Humans are the host of infection and there would not appear to be other meaningful animal reservoirs of E. histolytica. Entamoeba. histolytica can be present in sewage and contaminated water. The infection is mainly transmitted via ingestion of water or food contaminated by faeces containing E. histolytica cysts. Clinical features of amoebiasis range from asymptomatic colonization to amoebic dysentery and invasive extraintestinal amoebiasis, which is manifested most commonly in the form of abscesses in liver and lungs. The epidemiology of amoebiasis has dramatically changed since the separation of E. histolytica and E. dispar species and the worldwide prevalence of these species has not been estimated until recently. Morever, E. moshkovskii, another morphologically indistinguishable human parasitic Entamoeba was not mentioned or considered as a contributor to the prevalence figures in endemic areas. Amoebiasis is still a major health problem especially in aboriginal settlements and amongst people living in remote area in Malaysia. However, until now there is only one data currently available to indicate the true prevalence and incidence of E. histolytica and E. dispar. Further studies are needed to determine the burden of E. histolytica, E. dispar and E. moshkovskii infections in Malaysia. In the present review, we briefly summarize all methods use in diagnosing Entamoeba species, ranging from microscopic identification to molecular detection such as culture and isoenzyme analysis, antibody detection tests, antigen detection tests, immunochromatographic assays, conventional PCR, real-time PCR and loop-mediated isothermal amplification (LAMP).

Use of PCR to detect Entamoeba gingivalis in diseased gingival pockets and demonstrate its absence in healthy gingival sites

Investigators using light microscopy have identified the protozoan parasite Entamoeba gingivalis from diseased gingival pockets for nearly 100 years. The objective of the present investigation was to develop a molecular biology approach for determining the presence of E. gingivalis in both diseased gingival pockets and healthy gingival sites. For this, a previously developed conventional polymerase chain reaction (PCR) was evaluated and a real-time polymerase chain reaction assay was developed. Paper points were inserted into the base of the sulcus of both diseased gingival pockets and healthy gingival sites. DNA was extracted using the QIAamp DNA mini kit, and subsequently analyzed using conventional and real-time PCR analysis. A previously described primer set specific for the small subunit ribosomal RNA gene (SSU rDNA) of E. gingivalis was used for the conventional PCR. For the real-time PCR, a primer set was designed to amplify a 135-bp fragment inside the SSU rDNA of E. gingivalis. A conventional PCR assay detected E. gingivalis in 27% of diseased gingival pockets. The real-time PCR using a different primer set detected protozoa in 69% of diseased pocket sites. Thus, the latter technique proved more sensitive for detection of E. gingivalis. No E. gingivalis were detected in any of the healthy gingival pocket sites using either type of PCR assay. Results support a concept that the presence of E. gingivalis is associated only with diseased gingival pocket sites. The newly described methodology may also serve to provide a novel eukaryotic cell marker of disease status in gingival pockets.

Pathogen destruction and solids decomposition in composting latrines: study of fundamental mechanisms and user operation in rural Panama

The relationship between temperature, high pH, desiccation, decomposition, pathogen destruction, and user operation in active double vault urine diverting (DVUD) composting latrines located in the Bocas del Toro region of Panama was assessed. Latrine samples were analyzed for temperature, pH, % moisture, carbon-to-nitrogen (C/N) ratio, and presence of specific pathogens. Surveys and visual inspections were used to verify use and type of dry material desiccant added. Measurements supported findings that compost latrines do not reach temperatures sufficient to destroy all pathogens. pH measurements showed that many latrines were operating within the range for ideal aerobic decomposition, a pH of 7.5-8.5, but only 17% of latrines measured pH 9 or above. Almost 100% of composting latrine users added sawdust and wood ash, to lower moisture level and provide carbon for decomposition. However, the recommended amount of desiccant added was insufficient to reduce moisture to the suggested 25% for pathogen destruction and C/N ratios remained in the range of raw human faeces. Importantly, pathogens, mainly helminths, were still present in compost stored for the 6-month contact time. The latrines have conflicting goals of pathogen destruction and aerobic decomposition. Recommendations are made regarding operation of composting latrines and disposal of composted material.

Validation and utilization of PCR for differential diagnosis and prevalence determination of Entamoeba histolytica/Entamoeba dispar in Salvador City, Brazil

Amoebiasis is an infection caused by Entamoeba histolytica and is a potential health risk in countries in which health barriers are inappropriate. Since the discovery of Entamoeba dispar, the prevalence of amoebiasis has been modified.

OBJECTIVE

This study has standardized the PCR technique applied for the diagnosis of different species of the E. histolytica/E. dispar complex and has evaluated the prevalence of infection among patients attending private and public clinical laboratories in Salvador City, Bahia State, Brazil.

RESULTS

Analysis of 52,704 stool samples by microscopic examination demonstrated that 1,788 (3.4%) were positive for the E. histolytica/E. dispar complex and infection occurred more often in samples originated from public clinical laboratories (5.0%) than those that came from private laboratories (3.2%). PCR performed in approximately 15% (262) E. histolytica/E. dispar complex positive samples, randomly chosen, amplified 227 samples (86.6%), all of them positive for E. dispar. The non-amplified 35 samples (13.4%) were also negative for E. histolytica-specific galactose adhesin. Moreover, to exclude a probable infection caused by E. hartmanni, morphometric analysis demonstrated that non-amplified samples had cyst sizes comparable to E. histolytica/E. dispar (>10 µm).

CONCLUSION

The absence of amplification of these samples indicates the presence of PCR inhibitors in the stool samples or the presence of DNA from Entamoeba species other than E. dispar, E. histolytica or E. hartmanni.