Effect of magnetic field on the growth of the cultured Entamoeba histolytica isolated from patients in Palestine.

Static magnetic field (SMF) is generated in vicinity of moving charge or current passing through conductor. In this study, we aimed to investigate the effect of SMF on the growth of the cultured Entamoeba histolytica (E. histolytica) trophozoites. Different SMF strengths with maximum value equals 30 mT (mT) was applied on the E.histolytica for different periods of times: 0 h, 24 h, 48 h, and 72 h. A modified diphasic liver infusion agar medium was used for culturing E. histolytica in vitro. The results showed the successful stabilization of culture of E. histolytica trophozoites. If we kept the sample for longer time, e. g. 14 days, the growth rate decreases to zero. When applying 10 mT and 15 mT SMF on the sample, it is found that the cultivated E. histolytica trophozoites dies after 4 and 2 days respectively. The experiments suggested that the SMF inhibited the growth and the propagation of E. histolytica cells. In addition, it completely killed all the cells in a short time interval which depend on the SMF strength. It is concluded that the SMFs inhibits the growth of E. histolytica and change the morphology of these cells. Thus, we recommend to use SMF as treatment to mitigate the growth of E. histolytica.

Loop-mediated isothermal amplification (LAMP) reaction as viable PCR substitute for diagnostic applications: a comparative analysis study of LAMP, conventional PCR, nested PCR (nPCR) and real-time PCR (qPCR) based on Entamoeba histolytica DNA derived from faecal sample.

BACKGROUND: This study reports the analytical sensitivity and specificity of a Loop-mediated isothermal amplification (LAMP) and compares its amplification performance with conventional PCR, nested PCR (nPCR) and real-time PCR (qPCR). All the assays demonstrated in this study were developed based on Serine-rich Entamoeba histolytica protein (SREHP) gene as study model. RESULTS: A set of SREHP gene specific LAMP primers were designed for the specific detection of Entamoeba histolytica. This set of primers recorded 100% specificity when it was evaluated against 3 medically important Entamoeba species and 75 other pathogenic microorganisms. These primers were later modified for conventional PCR, nPCR and qPCR applications. Besides, 3 different post-LAMP analyses including agarose gel electrophoresis, nucleic acid lateral flow immunoassay and calcein-manganese dye techniques were used to compare their limit of detection (LoD). One E. histolytica trophozoite was recorded as the LoD for all the 3 post-LAMP analysis methods when tested with E. histolytica DNA extracted from spiked stool samples. In contrast, none of the PCR method outperformed LAMP as both qPCR and nPCR recorded LoD of 100 trophozoites while the LoD of conventional PCR was 1000 trophozoites. CONCLUSIONS: The analytical sensitivity comparison among the conventional PCR, nPCR, qPCR and LAMP reveals that the LAMP outperformed the others in terms of LoD and amplification time. Hence, LAMP is a relevant alternative DNA-based amplification platform for sensitive and specific detection of pathogens.

AIG1 affects in vitro and in vivo virulence in clinical isolates of Entamoeba histolytica.

The disease state of amebiasis, caused by Entamoeba histolytica, varies from asymptomatic to severe manifestations that include dysentery and extraintestinal abscesses. The virulence factors of the pathogen, and host defense mechanisms, contribute to the outcomes of infection; however, the underlying genetic factors, which affect clinical outcomes, remain to be fully elucidated. To identify these genetic factors in E. histolytica, we used Illumina next-generation sequencing to conduct a comparative genomic analysis of two clinical isolates obtained from diarrheal and asymptomatic patients (strains KU50 and KU27, respectively). By mapping KU50 and KU27 reads to the genome of a reference HM-1:IMSS strain, we identified two genes (EHI_089440 and EHI_176590) that were absent in strain KU27. In KU27, a single AIG1 (avrRpt2-induced gene 1) family gene (EHI_176590) was found to be deleted, from a tandem array of three AIG1 genes, by homologous recombination between the two flanking genes. Overexpression of the EHI_176590 gene, in strain HM-1:IMSS cl6, resulted in increased formation of cell-surface protrusions and enhanced adhesion to human erythrocytes. The EHI_176590 gene was detected by PCR in 56% of stool samples from symptomatic patients infected with E. histolytica, but only in 15% of stool samples from asymptomatic individuals. This suggests that the presence of the EHI_176590 gene is correlated with the outcomes of infection. Taken together, these data strongly indicate that the AIG1 family protein plays a pivotal role in E. histolytica virulence via regulation of host cell adhesion. Our in-vivo experiments, using a hamster liver abscess model, showed that overexpression or gene silencing of EHI_176590 reduced and increased liver abscess formation, respectively. This suggests that the AIG1 genes may have contrasting roles in virulence depending on the genetic background of the parasite and host environment.

Intestinal parasitosis, anaemia and risk factors among pre-school children in Tigray region, northern Ethiopia.

BACKGROUND: Intestinal parasitic infections (IPIs) and anaemia are major health problems. This study assessed the prevalence of intestinal parasitic infections, anaemia and associated factors among pre-school children in rural areas of the Tigray region, northern Ethiopia. METHODS: A community based cross-sectional study was conducted among 610 pre-school children in rural communities of Northern Ethiopia from June 2017 to August 2017. Stool specimens were examined for the presence of trophozoites, cysts, oocysts, and ova using direct, formal-ethyl acetate concentration, Kato-Katz, and Ziehl-Neelsen techniques. Haemoglobin was measured using a HemoCue spectrometer. RESULTS: Among the 610 participating pre-school children in the study, the prevalence of IPIs and anaemia were 58% (95% conference interval (CI): 54.1-61.9%) and 21.6% (95% CI: 18.5-25.1%), respectively. Single, double, and triple parasitic infections were seen in 249 (41, 95% CI: 37-45%), 83 (14, 95% CI: 11-17%), and 22 (3.6, 95% CI: 2.4-5.4%) children, respectively. Of the seven intestinal parasitic organisms recorded from the participants, Entamoeba histolytica/dispar was the most prevalent 220 (36.1%) followed by Giardia lamblia 128 (20.1%), and Hymenolepis nana 102 (16.7%). Mixed infections were common among G. lamblia, E. histolytica/dispar and Cryptosporidium spp. oocyst. Intestinal parasitic infection prevalence increased from 47% in children aged 6-11 months to 66% in those aged 48-59 months; the prevalence ratio (PR) associated with a one-year increase in age was 1.08 (95% CI: 1.02-1.14, p = 0.009). Age-adjusted prevalence was higher in children who had been dewormed (PR = 1.2; 95% CI: 1.00-1.4, p = 0.045), and lower in households having two or more children aged under five (PR = 0.76, 95% CI: 0.61-0.95, p = 0.015). Anaemia rose from 28% in children aged 6-11 months to 43% in those aged 12-23 months, then fell continuously with age, reaching 7% in those aged 48-59 months. Age adjusted, anaemia was more prevalent in households using proper disposal of solid waste (PR = 1.5, 95% CI: 0.1-2.10, p = 0.009) while eating raw meat (PR = 0.49, 95% CI: 0.45-0.54, p = 0.000), any maternal education (PR = 0.64 95% CI: 0.52-0.79, p = 0.000), and household water treatment (PR = 0.75, 95% CI: 0.56-1.0, p = 0.044) were associated with lower prevalence of anaemia. CONCLUSIONS: More than half of the children were infected with intestinal parasites, while anaemia prevalence was concentrated in the 12-23 month age group. This study has identified a number of potentially modifiable risk factors to address the significant prevalence of IPIs and anaemia in these children. Improvements in sanitation, clean water, hand hygiene, maternal education could address both short and long-term consequences of these conditions in this vulnerable population.

Case report: multiple and atypical amoebic cerebral abscesses resistant to treatment.

BACKGROUND: The parasite Entamoeba histolytica is the causal agent of amoebiasis, a worldwide emerging disease. Amebic brain abscess is a form of invasive amebiasis that is both rare and frequently lethal. This condition always begins with the infection of the colon by E. histolytica trophozoites, which subsequently travel through the bloodstream to extraintestinal tissues. CASE PRESENTATION: We report a case of a 71-year-old female who reported an altered state of consciousness, disorientation, sleepiness and memory loss. She had no history of hepatic or intestinal amoebiasis. A preliminary diagnosis of colloidal vesicular phase neurocysticercosis was made based on nuclear magnetic resonance imaging (NMRI). A postsurgery immunofluorescence study was positive for the 140 kDa fibronectin receptor of E. histolytica, although a serum analysis by ELISA was negative for IgG antibodies against this parasite. A specific E. histolytica 128 bp rRNA gene was identified by PCR in biopsy tissue. The final diagnosis was cerebral amoebiasis. The patient underwent neurosurgery to eliminate amoebic abscesses and was then given a regimen of metronidazole, ceftriaxone and dexamethasone for 4 weeks after the neurosurgery. However, a rapid decline in her condition led to death. CONCLUSIONS: The present case of an individual with a rare form of cerebral amoebiasis highlights the importance of performing immunofluorescence, NMRI and PCR if a patient has brain abscess and a poorly defined diagnosis. Moreover, the administration of corticosteroids to such patients can often lead to a rapid decline in their condition.

Genetic variability of E. histolytica strains based on the polymorphism of the SREHP gene using nested PCR-RFLP in Erbil, North Iraq.

E. histolytica is an intestinal parasite that causes asymptomatic infection mostly; however, it may also cause amoebic dysentery and liver abscess. Molecular identification is required in epidemiological studies due to the presence of morphologically identical nonpathogenic species. Therefore, this study was conducted to first evaluate the prevalence rate of E. histolytica among symptomatic individuals of Erbil city, and to investigate the genetic diversity of the parasite in a limited geographic area. Accordingly, a total of 2026 samples were examined microscopically, and confirmed by nested PCR for 18s rRNA gene. The results showed that the prevalence rate of E. histolytica was 1.97% (40 samples) among symptomatic patients. The SREHP gene was used as a marker to show the genetic polymorphism of E. histolytica; however, to compare the genetic diversity of symptomatic with asymptomatic isolates, 57 asymptomatic samples were obtained from our previous study. The amplified products of the SREHP gene were digested by AluI endonuclease, and DNA banding patterns were analysed. Results showed 29 different DNA patterns among the 97 symptomatic and asymptomatic samples, 62 of which shared similar DNA patterns. However, 8 different DNA patterns were observed among asymptomatic samples, whereas 15 distinct patterns were observed among symptomatic isolates. In conclusion, this study found that the prevalence rate of E. histolytica was relatively low; relatively high genetic diversity was observed in a restricted endemic area; with higher rates of variability in symptomatic rather than in asymptomatic isolates, indicating a possible correlation between the genotype of E. histolytica and their clinical outcome.

Fulminant amebic colitis: An unusual postoperative complication of intraabdominal malignancy.

Amebiasis caused by protozoa Entamoeba histolytica (EH) is the third leading parasitic cause of human mortality. Although amebiasis is endemic in India, only about 10% of the infected individuals manifest disease. Clinical spectrum of amebiasis ranges from asymptomatic colonization to amebic colitis to hemorrhagic and fulminant colitis. Factors causing an invasive infection are not completely understood. Pathogen virulence, host immunity, and ability of the pathogen to evade host immune response play vital role in determining the disease course. Host factors such as immunocompromised states may make an individual susceptible to develop symptomatic infection. Malignancies usually result in chronic debilitation which may make the individual prone to develop invasive amebiasis with rapid progression. We report two cases of invasive amebiasis which developed a fulminant course in the immediate postoperative period after abdominal surgeries for visceral malignancies.

Successful surgical drainage with intraoperative ultrasonography for amebic liver abscess refractory to metronidazole and percutaneous drainage: a case report.

BACKGROUND: Metronidazole (MNZ) has been clearly established as a medication for amebic liver abscess. In uncomplicated cases, surgical drainage should be avoided. We report a case of amebic liver abscess refractory to MNZ that was successfully treated using preoperative computed tomography (CT) and percutaneous and surgical drainage with intraoperative ultrasonography (IOUS). CASE PRESENTATION: A 53-year-old man with high-grade fever was diagnosed with a cystic lesion on his right hepatic lobe using CT. Percutaneous drainage was performed, and antibacterial drugs were administered. However, the infection and condition of the patient worsened. Entamoeba histolytica was detected from pus within the mediastinal cavity. Hence, the patient was diagnosed with amebic liver abscess. After the diagnosis was established, we administered MNZ for 10 days. Despite this, the patient's physical condition did not improve. Blood tests suggested impending disseminated intravascular coagulation (DIC). We performed surgical intervention to drain the amebic liver abscess refractory to conservative treatment. During surgery, imaging information from preoperative CT and IOUS enabled us to recognize the anatomical structures and determine the incision lines of the hepatic capsule and hepatic tissue. The patient's DIC immediately regressed after surgery. Unfortunately, malnutrition and disuse syndrome contributed to the patient's long recovery period. He was discharged 137 days post-surgery. CONCLUSIONS: We reported a case of amebic liver abscess refractory to conservative treatment. Surgical drainage with preoperative CT and IOUS allowed us to safely and effectively perform complex abscess decompression.

Intestinal parasites including Cryptosporidium, Cyclospora, Giardia, and Microsporidia, Entamoeba histolytica, Strongyloides, Schistosomiasis, and Echinococcus: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice.

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of intestinal parasites in the pre- and post-transplant period. Intestinal parasites are prevalent in the developing regions of the world. With increasing travel to and from endemic regions, changing immigration patterns, and the expansion of transplant medicine in developing countries, they are increasingly recognized as a source of morbidity and mortality in solid-organ transplant recipients. Parasitic infections may be acquired from the donor allograft, from reactivation, or from de novo acquisition post-transplantation. Gastrointestinal multiplex assays have been developed; some of the panels include testing for Cryptosporidium, Cyclospora, Entamoeba histolytica, and Giardia, and the performance is comparable to conventional methods. A polymerase chain reaction test, not yet widely available, has also been developed to detect Strongyloides in stool samples. New recommendations have been developed to minimize the risk of Strongyloides donor-derived events. Deceased donors with epidemiological risk factors should be screened for Strongyloides and recipients treated if positive as soon as the results are available. New therapeutic agents and studies addressing the optimal treatment regimen for solid-organ transplant recipients are unmet needs.

Update on laboratory diagnosis of amoebiasis.

Amoebiasis, an enteric protozoan disease caused by Entamoeba histolytica, is a public health problem in many developing countries, causing up to 100,000 fatal cases annually. Detection of the pathogenic E. histolytica and its differentiation from the non-pathogenic Entamoeba spp. play a crucial role in the clinical management of patients. Laboratory diagnosis of intestinal amoebiasis in developing countries still relies on labour-intensive and insensitive methods involving staining of stool sample and microscopy. Newer and more sensitive methods include a variety of antigen detection ELISAs and rapid tests; however, their diagnostic sensitivity and specificity seem to vary between studies, and some tests do not distinguish among the Entamoeba species. Molecular detection techniques are highly sensitive and specific and isothermal amplification approaches may be developed into field-applicable tests; however, cost is still a barrier for their use as a routine laboratory test method in most endemic areas. Laboratory diagnosis of extraintestinal amoebiasis faces challenges of lack of definitive detection of current infection and commercially available point-of-care tests. For both types of amoebiasis, there is still a need for highly sensitive and specific tests that are rapid and cost-effective for use in developing countries where the disease is prevalent. In recent years, new molecules of diagnostic value are being discovered and new tests developed. The advances in 'omics' technologies are enabling discoveries of new biomarkers that may help distinguish between different infection stages.

Prevalence of feco-oral transmitted protozoan infections and associated factors among university students in Ethiopia: a cross-sectional study.

BACKGROUND: An estimated 60% of the world's population is infected with one form of intestinal parasites. Amoebiasis and giardiasis are among the leading intestinal protozoan infections that affected mankind. However, literature that shows the magnitude of the problem among university students in Ethiopia is at scarce. Therefore, this study was aimed at assessing the prevalence of feco-oral transmitted protozoan infections and associated factors among sport festival participant universities in Ethiopia. METHODS: A cross-sectional study design was conducted among 483 randomly selected university sport festival participant students. A self-administered questionnaire was used to collect the data. Stool specimens were examined using direct wet mount and formol-ether concentration techniques. The data were entered into Epi Info version 6.04 and were analyzed using SPSS version 20.0 statistical software. Multivariable logistic regression analysis was done to control the possible confounders and an odds ratio with a 95% confidence interval at p < 0.05 was used to identify an association between variables. RESULT: The overall prevalence of intestinal protozoan infections was 140(28.9%) with the predominantly higher prevalence of E. histolytica/E. dispar 95(19.7%). The female respondents were at lower risk of infections compared to their male counterparts (AOR = 0.48, 95% CI: 0.22, 0.97]. Participants with educated father (AOR = 0.62, 95% CI: 0.12, 0.86) and those who received pocket money of > 347 Ethiopian Birr (~ 14 USD) per month (AOR = 0.20, 95% CI: 0.12, 0.74) were at lower risk of infections. However, being married (AOR = 1.42, 95% CI: 1.10, 2.23), rural resident (AOR = 1.82, 95% CI: 1.21, 3.32) and university stay for two or more years (AOR = 2.21, 95%CI: 1.48, 3.87) were more likely to be infected with protozoan infections. CONCLUSION: The prevalence of intestinal protozoan infection among students who attend higher educational institutions was very high. Infection prevention strategies should be undertaken at respective universities with special focus to senior students and students from the rural area.

Intestinal parasitosis in relation to CD4 count and anemia among ART initiated patients in St. Mary Aksum general hospital, Tigray, Ethiopia.

BACKGROUND: The geographical distribution of intestinal parasites with conditions of poverty in most countries of sub-Saharan Africa coincides with that of HIV/AIDS. However, there is paucity of studies investigating the relationship between intestinal parasitic infections with CD4 counts and anemia in HIV/AIDS patients starting Antiretroviral Therapy (ART) in this region particularly and in Ethiopia in general. The aim of this study was to determine the prevalence of intestinal parasitic infections in relation to CD4 count and anemia among ART-initiated patients in St. Mary Aksum General Hospital, Tigray, Ethiopia. METHODS: A cross-sectional study was conducted among randomly selected 242 ART-initiated participants during February to April 2017 in St. Mary Aksum General hospital. Data was collected using structured questionnaire and laboratory examination. Logistic regression was applied to assess any association between explanatory factors and outcome variables (P values < 0.05). RESULT: The overall prevalence of intestinal parasites was 26.4% and among the six types of parasitic genera identified Entamoeba histolytica/dispar (18.6%) and Giardia lamblia (2.1%) were the leading. According to the multivariate analysis, lack of hand washing before meal, eating uncooked vegetables, history of taking anti-parasite medication, stool consistency, and anemia were strongly associated with intestinal parasitosis. CONCLUSION: There was a high prevalence of intestinal parasites among HIV positive individuals. Intervention measures such as deworming, improving hygiene and sanitation practices should be strengthened to reduce the burden of intestinal parasites among people living with HIV.

Development and evaluation of molecular tools for detecting and differentiating intestinal amoebae in healthy individuals.

Amoebae are single-celled parasites frequently colonizing human gut. However, few molecular tools are available for accurate identification. Here, we evaluated a panel of polymerase chain reactions (PCRs) targeting Entamoeba histolytica, Entamoeba dispar, Entamoeba coli, Entamoeba hartmanni, Entamoeba polecki, Endolimax nana and Iodamoeba bütschlii. Thirty-six faecal samples (18 containing at least one amoeba species by microscopy and 18 microscopy negative for amoebae) were tested. Real-time PCRs were used for detection and differentiation of E. histolytica and E. dispar. Conventional PCR with Sanger sequencing were applied for detection and differentiation of E. coli, E. hartmanni, E. polecki, E. nana and I. bütschlii. All microscopy results were confirmed by DNA-based methods. However, more samples were positive for single and mixed amoebic species by DNA-based assays than by microscopy (22 vs 18 and 7 vs 1, respectively). DNA sequencing allowed identification of E. coli subtypes (ST1 and ST2), showed low intra-specific variation within E. hartmanni, identified two phylogenetically distinct groups within E. nana, and identified Iodamoeba at the ribosomal lineage level. Taking into account the high intra-genetic diversity within some of the species at the small subunit (SSU) rRNA gene level, amplification of SSU rRNA genes with subsequent sequencing represents a useful method for detecting, differentiating and subtyping intestinal amoebae.

Are immunoenzymatic tests for intestinal protozoans reliable when used on archaeological material?

Intestinal protozoans found in ancient human samples have been studied primarily by microscopy and immunodiagnostic assays. However, such methods are not suitable for the detection of zoonotic genotypes. The objectives of the present study were to utilize immunoenzimatic assays for coproantigen detection of Cryptosporidium sp., Giardia duodenalis, and Entamoeba histolytica/Entamoeba dispar in sixty ancient human and animal samples collected from 14 archaeological sites in South America, and to carry out a critical analysis of G. duodenalis according to results obtained from three diagnostic methodologies: microscopy, immunodiagnostic tests (immunoenzymatic and immunofluorescence), and molecular biology (PCR and sequencing). More than half (31/60) of the samples analyzed using immunoenzymatic tests were positive for at least one of the intestinal protozoans, with 46.6% (28/60) corresponding to G. duodenalis, 26.6% (16/60) to Cryptosporidium sp., and 5% (3/60) to E. histolytica/E. dispar. Cryptosporidium sp. and G. duodenalis coinfection was observed in 15% (9/60) of the samples, whereas all three protozoans were found in 5% (3/60) of samples. In the Northeast Region of Brazil, by immunoenzymatic tests there is evidence that G. duodenlais and Cryptosporidium sp. have infected humans and rodents for at least 7150 years. However, for G. duodenalis, the results from the three diagnostic tests were discordant. Specifically, despite the efficiency of the molecular biology assay in the experimental models, G. duodenalis DNA could not be amplified from the ancient samples. These results raise the following question: Are all ancient samples positive for coproantigen of G. duodenalis by immunoenzymatic tests truly positive? This scenario highlights the importance of further studies to evaluate the sensitivity and specificity of the immunoenzymatic method in the archaeological context.

[Preliminary Study on PCR Method for Laboratory Diagnosis with Fecal Specimens of Entamoeba histolytica Infection].

OBJECTIVE: To develop a PCR method for Entamoeba histolytica（ E.histolytica) detection in fecal specimens, and to compare the performance of PCR to that of microscopy and ELISA. METHODS: Two pairs of self-designed primers and 2 pairs of primers from references based on small subunit ribosome RNA (SSU rRNA) fragment of E. histolytica standard strain were synthetized. DNA from E. histolytica reference strain were amilified by the conventional PCR using the 4 pairs of primers. 221 stool samples from diarrhea patients were collected and detected for E. histolytica by three methods: Entamoeba trophozoites and cysts detection by microscopy, E. histolytica-specific antigen detection using enzyme-linked immunosorbent assay (ELISA) kit ( E. HISTOLYTICA II), amplification of SSU rRNA fragment of E. histolytica by PCR method. Positive rate of three methods were compared by chi-square test, and Kappa test was applied to determine the concordance among the three methods. RESULTS: Specific fragments of E. histolytica were amplified by the PCR method we developed in this study. Positive rates of PCR, microscopy and ELISA were 2.26%, 0.90% and 9.50%, respectively. The positive rates of the three methods were significantly different ( χ 2 =23.34, P<0.01). The Kappa value of PCR and microscopy was 0.216, and that of PCR and ELISA method was -0.134, both of which showed a weak consistency. PCR results showed best consistency with clinical diagnosis. CONCLUSION: The PCR method we established in this study has a better performance in accuracy than microscopy and ELISA have in laboratory diagnosis of E. histolytica infection.

When IBD is not IBD.

Entamoeba histolytica colitis can mimic Crohn's disease. However, a fulminant infection can be life-threatening, especially after exposure to systemic steroids. We present a case of the patient who was initially diagnosed with ileocolonic Crohn's disease, but developed a hepatic E histolytica abscess while undergoing anti-TNF therapy. After revision of the initial diagnostic biopsies, the diagnosis was questioned and E histolytica was confirmed using PCR and histopathology. As intestinal amoebiasis is the most common form of amoebic infection, care should be taken in case of refractory IBD or at initial diagnosis in patients who travelled to endemic areas. We therefore discuss the epidemiology, clinical features, diagnostic tools and pathophysiology of E Histolytica in order to raise awareness among gastroenterologists treating patients with inflammatory bowel disease.

Amoebiasis in Iran: a systematic review and meta-analysis.

A comprehensive meta-analysis study was performed to estimate the reliable national prevalence and molecular epidemiology of amoebiasis in Iran. Nine English and Persian databases were searched to achieve the relevant studies. Pooled estimates were generated and meta-regression was performed. We identified 71 eligible articles involving 330 930 subjects from 25 provinces to be included in the final analysis. Moreover, 17 studies compromising 462 polymerase chain reaction (PCR)-positive isolates performed molecular analysis to inter-species differentiation. The pooled prevalence of Entamoeba infection among Iranian population was about 1% (95% CI 0.8-2.0%). Moreover, regarding Human Development Index (HDI), a higher prevalence was observed in undeveloped provinces. Out of 462 PCR-positive isolates, 83% (95% CI 69-94%) and 12% (95% CI 3-24%) were Entamoeba dispar, Entamoeba histolytica, respectively. In subgroup analysis based on molecular results, in general, population prevalence of Entamoeba dispar and E. histolytica were 91% (95% CI 80-99%) and 7%, (95% CI 0-19%), respectively, while prevalence of these species in patients with gastrointestinal disorders were 75% (95% CI 45-96%) and 18% (95% CI 1-43%), respectively. Our findings indicate the low burden of amoebiasis in Iran. E. dispar, that is mostly non-pathogenic, was identified as most prevalent species. Nevertheless, we suggest more public health interventions in areas with lower HDI.

The detection of Entamoeba histolytica and Toxoplasma gondii in wastewater.

To increase current knowledge on the epidemiology of protozoan parasites in wastewater treatment plants (WWTP), the occurrence of Entamoeba histolytica and Toxoplasma gondii in raw and treated wastewater was investigated. Samples were collected from WWTP twice a month over a period of 8 months. Determination of protozoa was performed using polymerase chain reaction (PCR) and light microscopy. After concentration and purification of wastewater samples, DNA extraction was conducted followed by PCR amplification of small subunit ribosomal RNA (SSU rRNA) gene sequences of E. histolytica and B1 gene of T. gondii. Loop-Mediated Isothermal Amplification (LAMP) primer set was designed from E. histolytica hemolysin gene HLY6. Amplification of DNA in the LAMP mixture was monitored by naked eye as a blue color solution after addition of, hydroxynaphthol blue (HNB) to the reaction tube. Light microscopy revealed the presence of Entamoeba in all raw wastewater samples and treated water samples. PCR amplification of DNA products revealed that all, (9/9) wastewater samples were positive for Entamoeba. None was positive for Toxoplasma. These findings, which corroborate recent observations, indicate that E. histolytica may pose a public health risk.

Epidemiology and factors associated with amoebic liver abscess in northern Sri Lanka.

BACKGROUND: Clinically diagnosed amoebic liver abscess (ALA) caused by Entamoeba histolytica has been an important public health problem in Jaffna district, northern Sri Lanka for last three decades. In order to draw up a control strategy for elimination of this condition, knowledge of its epidemiology and factors associated with this condition in the local context is vital. METHODS: All clinically diagnosed ALA patients admitted to the Teaching Hospital, Jaffna during the study period were included in the study and the data were collected using an interviewer administered questionnaire. One hundred blood samples from randomly selected toddy (a local alcoholic drink consisting of the fermented sap of the Palmyrah palm) consumers and 200 toddy samples were collected. Toddy samples were cultured in Robinson's medium to establish the presence of Entamoeba histolytica in the sample. Climatic data and the total toddy sales in the district were obtained from the Meteorological and Excise Departments respectively. A sub group of randomly selected 100 patients were compared with 100 toddy consumers who were negative for E. histolytica antibody to explore the potential risk factors. RESULTS: Between July 2012 and July 2015, 346 of 367 ALA patients were enrolled in this study. Almost all patients (98.6%) were males with a history of heavy consumption of alcohol (100%). Almost all (94.2%) were within the age group 31-50 years. None of the cultured toddy samples grew E. histolytica. The monthly incidence of disease peaked in the dry season, matching the total toddy sales in the district. Age, type of alcohol and frequency of drinking were identified as potential risk factors whereas frequency of alcohol consumption and type of alcohol (consuming toddy and arrack) were identified as the independent risk factors. Moreover, the knowledge, attitude and practices towards ALA were poor among participants and the control group. CONCLUSIONS: Though the number of cases has declined in recent years, ALA still remains as an important public health problem in Jaffna district. The transmission route of E. histolytica leading to ALA has to be further explored. Moreover, greater awareness among the public who are at risk would be beneficial in order to eliminate the disease.