Blastocystis Sp Research Articles

Human intestinal parasites in Mahajanga, Madagascar: The kingdom of the protozoa.

IntroductionIntestinal parasitic infections are a major public health problem in inter-tropical areas. The aim of our study was to describe the situation in Mahajanga, Madagascar with a particular focus on two protozoa, Dientamoeba fragilis and Blastocystis sp.MethodsThis was a prospective study from February to June 2015. Stool samples from symptomatic hospitalized patients and asymptomatic volunteers were submitted to microscopy and molecular assays in order to detect parasites.ResultsA wide panel of intestinal parasites were identified among the 265 included subjects, protozoa being the most prevalent with 72.8% whereas the prevalence of helminths and microsporidia was of 7.9% and 4.5%, respectively. Blastocystis sp. was the most prevalent protozoa (64.5% of the entire cohort) followed by various amoebas (35.5%) and flagellates (27,5%). We only detected subtypes 1, 2 and 3 of Blastocystis sp. Among the patients positive for D. fragilis (9.4%), 23 carried genotype 1 and 1 genotype 2. For the first time, we detected in 4 human stools the DNA of a recently described protozoon, Simplicimonas similis. Interestingly, subjects living in urban areas harbored significantly more different parasitic species than subjects living in rural areas with a correlation between sanitary level of neighborhood and protozoan infection. However, there was no difference in prevalence of digestive symptoms between parasite-free and parasite-infected subjects, except for Giardia intestinalis which had more symptomatic carriers.DiscussionOur study reveals a high overall parasite prevalence, similar to what had been found in 2003 in the same city and to other prevalence studies conducted in Africa. The poor access of the population to sanitary infrastructures may explain this result. Data from our study provide valuable key for sanitation programs and prevention of fecal-related infectious diseases.

Comparison of Direct Examination and In Vitro Culture for the Detection of Blastocystis spp. in Orang Asli Stool Samples

Microscopy-based technique has been widely used in the detection of Blastocystis sp. This study was conducted to compare the techniques used for screening of Blastocystis sp., namely in vitro cultivation of stool specimens in Jones’ medium (IVC) followed by Wheatley Trichrome staining and direct examination of stool samples preserved with polyvinyl alcohol (PVA) followed by Wheatley Trichrome staining with single-round polymerase chain reaction (PCR) as the reference technique. The study was performed on 466 stool samples obtained from the aboriginal community in Pahang, Malaysia. IVC showed higher detection rate of Blastocystis sp. (35.6%) than PVA (20.0%). Single-round PCR detected Blastocystis sp. in 41.0% of the stool specimens. The sensitivity and specificity of PVA and IVC in comparison to the reference technique were 75.3% (95% CI: 65.2-83.6) and 68.5% (CI: 63.7-73.3) and 88.6% (CI: 82.7-93.0) and 86.3% (CI: 81.9-90.0), respectively. The agreement between the reference technique and PVA showed statistically significant fair agreement by Cohen Kappa statistics of (K=0.318, p<0.001), meanwhile statistically significant substantial agreement was observed between PCR and IVC by Cohen Kappa (K=0.727, p<0.001). Therefore, in vitro cultivation in Jones’ medium followed by Wheatley Trichrome staining of stool specimens should be used as a screening technique in the detection of Blastocystis sp. infections.

Drinking unboiled water is the risk factor of blastocystis incidence in rural community Thailand from prospective cohort study

Introduction Blastocystis sp. is one of the most common intestinal protozoa in humans, which is found to be asymptomatic. Recently, there are reports suggesting it is to be pathogenic in immunocompromised host. The patients will present with history of watery stool and diarrhea. Despite the discovery of Blastocystis approximately 100 years ago, limited information is available regarding its incidence and risk factors. The aim of this study was to identify the incidence and the risk factors associated with Blastocystis infection in the rural community of Thailand. Methods The prospective cohort study was performed between February and December 2016 in PhraPloeng community, Khao Cha Kan district, Sakaeo province, Thailand. All stool samples were tested for the presence of Blastocystis sp. By direct microscopy of native (0.09% NaCl) and culture john media techniques. Cox's proportional hazard regression analyses were performed to identify potential risk factors for infection. Results Total of 354 persons who primary identified as Blastocystis negative at baseline in February 2016 were enrolled into this study. In the 10 months follow-up, we identified 26 new cases of Blastocystis infection and this participants contribute total person time of follow-up as 289.8 person-years. The incidence for Blastocystis infection is 8.97 per 100 person-years. In addition, we also follow-up of 50 infected participants from the baseline, which show the incidence of spontaneous recovery and persistence or reinfection as 75.73 per 100 person-years and 46.41 per 100 person-years, respectively. After adjusted for potential confounding factors by using multivariable Cox's proportional hazard regression analysis, we found that drinking unboiled water is independently associated with incidence of Blastocystis infection (IRR = 3.1, 95% CI = 1.11–8.47). Conclusions A high incidence of Blastocystis sp. infection was found in rural community of Thailand, which was 5 times higher than the orphanage study in Bangkok. Unboiled water impact of the incidence of Blastocystis sp. was highlighted as the risk factor for the infection. The results implicate the waterborne transmission of Blastocystis sp.

The Effect of Proton Pump Inhıbıtor Usage on the Incidence of Blastocystis sp.

Amaç: Blastocystis sp. insanlarda en sık görülen intestinal sistem protozoonlarından biridir ve kontamine olmuş gıdalarla ve su ile fekal oral yolla bulaşmaktadır. Gastrointestinal sistem hastalıklarında çoğunlukla kullanılan proton pompa inhibitörlerinin (PPI), midenin pH’nı yükselttiği bilinmektedir. Bu çalışma, PPI kullanımının Blastocystis sp.’nin görülme sıklığı üzerine etkisini araştırmak amacı ile yapılmıştır.Gereç ve Yöntem: Çalışmaya ……… Üniversitesi Tıp Fakültesi Parazitoloji Laboratuvarı’na Gastroenteroloji polikliniğinden Ocak 2013 - Haziran 2013 tarihleri arasında rutin dışkı incelemesi için gönderilen ve 1 ay içerisinde düzenli olarak PPI kullanımı olan 100 hasta ile, hiç PPI kullanımı olmayan; fakat gastrointestinal şikayetleri olan 100 hasta dahil edilmiştir. Kontrol grubunu ise hiç polikliniğe başvurmamış 100 sağlıklı birey oluşturmuştur. Dışkı örnekleri bekletilmeden nativ-lugal yöntemi ile incelenmiştir. Bulgular: Çalışmamızda PPI kullananların %24’ünde, kullanmayanların %5’inde ve kontrol grubunun %8’inde Blastocystis sp. saptanmıştır. Proton pompa inhibitörlerini kullanan grupta Blastocystis sp. görülme sıklığı anlamlı düzeyde daha yüksek bulunmuştur (X2=8,883, p&amp;lt;0.001). Sonuç: Çalışma bulgularımıza dayanarak PPI kullananlarda blastosistosis’ in göz ardı edilmemesi gerektiği kanaatine varılmıştır. Mevcut literatüre göre yapmış olduğumuz bu çalışma; Blastocystis sp.’nin görülme sıklığı ile PPI kullanımı arasındaki ilişkiyi inceleyen ilk çalışma olup, gelecekte yapılacak benzeri çalışmalara referans oluşturması bakımından önem arz etmektedir.

Association of Helicobacter pylori and protozoal parasites in patients with chronic diarrhoea

IntroductionAn association of Helicobacter pylori and common protozoal parasites in patients with abdominal discomfort and chronic diarrhoea is unclear and may be pathological.Materials and methodsOne hundred and sixty-one patients with diarrhoea were compared to 114 age and sex matched controls. Stool samples were examined by microscopy and DNA extracted for PCR with specific primers for H. pylori and protozoal parasites Blastocystis sp., Entamoeba sp. (Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii) and Giardia duodenalis (G. duodenalis).ResultsThere was a marked difference in the presence of parasites between patients and controls: no parasite 42/75%, one parasite 42/15%, two or more parasites 16/10%, respectively (p < 0.001). Patients with diarrhoea were more likely to be infected with Blastocystis sp (p < 0.001), E. histolytica (p = 0.027) and E moshkovskii (p = 0.003). There was no difference in the frequency of H. pylori (p = 0.528), G duodenalis (p = 0.697) or E dispar (p = 0.425). Thirty-three patients and 27 controls had H. pylori infection. Of these, 22 patients and 6 controls were infected with Blastocystis sp (p = 0.001), 6 patients and no controls were infected with E. histolytica (p = 0.02), whilst 7 patents and 9 controls were infected with E dispar (p = 0.292).ConclusionIn this population, diarrhoea is linked to infection with Blastocystis sp, E. histolytica and E moshkoviskii. In H. pylori infection, diarrhoea is linked to Blastocystis sp and E. histolytica infection. These associations may be linked pathogenically.

A Comparison of a Modified Formalin-Ether Concentration Technique with a Commercial (Feconomics®) Method and Its Two Modifications in the Investigation of Blastocystis sp.

A Comparison of a Modified Formalin-Ether Concentration Technique with a Commercial (Feconomics®) Method and Its Two Modifications in the Investigation of Blastocystis sp.

PREVALENCE AND RISK FACTORS OF BLASTOCYSTIS SP. INFECTION AMONG PRIMARY SCHOOL CHILDREN IN A RURAL COMMUNITY, CENTRAL THAILAND

Background:Blastocystissp., a protozoan parasite, has been globally reported as one of the most common intestinal parasitic infections in humans. Water transmission plays an important role for the route of transmission of this organism to humans. Objectives:To determine the prevalence and risk factors of Blastocystissp.infection among schoolchildren in a rural community, central Thailand. Materials and Methods:In November 2015, schoolchildren from four primary schools (School A, B, C and D) at a rural community of Sanamchaikate district, Chacherngsao Province, central Thailand were enrolled into the study. Stool samples collected from participants were examined using wet preparation, phosphate buffered saline-ethyl acetate and Kato-Katz techniques. Short-term cultivation for Blastocystis sp. was performed using Jone’s medium supplemented with 10% horse serum. Strongyloides stercoralis was also detected using agar plate culture technique. Results:A total of 501 school children were analyzed. The mean age at diagnosis was 9.996±1.59years. The prevalence of overall parasitic infections was 17.8% and were diagnosed as follows: Blastocystis sp. in 64 participants (12.8%), Giardia duodenalis (1.4%), Entamoeba coli (1.0%), Opisthorchis viverrini(0.8%), Enterobius vermicuralis (0.6%), and Strongyloides stercolaris (0.4%). A significantly increased risk of Blastocystis sp.infection was found in children studying at the School B, C and A when compared with those studying at School D (p =0.001, OR =4.36, 95% CI =1.83-10.39, p =0.032, OR= 2.89,95% CI =1.10-7.64, and p =0.033, OR =2.2, 95% CI =1.06-4.54, respectively). Drinking water was suspected to be the source of transmission. However, screening by PCR at the 18S rRNA gene for Blastocystis sp. could not detect the parasites from any sources of drinking water samples collected from the four schools. Conclusion:Themost predominant intestinal protozoa infection in the study school children was Blastocystis sp. The high prevalence of protozoa infection could reflect the hygienic conditions of the children. Thus, health education and the control of intestinal parasitic infections are necessary to these children.

In vitro and in vivo thermal stress induces proliferation of Blastocystis sp.

Blastocystis sp. is known to be the most commonly found intestinal protozoan parasite in human fecal surveys and has been incriminated to cause diarrhea and abdominal bloating. Binary fission has been widely accepted as the plausible mode of reproduction for this parasite. The present study demonstrates that subjecting the parasites in vitro to higher temperature shows the proliferation of parasite numbers in cultures. Transmission electron microscopy was used to compare the morphology of Blastocystis sp. subtype 3 isolated from a dengue patient having high fever (in vivo thermal stress) and Blastocystis sp. 3 maintained at 41°C (in vitro thermal stress) and 37°C (control). Fluorescence stains like acridine orange (AO) and 4',6'-diamino-2-phenylindole (DAPI) were used to demonstrate the viability and nuclear content of the parasite for both the in vitro and in vivo thermal stress groups of parasites. Blastocystis sp. at 37°C was found to be mostly vacuolar whereas the in vitro thermal stressed isolates at 41°C were granular with electron dense material seen to protect the granules within the central body. Parasites of the in vivo thermal stressed group showed similar ultrastructure as the in vitro ones. AO and DAPI staining provided evidence that these granules are viable which develop into progenies of Blastocystis sp. These granular forms were then observed to rupture and release progenies from the mother cells whilst the peripheral cytoplasmic walls were seen to degrade. Upon exposure to high temperature both in vitro and in vivo, Blastocystis sp. in cultures show higher number of granular forms seen to be protected by the electron dense material within the central body possibly acting as a protective mechanism. This is possibly to ensure the ability to survive for the granules to be developed as viable progenies for release into the host system.

Blastocystis subtypes isolated from irritable bowel syndrome patients and co-infection with Helicobacter pylori.

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disease presenting clinically by abdominal pain with alteration of bowel habits. Although IBS has uncertain etiology, chronic gut inflammation due to persistent exposure to an infectious agent including Blastocystis sp. was proposed. The aim of this study was to detect the prevalence of Blastocystis sp. subtype (ST) isolated from stool of IBS patients and to assess Blastocystis sp. and H. pylori co-infection in IBS patients from Beni-Suef Governorate, Egypt. Stool samples were collected from 115 IBS patients, following Rome III criteria. All stool samples were microscopically examined by wet mount and permanent trichrome stain, cultured on Jones' medium with further sequencing of positive Blastocystis isolates and screened for detection of H. pylori coproantigen. Blastocystis sp. was the predominant parasite in IBS patients; it had statistical significant association with both rural residence (OR = 10) and flatulence (OR = 8.2). There was a predominance of Blastocystis sp. ST3 (81%) followed by ST1 (19%). Blastocystis culture results (19.1%) were superior than microscopy (16.5%). The majority of Blastocystis-positive IBS patients (72.7%) were co-infected with H. pylori with statistical significance; however, H. pylori was higher in Blastocystis-negative IBS patients (47/64) than in Blastocystis-positive IBS patients (17/64). Interestingly, IBS is usually associated with gut dysbiosis, while the most prevalent parasite in our IBS patients was Blastocystis sp., which is frequently found in asymptomatic individuals. Whether Blastocystis sp. is a cause or a consequence of IBS still needs further investigation, with a particular focus on correlation of IBS with different Blastocystis sp. subtypes and gut microbiomes.

Proteogenomics Gets onto the Regulation of mRNA Decoding and Translation into Protein.

Proteogenomics, the integrative analysis of the proteome and the genome, increasingly provides protein-level insights about the regulation of gene expression and protein translation. Armengaud et al. (Proteomics 2017, 17, 1700211) nicely illustrate this trend with the first in-depth proteomic analysis of the eukaryotic and unicellular intestinal parasite Blastocystis sp. Not only this work constitutes an important milestone toward the proteogenomics profile of this human pathogen, but also it demonstrates at the protein level the occurrence of a specific mechanism of mRNA decoding. GU-rich motifs located downstream of mRNA polyadenylation sites create termination codons that ultimately result in the synthesis of proteins with lower molecular weight than predicted from gene sequence. Thus, the scope of proteogenomics now extends to the regulation of mRNA translation into proteins, providing a proof of concept for future studies in multicellular eukaryotes such as humans and plants.

Exacerbation of colon carcinogenesis by Blastocystis sp.

Colorectal cancer (CRC) is one the most commonly diagnosed cancers worldwide and the number is increasing every year. Despite advances in screening programs, CRC remains as the second leading cause of cancer deaths in the United States. Oxidative stress plays an important role in the molecular mechanisms of colorectal cancer (CRC) and has been shown to be associated with Blastocystis sp., a common intestinal microorganism. In the present study, we aimed to identify a role for Blastocystis sp. in exacerbating carcinogenesis using in vivo rat model. Methylene blue staining was used to identify colonic aberrant crypt foci (ACF) and adenomas formation in infected rats whilst elevation of oxidative stress biomarker levels in the urine and serum samples were evaluated using biochemical assays. Histological changes of the intestinal mucosa were observed and a significant number of ACF was found in Blastocystis sp. infected AOM-rats compared to the AOM-controls. High levels of urinary oxidative indices including advanced oxidative protein products (AOPP) and hydrogen peroxide were observed in Blastocystis sp. infected AOM-rats compared to the uninfected AOM-rats. Our study provides evidence that Blastocystis sp. has a significant role in enhancing AOM-induced carcinogenesis by resulting damage to the intestinal epithelium and promoting oxidative damage in Blastocystis sp. infected rats.

Molecular Epidemiology of Blastocystis sp. in Various Animal Groups from Two French Zoos and Evaluation of Potential Zoonotic Risk.

Blastocystis sp. is a common intestinal parasite infecting humans and a wide range of animals worldwide. It exhibits an extensive genetic diversity and 17 subtypes (STs) have thus far been identified in mammalian and avian hosts. Since several STs are common to humans and animals, it was proposed that a proportion of human infections may result from zoonotic transmission. However, the contribution of each animal source to human infection remains to be clarified. Therefore, the aim of this study was to expand our knowledge of the epidemiology and host specificity of this parasite by performing the largest epidemiological survey ever conducted in animal groups in terms of numbers of species screened. A total of 307 stool samples from 161 mammalian and non-mammalian species in two French zoos were screened by real-time PCR for the presence of Blastocystis sp. Overall, 32.2% of the animal samples and 37.9% of the species tested were shown to be infected with the parasite. A total of 111 animal Blastocystis sp. isolates were subtyped, and 11 of the 17 mammalian and avian STs as well as additional STs previously identified in reptiles and insects were found with a varying prevalence according to animal groups. These data were combined with those obtained from previous surveys to evaluate the potential risk of zoonotic transmission of Blastocystis sp. through the comparison of ST distribution between human and animal hosts. This suggests that non-human primates, artiodactyls and birds may serve as reservoirs for human infection, especially in animal handlers. In contrast, other mammals such as carnivores, and non-mammalian groups including reptiles and insects, do not seem to represent significant sources of Blastocystis sp. infection in humans. In further studies, more intensive sampling and screening of potential new animal hosts will reinforce these statements and expand our understanding of the circulation of Blastocystis sp. in animal and human populations.

Prevalence and Subtype Identification of Blastocystis sp. in Healthy Individuals in the Tunis Area, Tunisia

Blastocystis sp. is currently the most common eukaryotic parasite found in humans. Despite its potential public health impact, epidemiological data regarding its prevalence and molecular subtype (ST) distribution in Maghreb are rarely reported. Therefore, the aim of this study was to determine the prevalence of the parasite in a cohort of healthy food handler Tunisian individuals and to acquire the first molecular data regarding the distribution of Blastocystis sp. STs in this country. Therefore, 524 fecal samples were collected, and 68 of them (13%) were identified as positive for the parasite by direct-light microscopy of smears. Seventeen samples of 100 negative by microscopy were also shown to be positive by real-time quantitative polymerase chain reaction. Among all the positive samples, 61 Blastocystis isolates were subtyped using partial small subunit ribosomal RNA gene analysis. ST3 was the most abundant (51%) followed by ST1 (30%), ST2 (16%), and ST4 and ST7 (both 1.6%).

Occurrence of Blastocystis sp. in water catchments at Malay villages and Aboriginal settlement during wet and dry seasons in Peninsular Malaysia.

In the tropics, there are too few studies on isolation of Blastocystis sp. subtypes from water sources; in addition, there is also an absence of reported studies on the occurrence of Blastocystis sp. subtypes in water during different seasons. Therefore, this study was aimed to determine the occurrence of Blastocystis sp. subtypes in river water and other water sources that drained aboriginal vicinity of highly endemic intestinal parasitic infections during wet and dry seasons. Water samples were collected from six sampling points of Sungai Krau (K1–K6) and a point at Sungai Lompat (K7) and other water sources around the aboriginal villages. The water samples were collected during both seasons, wet and dry seasons. Filtration of the water samples were carried out using a flatbed membrane filtration system. The extracted DNA from concentrated water sediment was subjected to single round polymerase chain reaction and positive PCR products were subjected to sequencing. All samples were also subjected to filtration and cultured on membrane lactose glucuronide agar for the detection of faecal coliforms. During wet season, Blastocystis sp. ST1, ST2 and ST3 were detected in river water samples. Blastocystis sp. ST3 occurrence was sustained in the river water samples during dry season. However Blastocystis sp. ST1 and ST2 were absent during dry season. Water samples collected from various water sources showed contaminations of Blastocystis sp. ST1, ST2, ST3 and ST4, during wet season and Blastocystis sp. ST1, ST3, ST8 and ST10 during dry season. Water collected from all river sampling points during both seasons showed growth of Escherichia coli and Enterobacter aerogenes, indicating faecal contamination. In this study, Blastocystis sp. ST3 is suggested as the most robust and resistant subtype able to survive in any adverse environmental condition. Restriction and control of human and animal faecal contaminations to the river and other water sources shall prevent the transmission of Blastocystis sp. to humans and animals in this aboriginal community.

Subtype analysis of Blastocystis sp. isolates from asymptomatic individuals in an urban community in the Philippines

Blastocystis sp. is a commonly reported enteric protistan parasite in faecal specimens with a worldwide distribution afflicting both humans and a wide range of animals. The aim of this study is to characterize the subtypes (STs) of Blastocystis sp. isolates from asymptomatic individuals in an urban community in Pateros, Metro Manila, Philippines. The 600-bp small subunit ribosomal RNA (SSU rRNA) barcoding region of Blastocystis sp. isolates was amplified and sequenced using the primers RD5 and BhRDr. Subtypes were identified by uploading the sequences onto the Basic Local Alignment and Search Tool (BLAST) websites, the Blastocystis Subtype (18S) and Sequence Typing (MLST) Database and by construction of a phylogenetic tree. Twenty-nine (29) out of 35 individuals were detected positive for Blastocystis sp. ST3 is the most common among the three STs detected (65.5%), followed by ST1 (31.0%) and ST4 (3.44%). This study showed that DNA barcoding can serve as a helpful tool to investigate the diversity of Blastocystis sp. in the Philippines.

Granular Formation during Apoptosis in Blastocystis sp. Exposed to Metronidazole (MTZ).

The role and function of the granular life cycle stage in Blastocystis sp, remains uncertain despite suggestions being made that the granules are metabolic, reproductive and lipid in nature. This present study aims to understand granular formation by triggering apoptosis in Blastocystis sp. by treating them with metronidazole (MTZ). Blastocystis sp.cultures of 4 sub-types namely 1, 2, 3 and 5 when treated with 0.01 and 0.0001 mg/ml of metronidazole (MTZ) respectively showed many of the parasites to be both viable and apoptotic (VA). Treated subtype 3 isolates exhibited the highest number of granular forms i.e. 88% (p<0.001) (0.0001 mg/ml) and 69% (p<0.01) (0.01 mg/ml) respectively at the 72 h in in vitro culture compared to other subtypes. These VA forms showed distinct granules using acridine orange (AO) and 4’,6-diamino-2-phenylindole (DAPI) staining with a mean per cell ranging from 5 in ST 5 to as high as 16 in ST 3. These forms showed intact mitochondria in both viable apoptotic (VA) and viable non-apoptotic (VNA) cells with a pattern of accumulation of lipid droplets corresponding to viable cells. Granular VA forms looked ultra-structurally different with prominent presence of mitochondria-like organelle (MLO) and a changed mitochondrial trans-membrane potential with thicker membrane and a highly convoluted inner membrane than the less dense non-viable apoptotic (NVA) cells. This suggests that granular formation during apoptosis is a self-regulatory mechanism to produce higher number of viable cells in response to treatment. This study directs the need to search novel chemotherapeutic approaches by incorporating these findings when developing drugs against the emerging Blastocystis sp. infections.

Detection of Blastocystis sp. Infection using different investigation techniques in children with or without acute diarrhea

Detection of Blastocystis sp. Infection using different investigation techniques in children with or without acute diarrhea

Predominance of Blastocystis sp. Infection among School Children in Peninsular Malaysia.

BackgroundOne of the largest cross-sectional study in recent years was carried out to investigate the prevalence of intestinal parasitic infections among urban and rural school children from five states namely Selangor, Perak, Pahang, Kedah and Johor in Peninsula Malaysia. This information would be vital for school authorities to influence strategies for providing better health especially in terms of reducing intestinal parasitism.Methods and Principal FindingsA total of 3776 stool cups was distributed to 26 schools throughout the country. 1760 (46.61%) responded. The overall prevalence of intestinal parasitic infection in both rural and urban areas was 13.3%, with Blastocystis sp (10.6%) being the most predominant, followed by Trichuris trichiura (3.4%), Ascaris lumbricoides (1.5%) and hook worm infection (0.9%). Only rural school children had helminthic infection. In general Perak had the highest infection (37.2%, total, n = 317), followed by Selangor (10.4%, total, n = 729), Pahang (8.6%, total, n = 221), Kedah (6.2%, total, n = 195) and Johor (3.4%, total, n = 298). School children from rural schools had higher infection (13.7%, total, n = 922) than urban school children (7.2%, total, n = 838). Subtype (ST) 3 (54.3%) is the most predominant ST with persons infected with only ST1 and ST3 showing symptoms. Blastocystis sp infection significantly associated with low household income, low parent’s education and presence of symptoms (p<0.05).ConclusionIt is critical that we institute deworming and treatment to eradicate the parasite especially in rural school children.

Prevalence and genetic diversity of the intestinal parasites Blastocystis sp. and Cryptosporidium spp. in household dogs in France and evaluation of zoonotic transmission risk

Several parasites including the protozoa Blastocystis sp. and Cryptosporidium spp. may be causative agents of gastrointestinal symptoms in domestic dogs, and there may be a potential risk of transmission to owners. While France is one of the largest European countries in terms of its canine population, little data is available about the molecular epidemiology of these two parasites. The purpose of this study was to determine the prevalence of intestinal parasites in household dogs in France, and to evaluate the zoonotic risk of Blastocystis sp. and Cryptosporidium spp. by genotyping the corresponding isolates. To this end, 116 faecal samples were collected from household dogs regardless of breed, age or gender, living in the Lyons area, France. Various intestinal protozoa and helminths were identified by light microscopy. Screening for Blastocystis sp. and Cryptosporidium spp. were subsequently performed by PCR targeting the small subunit (SSU) rDNA coding region, followed by direct sequencing of the PCR products and analysis of the sequences obtained for genotyping. The overall prevalence of dogs infected with at least one gastrointestinal parasite was 42.2% (49/116). After light microscopy examination of faecal samples, the most common parasites found were the protozoa Giardia sp. (25.0%) and Cystoisospora sp. (19.8%). Using molecular methods, four dogs (3.4%) were shown to be infected by Blastocystis sp. and carried either subtype (ST) 2, commonly identified in various animal groups, or ST10, frequently found in bovids. Three dogs (2.6%) were positive for C. canis, infecting humans episodically. The low prevalence of both parasites, combined with the identification of C. canis and Blastocystis sp. ST2 and ST10 in the canine population, strongly suggests that dogs play a negligible role as zoonotic reservoirs for both parasites and do not seem to be natural hosts of Blastocystis sp.

Prevalence and Risk Factors for Blastocystis Infection Among Children and Caregivers in a Child Care Center, Bangkok, Thailand.

In September 2009, a cross-sectional study was conducted to evaluate parasitic infections in a child care center in Khlong Toei, Bangkok, Thailand. Of 503 children and staff members, 258 (51.3%) stool samples and questionnaires were obtained. The most common parasitic infection was Blastocystis sp. (13.6%). Blastocystis sp. subtype 3 was predominantly found (80.0%), followed by subtypes 2 (12.0%) and 1 (8.0%). The prevalence of Blastocystis infection varied among different age groups. The prevalence of Blastocystis infection in non-HIV-infected children aged < 10 and 10-19 years were 14.5% and 10.3%, respectively, which were not significantly different. All 31 HIV-infected children were not infected with Blastocystis sp. The most likely reason could be the result of properly using prevention measures for this specific group.