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

Nithyamathi K, Chandramathi S, Kumar S

PLoS One, 2016;11(2):e0136709.
PMID: 26914483 DOI: 10.1371/journal.pone.0136709

BACKGROUND: One 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 FINDINGS: A 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).
CONCLUSION: It is critical that we institute deworming and treatment to eradicate the parasite especially in rural school children.

Matched MeSH terms: Blastocystis Infections/epidemiology*; Blastocystis Infections/parasitology; Blastocystis Infections/prevention & control; Blastocystis/classification; Blastocystis/genetics; Blastocystis/isolation & purification
Fulltext Molecular epidemiology of blastocystosis in Malaysia: does seasonal variation play an important role in determining the distribution and risk factors of Blastocystis subtype infections in the Aboriginal community?

Noradilah SA, Moktar N, Anuar TS, Lee IL, Salleh FM, Manap SNAA, et al.

Parasit Vectors, 2017 Jul 31;10(1):360.
PMID: 28760145 DOI: 10.1186/s13071-017-2294-2

BACKGROUND: Alternating wet and dry seasons may play an important role in the acquisition and distribution of Blastocystis subtype infection in the tropics. This cross-sectional study was therefore conducted to provide the prevalence of Blastocystis and to determine the potential risk factors associated with each subtype during the wet and dry seasons in the Aboriginal community, Pahang, Malaysia.
METHODS: A total of 473 faecal samples were collected: 256 (54.1%) and 217 (45.9%) samples were obtained during the wet (October-November 2014) and the dry season (June 2015), respectively. All fresh faecal samples were subjected to molecular analysis for subtype and allele identification.
RESULTS: Of the 473 samples, 42.6% and 37.8% were positive for Blastocystis ST1, ST2, ST3 and ST4 during wet and dry seasons, respectively. Prevalence of Blastocystis ST1 was significantly higher during the wet season compared to the dry season (Z = 2.146, P

Matched MeSH terms: Blastocystis Infections/ethnology*; Blastocystis Infections/parasitology; Blastocystis Infections/transmission; Blastocystis/genetics*
Occurrence of Blastocystis sp. in water catchments at Malay villages and Aboriginal settlement during wet and dry seasons in Peninsular Malaysia

Noradilah SA, Lee IL, Anuar TS, Salleh FM, Abdul Manap SN, Mohd Mohtar NS, et al.

PeerJ, 2016;4:e2541.
PMID: 27761331

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.

Matched MeSH terms: Blastocystis Infections; Blastocystis
Modified fields' stain: ideal to differentiate Dientamoeba fragilis and Blastocystis sp

Ragavan AD, Govind SK

Parasitol Res, 2015 Mar;114(3):1163-6.
PMID: 25614298 DOI: 10.1007/s00436-014-4296-8

Dientamoeba fragilis, a trichomonad parasite is usually found in the gastrointestinal tract of human, and it is known to be the cause for gastrointestinal disease. The parasite is globally distributed and mostly found in rural and urban areas. The parasite is found in humans and nonhuman primates such as the macaques, baboons, and gorillas. Often, the parasite is confused with another largely found organism in stools called Blastocystis sp. especially when seen directly under light microscopy on culture samples containing both parasites. Both sometimes are seen with two nuclei with sizes tending to be similar which complicates identification. Stools were collected fresh from nine previously diagnosed persons infected with D. fragilis who also were found to be positive for Blastocystis sp. Samples were then cultured in Loeffler's medium and were stained with Giemsa, iron hematoxylin, and modified Fields' (MF) stain, respectively. D. fragilis was differentiated from Blastocystis sp. when stained with MF stain by the presence of a thinner outer membrane with clearly demarcated nuclei in the center of the cell whilst Blastocystis sp. had a darker and thicker stained outer membrane with the presence of two nuclei. The staining contrast was more evident with modified Fields' stain when compared with the other two. The simplicity in preparing the stain as well as the speed of the staining procedure make MF stain an ideal alternate. The modified Fields' stain is faster and easier to prepare when compared to the other two stains. MF stain provides a better contrast differentiating the two organisms and therefore provides a more reliable diagnostic method to precisely identify one from the other especially when cultures show mixed infections.

Matched MeSH terms: Blastocystis Infections/diagnosis*; Blastocystis Infections/parasitology; Blastocystis/cytology*; Blastocystis/isolation & purification
Fulltext Phenotypic variation in Blastocystis sp. ST3

Ragavan ND, Govind SK, Chye TT, Mahadeva S

Parasit Vectors, 2014;7:404.
PMID: 25174569 DOI: 10.1186/1756-3305-7-404

Blastocystis, is one of the most common human intestinal protozoan, which has many conflicting reports on its pathogenic role. Gut conditions which obviously varies in asymptomatic individuals, symptomatic and irritable bowel syndrome (IBS) patients in terms of gut flora, pH, osmotic pressure and water potentials could play an important role in its pathogenicity. The present study is the first study to investigate phenotypic characteristics of Blastocystis sp. ST3 isolated from asymptomatic, symptomatic and IBS isolates.

Matched MeSH terms: Blastocystis Infections/parasitology*; Blastocystis/physiology*; Blastocystis/ultrastructure*
Fulltext Blastocystis sp. in Irritable Bowel Syndrome (IBS)--Detection in Stool Aspirates during Colonoscopy

Ragavan ND, Kumar S, Chye TT, Mahadeva S, Shiaw-Hooi H

PLoS One, 2015;10(9):e0121173.
PMID: 26375823 DOI: 10.1371/journal.pone.0121173

Blastocystis is one of the most common gut parasites found in the intestinal tract of humans and animals. Its' association with IBS is controversial, possibly as a result of irregular shedding of parasites in stool and variation in stool detection. We aimed to screen for Blastocystis in colonic stool aspirate samples in adult patients with and without IBS undergoing colonoscopy for various indications and measure the interleukin levels (IL-8, IL-3 and IL-5). In addition to standard stool culture techniques, polymerase chain reaction (PCR) techniques were employed to detect and subtype Blastocystis. All the serum samples collected were subjected for ELISA studies to measure the interleukin levels (IL-8, IL-3 and IL-5). Among 109 (IBS n = 35 and non-IBS n = 74) adults, direct stool examination and culture of colonic aspirates were initially negative for Blastocystis. However, PCR analysis detected Blastocystis in 6 (17%) IBS and 4 (5.5%) non-IBS patients. In the six positive IBS patients by PCR method, subtype 3 was shown to be the most predominant (3/6: 50%) followed by subtype 4 (2/6; 33.3%) and subtype 5 (1/6; 16.6%). IL-8 levels were significantly elevated in the IBS Blasto group and IBS group (p<0.05) compared to non-IBS and non-IBS Blasto group. The level of IL-3 in were seen to be significantly higher in than IBS Blasto group and IBS group (p<0.05) compared to non-IBS. Meanwhile, the IL-5 levels were significantly higher in IBS Blasto group (p<0.05) compared to non-IBS and non-IBS Blasto group. This study implicates that detecting Blastosystis by PCR method using colonic aspirate samples during colonoscopy, suggests that this may be a better method for sample collection due to the parasite's irregular shedding in Blastocystis-infected stools. Patients with IBS infected with parasite showed an increase in the interleukin levels demonstrate that Blastocystis does have an effect in the immune system.

Matched MeSH terms: Blastocystis/isolation & purification*; Blastocystis/physiology
Factors that influence the shedding of Blastocystis cysts in an irritable bowel syndrome (IBS) patient--an evidence-based case study

Ragavan ND, Govind SK, Chye TT, Mahadeva S

Parasitol Res, 2015 Aug;114(8):2999-3005.
PMID: 25982571 DOI: 10.1007/s00436-015-4502-3

Blastocystis is one of the most common gut parasites found in the intestinal tract of humans and animals. We have previously reported the irregular shedding of Blastocystis cysts in stools from infected patients. In the present study, we assess the factors influencing shedding patterns from a Blastocystis ST3-infected IBS patient. The stools samples were voluntarily submitted for examination for a period of 30 days from Blastocystis ST3-infected IBS patient. A questionnaire on the factors that could influence the shedding pattern of the cysts was designed to assess the following information: (a) the frequency of frequenting the toilet in a day, (b) the timing of frequenting the toilet, (c) the stool forms, (d) the type of mood the patient was in when frequenting the toilet and (e) food intake. A total of 79 stool samples were collected for 30 days. The highest number of cysts recorded when the patient visited the toilet three times a day was 22.2 × 10(6) cysts/g. Frequenting the toilet between 6 a.m. to 11.59 a.m. showed the highest number of cysts, i.e. 21.7 × 10(6) cysts/g. Semi-solid forms showed the highest cyst count, i.e. 2.00 × 10(6) cysts/g. Irregular shedding of cysts was seen in 10 out of 30 days where the widest range recorded on day 17 was between 0 to 1.2 × 10(6) cysts/g. The average daily cyst count on days of emotional fluctuations was from 0 to 5.13 × 10(6) cysts/g. In conclusion, the study confirms that there are factors influencing shedding patterns of Blastocystis, and these have important implications when it comes to diagnosis and transmission of the parasite.

Matched MeSH terms: Blastocystis Infections/parasitology*; Blastocystis/isolation & purification*
Small forms of Blastocystis hominis

Rajah S, Suresh K, Vennila GD, Khairul Anuar A, Saminathan R

JUMMEC, 2002;7:77-79.

Matched MeSH terms: Blastocystis hominis
Blastocystis in animal handlers

Rajah Salim H, Suresh Kumar G, Vellayan S, Mak JW, Khairul Anuar A, Init I, et al.

Parasitol Res, 1999 Dec;85(12):1032-3.
PMID: 10599928

The present study investigated whether people working closely with animals were at higher risk of getting infected with Blastocystis hominis. The prevalence of the parasite was determined in two population groups, i.e., animal handlers and normal healthy individuals who did not work with animals. In all, 105 stool samples were collected from animal handlers from 2 local research institutions, a local zoo, and a local abattoir and 163 stool samples were collected from normal healthy individuals residing in high-rise flats in the city. The in vitro culture method used in the study detected that 41% of 105 animal handlers and 17% of 163 flat-dwellers in the city were positive for Blastocystis. This statistically significant finding (P = 0.0000313) shows that people who work closely with animals do stand at risk of acquiring Blastocystis infection.

Matched MeSH terms: Blastocystis Infections/epidemiology*; Blastocystis Infections/parasitology; Blastocystis Infections/transmission*; Blastocystis/isolation & purification*
Fulltext Amoebic forms of Blastocystis spp. - evidence for a pathogenic role

Rajamanikam A, Govind SK

Parasit Vectors, 2013;6(1):295.
PMID: 24499467 DOI: 10.1186/1756-3305-6-295

Blastocystis spp. are one of the most prevalent parasites isolated from patients suffering from diarrhea, flatulence, constipation and vomiting. It's pathogenicity and pathophysiology remains controversial to date. Protease activity and amoebic forms have been reported previously in symptomatic isolates but there has been no conclusive evidence provided to correlate the protease activity and any specific life cycle stage of the parasite thus far.

Matched MeSH terms: Blastocystis Infections/parasitology*; Blastocystis/cytology*; Blastocystis/enzymology; Blastocystis/growth & development; Blastocystis/pathogenicity
Exacerbated symptoms in Blastocystis sp.-infected patients treated with metronidazole: two case studies

Rajamanikam A, Kumar S, Samudi C, Kudva M

Parasitol Res, 2018 Aug;117(8):2585-2590.
PMID: 29872961 DOI: 10.1007/s00436-018-5948-x

Blastocystis sp. is a gastrointestinal (GI) protozoan parasite reported to cause non-specific GI symptoms including diarrhea, flatulence, abdominal pain, and nausea. Complete eradication of Blastocystis sp. is rather challenging even with the drug of choice, i.e., metronidazole. Here, we report on two Blastocystis sp.-infected individuals, who presented increased parasite load and exacerbated symptoms upon treatment with the usual recommended dosage and regime of metronidazole. The two studies uniquely demonstrate for the first time a cyst count as high as fivefold more than the original cyst count before treatment and show an exacerbation of GI symptoms despite treatment. The study provides additional support in recognizing metronidazole resistance in Blastocystis sp. and its consequences towards the pathogenicity of the parasite.

Matched MeSH terms: Blastocystis Infections/drug therapy; Blastocystis Infections/physiopathology*; Blastocystis/drug effects; Blastocystis/pathogenicity
Fulltext Resistance towards metronidazole in Blastocystis sp.: A pathogenic consequence

Rajamanikam A, Hooi HS, Kudva M, Samudi C, Kumar S

PLoS One, 2019;14(2):e0212542.
PMID: 30794628 DOI: 10.1371/journal.pone.0212542

Blastocsytis sp. is a protozoan parasite that has been linked to common gastrointestinal illnesses. Metronidazole, the first line therapy, was reported to show frequent inefficacy. Previously, Blastocystis sp. isolated from different population showed varying metronidazole resistance. However, the effect of metronidazole treatment on pathogenic potentials of Blastocystis sp. isolated from different populations, which is known to have different gut environment, is unclear. This study investigates the in vitro effect of metronidazole on the pathogenic potentials of Blastocystis sp. isolated from urban and orang asli individuals. Blastocystis sp. ST 3 isolated from symptomatic and asymptomatic individuals were treated with a range of metronidazole concentration. The parasites' growth characteristics, apoptotic rate, specific protease activity and the ability to proliferate cancer cells were analyzed upon treatment with 0.001 mg/l metronidazole. The study demonstrates that Blastocystis sp. isolates showed increase in the parasite numbers especially the amoebic forms (only in urban isolates) after treating with metronidazole at the concentration of 0.001 mg/ml. High number of cells in post-treated isolates coincided with increase of apoptosis. There was a significant increase in cysteine protease of Blastocystis sp. isolates upon treatment despite the initial predominance of serine protease in asymptomatic isolates. Metronidazole resistant Blastocystis sp. also showed significant increase in cancer cell proliferation. Resistance to metronidazole did not show significant different influence on the pathogenicity between Blastocystis sp. isolated from urban and orang asli individual. However, an increase in parasite numbers, higher amoebic forms, cysteine protease and ability to proliferate cancer cells implicates a pathogenic role. The study provides evidence for the first time, the effect of metronidazole towards enhancing pathogenic potentials in Blastocystis sp. when isolated from different gut environment. This necessitates the need for reassessment of metronidazole treatment modalities.

Matched MeSH terms: Blastocystis Infections/drug therapy*; Blastocystis Infections/pathology
Increase number of mitochondrion-like organelle in symptomatic Blastocystis subtype 3 due to metronidazole treatment

Raman K, Kumar S, Chye TT

Parasitol Res, 2016 Jan;115(1):391-6.
PMID: 26481491 DOI: 10.1007/s00436-015-4760-0

Blastocystis sp., an intestinal organism is known to cause diarrhea with metronidazole regarded as the first line of treatment despite reports of its resistance. The conflicting reports of variation in drug treatment have been ascribed to subtype differences. The present study evaluated in vitro responses due to metronidazole on ST3 isolated from three symptomatic and asymptomatic patients, respectively. Symptomatic isolates were obtained from clinical patients who showed symptoms such as diarrhea and abdominal bloating. Asymptomatic isolates from a stool survey carried out in a rural area. These patients had no other pathogens other than Blastocystis. Ultrastructural studies using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed drug-treated ST3 from symptomatic patients were irregular and amoebic with surface showing high-convoluted folding when treated with metronidazole. These organisms had higher number of mitochondrion-like organelle (MLO) with prominent cristae. However, the drug-treated ST3 from asymptomatic persons remained spherical in shape. Asymptomatic ST3 showed increase in the size of its central body with the MLO located at the periphery.

Matched MeSH terms: Blastocystis Infections/drug therapy; Blastocystis Infections/parasitology*; Blastocystis/classification; Blastocystis/drug effects*; Blastocystis/ultrastructure
Fulltext Current status of Blastocystis sp. in animals from Southeast Asia: a review

Rauff-Adedotun AA, Mohd Zain SN, Farah Haziqah MT

Parasitol Res, 2020 Nov;119(11):3559-3570.
PMID: 32951145 DOI: 10.1007/s00436-020-06828-8

Blastocystis is the most frequently observed eukaryotic gastrointestinal symbiont in humans and animals. Its low host specificity and zoonotic potential suggest that animals might serve as possible reservoirs for transmission. The prevalence and subtype distributions of Blastocystis sp. in animal populations in Southeast Asia, a hotspot for zoonotic diseases, are reviewed. Recommendations for future research aimed at understanding the zoonotic role of Blastocystis are also included. Seven countries have, so far, reported Blastocystis infection in various animals, such as livestock, poultry, companion animals, and non-human primates. Pigs were the most studied animals, and there were records of 100% prevalence in pigs, cattle, and ostriches. Using polymerase chain reaction (PCR)-based approaches, twelve Blastocystis sp. subtypes (STs), namely ST1, ST2, ST3, ST4, ST5, ST6, ST7, ST8, ST9, ST10, ST12, and ST14 have been recognised infecting animals of Southeast Asia. ST1 and ST5 were the most frequently identified, and Malaysia observed the most diverse distribution of subtypes. Further investigations on Blastocystis sp. in various animal hosts, using adequate sample sizes and uniform detection methods, are essential for a better understanding of the distribution of this organism. Detailed genome studies, especially on STs shared by humans and animals, are also recommended.

Matched MeSH terms: Blastocystis Infections/epidemiology; Blastocystis Infections/veterinary*; Blastocystis/genetics; Blastocystis/isolation & purification*
Prevalence and subtypes of Blastocystis among migrant workers from different working sectors in Peninsular Malaysia

Sahimin N, Meor Termizi FH, Rajamanikam A, Mohd Nazri NA, Govind SK, Mohd Zain SN

Parasitol Res, 2020 Oct;119(10):3555-3558.
PMID: 32875397 DOI: 10.1007/s00436-020-06865-3

Blastocystis sp. is a common enteric parasite of humans and animals associated with inadequate sanitation and poor personal hygiene. Over the years, the Malaysian thriving economy has been facilitated largely by migrant workers from developing countries, and there is concern that diseases endemic to their countries may be imported. Therefore, this study aimed to determine the current status of Blastocystis infection as well as subtypes (STs) from fecal samples among migrant workers in Selangor and Kuala Lumpur, Malaysia. Overall, almost a third of the study cohort (30.9%; n = 68/220) screened were infected with Blastocystis sp. predominantly with ST3 (54.5%; n = 12), followed by ST1 (36.4%; n = 8) and ST2 (9.1%; n = 2). Infection levels was almost similar among the different sectors; manufacturing (32.8%), domestic service (32.3%), and food service (27.3%) with common symptoms for infection included stomach and abdominal pain or discomfort and diarrhea (48.5%; n = 33). None of the socio-demographic risk factors evaluated were significant. Therefore, this study warrants continuous monitoring as well as understanding the impact of transmission among the migrant community with the local population especially those involved in food service sector.

Matched MeSH terms: Blastocystis Infections/diagnosis; Blastocystis Infections/epidemiology*; Blastocystis Infections/parasitology*; Blastocystis/classification*; Blastocystis/genetics; Blastocystis/isolation & purification*
Wild hosts and microscopic worlds: Investigating the morphology and surface ultrastructure of Blastocystis sp. in avian and non-human primate species

Sanggari A, Attah AO, Yahaya ZS, Farah Haziqah MT

Trop Biomed, 2023 Dec 01;40(4):392-399.
PMID: 38308825 DOI: 10.47665/tb.40.4.003

Blastocystis is a prevalent infectious agent found in the gastrointestinal tract of humans and animals. While the morphology of Blastocystis has been extensively studied, there is still a lack of comprehensive research on its ultrastructure, especially regarding surface characteristics and their correlation with pathogenic potential. Additionally, the subtyping of Blastocystis does not provide information on the isolate's pathogenicity. This study aimed to examine the morphology and the cell surface of Blastocystis in avian and non-human primates, including peafowl, pheasant, and lion-headed tamarin. By employing light microscopy and scanning electron microscopy (SEM), this study provides the first evidence of the cellular and surface features of Blastocystis in these animal species. Our findings revealed distinct variations in cell size, shape, and surface morphology among the different host species. Notably, the isolates from peafowl exhibited larger cell sizes compared to the isolates from the pheasant. However, interestingly, both animal species were found to exhibit the same Blastocystis ST6. It was also observed that the surface structure of Blastocystis from different hosts displayed a diverse range of patterns, including mesh-like appearances, deep indentations, and attachments to bacteria. Additionally, findings also revealed the presence of a rough surface structure in peafowl, a characteristic that has been previously linked to pathogenicity and symptomatic infection in animals, as indicated by earlier studies. The findings contribute to our understanding of the morphological features and the surface characteristic of Blastocystis in different host species, shedding light on the parasite's adaptations and potential implications for host health.

Matched MeSH terms: Blastocystis*
Fulltext A preliminary study of Blastocystis hominis in some development areas in Alor Gajah District Melaka

Shafariatul Akmar Ishak, Hidayatulfathi Othman, Mazrura Sahani

Jurnal Sains Kesihatan Malaysia, 2008;6(1):109-115.
MyJurnal

A descriptive study was conducted to evaluate the prevalence of Blastocystis hominis in children aged between 1-12 years old from randomly selected villages in Alor Gajah district Melaka. The sampling was carried out from 1st to 7th of July of 2006. A total of 48 faecal samples were obtained from the children in those studied villages. The faecal specimens were examined by direct saline wet moun, formalin ethyl acetate concentration and trichrome staining method. It was found that 45.8% (22 out of 48) of the examined children were infected with Blastocystis hominis . Based on the results, the cumulative prevalence of three methods used showed that Blastocystis hominis infection in female children higher compared to male children. Whilst the schooling children aged of 6 to 12 years had a higher prevalence than pre school children at the age of 1-5 years. In term of diagnosis, formalin ethyl acetate concentration method showed prevalence of detection at 60.9%. It was followed by direct saline wet mount (43.5%) and trichrome staining at 34.8%.

Matched MeSH terms: Blastocystis Infections; Blastocystis hominis
Epitope variances demonstrated by Blastocystis sp. ST3 symptomatic and asymptomatic isolates

Sheela DS, Chandramathi S, Suresh K

Trop Biomed, 2020 Mar 01;37(1):210-217.
PMID: 33612732

Blastocystis sp. is an enteric protozoan parasite of humans and many animals. Blastocystis sp. subtype 3 (ST3) proves to be the highest frequency case in most populations around the world and it is further distinguished into symptomatic and asymptomatic isolates based on the clinical symptoms exhibited by infected individuals. Phenotypic and genotypic studies implicate the distinctiveness of this parasite which may describe its pathogenesis. However, the antigenic distinctiveness which describes the antibody mediated cell lysis of this parasite has not been explored. This study was aimed to identify the cross-reactivity and cytotoxicity effect between three isolates of symptomatic and asymptomatic Blastocystis sp. ST3 respectively. Antigen specificity and diversity of this parasite was performed by coculturing sera (10-fold dilution) obtained from mice immunised with Blastocystis sp. symptomatic and asymptomatic antigens and the respective Blastocystis sp. ST3 live cells through complement dependant cell cytotoxicity (CDC) assay. The results obtained has shown that, the sera (at 10-fold diluted concentration) from symptomatic and asymptomatic solubilised antigen immunised mice were able to specifically lyse the respective live parasites with an average percentage of 82% and 86% respectively. There were almost 50% crossreactivity observed between the three isolates of Blastocystis sp. ST3 from symptomatic and asymptomatic group proving high antigen diversity or rather low antigen specificity within the same group. However, there was only 17% cross-reactivity observed between the mice sera and parasitic cells of different groups (symptomatic vs asymptomatic isolates) suggesting high specificity between these two groups. We, for the first time have proven that through CDC analysis there were epitopes dissimilarities between Blastocystis sp. ST3 symptomatic and asymptomatic isolates which may allow the parasite to set up diverse immune modulations such as imbalanced Th1/Th2 responses in an infected host.

Matched MeSH terms: Blastocystis Infections/immunology; Blastocystis Infections/parasitology*; Blastocystis/immunology*
A case report of Blastocystis infection and Steven Johnson's syndrome

Singh A, Priyadarshi K, Raj T, Banerjee T

Trop Biomed, 2019 Dec 01;36(4):987-992.
PMID: 33597468

Blastocystis species (spp.) is an emerging pathogen. There are several unsolved issues linked to this parasite ranging from its nomenclature, commensal status, standardization of laboratory diagnostic methods, genotypes and treatment. Recently, there has been an increase in reports of Blastocystis spp. from symptomatic cases which provide enough evidence of its pathogenic potential. A range of signs and symptoms, from gastro-intestinal to cutaneous manifestations have been attributed to Blastocystis infection. Few reports have established an association between intestinal infection with Blastocystis spp. and skin manifestations in form of urticaria, palmoplantar pruritus and allergy with complete resolution of cutaneous lesions with eradication of the parasite. In this report, we describe a case of Steven Johnson's syndrome (SJS) in a 6 years old girl along with infection with Blastocystis spp. marked by diarrhea and abdominal pain. Stool examination revealed the presence of all forms of the parasite with subsequent decrease in parasite burden and diarrhea over a period of time. Interestingly, the clearance of Blastocystis spp. from stool was followed by recovery from skin lesions and other symptoms. In this case, the course of SJS was clearly associated with Blastocystis infection. Though skin manifestation with Blastocystis infection has been previously reported, this is the first report of its association with SJS. This report indicates newer insights of the parasite that are less well studied.

Matched MeSH terms: Blastocystis Infections/diagnosis*
Fulltext Blastocystis hominis infection, a cause of human diarrhea

Sinniah B, Rajeswari B

Southeast Asian J. Trop. Med. Public Health, 1994 Sep;25(3):490-3.
PMID: 7777913

Blastocystis hominis has long been described as a non pathogenic protozoan parasite until recently when claims have been made that it can result in pathogenic conditions. Of the 729 stool samples (614 from survey and 115 from pediatric wards) examined, 18.1% of them were found to be positive for one or more intestinal protozoan cyst. The commonest was Giardia intestinalis (8.4%) Followed by Entamoeba coli (7.1%) and Entamoeba histolytica (5.1%) in the normal children without symptoms of diarrhea. When diarrheic stools were examined, the commonest parasite encountered was Giardia (20.4%), followed by E. coli (15.9%) and E. histolytica (9.7%). Blastocystis was observed in 4.4% of the children who had diarrhea and 1.1% among the children taken from the normal population in the rural areas.

Matched MeSH terms: Blastocystis Infections/epidemiology*; Blastocystis hominis*

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