Displaying publications 21 - 40 of 51 in total

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  1. 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
  2. Tan TC, Suresh KG, Smith HV
    Parasitol Res, 2008 Dec;104(1):85-93.
    PMID: 18795333 DOI: 10.1007/s00436-008-1163-5
    Despite frequent reports on the presence of Blastocystis hominis in human intestinal tract, its pathogenicity remains a matter of intense debate. These discrepancies may be due to the varying pathogenic potential or virulence of the isolates studied. The present study represents the first to investigate both phenotypic and genotypic characteristics of B. hominis obtained from symptomatic and asymptomatic individuals. Symptomatic isolates had a significantly greater size range and lower growth rate in Jones' medium than asymptomatic isolates. The parasite cells of symptomatic isolates exhibited rougher surface topography and greater binding affinity to Canavalia ensiformis (ConA) and Helix pomatia (HPA). The present study also identifies further phenotypic characteristics, which aided in differentiating the pathogenic forms from the non-pathogenic forms of B. hominis. Blastocystis subtype 3 was found to be correlated well with the disease.
    Matched MeSH terms: Blastocystis Infections/parasitology*; Blastocystis Infections/physiopathology*
  3. Tan TC, Suresh KG, Thong KL, Smith HV
    Parasitol Res, 2006 Sep;99(4):459-65.
    PMID: 16628457
    Genomic DNA from 16 Blastocystis hominis isolates comprising of eight asymptomatic isolates (A1-A8) and eight symptomatic isolates (S1-S8) was amplified by arbitrarily primed polymerase chain reaction (AP-PCR) using 38 arbitrary 10-mer primers. Six primers (A10, B5, C20, D1, F6, and F10) generated reproducible DNA fingerprints. AP-PCR amplification revealed similar DNA fingerprints among all symptomatic isolates (S1-S8) with common bands at 850 bp using primer A10, 920 bp using primer B5, and 1.3 kbp using primer D1. Isolates A1, A3, A4, A5, A6, and A7 showed similar DNA banding patterns and all asymptomatic isolates (A1-A8) shared a major band at 1 kbp using primer B5. Isolates A2 and A8 showed distinct DNA banding patterns that differed from the remainder of the isolates. The results of the phylogenetic analyses showed that all symptomatic isolates (S1-S8) formed a clade with >70% similarity among the isolates and which were clearly separate from asymptomatic isolates A1, A3, A4, A5, A6, and A7. Asymptomatic isolates A2 and A8 formed two distinct and separate clades. AP-PCR revealed higher genetic variability within the asymptomatic isolates than within the symptomatic isolates. The present study suggests that AP-PCR can be a valuable method for differentiating between isolates of B. hominis and our results support the hypothesis that our asymptomatic and symptomatic B. hominis isolates may represent two different strains/species with varying pathogenic potential.
    Matched MeSH terms: Blastocystis Infections/diagnosis; Blastocystis Infections/microbiology*
  4. Dhurga DB, Suresh KG, Tan TC, Chandramathi S
    Trans R Soc Trop Med Hyg, 2012 Dec;106(12):725-30.
    PMID: 23141370 DOI: 10.1016/j.trstmh.2012.08.005
    Previous studies have shown that apoptosis-like features are observed in Blastocystis spp., an intestinal protozoan parasite, when exposed to the cytotoxic drug metronidazole (MTZ). This study reports that among the four subtypes of Blastocystis spp. investigated for rate of apoptosis when treated with MTZ, subtype 3 showed the highest significant increase after 72h of in vitro culture when treated with MTZ at 0.1mg/ml (79%; p<0.01) and 0.0001mg/ml (89%; p<0.001). The close correlation between viable cells and apoptotic cells for both dosages implies that the pathogenic potential of these isolates has been enhanced when treated with MTZ. This suggests that there is a mechanism in Blastocystis spp. that actually regulates the apoptotic process to produce higher number of viable cells when treated. Apoptosis may not just be programmed cell death but instead a mechanism to increase the number of viable cells to ensure survival during stressed conditions. The findings of the present study have an important contribution to influence chemotherapeutic approaches when developing drugs against the emerging Blastocystis spp. infections.
    Matched MeSH terms: Blastocystis Infections/drug therapy; Blastocystis Infections/parasitology*
  5. Anuar TS, Ghani MK, Azreen SN, Salleh FM, Moktar N
    Parasit Vectors, 2013;6:40.
    PMID: 23433099 DOI: 10.1186/1756-3305-6-40
    Blastocystis has been described as the most common intestinal parasite in humans and has an increased impact on public health. However, the transmission of this parasite has not been conclusively determined.
    Matched MeSH terms: Blastocystis Infections/epidemiology*; Blastocystis Infections/transmission*
  6. Init I, Mak JW, Top S, Zulhainan Z, Prummongkol S, Nissapatorn V, et al.
    PMID: 15115079
    The objective of this study was to characterize the polypeptides associated with cysts of Blastocystis hominis. This form is believed to be infective and plays a role in parasite resistance to anti-B. hominis drugs currently used for treatment of Blastocystis associated diarrhea. Cysts were induced through in vitro culture of the parasite in complete medium supplemented with bacterial extract with trypticase, metronidazole or doxycycline. SDS-PAGE analysis showed almost similar polypeptide patterns of parasite extracts obtained from in vitro cultured parasites before and after exposure with the three supplements. Polypeptide bands at 76, 58.5, 48, 45, 40, 38, 32, 25 and 22 kDa were constantly seen in all antigenic preparations and no specific cyst-associated polypeptide was present. However, on immunoblot analysis, 3 out of 16 blastocystosis human sera identified a cyst-associated polypeptide at 60 kDa in all parasite extracts prepared from cultures with the three supplements. In addition, there were associated morphological changes detected in these parasites stained with acridine orange and observed under fluorescence microscopy. Metronidazole induced cyst forms (reddish cells) as early as 12 hours post-exposure; more cyst production (with stronger immunoblot bands) occurred after 24 hours exposure. However, cysts rupture with release and destruction of B. hominis daughters cells occurred after 48 hours exposure. Doxycycline induced less cyst-like forms at 24 hours (weaker 60 kDa band) and less destruction of the cysts (60 kDa band still present at 72 hours post exposure). Bacterial extract and trypticase also induced cysts at 12 hours with increasing numbers up to 72 hours exposure (corresponding increase in intensity of 60 kDa band from samples harvested at 12 to 72 hours post exposure) without any sign of deleterious effect on the parasite.
    Matched MeSH terms: Blastocystis Infections/drug therapy; Blastocystis Infections/parasitology*
  7. Haresh K, Suresh K, Khairul Anus A, Saminathan S
    Trop Med Int Health, 1999 Apr;4(4):274-7.
    PMID: 10357863
    Isolates of Blastocystis hominis from infected immigrant workers from Indonesia, Bangladesh and infected individuals from Singapore and Malaysia were assessed for growth pattern and degree of resistance to different concentrations of metronidazole. Viability of the cells was assessed using eosin-brillian cresyl blue which stained viable cells green and nonviable cells red. The Bangladeshi and Singaporean isolates were nonviable even at the lowest concentration of 0.01 mg/ml, whereas 40% of the initial inoculum of parasites from the Indonesian isolate at day one were still viable in cultures with 1.0 mg/ml metronidazole. The study shows that isolates of B. hominis of different geographical origin have different levels of resistance to metronidazole. The search for more effective drugs to eliminate th parasite appears inevitable, especially since surviving parasites from metronidazole cultures show greater ability to multiply in subcultures than controls.
    Matched MeSH terms: Blastocystis Infections/drug therapy; Blastocystis Infections/parasitology*
  8. 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*
  9. 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*
  10. Chandrasekaran H, Govind SK, Panchadcharam C, Bathmanaban P, Raman K, Thergarajan G
    Parasit Vectors, 2014;7:469.
    PMID: 25358755 DOI: 10.1186/s13071-014-0469-7
    Blastocystis sp., a widely prevalent intestinal protozoan parasite is found in a wide range of animals, including humans. The possibility of zoonotic transmission to human from birds especially ostriches led us to investigate on the cross infectivity of Blastocystis sp. isolated from the ostrich feces as well as the phenotypic and subtype characteristics. There is a need to investigate this especially with the rising number of ostrich farms due to the growing global ostrich industry.
    Matched MeSH terms: Blastocystis Infections/parasitology; Blastocystis Infections/veterinary*
  11. Chandramathi S, Suresh K, Kuppusamy UR
    Ann Trop Med Parasitol, 2010 Jul;104(5):449-52.
    PMID: 20819313 DOI: 10.1179/136485910X12743554760423
    Matched MeSH terms: Blastocystis Infections/enzymology*; Blastocystis Infections/epidemiology
  12. Chuong LS, Suresh K, Mak JW, Init I, Kathijah O
    PMID: 9253897
    Matched MeSH terms: Blastocystis Infections/epidemiology*; Blastocystis Infections/transmission
  13. Thergarajan G, Kumar S, Bhassu S, Omar SFBS, Rampal S
    PLoS One, 2019;14(3):e0211034.
    PMID: 30893309 DOI: 10.1371/journal.pone.0211034
    Increasing incidences of dengue have become a global health threat with major clinical manifestation including high fever and gastrointestinal symptoms. These symptoms were also expressed among Blastocystis sp. infected individuals, a parasite commonly seen in human stools. This parasite has been previously reported to replicate faster upon exposure to high temperature. The present study is a hospitalized-based cross-sectional study involved the collection of faecal sample from dengue patients. Stool examination was done by in vitro cultivation to isolate Blastocystis sp. Growth pattern of all the positive isolates were analyzed to identify the multiplication rate of Blastocystis sp. isolated from dengue patients. Distribution of Blastocystis sp. among dengue patients was 23.6%. Dengue patients who were positive for Blastocystis sp. infection denoted a significantly higher fever rate reaching 38.73°C (p<0.05) compared to the non-Blastocystis sp. infected patients (38.44°C). It was also found that Blastocystis sp. infected patients complained of frequenting the toilet more than five times a day (p<0.05) compared to those who were non-Blastocystis sp. infected. At the same time, the duration of hospitalization was significantly longer (p<0.05) for Blastocystis sp. infected dengue patients compared to the non-Blastocystis sp. infected patients. Besides, Blastocystis sp. isolated from dengue patients (in vivo thermal stress) showed a higher growth rate compared to the non-dengue isolated which was exposed to high temperature (in vitro thermal stress). Our findings suggest that presence of Blastocystis sp. during dengue infection could trigger the increase of temperature which could be due to highly elevated pro inflammatory cytokines by both parasitic and virus infection. This could justify why the temperature in Blastocystis sp. infected dengue patients is higher compared to the non-Blastocystis sp. infected patients. Higher temperature could have triggered a greater parasite multiplication rate that contributed to the aggravation of the gastrointestinal symptoms.
    Matched MeSH terms: Blastocystis Infections/metabolism*; Blastocystis Infections/parasitology
  14. 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*
  15. Suresh K, Smith HV, Tan TC
    Appl Environ Microbiol, 2005 Sep;71(9):5619-20.
    PMID: 16151162
    Blastocystis cysts were detected in 38% (47/123) (37 Scottish, 17 Malaysian) of sewage treatment works. Fifty percent of influents (29% Scottish, 76% Malaysian) and 28% of effluents (9% Scottish, 60% Malaysian) contained viable cysts. Viable cysts, discharged in effluent, provide further evidence for the potential for waterborne transmission of Blastocystis.
    Matched MeSH terms: Blastocystis Infections/parasitology; Blastocystis Infections/transmission
  16. Tan TC, Tan PC, Sharma R, Sugnaseelan S, Suresh KG
    Parasitol Res, 2013 Jan;112(1):85-9.
    PMID: 22961236 DOI: 10.1007/s00436-012-3107-3
    Blastocystis sp. is a common intestinal parasite found in humans and animals. The possibility of zoonotic transmission to humans from livestock especially goats led us to investigate the genetic diversity of caprine Blastocystis sp. obtained from five different farms in Peninsular Malaysia. Moreover, there is a lack of information on the prevalence as well as genetic diversity of Blastocystis sp. in goat worldwide. Results showed that 73/236 (30.9 %) of the goats were found to be positive for Blastocystis infection. The most predominant Blastocystis sp. subtype was ST1 (60.3 %) followed by ST7 (41.1 %), ST6 (41.1 %), and ST3 (11.0 %) when amplified by PCR using sequenced-tagged site (STS) primers. Four farms had goats infected only with ST1 whereas the fifth showed mixed infections with multiple STs. The proximity of the fifth farm to human dwellings, nearby domesticated animals and grass land as opposed to a sterile captive environment in the first four farms may account for the multiple STs seen in the fifth farm. Since ST1, ST3, ST6 and ST 7 were previously reported in human infection worldwide in particular Malaysia, the potential of the zoonotic transmission of blastocystosis should not be disregarded. The implications of different farm management systems on the distribution of Blastocystis sp. STs are discussed.
    Matched MeSH terms: Blastocystis Infections/epidemiology; Blastocystis Infections/parasitology; Blastocystis Infections/veterinary*
  17. Abdulsalam AM, Ithoi I, Al-Mekhlafi HM, Ahmed A, Surin J, Mak JW
    Parasitology, 2012 Jul;139(8):1014-20.
    PMID: 22444778 DOI: 10.1017/S0031182012000340
    Blastocystis infection has a worldwide distribution especially among the disadvantaged population and immunocompromised subjects. This study was carried out to determine the prevalence and the association of Blastocystis infection with the socio-economic characteristics among 300 primary schoolchildren, living in rural communities in Lipis and Raub districts of Pahang state, Malaysia. Stool samples were collected and examined for the presence of Blastocystis using direct smear microscopy after in vitro cultivation in Jones' medium. The overall prevalence of Blastocystis infection was found to be as high as 25.7%. The prevalence was significantly higher among children with gastrointestinal symptoms as compared to asymptomatic children (x2 =4.246; P=0.039). Univariate and multivariate analyses showed that absence of a piped water supply (OR=3.13; 95% CI=1.78, 5.46; P<0.001) and low levels of mothers' education (OR=3.41; 95% CI=1.62, 7.18; P<0.01) were the significant predictors of Blastocystis infection. In conclusion, Blastocystis is prevalent among rural children and the important factors that determine the infection were the sources of drinking water and mothers' educational level. Interventions with provision of clean water supply and health education especially to mothers are required.
    Matched MeSH terms: Blastocystis Infections/diagnosis; Blastocystis Infections/epidemiology*; Blastocystis Infections/physiopathology
  18. Chandramathi S, Suresh K, Shuba S, Mahmood A, Kuppusamy UR
    Parasitology, 2010 Apr;137(4):605-11.
    PMID: 19961647 DOI: 10.1017/S0031182009991351
    Numerous studies have revealed the presence of oxidative stress in parasitic infections. However, such studies were lacking in the Malaysian population. Previously, we have provided evidence that oxidative stress is elevated in Malaysians infected with intestinal parasites. Stool examinations revealed that about 47.5% of them were infected with the polymorphic protozoa, Blastocystis hominis. However, they were found to have mixed infection with other intestinal parasites.
    Matched MeSH terms: Blastocystis Infections/blood; Blastocystis Infections/metabolism*; Blastocystis Infections/urine
  19. 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
  20. 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*
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