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  1. Fulltext Three members of Opisthomonorcheides Parukhin, 1966 (Digenea: Monorchiidae) from carangid fishes (Perciformes) from Indonesia, with a review of the genus
    Bray RA, Palm HW, Cutmore SC, Cribb TH
    Syst Parasitol, 2017 05;94(4):443-462.
    PMID: 28337682 DOI: 10.1007/s11230-017-9717-5
    Three species of Opisthomonorcheides Parukhin, 1966 are reported for the first time from Indonesian waters: O. pampi (Wang, 1982) Liu, Peng, Gao, Fu, Wu, Lu, Gao & Xiao, 2010 and O. ovacutus (Mamaev, 1970) Machida, 2011 from Parastromateus niger (Bloch), and O. decapteri Parukhin, 1966 from Atule mate (Cuvier). Both O. pampi and O. ovacutus can now be considered widespread in the Indo-Pacific region, with earlier records of these species being from Fujian Province, China and Penang, Malaysia, respectively. We redescribe O. decapteri from one of its original hosts, Atule mate, off New Caledonia, and report this species from Jakarta Bay, Indonesia, extending its range throughout the Indian Ocean into the south-western Pacific. All three species possess a genital atrium that is long, sometimes very long, and a genital pore that is located in the forebody. This validates the interpretation that the original description was erroneous in reporting the genital pore in the hindbody, well posterior to the ventral sucker. These observations verify the synonymy of Retractomonorchis Madhavi, 1977 with Opisthomonorcheides. A major discrepancy between the species of Opisthomonorcheides is that some are described with the uterus entering the terminal organ laterally and some with it entering terminally; this feature needs further analysis. Based on the length of the genital atrium and the posterior extent of the vitellarium, the 27 species of Opisthomonorcheides considered valid can be divided into four groups. Among the 53 host records analysed, the families Carangidae (53% of records), Stromateidae (17%) and Serranidae (5.7%) are the most common; the reports are overwhelmingly from members of the Perciformes (91%), with further records in the Clupeiformes (5.7%), Gadiformes (1.9%) and Pleuronectiformes (1.9%). Two fish genera (Parastromateus Bleeker and Pampus Bonaparte) dominate the recorded hosts, with the black pomfret Parastromateus niger harbouring six species, the silver pomfret Pampus argenteus (Euphrasen) harbouring six, and the Chinese silver pomfret P. chinensis (Euphrasen) two. A host-parasite checklist is presented. We discuss the host-specificity of members of the genus, questioning some records such as that of O. decapteri in a deep-sea macrourid. We also comment on the morphological similarity, but phylogenetic distance, between the various Pomfret species, advancing the possibility that a series of host misidentifications has occurred. Sequences of the ITS2 rDNA gene generated for O. pampi and O. ovacutus are briefly discussed and molecular data are lodged in the GenBank database.
    Matched MeSH terms: Perciformes/parasitology*
  2. Molecular phylogeography and genetic diversity of Angiostrongylus cantonensis and A. malaysiensis (Nematoda: Angiostrongylidae) based on 66-kDa protein gene
    Eamsobhana P, Yong HS, Song SL, Gan XX, Prasartvit A, Tungtrongchitr A
    Parasitol Int, 2019 Feb;68(1):24-30.
    PMID: 30267903 DOI: 10.1016/j.parint.2018.09.006
    Angiostrongylus cantonensis is the main causative agent of human angiostrongyliasis. A sibling species, A. malaysiensis has not been unequivocally incriminated to be involved in human infections. To date, there is only a single report on the application of the partial 66-kDa protein gene sequence for molecular differentiation and phylogeny of Angiostrongylus species. Nucleotide sequences of the 66-kDa protein gene of A. cantonensis and A. malaysiensis from Thailand, as well as those of the laboratory strains of A. cantonensis from Thailand and Hawaii, A. cantonensis from Japan and China, A. malaysiensis from Malaysia, and A. costaricensis from Costa Rica, were used for the reconstruction of phylogenetic tree by the maximum likelihood (ML) method and the haplotypes by the median joining (MJ) network. The ML phylogenetic tree contained two major clades with a full support bootstrap value - (1) A. cantonensis and A. malaysiensis, and (2) A. costaricensis. A. costaricensis was basal to A. cantonensis and A. malaysiensis. The genetic distance between A. cantonensis and A. malaysiensis ranged from p = .82% to p = 3.27%, that between A. cantonensis and A. costaricensis from p = 4.90% to p = 5.31%, and that between A. malaysiensis and A. costaricensis was p = 4.49% to p = 5.71%. Both A. cantonensis and A. malaysiensis possess high 66-kDa haplotype diversity. There was no clear separation of the conspecific taxa of A. cantonensis and A. malaysiensis from different geographical regions. A more intensive and extensive sampling with larger sample size may reveal greater haplotype diversity and a better resolved phylogeographical structure of A. cantonensis and A. malaysiensis.
    Matched MeSH terms: Strongylida Infections/parasitology
  3. Importance of Theranostics in Rare Brain-Eating Amoebae Infections
    Anwar A, Siddiqui R, Khan NA
    ACS Chem Neurosci, 2019 01 16;10(1):6-12.
    PMID: 30149693 DOI: 10.1021/acschemneuro.8b00321
    Pathogenic free-living amoebae including Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri cause infections of the central nervous system (CNS), which almost always prove fatal. The mortality rate is high with the CNS infections caused by these microbes despite modern developments in healthcare and antimicrobial chemotherapy. The low awareness, delayed diagnosis, and lack of effective drugs are major hurdles to overcome these challenges. Nanomaterials have emerged as vital tools for concurrent diagnosis and therapy, which are commonly referred to as theranostics. Nanomaterials offer highly sensitive diagnostic systems and viable therapeutic effects as a single modality. There has been good progress to develop nanomaterials based efficient theranostic systems against numerous kinds of tumors, but this field is yet immature in the context of infectious diseases, particularly parasitic infections. Herein, we describe the potential value of theranostic applications of nanomaterials against brain infections due to pathogenic amoebae.
    Matched MeSH terms: Brain/parasitology*
  4. Blastocystis sp., Parasite Associated with Gastrointestinal Disorders: An Overview of its Pathogenesis, Immune Modulation and Therapeutic Strategies
    Kumarasamy V, Anbazhagan D, Subramaniyan V, Vellasamy S
    Curr Pharm Des, 2018;24(27):3172-3175.
    PMID: 30084327 DOI: 10.2174/1381612824666180807101536
    Blastocystis sp. is a unicellular parasitic microorganism commonly found in the gastrointestinal tracts of humans and animals. It causes symptomatic or asymptomatic infection and its route of transmission is via fecal-oral. High prevalence of Blastocystis infection in developing countries is usually due to poor hygiene practices, exposure to animals infected with the parasite and intake of contaminated water or food. Blastocystis infected individuals often suffer from diarrhea, abdominal pain, nausea, and stomach bloating. Even though pathogenicity of Blastocystis is unclear, it is commonly associated with irritable bowel syndrome. In this review, we have analysed the evidence that shows the association between this microorganism and gastrointestinal disorders. There have been a number of studies which showed that the pathogenicity of Blastocystis is related to its different STs. The pathogenicity is speculated to be due to cysteine proteases formation which stimulates mucosal cells to release interleukin-8 which has been associated with extreme dehydration and gut inflammation. In vitro studies on human colonic epithelial cells revealed that incubation of Blastocystis modulated the host immune response by stimulating the formation of pro-inflammatory cytokines and granulocyte macrophage colonystimulating factor. Metronidazole is found to be the first-line drug of choice. Another treatment option is the combination therapy with trimethoprim/sulfamethoxazole.
    Matched MeSH terms: Blastocystis/parasitology
  5. Fulltext Within-population genetic diversity and population structure of Plasmodium knowlesi merozoite surface protein 1 gene from geographically distinct regions of Malaysia and Thailand
    Ahmed MA, Chu KB, Vythilingam I, Quan FS
    Malar J, 2018 Nov 29;17(1):442.
    PMID: 30497496 DOI: 10.1186/s12936-018-2583-z
    BACKGROUND: The C-terminal 42 kDa domain of Plasmodium knowlesi merozoite surface protein 1 (PkMSP1) is a potential asexual blood-stage vaccine candidate, however, only a limited number of clinical isolates have been analysed from Malaysia and no inter-country comparative diversity study has been conducted. In the present study, nucleotide diversity, haplotypes and natural selection levels of pkmsp1 in clinical samples from geographically distinct regions of Malaysia and Thailand were investigated. The overall population structure of the parasite from the region was determined.

    METHODS: Eleven full-length pkmsp1 sequences obtained from clinical isolates of Malaysia along with the H-strain were downloaded from the database for domain wise characterization of pkmsp1 gene. Additionally, 76 pkmsp-142 sequences from Thailand and Malaysia were downloaded from the database for intra and inter-population analysis. DnaSP 5.10 and MEGA 5.0 software were used to determine genetic diversity, polymorphism, haplotypes and natural selection. Genealogical relationships were determined using haplotype network tree in NETWORK software v5.0. Population genetic differentiation index (FST) of parasites were analysed using Arlequin v3.5.

    RESULTS: Sequence analysis of 11 full-length pkmsp1 sequences along with the H-strain identified 477 (8.4%) polymorphic sites, of which 107 were singleton sites. The overall diversity observed in the full-length genes were high in comparison to its ortholog pvmsp1 and the 4 variable domains showed extensive size variations. The nucleotide diversity was low towards the pkmsp1-42 compared to the conserved domains. The 19 kDa domain was less diverse and completely conserved among isolates from Malaysian Borneo. The nucleotide diversity of isolates from Peninsular Malaysia and Thailand were higher than Malaysian Borneo. Network analysis of pkmsp1-42 haplotypes showed geographical clustering of the isolates from Malaysian Borneo and grouping of isolates from Peninsular Malaysia and Thailand. Population differentiation analysis indicated high FST values between parasite populations originating from Malaysian Borneo, Peninsular Malaysia and Thailand attributing to geographical distance. Moderate genetic differentiation was observed for parasite populations from Thailand and Peninsular Malaysia. Evidence of population expansion and purifying selection were observed in all conserved domains with strongest selection within the pkmsp1-42 domain.

    CONCLUSIONS: This study is the first to report on inter country genetic diversity and population structure of P. knowlesi based on msp1. Strong evidence of negative selection was observed in the 42 kDa domain, indicating functional constrains. Geographical clustering of P. knowlesi and moderate to high genetic differentiation values between populations identified in this study highlights the importance of further evaluation using larger number of clinical samples from Southeast Asian countries.

    Matched MeSH terms: Malaria/parasitology*
  6. Fulltext Using satellite-measured relative humidity for prediction of Metisa plana's population in oil palm plantations: A comparative assessment of regression and artificial neural network models
    Ruslan SA, Muharam FM, Zulkafli Z, Omar D, Zambri MP
    PLoS One, 2019;14(10):e0223968.
    PMID: 31626637 DOI: 10.1371/journal.pone.0223968
    Metisa plana (Walker) is a leaf defoliating pest that is able to cause staggering economical losses to oil palm cultivation. Considering the economic devastation that the pest could bring, an early warning system to predict its outbreak is crucial. The state of art of satellite technologies are now able to derive environmental factors such as relative humidity (RH) that may influence pest population's fluctuations in rapid, harmless, and cost-effective manners. This study examined the relationship between the presence of Metisa plana at different time lags and remote sensing (RS) derived RH by using statistical and machine learning approaches. Metisa plana census data of cumulated larvae instar 1, 2, 3, and 4 were collected biweekly in 2014 and 2015 in an oil palm plantation in Muadzam Shah, Pahang, Malaysia. Relative humidity values derived from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images were apportioned to 6 time lags; 1 week (T1), 2 weeks (T2), 3 week (T3), 4 weeks (T4), 5 week (T5) and 6 weeks (T6) and paired with the respective census data. Pearson's correlation was carried out to analyse the relationship between Metisa plana and RH at different time lags. Regression analyses and artificial neural network (ANN) were also conducted to develop the best prediction model of Metisa plana's outbreak. The results showed relatively high correlations, positively or negatively, between the presences of Metisa plana with RH ranging from 0.46 to 0.99. ANN was found to be superior to regression models with the adjusted coefficient of determination (R2) between the actual and predicted Metisa plana values ranging from 0.06 to 0.57 versus 0.00 to 0.05. The analysis on the best time lags illustrated that the multiple time lags were more influential on the Metisa plana population than the individual time lags. The best Metisa plana prediction model was derived from T1, T2 and T3 multiple time lags modelled using the ANN algorithm with R2 value of 0.57, errors below 1.14 and accuracies above 93%. Based on the result of this study, the elucidation of Metisa plana's landscape ecology was possible with the utilization of RH as the predictor variable in consideration of the time lag effects of RH on the pest's population.
    Matched MeSH terms: Arecaceae/parasitology*
  7. Intestinal parasites in hemodialysis patients from developing countries: A systematic review and meta-analysis
    Taghipour A, Olfatifar M, Rostami A, Foroutan M, Vasigala V, Norouzi M
    Hemodial Int, 2020 01;24(1):12-21.
    PMID: 31804770 DOI: 10.1111/hdi.12796
    Intestinal parasitic infection (IPI) is the main cause of gastrointestinal complications in hemodialysis patients due to their impaired immune systems. We conducted a systematic review and meta-analysis to evaluate the prevalence and odds ratio (OR) of IPIs in this population. Relevant eligible studies were identified by searching the PubMed, Science Direct, Scopus, Web of Science, and Google scholar databases up to January 30, 2019. A random-effects meta-analysis model was used to estimate the pooled prevalence, OR, and 95% confidence intervals (CI). Twenty-two studies, from Turkey, Iran, Brazil, Egypt, Saudi Arabia, Pakistan, and Malaysia met eligibility criteria for analysis, and included 11 using a case-control design (980 patients and 893 controls) and 11 studies using a cross-sectional design (a total of 1455 participants). Cross-sectional studies suggested that the pooled prevalence of IPIs in hemodialysis patients was 24% (95% CI, 14-36%; 307/1455). In studies using a case-control design, the pooled prevalence of IPIs in hemodialysis patients (30%, 330/980) was found to be significantly higher than controls (10%, 115/893) (OR, 3.40; 95%CI, 2.37-4.87). With respect to the parasites, Cryptosporidium spp. (OR, 4.49; 95%CI, 2.64-7.64) and Blastocystis sp. (OR, 4.03; 95%CI, 1.20-13.51) were significantly higher in hemodialysis patients compared to the controls. The current study revealed a high prevalence of IPIs in hemodialysis patients from countries in which the baseline prevalence of parasitic infection is high. We recommend that periodic screenings for IPIs in such countries should be incorporated into the routine clinical care of hemodialysis patients.
    Matched MeSH terms: Intestinal Diseases, Parasitic/parasitology*
  8. Fulltext Long-Tailed Macaque Response to Deforestation in a Plasmodium knowlesi-Endemic Area
    Stark DJ, Fornace KM, Brock PM, Abidin TR, Gilhooly L, Jalius C, et al.
    Ecohealth, 2019 12;16(4):638-646.
    PMID: 30927165 DOI: 10.1007/s10393-019-01403-9
    Land-use changes can impact infectious disease transmission by increasing spatial overlap between people and wildlife disease reservoirs. In Malaysian Borneo, increases in human infections by the zoonotic malaria Plasmodium knowlesi are hypothesised to be due to increasing contact between people and macaques due to deforestation. To explore how macaque responses to environmental change impact disease risks, we analysed movement of a GPS-collared long-tailed macaque in a knowlesi-endemic area in Sabah, Malaysia, during a deforestation event. Land-cover maps were derived from satellite-based and aerial remote sensing data and models of macaque occurrence were developed to evaluate how macaque habitat use was influenced by land-use change. During deforestation, changes were observed in macaque troop home range size, movement speeds and use of different habitat types. Results of models were consistent with the hypothesis that macaque ranging behaviour is disturbed by deforestation events but begins to equilibrate after seeking and occupying a new habitat, potentially impacting human disease risks. Further research is required to explore how these changes in macaque movement affect knowlesi epidemiology on a wider spatial scale.
    Matched MeSH terms: Macaca fascicularis/parasitology*
  9. Identification of Host Proteins Interacting with Toxoplasma gondii SAG1 by Yeast Two-Hybrid Assay
    Lai MY, Abdul-Majid N, Lau YL
    Acta Parasitol, 2019 Sep;64(3):575-581.
    PMID: 31165984 DOI: 10.2478/s11686-019-00066-4
    Toxoplasma gondii is one of the most successful human pathogens. To eliminate the infection, identification of receptors or binding partners from humans is indeed urgent. T. gondii surface antigen is the ultimate component involved during the attachment of parasite into host cell. However, mechanism of invasion between SAG and host-cell membrane remains unclear. Yeast two-hybrid experiment was used to identify the binding partners from cDNA human library by using T. gondii SAG1 as bait. Mated yeast cells were plated on DDO/X plates to confirm only prey plasmid that expressing interacting protein was selected. We detected 39 clones interacted with SAG1 based on a series of the selection procedures. After colony PCR, only 29 clones were positive and subsequently sent for sequencing. The yeast plasmids for true positive clones were rescued by transformation into E. coli TOP 10F' cells. Twenty-two clones were further examined by small-scale Y2H experiment. The results indicated that a strong interaction existed between Homo sapiens lysine-rich coil-coiled and SAG1 protein, which could activate the expressions of the reporter genes in diploid yeast. Co-immunoprecipitation experiment result indicated the binding between this prey and SAG1 protein was significant (Mann-Whitney U test, Z = - 1.964, P = 0.05). H. sapiens lysine-rich coil-coiled protein was found to be interacted with SAG1. This prey protein may serve as the potential drug target in vaccination study.
    Matched MeSH terms: Toxoplasmosis/parasitology
  10. Fulltext Plasmodium knowlesi from archival blood films: further evidence that human infections are widely distributed and not newly emergent in Malaysian Borneo
    Lee KS, Cox-Singh J, Brooke G, Matusop A, Singh B
    Int J Parasitol, 2009 Aug;39(10):1125-8.
    PMID: 19358848 DOI: 10.1016/j.ijpara.2009.03.003
    Human infections with Plasmodium knowlesi have been misdiagnosed by microscopy as Plasmodium malariae due to their morphological similarities. Although microscopy-identified P. malariae cases have been reported in the state of Sarawak (Malaysian Borneo) as early as 1952, recent epidemiological studies suggest the absence of indigenous P. malariae infections. The present study aimed to determine the past incidence and distribution of P. knowlesi infections in the state of Sarawak based on archival blood films from patients diagnosed by microscopy as having P. malariae infections. Nested PCR assays were used to identify Plasmodium species in DNA extracted from 47 thick blood films collected in 1996 from patients in seven different divisions throughout the state of Sarawak. Plasmodium knowlesi DNA was detected in 35 (97.2%) of 36 blood films that were positive for Plasmodium DNA, with patients originating from all seven divisions. Only one sample was positive for P. malariae DNA. This study provides further evidence of the widespread distribution of human infections with P. knowlesi in Sarawak and its past occurrence. Taken together with data from previous studies, our findings suggest that P. knowlesi malaria is not a newly emergent disease in humans.
    Matched MeSH terms: Malaria/parasitology
  11. Immunohistochemical evaluation of interleukin-23 and cyclooxygenase-2 in the muscles of mice infected with Trichinella spiralis
    El-Aswad BEW, Ammar AI, Mahmoud SF, Soliman SS, Abd El-Atty AF
    Trop Biomed, 2020 Mar 01;37(1):75-88.
    PMID: 33612720
    The course of Trichinella (T.) spiralis infection includes intestinal and muscle phases. The aims of this work were to evaluate IL-23 and cyclooxygenase-2 (COX-2) by immunohistochemistry in the muscles of T. spiralis infected mice in a time-course study and to correlate their level with the serum levels of IL-23, IFN-γ, IL-4 and IL-10 cytokines. The mice were divided into an un-infected control group (UC) (10 mice) and 5 infected mouse groups (each 10 mice/group. Each mouse was infected with 200 T. spiralis larvae) and sacrificed on days 7, 14, 21, 28 and 35 post-infection (dpi). IL-23 showed weak expression (+1) on the 21st dpi, then it became moderately expressed (+2) on the 28th dpi and on day 35 pi, the immunoreactivity was strong (+3). COX-2 expressed weakly on 14 dpi, while the other mouse groups (21, 28 and 35) showed strong (+3) expression. IL-23 serum concentrations increased gradually in a significant pattern, in comparison to that of UC mice, from the 21st dpi to the end of the experiment. IFN-γ increased gradually and was significantly higher than those of UC mice from the 7th dpi, reached its maximum level on the 21st dpi, after which it decreased non-significantly. IL-4 up-regulated significantly in all infected groups in comparison to UC mice achieving its highest level on the 21st dpi and decreased after that. IL-10 increased significantly on the 7th dpi, but dropped at the 14th dpi, then reached its peak on the 21st dpi, and decreased again on the 28th and 35th dpi. In conclusion, T. spiralis infection caused increased expression of IL-23 and COX-2 in the muscle of infected mice, the effect being strongest on the 35th day. Also, the infection induced a mixed Th1/Th2 profile with a predominance of Th2 at the early muscle phase, after which the immune repose became mainly Th2.
    Matched MeSH terms: Muscles/parasitology*
  12. 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/parasitology*
  13. Risk factors associated with soil transmitted helminth (STH) infection in two indigenous communities in Malaysia
    Nisha M, Aiman M, Asyhira N, Syafiq H, Atiqah N, Kumarasamy V, et al.
    Trop Biomed, 2020 Jun 01;37(2):379-388.
    PMID: 33612807
    Soil-transmitted helminth (STH) could possibly cause mild to severe health effects such as diarrhea, weakness, intestinal blood loss, and impaired cognitive development and growth. In Malaysia, previous studies depicted a high prevalence rate of STH was due to poor hygiene practice and low efficacies of anthelminthic drugs. This study was conducted to investigate hand hygiene practice and WASH criteria's (Water, sanitation and hygiene) related to STH infection among two indigenous tribes in Peninsular Malaysia. A cross-sectional study was carried out to study the relationship among STH infection compared to water quality, sanitation, and hygiene conditions. A total of 190 individuals from two indigenous villages participated in the study, with ages ranging from 5 to 60 years old. In addition, Pearson's Chisquare (X2) test was utilized to test the relationship among STH with demographic socioeconomic and behavioral factors. The confidence interval (CI) of 95% is used to estimate the precision of the odds ratio (OR). Multivariate logistic regression models were also used to identify the risk factors associated with STH infections. The overall findings indicated a prevalence rate of 72% for STH, and distributed mainly among children aged < 12 years. Furthermore, multivariate analyses using logistic regression revealed chronic health problems, incorrect hand washing, and walking bare footed were associated with STH infection. Overall results indicated high prevalence of STH among the indigenous villagers, which aligns with the published literature and proves to be a problem need to be addressed as neglected disease. Interestingly, there was a significant relationship between the presences of chronic diseases and STH infection, which prompted other questions the awareness needs to be educated and the simple and low-cost intervention on the proper way of hand washing may help to reduce STH infection in these indigenous communities.
    Matched MeSH terms: Soil/parasitology*
  14. Sub-lethal concentrations of artemisinin alter pH of the digestive vacuole of the malaria parasite, Plasmodium falciparum
    Ibrahim N, Roslee A, Azlan M, Abu-Bakar N
    Trop Biomed, 2020 Mar 01;37(1):1-14.
    PMID: 33612713
    An appropriate pH maintenance within a membrane-enclosed organelle is vital for the occurrence of biological processes. Artemisinin (ART), a potent antimalarial drug has been reported to target the digestive vacuole (DV) of Plasmodium falciparum, which might alter the pH of the organelle, thereby impairing the hemoglobin degradation and subsequent heme detoxification. Hence, a flow cytometry-based technique using fluorescein isothiocyanate-dextran (FITC-dextran) as a ratiometric pH probe was employed to measure the pH of the DV of the malaria parasite treated with ART. Based on the pH calibration curve generated, the steady-state pH of the acidic DV of the non-treated parasites was 5.42 ± 0.11, indicating that FITC-dextran is suitable for detection of physiological pH of the organelle. The alteration of the DV pH occurred when the parasites were treated with ART even at the sub-lethal concentrations (15 and 30 nM) used. The similar effect was shown by the parasites treated with a standard proton pump inhibitor, concanamycin A. This suggests that ART might have altered the DV pH at lower levels than the level needed to kill the parasite. This study has important implications in designing new ART treatment strategies and in generating new endoperoxide-based antimalarial drugs pertaining to the interruption of the pH regulation of the malaria parasite's DV.
    Matched MeSH terms: Erythrocytes/parasitology
  15. Seroprevalence of Toxoplasmosis among Hemato-oncology patients in Kelantan
    Kholib-Jati AK, Wan-Ahmad WMA, Mohamad S, Wan-Mahmood WH, Husin A, Wan-Ab-Rahman WS
    Trop Biomed, 2020 Mar 01;37(1):218-226.
    PMID: 33612733
    Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii that is prevalent in humans and animals. This study was aimed to determine the seroprevalence of T. gondii infection among hemato-oncology patients and its association with sociodemographic and behavioural characteristics. This cross-sectional study was conducted at the Hospital Universiti Sains Malaysia (USM) involving 56 blood samples from hemato-oncology patients. Anti-T. gondii IgG and IgM antibodies and IgG avidity were determined using enzyme-linked immunosorbent assays (ELISA). The association of T. gondii exposure, sociodemographic, and behavioural characteristics were assessed by a questionnaire and face-to-face interviews. Twenty-eight (50%) patients were seropositive for T. gondii antibodies, where 27 (48.21%) patients were IgG+/IgM- and one patient (1.79%) was IgG+/IgM+ with high avidity index, indicating infection of more than 20 weeks. A univariate analysis showed that age, gender, ethnicity, marital status, educational level, employment status, stem cell transplant, blood transfusion, close contact with cats, water supply, and consumption of undercooked meat were not significantly associated with Toxoplasma seropositivity (p < 0.05). Our study has demonstrated, for the first time, the serological evidence of T. gondii exposure among hemato-oncology patients in Hospital USM. Our findings indicated that latent toxoplasmosis was relatively prevalence among our patients. Therefore, serological screening tests should be considered for immunocompromised patients as well as the implementation of health education programmes to encourage a healthy lifestyle and the consumption of healthy food among them.
    Matched MeSH terms: Hematologic Neoplasms/parasitology*
  16. Purification of Plasmodium and Babesia- infected erythrocytes using a non-woven fabric filter
    Tao ZY, Liu WP, Dong J, Feng XX, Yao DW, Lv QL, et al.
    Trop Biomed, 2020 Dec 01;37(4):911-918.
    PMID: 33612745 DOI: 10.47665/tb.37.4.911
    The purification of parasite-infected erythrocytes from whole blood containing leucocytes is crucial for many downstream genetic and molecular assays in parasitology. Current methodologies to achieve this are often costly and time consuming. Here, we demonstrate the successful application of a cheap and simple Non-Woven Fabric (NWF) filter for the purification of parasitized red blood cells from whole blood. NWF filtration was applied to the malaria-parasitized blood of three strains of mice, and one strain of rat, and to Babesia gibsoni parasitized dog blood. Before and after filtration, the white blood cell (WBC) removal rates and red blood cell (RBC) recovery rates were measured. After NWF filter treatment of rodent malaria-infected blood, the WBC removal rates and RBC recovery rates were, for Kunming mice: 99.51%±0.30% and 86.12%±8.37%; for BALB/C mice: 99.61%±0.15% and 80.74%±7.11%; for C57 mice: 99.71%±0.12% and 84.87%±3.83%; for Sprague-Dawley rats: 99.93%±0.03% and 83.30%±2.96%. Microscopy showed WBCs were efficiently removed from infected dog blood samples, and there was no obvious morphological change of B. gibsoni parasites. NWF filters efficiently remove leukocytes from malaria parasite-infected mouse and rat blood, and are also suitable for filtration of B. gibsoni-infected dog blood.
    Matched MeSH terms: Erythrocytes/parasitology*
  17. Trichinella spiralis: RNAi-mediated silencing of serine protease results in reduction of intrusion, development and fecundity
    Yang DQ, Zeng Y, Sun XY, Yue X, Hu CX, Jiang P, et al.
    Trop Biomed, 2020 Dec 01;37(4):932-946.
    PMID: 33612747 DOI: 10.47665/tb.37.4.932
    In previous studies, a Trichinella spiralis serine protease (TsSP) was identified in excretion/secretion (ES) products from intestinal infective L1 larvae (IIL1) using immunoproteomics. The complete cDNA sequence of TsSP gene was 1372 bp, which encoded 429 amino acids with 47.55 kDa. The TsSP was transcribed and expressed at all T. spiralis life cycle phases, as well as mainly located at the cuticle and stichosome of the parasitic nematode. Recombinant TsSP bind to intestinal epithelial cells (IEC) and promoted larva invasion, however, its exact function in invasion, development and reproduction are still unknown. The aim of this study was to confirm the biological function of TsSP during T. spiralis invasion and growth using RNA interference (RNAi) technology. The results showed that on 1 day after electroporation using 2.5 µM siRNA156, TsSP mRNA and protein expression of muscle larvae (ML) was suppressed by 48.35 and 59.98%, respectively. Meanwhile, silencing of TsSP gene by RNAi resulted in a 61.38% decrease of serine protease activity of ML ES proteins, and a significant reduction of the in vitro and in vivo invasive capacity of IIL1 to intrude into the IEC monolayer and intestinal mucosa. When mice were infected with siRNA 156-transfected larvae, adult worm and muscle larva burdens were decreased by 58.85 and 60.48%, respectively. Moreover, intestinal worm growth and female fecundity were evidently inhibited after TsSP gene was knockdown, it was demonstrated that intestinal adults became smaller and the in vitro newborn larval yield of females obviously declined compared with the control siRNA group. The results indicated that knockdown of TsSP gene by RNAi significantly reduced the TsSP expression and enzymatic activity, impaired larvae intrusion and growth, and lowered the female reproductive capacity, further verified that TsSP might participate in diverse processes of T. spiralis life cycle, it will be a new prospective candidate molecular target of anti-Trichinella vaccines.
    Matched MeSH terms: Intestinal Mucosa/parasitology
  18. Fulltext Modelling the ability of mass drug administration to interrupt soil-transmitted helminth transmission: Community-based deworming in Kenya as a case study
    Chong NS, Smith SR, Werkman M, Anderson RM
    PLoS Negl Trop Dis, 2021 08;15(8):e0009625.
    PMID: 34339450 DOI: 10.1371/journal.pntd.0009625
    The World Health Organization has recommended the application of mass drug administration (MDA) in treating high prevalence neglected tropical diseases such as soil-transmitted helminths (STHs), schistosomiasis, lymphatic filariasis, onchocerciasis and trachoma. MDA-which is safe, effective and inexpensive-has been widely applied to eliminate or interrupt the transmission of STHs in particular and has been offered to people in endemic regions without requiring individual diagnosis. We propose two mathematical models to investigate the impact of MDA on the mean number of worms in both treated and untreated human subpopulations. By varying the efficay of drugs, initial conditions of the models, coverage and frequency of MDA (both annual and biannual), we examine the dynamic behaviour of both models and the possibility of interruption of transmission. Both models predict that the interruption of transmission is possible if the drug efficacy is sufficiently high, but STH infection remains endemic if the drug efficacy is sufficiently low. In between these two critical values, the two models produce different predictions. By applying an additional round of biannual and annual MDA, we find that interruption of transmission is likely to happen in both cases with lower drug efficacy. In order to interrupt the transmission of STH or eliminate the infection efficiently and effectively, it is crucial to identify the appropriate efficacy of drug, coverage, frequency, timing and number of rounds of MDA.
    Matched MeSH terms: Soil/parasitology
  19. A rapid sporozoite ELISA using 3,3',5,5'-tetramethylbenzidine as the substrate chromogen
    Lee M, Harrison BA, Lewis GE
    Am J Trop Med Hyg, 1990 Apr;42(4):314-9.
    PMID: 2184690 DOI: 10.4269/ajtmh.1990.42.314
    A modified version of the standard 2-site sporozoite enzyme-linked immunosorbent assay (ELISA) using 3,3',5,5'-tetramethylbenzidine (TMB) as the substrate chromogen solution was adapted for rapid detection and identification of Plasmodium falciparum and P. vivax circumsporozoite (CS) proteins. The TMB-ELISA was evaluated using sporozoites from experimentally infected mosquitoes and laboratory colonized uninfected mosquitoes. Our data indicate comparable sensitivity levels between the TMB-ELISA and the standard ELISA, i.e., 50 P. falciparum or P. vivax sporozoites/50 microliters of test solution. Reactions inherent to the method were specific and background reactivity was minimal. The TMB-ELISA is rapid (1 hr), simple, uses a minimal amount of monoclonal antibodies, and is suitable for use in a wide range of laboratories.
    Matched MeSH terms: Anopheles/parasitology
  20. Fulltext Asymptomatic and Submicroscopic Carriage of Plasmodium knowlesi Malaria in Household and Community Members of Clinical Cases in Sabah, Malaysia
    Fornace KM, Nuin NA, Betson M, Grigg MJ, William T, Anstey NM, et al.
    J Infect Dis, 2016 Mar 01;213(5):784-7.
    PMID: 26433222 DOI: 10.1093/infdis/jiv475
    Although asymptomatic carriage of human malaria species has been widely reported, the extent of asymptomatic, submicroscopic Plasmodium knowlesi parasitemia is unknown. In this study, samples were obtained from individuals residing in households or villages of symptomatic malaria cases with the aim of detecting submicroscopic P. knowlesi in this population. Four published molecular assays were used to confirm the presence of P. knowlesi. Latent class analysis revealed that the estimated proportion of asymptomatic individuals was 6.9% (95% confidence interval, 5.6%-8.4%). This study confirms the presence of a substantial number of asymptomatic monoinfections across all age groups; further work is needed to estimate prevalence in the wider community.
    Matched MeSH terms: Malaria/parasitology*
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