Displaying publications 201 - 220 of 232 in total

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  1. Sequence diversity and positive selection at the Duffy-binding protein genes of Plasmodium knowlesi and P. cynomolgi: Analysis of the complete coding sequences of Thai isolates
    Putaporntip C, Kuamsab N, Jongwutiwes S
    Infect Genet Evol, 2016 Oct;44:367-375.
    PMID: 27480919 DOI: 10.1016/j.meegid.2016.07.040
    Plasmodium knowlesi and P. cynomolgi are simian malaria parasites capable of causing symptomatic human infections. The interaction between the Duffy binding protein alpha on P. knowlesi merozoite and the Duffy-antigen receptor for chemokine (DARC) on human and macaque erythrocyte membrane is prerequisite for establishment of blood stage infection whereas DARC is not required for erythrocyte invasion by P. cynomolgi. To gain insights into the evolution of the PkDBP gene family comprising PkDBPα, PkDBPβ and PkDBPγ, and a member of the DBP gene family of P. cynomolgi (PcyDBP1), the complete coding sequences of these genes were analyzed from Thai field isolates and compared with the publicly available DBP sequences of P. vivax (PvDBP). The complete coding sequences of PkDBPα (n=11), PkDBPβ (n=11), PkDBPγ (n=10) and PcyDBP1 (n=11) were obtained from direct sequencing of the PCR products. Nucleotide diversity of DBP is highly variable across malaria species. PcyDBP1 displayed the greatest level of nucleotide diversity while all PkDBP gene members exhibited comparable levels of diversity. Positive selection occurred in domains I, II and IV of PvDBP and in domain V of PcyDBP1. Although deviation from neutrality was not detected in domain II of PkDBPα, a signature of positive selection was identified in the putative DARC binding site in this domain. The DBP gene families seem to have arisen following the model of concerted evolution because paralogs rather than orthologs are clustered in the phylogenetic tree. The presence of identical or closely related repeats exclusive for the PkDBP gene family suggests that duplication of gene members postdated their divergence from the ancestral PcyDBP and PvDBP lineages. Intragenic recombination was detected in all DBP genes of these malaria species. Despite the limited number of isolates, P. knowlesi from Thailand shared phylogenetically related domain II sequences of both PkDBPα and PkDBPγ with those from Peninsular Malaysia, consistent with their geographic proximity.
    Matched MeSH terms: Parasites
  2. Fulltext The health of Malaysia’s “Orang Asli” peoples: a review of the scientific evidence on nutritional outcome, parasite infestations, and discussion on implications for clinical practice
    Phua, K.L.
    Malaysian Journal of Public Health Medicine, 2015;15(1):0-0.
    MyJurnal
    The Orang Asli of Malaysia continue to experience poor health. There appears to be stagnation of certain aspect of their health status. Underweight (low weight-for-age) and stunting (low height-for-age) are significant amongst Orang Asli children. Worm infestation such as Ascaris, Trichuris and hookworm continue to afflict Orang Asli communities in Malaysia. Orang Asli communities can also be afflicted by other kinds of parasites, e.g. malaria parasites, microsporida parasites and Cryptosporidium parasites. Thus, primary care doctors who treat Orang Asli patients should be on the lookout for malnutrition and its effects (including anaemia, iodine deficiency, Vitamin A deficiency) as well as worm and parasite infestations. Such patients may need to undergo de-worming at regular intervals because of the tendency to get re-infected. Primary care doctors also need to be aware of possible interactions between infestations and nutritional deficiencies.
    Matched MeSH terms: Parasites
  3. Fulltext Revisiting the global problem of cryptosporidiosis and recommendations
    Shrivastava AK, Kumar S, Smith WA, Sahu PS
    Trop Parasitol, 2017 Jan-Jun;7(1):8-17.
    PMID: 28459010 DOI: 10.4103/2229-5070.202290
    Cryptosporidiosis is a gastrointestinal illness caused by the protozoan parasite Cryptosporidium species, which is a leading cause of diarrhea in a variety of vertebrate hosts. The primary mode of transmission is through oral routes; infections spread with the ingestion of oocysts by susceptible animals or humans. In humans, Cryptosporidium infections are commonly found in children and immunocompromised individuals. The small intestine is the most common primary site of infection in humans while extraintestinal cryptosporidiosis occurs in immunocompromised individuals affecting the biliary tract, lungs, or pancreas. Both innate and adaptive immune responses play a critical role in parasite clearance as evident from studies with experimental infection in mice. However, the cellular immune responses induced during human infections are poorly understood. In this article, we review the currently available information with regard to epidemiology, diagnosis, therapeutic interventions, and strategies being used to control cryptosporidiosis infection. Since cryptosporidiosis may spread through zoonotic mode, we emphasis on more epidemiological surveillance-based studies in developing countries with poor sanitation and hygiene. These epidemiological surveys must incorporate fecal source tracking measures to identify animal and human populations contributing significantly to the fecal burden in the community, as mitigation measures differ by host type.
    Matched MeSH terms: Parasites
  4. An ecological study of Paragonimus in Malaysia
    Kim JS
    Kisaengchunghak Chapchi, 1978 Jun;16(1):47-53.
    PMID: 12902783
    An ecologic study on Paragonimus in Malaysia was attempted from May to September 1967. Seven streams located in various directions and distances from Kuala Lumpur were surveyed for the study of intermediate hosts, snail and crab. One Malayan village and one aborigine village where infected crabs were found, and two tuberculosis hospitals in K.L. were surveyed for the study of human population. Intradermal tests along with sputum or stool examination to detect human infection by Paragonimus were employed. Wild animals, only a few, were shot in the vicinity of the aborigine village and several domestic cats from the Malayan village were bought. These animals were autopsied and examined for adult Paragonimus. Among five species of crab collected from the study areas, only two species, Potamon jahorenes and Parathelphusa maculata were found to be infected with Paragonimus. P. maculata seemed to be better crab host for the Paragonimus because this species had higher infection rate and metacercarial density than the other in the very same area. Three out of seven streams had infected crabs and the infection rate as well as the infection intensity varied from one stream to another. Only avilable snail in the streams was identified as Brotia costula. The infection rate of the snail was very low, six snails out of 11,898, which is about the same rate reported from other countries. Infected snail, however, had thousands of rediae uncountable containing about twelve microcercocercariae in each redia, sufficient enough to maintain the life cycle of the parasite even with only a few infected snail, the amplifier. This is the first confirmed report on the snail host of Paragonimus from Malaysia where the existence of Paragonimus had been reported in 1923. The first trial to study human population by means of intradermal test, sputum and/or stool examinations in Malaysia showed no evidence of human infection of Paragonimus. The number of animals, wild and domestic, examined for natural infection was too small to draw any statement. These examined animals were all negative for adult Paragonimus. Even though more extensive studies on wild animals and human population may be necessary for the definite conclusion, the facts that infected crabs from jungle stream where human contacts are extreamely rare, and also highly infected crabs from the area where none of humans or domestic animals were infected, strongly suggest the life cycle of Paragonimus in this area may be maintained by wild animal hosts rather than by human host. The morphology of all stages of the parasite, the pattern of penetrating glands, flame cells and excretroy bladder of cercaria, lancet shaped single cuticular spines and 6 branched ovary of adult worm obtained from experimentally infected cat, and the shape of egg including all measurements agree well with the characteristics of Paragonimus westermani.
    Matched MeSH terms: Parasites
  5. Fulltext Eosinophilic Gastroenteritis as the initial manifestation of Hypereosinophilic Syndrome
    Narisa, S.S., Shanti, P., Jeevinesh, N.A., Sakthiswary, R.
    Medicine & Health, 2013;8(2):0-0.
    MyJurnal
    Eosinophilic gastroenteritis, an inflammatory disease of unknown etiology, commonly involves the stomach and small intestine with eosinophilic infiltration. Here, we report an unusual case of eosinophilic gastroenteritis involving the entire digestive tract as a manifestation of hypereosinophilic syndrome (HES). A 22-year-old woman presented to us with diarrhoea, pleural effusion, ascites and marked peripheral oeosinophilia. Stool specimens were negative for parasites, ova, bacteria, and fungi. Endoscopic studies showed pangastritis and duodenitis. Biopsy specimens of the oesophagus, stomach, duodenum, ileum, and colon demonstrated oeosinophilic infiltration. A diagnosis of hypereosinophilic syndrome with eosinophilic gastroenteritis involving the entire digestive tract was made. Hence, she was treated with prednisolone. Symptoms and peripheral oeosinophilia rapidly resolved with treatment, and radiological investigations revealed resolution of effusion. This case illustrates the wide spectrum of clinical manifestation of the disease, whereby it involves the entire digestive tract and it also emphasizes the diagnostic yields of endoscopic biopsies.
    Matched MeSH terms: Parasites
  6. Comparative study on mitogen activated protein kinase of plasmodium species by using in silico method
    Mohd Fakharul Zaman Raja Yahya, Hasidah Mohd Sidek
    Scientific Research Journal, 2012;9(1):1-14.
    MyJurnal
    Malaria parasites, Plasmodium can infect a wide range of hosts including humans and rodents. There are two copies of mitogen activated protein kinases (MAPKs) in Plasmodium, namely MAPK1 and MAPK2. The MAPKs have been studied extensively in the human Plasmodium, P. falciparum. However, the MAPKs from other Plasmodium species have not been characterized and it is therefore the premise of presented study to characterize the MAPKs from other Plasmodium species-P. vivax, P knowlesi, P berghei, P chabaudi and P.yoelli using a series of publicly available bioinformatic tools. In silico data indicates that all Plasmodium MAPKs are nuclear-localized and contain both a nuclear localization signal (NLS) and a Leucine-rich nuclear export signal (NES). The activation motifs of TDY and TSH were found to be fully conserved in Plasmodium MAPK1 and MAPK2, respectively. The detailed manual inspection of a multiple sequence alignment (MSA) construct revealed a total of 17 amino acid stack patterns comprising of different amino acids present in MAPK1 and MAPK2 respectively, with respect to rodent and human Plasmodia. It is proposed that these amino acid stack patterns may be useful in explaining the disparity between rodent and human Plasmodium MAPKs.
    Matched MeSH terms: Parasites
  7. Fulltext Food and water-borne protozoal diseases (FWBPD)
    Baha Latif
    Medical Health Reviews, 2009;2009(2):27-46.
    MyJurnal
    This review places emphasis on the food and water borne protozoal diseases like, cryptosporidiosis, giardiasis, cyclosporiasis, and toxoplasmosis which are endemic in many parts of the world. The article addresses cryptosporidiosis, giardiasis, cyclosporiasis, and toxoplasmosis. Cryptosporidium and Giardia are widespread in the environment and major outbreaks have occurred as a result of contaminated drinking water. Cyclospora has significance in the preparation and consumption of fresh food that have not received heat treatment. Toxoplasma gondii, transmission occur through contaminated water, unpasteurised milk and also the consumption of raw meat, which has been regarded as a major route of transmission to humans .These parasitic protozoa do not multiply in foods, but they may survive in or on moist foods for months especially in cool and damp environment. Their ecology makes control of these parasites difficult. Transmission, clinical manifestations, outbreaks, public health surveillance and control measures that are used for those diseases will be reviewed in this article.
    Matched MeSH terms: Parasites
  8. Fulltext Pathology of lymphatic filariasis
    Mak JW
    International e-Journal of Science, Medicine & Education, 2012;6 Suppl:S80-86.
    MyJurnal
    Developing and adult worms of the human lymphatic filarial parasites (Wuchereria bancrofti,
    Brugia malayi, and Brugia timori) are located mainly in the lymphatic system and occasionally in aberrant sites like subcutaneous and conjunctival cysts. Lymphatic
    pathology ranging from dilatation of lymphatic channels and lymphangiectasia are detected on ultrasonography in apparently healthy, amicrofilaraemic, but filarial antigen positive individuals in endemic areas. Microfilariae are distributed in various organs and may be associated with immune mediated pathology at these sites; tropical pulmonary eosinophilia is characterized by intense immune mediated destruction of microfilariae in the lung parenchyma. In the spleen and other sites, nodular granulomatous lesions can occur where microfilariae are trapped and destroyed. The finding of Wolbachia endosymbionts in all stages of lymphatic filarial parasites has provided new insight on the adverse reactions
    associated with anti-filarial chemotherapy. Inflammatory molecules mainly lipopolysaccharide (LPS)-like molecules released from endosymbionts on death of the
    parasites are largely responsible for the adverse reactions encountered during anti-filarial chemotherapy. Prenatal tolerance or sensitization to parasite derived molecules can immune-modulate and contribute to both pathology and susceptibility/resistance to infection. Pathological responses thus depend not only on exposure to filarial antigens/infection, but also on host-parasiteendosymbiont factors and to intervention with antifilarial treatment. Treatment induced or host mediated death of parasites are associated with various grades of inflammatory response, in which eosinophils and LPS from endosymbionts play prominent roles, leading to death of the parasite, granulomatous formation, organization and fibrosis. The non-human primate (Presbytis spp.) model of
    Brugia malayi developed for the tertiary screening of anti-filarial compounds has provided unique opportunities for the longitudinal study of the pathology associated with lymphatic filariasis. The pathology in this non-human primate model closely follows that seen in
    human lymphatic filarial infections and correlates with clinical evidence of lymphatic pathology as detected with ultrasonography. These studies also show that successful treatment as detected by loss of motility and calcification of worms on ultrasonography is associated with reversal of early dilatations of lymphatic channels.
    Matched MeSH terms: Parasites
  9. 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: Parasites
  10. Effects of Shape and Size of Cobalt Phosphate Nanoparticles against Acanthamoeba castellanii
    Anwar A, Chi Fung L, Anwar A, Jagadish P, Numan A, Khalid M, et al.
    Pathogens, 2019 Nov 22;8(4).
    PMID: 31766722 DOI: 10.3390/pathogens8040260
    T4 genotype Acanthamoeba are opportunistic pathogens that cause two types of infections, including vision-threatening Acanthamoeba keratitis (AK) and a fatal brain infection known as granulomatous amoebic encephalitis (GAE). Due to the existence of ineffective treatments against Acanthamoeba, it has become a potential threat to all contact lens users and immunocompromised patients. Metal nanoparticles have been proven to have various antimicrobial properties against bacteria, fungi, and parasites. Previously, different types of cobalt nanoparticles showed some promise as anti-acanthamoebic agents. In this study, the objectives were to synthesize and characterize the size, morphology, and crystalline structure of cobalt phosphate nanoparticles, as well as to determine the effects of different sizes of cobalt metal-based nanoparticles against A. castellanii. Cobalt phosphate octahydrate (CHP), Co3(PO4)2•8H2O, was synthesized by ultrasonication using a horn sonicator, then three different sizes of cobalt phosphates Co3(PO4)2 were produced through calcination of Co3(PO4)2•8H2O at 200 °C, 400 °C and 600 °C (CP2, CP4, CP6). These three types of cobalt phosphate nanoparticles were characterized using a field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analysis. Next, the synthesized nanoparticles were subjected to biological assays to investigate their amoebicidal, amoebistatic, anti-encystation, and anti-excystation effects against A. castellanii, as well as cell cytotoxicity. The overall results showed that 1.30 ± 0.70 µm of CHP microflakes demonstrated the best anti-acanthemoebic effects at 100 µg/mL, followed by 612.50 ± 165.94 nm large CP6 nanograins. However, amongst the three tested cobalt phosphates, Co3(PO4)2, the smaller nanoparticles had stronger antiamoebic effects against A. castellanii. During cell cytotoxicity analysis, CHP exhibited only 15% cytotoxicity against HeLa cells, whereas CP6 caused 46% (the highest) cell cytotoxicity at the highest concentration, respectively. Moreover, the composition and morphology of nanoparticles is suggested to be important in determining their anti-acathamoebic effects. However, the molecular mechanisms of cobalt phosphate nanoparticles are still unidentified. Nevertheless, the results suggested that cobalt phosphate nanoparticles hold potential for development of nanodrugs against Acanthamoeba.
    Matched MeSH terms: Parasites
  11. Fulltext Prevalence of malaria and its risk factors in Sabah, Malaysia
    Ramdzan AR, Ismail A, Mohd Zanib ZS
    Int J Infect Dis, 2019 Nov 27;91:68-72.
    PMID: 31785400 DOI: 10.1016/j.ijid.2019.11.026
    OBJECTIVES: The aim of this study was to determine the prevalence of malaria in Sabah and its potential risk factors.

    METHODS: This cross-sectional study analysed secondary data obtained from the health clinics in Sabah, Malaysia from January to August 2016. The Pearson Chi-square test was used to analyse the relationships between malaria infection and socio-demographic characteristics. Multivariable logistic regression was performed in order to determine the risk factors for malaria in Sabah.

    RESULTS: Out of 1222 patients, 410 (33.6%) had a laboratory-confirmed malaria infection. Infection by Plasmodium knowlesi accounted for the majority of malaria reports in Sabah (n=340, 82.9%). Multivariable analysis indicated that males (prevalence odds ratio 0.023, 95% confidence interval 0.012-0.047) and those living in a rural area (prevalence odds ratio 0.004, 95% confidence interval 0.002-0.009) were at higher risk 24.0-95.9) and those living in a rural area (adjusted odds ratio 212.6, 95% confidence interval 105.8-427.2) were at higher risk of acquiring a malaria infection.

    CONCLUSIONS: Malaria infections in Sabah, Malaysia are common, with P. knowlesi being the most common malaria parasite. The infection was associated with several socio-demographic and geographical factors. Thus, mitigation measures should be considered to address modifiable risk factors for malaria infection.

    Matched MeSH terms: Parasites
  12. Fulltext Diversity pattern of Plasmodium knowlesi merozoite surface protein 4 (MSP4) in natural population of Malaysia
    Ahmed MA, Saif A, Quan FS
    PLoS One, 2019;14(11):e0224743.
    PMID: 31751362 DOI: 10.1371/journal.pone.0224743
    Human infections due to the monkey malaria parasite Plasmodium knowlesi are increasingly being reported from Malaysia. The parasite causes high parasitaemia, severe and fatal malaria in humans thus there is a need for urgent measures for its control. The MSP4 is a potential vaccine candidate, which is well studied in Plasmodium falciparum and Plasmodium vivax; however, no study has been conducted in the orthologous gene of P. knowlesi. In this study, we investigated the level of polymorphisms, haplotypes, natural selection and population structure of full-length pkmsp4 in 32 clinical samples from Malaysian Borneo along with 4 lab-adapted strains. We found low levels of polymorphism across the gene with exon I showing higher diversity than the exon II. The C- terminal epidermal growth factor (EGF) domains and GPI-anchored region within exon II were mostly conserved with only 2 non-synonymous substitutions. Although 21 amino acid haplotypes were found, the frequency of mutation at the majority of the polymorphic positions was low. We found evidence of negative selection at the exon II of the gene indicating existence of functional constraints. Phylogenetic haplotype network analysis identified shared haplotypes and indicated geographical clustering of samples originating from Peninsular Malaysia and Malaysian Borneo. High population differentiation values were observed within parasite populations originating from Malaysian Borneo (Kapit, Sarikei and Betong) and laboratory-adapted strains obtained from Peninsular Malaysia and Philippines indicating distinct population structure. This is the first study to genetically characterize the full-length msp4 gene from clinical isolates of P. knowlesi from Malaysia and thus would be very useful for future rational vaccine studies. Further studies with higher number of samples and functional characterization of the protein will be necessary.
    Matched MeSH terms: Parasites
  13. Aryl Quinazolinone Derivatives as Novel Therapeutic Agents against Brain-Eating Amoebae
    Mungroo MR, Shahbaz MS, Anwar A, Saad SM, Khan KM, Khan NA, et al.
    ACS Chem Neurosci, 2020 08 19;11(16):2438-2449.
    PMID: 31961126 DOI: 10.1021/acschemneuro.9b00596
    Naegleria fowleri and Balamuthia mandrillaris are protist pathogens that infect the central nervous system, causing primary amoebic meningoencephalitis and granulomatous amoebic encephalitis with mortality rates of over 95%. Quinazolinones and their derivatives possess a wide spectrum of biological properties, but their antiamoebic effects against brain-eating amoebae have never been tested before. In this study, we synthesized a variety of 34 novel arylquinazolinones derivatives (Q1-Q34) by altering both quinazolinone core and aryl substituents. To study the antiamoebic activity of these synthetic arylquinazolinones, amoebicidal and amoebistatic assays were performed against N. fowleri and B. mandrillaris. Moreover, amoebae-mediated host cells cytotopathogenicity and cytotoxicity assays were performed against human keratinocytes cells in vitro. The results revealed that selected arylquinazolinones derivatives decreased the viability of B. mandrillaris and N. fowleri significantly (P < 0.05) and reduced cytopathogenicity of both parasites. Furthermore, these compounds were also found to be least cytotoxic against HaCat cells. Considering that nanoparticle-based materials possess potent in vitro activity against brain-eating amoebae, we conjugated quinazolinones derivatives with silver nanoparticles and showed that activities of the drugs were enhanced successfully after conjugation. The current study suggests that quinazolinones alone as well as conjugated with silver nanoparticles may serve as potent therapeutics against brain-eating amoebae.
    Matched MeSH terms: Parasites
  14. Immigrant Health Study. 7. Foreign workers study: blood parasites. [Abstract]
    Khairul Anuar A, Rohela M, Zurainee MN, Abdul Aziz A, Sivanandan S
    JUMMEC, 1998;3:63-63.
    Lymphatic filariasis is endemic in Asia. The infections persist as a major cause of clinical morbidity and a significant impediment to socioeconomic development. Its prevalence is increasing world wide, largely because of rapid unplanned urbanization in many endemic areas. It is estimated that at least 120 million people are infected. In our study on foreign workers, a total of 241 day time blood samples were collected. The countries represented were Bangladesh (134), Indonesia (103), Pakistan (3) and Myanmar(1). The tests conducted on blood samples were thick blood film for microfilaria and thin blood film for malaria and quantitation of eosinophiles using the Giemsa stain. Out of the 241 blood samples tested, one was positive for Wuchereria bancrofti and one other was positive for malaria (Plasmodium falciparum) each from Bangladesh and Indonesia respectively. As for the blood eosinophiles, 39 (16.18%) blood samples showed high eosinophilia. Fifteen (6.22%) were from Banglandesh and 24 (9.96%) were from Indonesia. The Bangladeshi male who was positive for Witcherrria bamuofti also showed eosinophilia of 22%. We believe that some of these cases with high eosinophilia, may be positive for microfilaria. We may have missed some cases because of the methodology we chose. Lymphatic filariasis is endemic in Bangladesh and Indonesia. In Malaysia W. brancrofti, especially in the cities have been eliminated. However their vectors for the transmission of W. bancrofti is rampant in the cities. With the influx of immigrants with W. bancrofti and in relation to their occupational nature, W. bancrofti may eventually be introduced into the community and change the whole facet of the disease in Malaysia.
    Matched MeSH terms: Parasites
  15. Immigrant Health Study. 5. Faecal pathogens in foreign workers. [Abstract]
    Suresh K, Rajah S, Khairul Anuar A, Anuar Zaini MZ, Saminathan R, Ramakrishnan S
    JUMMEC, 1998;3:62-63.
    One hundred seventy three stool samples were obtained from workers from Indonesia, Bangladesh, Myanmar, Pakistan and others. The stool samples were examined for Ascaris, Trichuris, Hookworm, Schistosomes, trematodes and cestodes. The protozaon parasites included Bnlantidiirrir coli, Blastocystis honlinis, Cyclospora cryptosporidium, Microsporidiirin, Entamoeeba histolytica, Giardia lamblia, lodamoeba butschilli. Of these 21.9%, 17% and 1% of the population studied had hookworm, Trichuris trichiura and Ascaris lumbricoides infections respectively. There was only one Indonesian reported to have Hymenolepis nana infections. The most common protozoan seen in the faecal sample is Blastocystis hominis (36%) followed by Giardia lamblia (4%). Most of the stools positive with these faecal pathogens were semisolid especially the ones positive for the protozoan. We have also shown Blastocystis from the Indonesian workers show very small forms almost 3-5 in size compared to the normal size of 10-15 pm in the other nationalities. These forms show a distinct growth profile in cultures and appears to be more resistant to temperature changes than Blastocystis seen in the other two nationalities. The high incidence of Hookworm and Trichuris infections is suggestive that if these workers are left unheated their productivity will be hampered by other possible serious complications such as anaemia, weight loss, abdominal pain with diarrhoea1 stools and nausea. There are increasing reports that Blastocystis hominis is pathogenic. Flatulence, abdominal discomfort and the increase in the frequency of the passing watery stool has been noted in patients infected with the parasite. Since most of the workers are generally housed in crowded rooms it is highly likely that this will facilitate transmission through the faecal-oral route of both Giardia and Blastocystis possibly increasing the incidences of these infections among workers.
    Matched MeSH terms: Parasites
  16. Fulltext Transcriptome Profiling of Toxoplasma gondii-Infected Human Cerebromicrovascular Endothelial Cell Response to Treatment with Monensin
    Harun MSR, Taylor M, Zhu XQ, Elsheikha HM
    Microorganisms, 2020 Jun 04;8(6).
    PMID: 32512820 DOI: 10.3390/microorganisms8060842
    Central to the progression of cerebral toxoplasmosis is the interaction of Toxoplasma gondii with the blood-brain barrier (BBB) endothelial cells. In the present work, we tested the hypothesis that inhibition of Wnt pathway signalling by the monovalent ionophore monensin reduces the growth of T. gondii infecting human brain microvascular endothelial cells (hBMECs) or microglial cells. The anti-parasitic effect of monensin (a Wnt signalling inhibitor) on the in vitro growth of T. gondii tachyzoites was investigated using two methods (Sulforhodamine B staining and microscopic parasite counting). The monensin inhibited T. gondii growth (50% inhibitory concentration [IC50] = 0.61 μM) with a selective index = 8.48 when tested against hBMECs (50% cytotoxic concentration [CC50] = 5.17 μM). However, IC50 of monensin was 4.13 μM with a SI = 13.82 when tested against microglia cells (CC50 = 57.08 μM), suggesting less sensitivity of microglia cells to monensin treatment. The effect of T. gondii on the integrity of the BBB was assessed by the transendothelial electrical resistance (TEER) assay using an in vitro human BBB model. The results showed that T. gondii infection significantly decreased hBMECs' TEER resistance, which was rescued when cells were treated with 0.1 µM monensin, probably due to the anti-parasitic activity of monensin. We also investigated the host-targeted effects of 0.1 µM monensin on global gene expression in hBMECs with or without T. gondii infection. Treatment of hBMECs with monensin did not significantly influence the expression of genes involved in the Wnt signalling pathway, suggesting that although inhibition of the Wnt signalling pathway did not play a significant role in T. gondii infection of hBMECs, monensin was still effective in limiting the growth of T. gondii. On the contrary, monensin treatment downregulated pathways related to steroids, cholesterol and protein biosynthesis and their transport between endoplasmic reticulum and Golgi apparatus, and deregulated pathways related to cell cycle and DNA synthesis and repair mechanisms. These results provide new insight into the host-modulatory effect of monensin during T. gondii infection, which merits further investigation.
    Matched MeSH terms: Parasites
  17. Heterologous expression of Plasmodium vivax apical membrane antigen 1 (PvAMA1) for binding peptide selection
    Chew CH, Lim YAL, Chua KH
    PeerJ, 2017;5:e3794.
    PMID: 28929019 DOI: 10.7717/peerj.3794
    BACKGROUND: Plasmodium is an obligate intracellular parasite. Apical membrane antigen 1 (AMA1) is the most prominent and well characterized malarial surface antigen that is essential for parasite-host cell invasion, i.e., for sporozoite to invade and replicate within hepatocytes in the liver stage and merozoite to penetrate and replicate within erythrocytes in the blood stage. AMA1 has long served as a potent antimalarial drug target and is a pivotal vaccine candidate. A good understanding of the structure and molecular function of this Plasmodium protein, particularly its involvement in host-cell adhesion and invasion, is of great interest and hence it offers an attractive target for the development of novel therapeutics. The present study aims to heterologous express recombinant Plasmodium AMA1 ectodomain of P. vivax (rPvAMA1) for the selection of binding peptides.

    METHODS: The rPvAMA1 protein was heterologous expressed using a tag-free Profinity eXact(TM) system and codon optimized BL21-Codon Plus (DE3)-RIL Escherichia coli strain and further refolded by dialysis for renaturation. Binding peptides toward refolded rPvAMA1 were panned using a Ph.D.-12 random phage display library.

    RESULTS: The rPvAMA1 was successfully expressed and refolded with three phage-displayed dodecapeptides designated as PdV1 (DLTFTVNPLSKA), PdV2 (WHWSWWNPNQLT), and PdV3 (TSVSYINNRHNL) with affinity towards rPvAMA1 identified. All of them exhibited positive binding signal to rPvAMA1 in both direct phage assays, i.e., phage ELISA binding assay and Western blot binding assay.

    DISCUSSION: Phage display technology enables the mapping of protein-protein interactions based on a simple principle that a library of phage particles displaying peptides is used and the phage clones that bind to the target protein are selected and identified. The binding sites of each selected peptides toward PvAMA1 (Protein Data Bank, PDB ID: 1W8K) were in silico predicted using CABS-dock web server. In this case, the binding peptides provide a valuable starting point for the development of peptidomimetic as antimalarial antagonists directed at PvAMA1.

    Matched MeSH terms: Parasites
  18. Screening and identification of host proteins interacting with Toxoplasma gondii SAG2 by yeast two-hybrid assay
    Lai MY, Lau YL
    Parasit Vectors, 2017 Oct 02;10(1):456.
    PMID: 28969712 DOI: 10.1186/s13071-017-2387-y
    BACKGROUND: The identification of receptors or binding partners of Toxoplasma gondii from humans is an essential activity. Many proteins involved in T. gondii invasion have been characterized, and their contribution for parasite entry has been proposed. However, their molecular interactions remain unclear.

    RESULTS: Yeast two-hybrid (Y2H) experiment was used to identify the binding partners of surface antigens of T. gondii by using SAG2 as bait. Colony PCR was performed and positive clones were sent for sequencing to confirm their identity. The yeast plasmids for true positive clones were rescued by transformation into E. coli TOP 10F' cells. The interplay between bait and prey was confirmed by β-galactosidase assay and co-immunoprecipitation experiment. We detected 20 clones interacting with SAG2 based on a series of the selection procedures. Following the autoactivation and toxicity tests, SAG2 was proven to be a suitable candidate as a bait. Thirteen clones were further examined by small scale Y2H experiment. The results indicated that a strong interaction existed between Homo sapiens zinc finger protein and SAG2, which could activate the expressions of the reporter genes in diploid yeast. Co-immunoprecipitation experiment result indicated the binding between this prey and SAG2 protein was significant (Mann-Whitney U-test: Z = -1.964, P = 0.05).

    CONCLUSIONS: Homo sapiens zinc finger protein was found to interact with SAG2. To improve the understanding of this prey protein's function, advanced investigations need to be carried out.

    Matched MeSH terms: Parasites
  19. Fulltext Detection of Sarcocyst in meat from local markets in Selangor: highlighting the use of Crude sample in PCR
    Azdayanti Muslim, Putri Shafinaz Sharudin, Atiqah Yunus, Norhabsah Omar, Alieya Zakaria, Norshafiqah Mohamad
    Journal of Clinical and Health Sciences, 2016;1(2):18-21.
    MyJurnal
    Sarcocystis spp. are obligate intracellular protozoan parasites which cause meat-borne parasitic disease. In Malaysia, sarcocystosis is seen as a potential emerging food-borne zoonosis after a series of large outbreak of human infections. Humans acquire infection either by ingestion of cyst in raw or undercooked infected meat or from sporocysts in contaminated food and water. The goal of this study is to identify the presence of sarcocystis parasites in meat of cattle, buffaloes, sheep and goats collected from local markets in Selangor, Malaysia. Methods: A total of 64 skeletal muscles samples (57 cattle, 2 buffaloes, 4 goats and 1 sheep) were collected from local markets. The samples were cut randomly into three pieces, squashed firmly between two glass slides and then examined microscopically for the presence of cysts. Results: Three samples of meat (4.69 %) from cattle (1), buffalo (1) and sheep (1) were found to be positive for cysts. The cysts were confirmed by PCR as sarcocystis sp. Conclusion: The results showed low prevalence of Sarcocystis infection in meat collected from local markets. However, since there is a transmission among the livestock, extra precaution should be taken in consideration to prevent the spreading of sarcocystosis from animals to human.
    Matched MeSH terms: Parasites
  20. Fulltext A combined human case of Dirofilaria ursi infection in dorsal subcutaneous tissue and Anisakis simplex sensu stricto (s.s.) infection in ventral subcutaneous tissue
    Yamada M, Shishito N, Nozawa Y, Uni S, Nishioka K, Nakaya T
    Trop Med Health, 2017;45:26.
    PMID: 29118653 DOI: 10.1186/s41182-017-0067-4
    Background: Dirofilaria ursi is a filarial nematode that parasitizes the subcutaneous tissues of the American black bear (Ursus americanus) and Japanese black bear (Ursus thiabetanus japonicus). D. ursi that has parasitized black bears has the potential to subsequently infect humans. In addition, extra-gastrointestinal anisakiasis is less common in Japan.

    Case presentation: We report a case of ventral subcutaneous anisakiasis and dorsal subcutaneous dirofilariasis that was acquired in Fukushima, in the northern part of Japan. The patient was an 83-year-old Japanese female, and subcutaneous parasitic granulomas were present on her left abdomen (near the navel) and left scapula. A pathological examination of the surgically dissected tissue sections from each region demonstrated eosinophilic granulomas containing different species of parasites. To enable the morphological and molecular identification of these parasites, DNA was extracted from paraffin-embedded sections using DEXPAT reagent, and the cytochrome oxidase 2 (COX2), internal transcribed spacer 1 (ITS1), 5.8S and ITS2 regions of the Anisakis larvae, and the 5S rRNA region of the male Dirofilaria were sequenced. The PCR products were examined and compared with DNA databases. Molecular analysis of the COX2 and 5S rRNA sequences of each worm revealed that the nematode found in the ventral region belonged to Anisakis simplex sensu stricto (s.s.) and the male Dirofilaria found in the dorsal region was classified as D. ursi.

    Conclusion: The present case showed a combined human case of D. ursi and A. simplex s.s. infections in subcutaneous tissues. The results of this study will contribute to the identification of unknown parasites in histological sections.
    Matched MeSH terms: Parasites
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