10 research outputs found

    Cryptosporidiosis in Southeast Asia: what's out there?

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    Cryptosporidiosis is a socioeconomically important, enteric disease caused by a group of protozoan parasites of the genus Cryptosporidium. The significant morbidity and mortality in animals and humans caused by this disease as well as its considerable impact on the water industry have made its prevention and control a global challenge, particularly given that there are presently no widespread, affordable or effective treatment or vaccination strategies. Although much is known about Cryptosporidium and the impact of cryptosporidiosis and other diarrhoeal diseases in developed countries, this is not the case for many developing countries in Africa, South America and Asia. In Southeast Asia, which represents an epicentre for emerging infectious diseases, cryptosporidiosis has been reported in countries, such as Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam. In most of these countries, the likely predisposing factors for cryptosporidiosis include rapid population growth and expanding urbanisation (which are often linked to inadequate municipal water supplies and poorly managed refuse disposal) as well as the tropical climate and the increasing prevalence of HIV/AIDS and other infectious diseases. Given the close proximity of these countries and the extent of migration within and among them, cryptosporidiosis can be difficult to control. National and regional surveillance is central to preventing and controlling cryptosporidiosis. To date, most studies of cryptosporidiosis in Southeast Asia have focus on estimating the prevalence of infection in humans and animals using conventional diagnostic techniques. Future investigations using reliable molecular tools should enable improved insights into the epidemiology, systematics and population genetics of Cryptosporidium in this region. An enhanced understanding of the transmission of cryptosporidial infections and the significance of environmental contamination will require a multidisciplinary approach, built on shared resources. Such an integrated approach would underpin stable and powerful partnerships in efforts to prevent and control this disease. The purpose of the present chapter is to review available data and information on cryptosporidiosis in Southeast Asia and to provide recommendations in the pursuit of a better understanding of Cryptosporidium in this region, in order to facilitate the development of effective multidisciplinary interventions to control cryptosporidiosis

    Soil-transmitted helminths of humans in Southeast Asia towards integrated control

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    Soil-transmitted helminths (STHs) pose significant public health challenges in many countries of Southeast Asia (SEA). Overall, approximately one-third of the world's cases of ascariasis, trichuriasis, and hookworm disease occur in the 11 major SEA countries. Various countries are at different stages in their response to controlling these diseases. For instance, in Malaysia and Thailand, the major burden of disease is confined to rural/remote, indigenous and/or refugee populations. In countries, such as Cambodia, Lao People's Democratic Republic and Vietnam, the burden remains high, although extensive deworming programmes are underway and are yielding encouraging results. The present chapter reviews the current status of STH infections in SEA, identifies knowledge gaps and offers a perspective on the development of improved, integrated surveillance and control in this geographical region. It indicates that advances in our understanding of the epidemiology of these parasites, through the strategic use of molecular and predictive (e.g. geographical information systems (GIS) and remote sensing (RS)) technologies, could readily underpin future research and control programmes. It is hoped that the gradual move towards integrated treatment/control programmes will assist substantially in decreasing the chronic disease burden linked to STHs, thus increasing human health and welfare, and supporting socio-economic growth and development in SEA countries

    Specific and genotypic identification of Cryptosporidium from a broad range of host species by nonisotopic SSCP analysis of nuclear ribosomal DNA

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    The accurate identification of Cryptosporidium (Protozoa: Apicomplexa) species and genotypes is central to the understanding of the transmission and to the diagnosis and control of cryptosporidiosis. In this study, we demonstrate the effectiveness of nonisotopic SSCP analysis of a ∼300 bp region of the small subunit (pSSU) of ribosomal DNA for the specific identification of and delineation among 18 different Cryptosporidium species and genotypes from a wide range of hosts. This mutation scanning approach allowed the rapid and reliable differentiation between species/genotypes differing by as little as 1.3% in the pSSU sequence, with the capacity to detect point mutations. The present findings confirm the usefulness of this tool for the rapid genetic screening of Cryptosporidium samples from any host species, providing a foundation for detailed systematic, epidemiological and ecological studies. Although applied herein to pSSU, this low cost approach should be applicable to a wide range of genetic loci for population genetic investigations of Cryptosporidium

    First molecular characterization of Giardia duodenalis from goats in Malaysia

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    In the present study, 310 faecal samples from goats from eight different farms in Malaysia were tested for the presence of Giardia using a PCR-coupled approach. The nested PCR for SSU amplified products of the expected size (�200 bp) from 21 of 310 (6.8) samples. Sixteen of these 21 products could be sequenced successfully and represented six distinct sequence types. Phylogenetic analysis of the SSU sequence data using Bayesian Inference (BI) identified Giardia assemblages A, B and E. The identification of the 'zoonotic' assemblages A and B suggests that Giardia-infected goats represent a possible reservoir for human giardiasis in Malaysia

    First genetic classification of Cryptosporidium and Giardia from HIV/AIDS patients in Malaysia

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    Given the HIV epidemic in Malaysia, genetic information on opportunistic pathogens, such as Cryptosporidium and Giardia, in HIV/AIDS patients is pivotal to enhance our understanding of epidemiology, patient care, management and disease surveillance. In the present study, 122 faecal samples from HIV/AIDS patients were examined for the presence of Cryptosporidium oocysts and Giardia cysts using a conventional coproscopic approach. Such oocysts and cysts were detected in 22.1 and 5.7 of the 122 faecal samples, respectively. Genomic DNAs from selected samples were tested in a nested-PCR, targeting regions of the small subunit (SSU) of nuclear ribosomal RNA and the 60 kDa glycoprotein (gp60) genes (for Cryptosporidium), and the triose-phosphate isomerase (tpi) gene (for Giardia), followed by direct sequencing. The sequencing of amplicons derived from SSU revealed that Cryptosporidium parvum was the most frequently detected species (64 of 25 samples tested), followed by C. hominis (24), C. meleagridis (8) and C. felis (4). Sequencing of a region of gp60 identified C. parvum subgenotype IIdA15G2R1 and C. hominis subgenotypes IaA14R1, IbA10G2R2, IdA15R2, IeA11G2T3R1 and IfA11G1R2. Sequencing of amplicons derived from tpi revealed G. duodenalis assemblage A, which is of zoonotic importance. This is the first report of C hominis, C. meleagridis and C. felis from Malaysian HIV/AIDS patients. Future work should focus on an extensive analysis of Cryptosporidium and Giardia in such patients as well as in domestic and wild animals, in order to improve the understanding of transmission patterns and dynamics in Malaysia. It would also be particularly interesting to establish the relationship among clinical manifestation, CD4 cell counts and genotypes/subgenotypes of Cryptosporidium and Giardia in HIV/AIDS patients. Such insights would assist in a better management of clinical disease in immuno-deficient patients as well as improved preventive and control strategies. (C) 2011 Elsevier B.V. All rights reserved

    First genetic classification of Cryptosporidium and Giardia from HIV/AIDS patients in Malaysia

    No full text
    Given the HIV epidemic in Malaysia, genetic information on opportunistic pathogens, such as Cryptosporidium and Giardia, in HIV/AIDS patients is pivotal to enhance our understanding of epidemiology, patient care, management and disease surveillance. In the present study, 122 faecal samples from HIV/AIDS patients were examined for the presence of Cryptosporidium oocysts and Giardia cysts using a conventional coproscopic approach. Such oocysts and cysts were detected in 22.1 and 5.7 of the 122 faecal samples, respectively. Genomic DNAs from selected samples were tested in a nested-PCR, targeting regions of the small subunit (SSU) of nuclear ribosomal RNA and the 60 kDa glycoprotein (gp60) genes (for Cryptosporidium), and the triose-phosphate isomerase (tpi) gene (for Giardia), followed by direct sequencing. The sequencing of amplicons derived from SSU revealed that Cryptosporidium parvum was the most frequently detected species (64 of 25 samples tested), followed by C. hominis (24), C. meleagridis (8) and C. felis (4). Sequencing of a region of gp60 identified C. parvum subgenotype IIdA15G2R1 and C. hominis subgenotypes IaA14R1, IbA10G2R2, IdA15R2, IeA11G2T3R1 and IfA11G1R2. Sequencing of amplicons derived from tpi revealed G. duodenalis assemblage A, which is of zoonotic importance. This is the first report of C hominis, C. meleagridis and C. felis from Malaysian HIV/AIDS patients. Future work should focus on an extensive analysis of Cryptosporidium and Giardia in such patients as well as in domestic and wild animals, in order to improve the understanding of transmission patterns and dynamics in Malaysia. It would also be particularly interesting to establish the relationship among clinical manifestation, CD4 cell counts and genotypes/subgenotypes of Cryptosporidium and Giardia in HIV/AIDS patients. Such insights would assist in a better management of clinical disease in immuno-deficient patients as well as improved preventive and control strategies. (C) 2011 Elsevier B.V. All rights reserved

    Digging deep into intramitochondrial symbiosis: dual transcriptomics of the hard tick Ixodes ricinus and its bacterial symbiont Midichloria mitochondrii

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    INTRODUCTION. Ixodes ricinus is a hard tick, widespread in Europe and in the Mediterranean basin, that can act as vector of multiple diseases of human and veterinary importance. Midichloria mitochondrii is a bacterial symbiont of this tick, capable of living in the intermembrane space of mitochondria (Beninati et al., 2004, Appl. Environ. Microbiol., 70:2596\u20132602). The bacterium was found to be present in most tick individuals (Lo et al., 2006, Environ. Microbiol., 8:1280-1287) and to be vertically transmitted to the progeny (Sassera et al., 2008, Appl. Environ. Microbiol., 74:6138-6140). To investigate the relationship between host and symbiont we designed an ad-hoc protocol of dual RNA-Seq to sequence the transcriptomes of both organisms in different phases of tick engorgement. MATERIALS AND METHODS. Ticks were collected on roe deer, cut in half and stored in RNALater on site, in order to freeze the transcription patterns in each stage. Ticks were dissected in RNALater and total RNA was extracted from ovaries and salivary glands. A custom library construction kit was designed and used in order to preserve transcripts from both organisms and to limit the prevalence of rRNA sequences in the sample (normally over 85%). The kit protocol included the use of custom designed probes for rRNA depletion. Libraries were sequenced on Illumina machines and the resulting reads were assembled to obtain a reference transcriptome to be used for downstream analyses. RESULTS AND CONCLUSIONS. Ticks were subjected to a custom protocol for RNA sequencing which allowed to obtain an average of 40 million reads per sample and over 50% of the reads were transcripts of host or symbiont. After assembly, over 18,000 tick transcripts and over 1,200 bacterial transcripts were obtained. Differential expression analysis will be performed in the upcoming months; so far, the main result of this work is the development of a sound protocol for dual RNA-seq in this system

    Eukaryote-conserved methylarginine is absent in diplomonads and functionally compensated in Giardia

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    Methylation is a common posttranslational modification of arginine and lysine in eukaryotic proteins. Methylproteomes are best characterized for higher eukaryotes, where they are functionally expanded and evolved complex regulation. However, this is not the case for protist species evolved from the earliest eukaryotic lineages. Here, we integrated bioinformatic, proteomic, and drug-screening data sets to comprehensively explore the methylproteome of Giardia duodenalis—a deeply branching parasitic protist. We demonstrate that Giardia and related diplomonads lack arginine-methyltransferases and have remodeled conserved RGG/RG motifs targeted by these enzymes. We also provide experimental evidence for methylarginine absence in proteomes of Giardia but readily detect methyllysine. We bioinformatically infer 11 lysine-methyltransferases in Giardia, including highly diverged Su(var)3-9, Enhancer-of-zeste and Trithorax proteins with reduced domain architectures, and novel annotations demonstrating conserved methyllysine regulation of eukaryotic elongation factor 1 alpha. Using massspectrometry, we identify more than 200 methyllysine sites in Giardia, including in species-specific gene families involved in cytoskeletal regulation, enriched in coiled-coil features. Finally, we use known methylation inhibitors to show that methylation plays key roles in replication and cyst formation in this parasite. This study highlights reduced methylation enzymes, sites, and functions early in eukaryote evolution, including absent methylarginine networks in the Diplomonadida. These results challenge the view that arginine methylation is eukaryote conserved and demonstrate that functional compensation of methylarginine was possible preceding expansion and diversification of these key networks in higher eukaryotes.Samantha J. Emery-Corbin, Joshua J. Hamey, Brendan R.E. Ansell, Balu Balan, Swapnil Tichkule, Andreas J. Stroehlein, Crystal Cooper, Bernie V. McInerney, Soroor Hediyeh-Zadeh, Daniel Vuong, Andrew Crombie, Ernest Lacey, Melissa J. Davis, Marc R. Wilkins, Melanie Bahlo, Staffan G. Svärd, Robin B. Gasser, and Aaron R. Je
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