The impact of albendazole treatment on the incidence of viral- and bacterial-induced diarrhea in school children in southern Vietnam: study protocol for a randomized controlled trial

Anthelmintics are one of the more commonly available classes of drugs to treat infections by parasitic helminths (especially nematodes) in the human intestinal tract. As a result of their cost-effectiveness, mass school-based deworming programs are becoming routine practice in developing countries. However, experimental and clinical evidence suggests that anthelmintic treatments may increase susceptibility to other gastrointestinal infections caused by bacteria, viruses, or protozoa. Hypothesizing that anthelmintics may increase diarrheal infections in treated children, we aim to evaluate the impact of anthelmintics on the incidence of diarrheal disease caused by viral and bacterial pathogens in school children in southern Vietnam.This is a randomized, double-blinded, placebo-controlled trial to investigate the effects of albendazole treatment versus placebo on the incidence of viral- and bacterial-induced diarrhea in 350 helminth-infected and 350 helminth-uninfected Vietnamese school children aged 6-15 years. Four hundred milligrams of albendazole, or placebo treatment will be administered once every 3 months for 12 months. At the end of 12 months, all participants will receive albendazole treatment. The primary endpoint of this study is the incidence of diarrheal disease assessed by 12 months of weekly active and passive case surveillance. Secondary endpoints include the prevalence and intensities of helminth, viral, and bacterial infections, alterations in host immunity and the gut microbiota with helminth and pathogen clearance, changes in mean z scores of body weight indices over time, and the number and severity of adverse events.In order to reduce helminth burdens, anthelmintics are being routinely administered to children in developing countries. However, the effects of anthelmintic treatment on susceptibility to other diseases, including diarrheal pathogens, remain unknown. It is important to monitor for unintended consequences of drug treatments in co-infected populations. In this trial, we will examine how anthelmintic treatment impacts host susceptibility to diarrheal infections, with the aim of informing deworming programs of any indirect effects of mass anthelmintic administrations on co-infecting enteric pathogens.ClinicalTrials.gov: NCT02597556 . Registered on 3 November 2015

The Mitochondrial Genome of Baylisascaris procyonis

BACKGROUND: Baylisascaris procyonis (Nematoda: Ascaridida), an intestinal nematode of raccoons, is emerging as an important helminthic zoonosis due to serious or fatal larval migrans in animals and humans. Despite its significant veterinary and public health impact, the epidemiology, molecular ecology and population genetics of this parasite remain largely unexplored. Mitochondrial (mt) genomes can provide a foundation for investigations in these areas and assist in the diagnosis and control of B. procyonis. In this study, the first complete mt genome sequence of B. procyonis was determined using a polymerase chain reaction (PCR)-based primer-walking strategy. METHODOLOGY/PRINCIPAL FINDINGS: The circular mt genome (14781 bp) of B. procyonis contained 12 protein-coding, 22 transfer RNA and 2 ribosomal RNA genes congruent with other chromadorean nematodes. Interestingly, the B. procyonis mtDNA featured an extremely long AT-rich region (1375 bp) and a high number of intergenic spacers (17), making it unique compared with other secernentean nematodes characterized to date. Additionally, the entire genome displayed notable levels of AT skew and GC skew. Based on pairwise comparisons and sliding window analysis of mt genes among the available 11 Ascaridida mtDNAs, new primer pairs were designed to amplify specific short fragments of the genes cytb (548 bp fragment) and rrnL (200 bp fragment) in the B. procyonis mtDNA, and tested as possible alternatives to existing mt molecular beacons for Ascaridida. Finally, phylogenetic analysis of mtDNAs provided novel estimates of the interrelationships of Baylisasaris and Ascaridida. CONCLUSIONS/SIGNIFICANCE: The complete mt genome sequence of B. procyonis sequenced here should contribute to molecular diagnostic methods, epidemiological investigations and ecological studies of B. procyonis and other related ascaridoids. The information will be important in refining the phylogenetic relationships within the order Ascaridida and enriching the resource of markers for systematic, population genetic and evolutionary biological studies of parasitic nematodes of socio-economic importance

Clear Genetic Distinctiveness between Human- and Pig-Derived Trichuris Based on Analyses of Mitochondrial Datasets

The whipworm, Trichuris trichiura, causes trichuriasis in ∼600 million people worldwide, mainly in developing countries. Whipworms also infect other animal hosts, including pigs (T. suis), dogs (T. vulpis) and non-human primates, and cause disease in these hosts, which is similar to trichuriasis of humans. Although Trichuris species are considered to be host specific, there has been considerable controversy, over the years, as to whether T. trichiura and T. suis are the same or distinct species. Here, we characterised the entire mitochondrial genomes of human-derived Trichuris and pig-derived Trichuris, compared them and then tested the hypothesis that the parasites from these two host species are genetically distinct in a phylogenetic analysis of the sequence data. Taken together, the findings support the proposal that T. trichiura and T. suis are separate species, consistent with previous data for nuclear ribosomal DNA. Using molecular analytical tools, employing genetic markers defined herein, future work should conduct large-scale studies to establish whether T. trichiura is found in pigs and T. suis in humans in endemic regions

The Mitochondrial Genome of Toxocara canis

Toxocara canis (Ascaridida: Nematoda), which parasitizes (at the adult stage) the small intestine of canids, can be transmitted to a range of other mammals, including humans, and can cause the disease toxocariasis. Despite its significance as a pathogen, the genetics, epidemiology and biology of this parasite remain poorly understood. In addition, the zoonotic potential of related species of Toxocara, such as T. cati and T. malaysiensis, is not well known. Mitochondrial DNA is known to provide genetic markers for investigations in these areas, but complete mitochondrial genomic data have been lacking for T. canis and its congeners. In the present study, the mitochondrial genome of T. canis was amplified by long-range polymerase chain reaction (long PCR) and sequenced using a primer-walking strategy. This circular mitochondrial genome was 14162 bp and contained 12 protein-coding, 22 transfer RNA, and 2 ribosomal RNA genes consistent for secernentean nematodes, including Ascaris suum and Anisakis simplex (Ascaridida). The mitochondrial genome of T. canis provides genetic markers for studies into the systematics, population genetics and epidemiology of this zoonotic parasite and its congeners. Such markers can now be used in prospecting for cryptic species and for exploring host specificity and zoonotic potential, thus underpinning the prevention and control of toxocariasis in humans and other hosts

A Portrait of the Transcriptome of the Neglected Trematode, Fasciola gigantica—Biological and Biotechnological Implications

Fasciola gigantica (Digenea) is an important foodborne trematode that causes liver fluke disease (fascioliasis) in mammals, including ungulates and humans, mainly in tropical climatic zones of the world. Despite its socioeconomic impact, almost nothing is known about the molecular biology of this parasite, its interplay with its hosts, and the pathogenesis of fascioliasis. Modern genomic technologies now provide unique opportunities to rapidly tackle these exciting areas. The present study reports the first transcriptome representing the adult stage of F. gigantica (of bovid origin), defined using a massively parallel sequencing-coupled bioinformatic approach. From >20 million raw sequence reads, >30,000 contiguous sequences were assembled, of which most were novel. Relative levels of transcription were determined for individual molecules, which were also characterized (at the inferred amino acid level) based on homology, gene ontology, and/or pathway mapping. Comparisons of the transcriptome of F. gigantica with those of other trematodes, including F. hepatica, revealed similarities in transcription for molecules inferred to have key roles in parasite-host interactions. Overall, the present dataset should provide a solid foundation for future fundamental genomic, proteomic, and metabolomic explorations of F. gigantica, as well as a basis for applied outcomes such as the development of novel methods of intervention against this neglected parasite

Sequencing technologies and genome sequencing

The high-throughput - next generation sequencing (HT-NGS) technologies are currently the hottest topic in the field of human and animals genomics researches, which can produce over 100 times more data compared to the most sophisticated capillary sequencers based on the Sanger method. With the ongoing developments of high throughput sequencing machines and advancement of modern bioinformatics tools at unprecedented pace, the target goal of sequencing individual genomes of living organism at a cost of $1,000 each is seemed to be realistically feasible in the near future. In the relatively short time frame since 2005, the HT-NGS technologies are revolutionizing the human and animal genome researches by analysis of chromatin immunoprecipitation coupled to DNA microarray (ChIP-chip) or sequencing (ChIP-seq), RNA sequencing (RNA-seq), whole genome genotyping, genome wide structural variation, de novo assembling and re-assembling of genome, mutation detection and carrier screening, detection of inherited disorders and complex human diseases, DNA library preparation, paired ends and genomic captures, sequencing of mitochondrial genome and personal genomics. In this review, we addressed the important features of HT-NGS like, first generation DNA sequencers, birth of HT-NGS, second generation HT-NGS platforms, third generation HT-NGS platforms: including single molecule Heliscope™, SMRT™ and RNAP sequencers, Nanopore, Archon Genomics X PRIZE foundation, comparison of second and third HT-NGS platforms, applications, advances and future perspectives of sequencing technologies on human and animal genome research

Understanding hydrological flow in karst to improve paleoclimate modelling of speleothems in SE Australia

Paleoclimate studies are an important tool to aid our current knowledge and understanding of past climatic conditions. This in turn can be used to make informed predictions about future climate change and improve natural resource management. In the last decade, paleoclimate research using speleothems has increased. Methods have been established and it has been demonstrated that they may be applied to successfully reconstruct paleoclimate records from stalagmites (Tan et. Al., 2003; Treble et. Al., 2003; Trouvet et. Al., 2009; Jex et. Al., 2011). A key parameter in the successful reconstruction of speleothem-based paleoclimate archives is the understanding of the karst hydrology influencing drip water that leads to calcite deposition (Baldini et. Al., 2006). The typically non-linear relationship between surface recharge and drip water response is highly complex and not yet fully understood (Baker and Brunson, 2003). For example McDonald et. Al. (2007) demonstrated that drips which responded simultaneously to recharge events still exhibited different delivery mechanisms and in turn exhibited discharge responses. To improve speleothems as a climate proxy, long term cave monitoring in two hydrologically different field sites in SE Australia (Wellington and Yarrangobilly caves) is being conducted. Drip water hydrology over a variety of flow regimes was characterised using over 30 drip water loggers. Distinct flow regimes and spatial variability were observed, indicating that drip waters experienced a wide variety of flow paths. It was evident that even over small spatial variations; surface to groundwater connectivity was considerably heterogeneous. To enhance the drip water study, a novel application was introduced to the cave monitoring program which used micro-temperature loggers to monitor heat signals in drip waters. This study is still in its infancy but has the potential to enhance current monitoring programs and produce greater information regarding flow regimes in speleothem formation

Dripwater organic matter and trace element geochemistry in a semi-arid karst environment: Implications for speleothem paleoclimatology

A series of four short-term infiltration experiments which revealed hydrochemical responses relevant to semi-arid karst environments were carried out above Cathedral Cave, Wellington, New South Wales (NSW), Australia. Dripwater samples were collected at two sites for trace element and organic matter analysis. Organic matter was characterised using fluorescence and interpreted using a PARAFAC model. Three components were isolated that represented unprocessed, soil-derived humic-like and fulvic-like material, processed humic/fulvic-like material and tryptophan-like fluorescence. Principal Component Analysis (PCA) performed on the entire dataset comprising trace element concentrations and PARAFAC scores revealed two dominant components that were identified as soil and limestone bedrock. The soil component was assigned based on significant contributions from the PARAFAC scores and additionally included Ba, Cu, Ni and Mg. The bedrock component included the expected elements of Ca, Mg and Sr as well as Si. The same elemental behaviour was observed in recent stalagmite growth collected from the site. Our experiments demonstrate that existing paleoclimate interpretations of speleothem Mg and Sr, developed in regions of positive water balance, are not readily applicable to water limited environments. We provide a new interpretation of trace element signatures unique to speleothems from water limited karst environments. © 2014, Elsevier Ltd