Trematode Infection Publications (33395)


Trematode Infection Publications

Acta Trop.
Acta Trop 2017 Jan 17. Epub 2017 Jan 17.
Graduate School of Human Development and Environment, Kobe University, 3-11, Tsurukabuto, Nada-ku, Kobe 657-8501 Japan. Electronic address:

The agouti ( Dasyprocta leporina ) is a New World wild rodent hunted for its meat in Trinidad and other Latin American countries. Studies on agouti under captive conditions have yielded some data on health-related aspects, but relatively very little is known about their wild counterparts. The environment of the agouti can influence the microflora and parasites harbored by the animals, which may contain zoonotic pathogens. Read More

Here, the microflora found on the nasal mucosa and sections of the intestinal tract and endoparasites of freshly shot agouti from various areas of Trinidad are described. Staphylococcus epidermidis , S. intermedius , Bacillus spp., Enterobacter spp. and Escherichia coli comprised the majority of bacteria isolated from the nasal mucosa whereas Escherichia coli , Streptococcus viridans, Bacillus spp. and Klebsiella pneumoniae were predominant in all sections of the intestinal tract. The fungi Aspergillus fumigatus , Aspergillus spp., Candida spp., Penicillium spp., and Mucor spp. were only isolated from the nasal cavity but not in any section of the intestinal tract. The parasites Strongyloides spp., Ascaridia spp., a hookworm, a trematode, and Trichuris spp. were detected at variable frequencies in each of the sections of the intestines (small intestine, large intestine, caecum), whereas Eimeria spp. were found in all sections (76.9%, 10 of 13 agoutis). These wild agoutis were presumably healthy at the time of death and represent animals that hunters may encounter. Some of the detected pathogens and parasites have the potential to cause opportunistic infections or infestations, especially in immune-compromised hosts.

Sci Rep
Sci Rep 2017 Jan 12;7:40615. Epub 2017 Jan 12.
Laboratorio de Inmunomodulación y Desarrollo de Vacunas, Departamento de Inmunobiología, Facultad de Medicina, Universidad de La República, Montevideo, Uruguay.

Fasciolosis is a trematode zoonosis of interest in public health and cattle production. We report here the immunostimulatory effect of a 66 mer mucin-like peptide from Fasciola hepatica (Fhmuc), which synergizes with lipopolysaccharide (LPS) to promote dendritic cell (DC) maturation, endowing these cells with Th1-polarizing capacity. Exposure of DCs to Fhmuc in presence of LPS induced enhanced secretion of pro-inflammatory cytokines and expression of co-stimulatory molecules by DCs, promoting their T cell stimulatory capacity and selectively augmenting IFN-γ secretion by allogeneic T cells. Read More

Furthermore, exposure of DCs to Fhmuc augmented LPS-induced Toll-like receptor (TLR) 4 expression on the cell surface. Finally, Fhmuc-conditioned DCs induced parasite specific-adaptive immunity with increased levels of IFN-γ secreted by splenocytes from vaccinated animals, and higher parasite-specific IgG antibodies. However, Fhmuc-treated DC conferred modest protection against F. hepatica infection highlighting the potent immuno-regulatory capacity of the parasite. In summary, this work highlights the capacity of a mucin-derived peptide from F. hepatica to enhance LPS-maturation of DCs and induce parasite-specific immune responses with potential implications in vaccination and therapeutic strategies.

Biomed Res Int
Biomed Res Int 2016 18;2016:7627358. Epub 2016 Dec 18.
Initiative for the Forecasting and Modeling of Infectious Diseases, Tufts University, Medford, MA 02155, USA; Department of Civil and Environmental Engineering, Tufts University School of Engineering, Medford, MA 02155, USA; Department of Public Health and Community Medicine, Tufts University School of Medicine, Boston, MA 02111, USA; Friedman School of Nutrition Science & Policy, Tufts University, Boston, MA 02111, USA.
Parasitology 2017 Jan 11:1-11. Epub 2017 Jan 11.
Department of Ecology and Evolutionary Biology,2019 Kraus Natural Sciences Building,830 North University Ave.,University of Michigan,Ann Arbor,MI 48109,USA.

Parasites can influence host population dynamics, community composition and evolution. Prediction of these effects, however, requires an understanding of the influence of ecological context on parasite distributions and the consequences of infection for host fitness. We address these issues with an amphibian - trematode (Digenea: Echinostomatidae) host-parasite system. Read More

We initially performed a field survey of trematode infection in first (snail) and second (larval green frog, Rana clamitans) intermediate hosts over 5 years across a landscape of 23 ponds in southeastern Michigan. We then combined this study with a tadpole enclosure experiment in eight ponds. We found echinostomes in all ponds during the survey, although infection levels in both snails and amphibians differed across ponds and years. Echinostome prevalence (proportion of hosts infected) in snails also changed seasonally depending on host species, and abundance (parasites per host) in tadpoles depended on host size and prevalence in snails. The enclosure experiment demonstrated that infection varied at sites within ponds, and tadpole survival was lower in enclosures with higher echinostome abundance. The observed effects enhance our ability to predict when and where host-parasite interactions will occur and the potential fitness consequences of infection, with implications for population and community dynamics, evolution and conservation.

Parasitology 2017 Jan 11:1-6. Epub 2017 Jan 11.
Department of Forestry and Natural Resources,Purdue University,715 West State Street,West Lafayette,IN 47907,USA.

Across host-parasite systems, there is evidence that pesticide exposure increases parasite loads and mortality following infection. However, whether these effects are driven by reductions in host resistance to infection or slower rates of parasite clearance is often unclear. Using controlled laboratory experiments, we examined the ability of larval northern leopard frogs (Lithobates pipiens) and American toads (Anaxyrus americanus) to resist and clear trematode (Echinoparyphium sp. Read More

) infections following exposure to the insecticide carbaryl. Northern leopard frogs exposed to 1 mg L-1 of carbaryl had 61% higher parasite loads compared with unexposed individuals, while there was no immediate effect of carbaryl on parasite encystment in American toads. However, when tadpoles were exposed to carbaryl and moved to freshwater for 14 days before the parasite challenge, we recovered 37 and 63% more parasites from carbaryl-exposed northern leopard frogs and American toads, respectively, compared with the control. No effects on clearance were found for either species. Collectively, our results suggest that pesticide exposure can reduce the ability of amphibians to resist parasite infections and that these effects can persist weeks following exposure. It is critical for researchers to incorporate species interactions into toxicity studies to improve our understanding of how contaminants affect ecological communities.

Heterophyidiasis is now a major public health threat in many tropical countries. Species in the trematode family Heterophyidae infecting humans include Centrocestus formosanus, Haplorchis pumilio, H. taichui, H. Read More

yokogawai, Procerovum varium and Stellantchasmus falcatus. For molecular phylogenetic and systematic studies on trematodes, we need more prospective markers for taxonomic identification and classification. This study provides near-complete ribosomal transcription units (rTU) from Haplorchis pumilio and H. taichui and demonstrates the use of 28S rDNA sequences for identification and phylogenetic analysis.
The near-complete ribosomal transcription units (rTU), consisting of 18S, ITS1, 5.8S, ITS2 and 28S rRNA genes and spacers, from H. pumilio and H. taichui from human hosts in Vietnam, were determined and annotated. Sequence analysis revealed tandem repetitive elements in ITS1 in H. pumilio and in ITS2 in H. taichui. A phylogenetic tree inferred from 28S rDNA sequences of 40 trematode strains/species, including 14 Vietnamese heterophyid individuals, clearly confirmed the status of each of the Vietnamese species: Centrocestus formosanus, Haplorchis pumilio, H. taichui, H. yokogawai, Procerovum varium and Stellantchasmus falcatus. However, the family Heterophyidae was clearly not monophyletic, with some genera apparently allied with other families within the superfamily Opisthorchioidea (i.e. Cryptogonimidae and Opisthorchiidae). These families and their constituent genera require substantial re-evaluation using a combination of morphological and molecular data. Our new molecular data will assist in such studies.
The 28S rDNA sequences are conserved among individuals within a species but varied between genera. Based on analysis of 40 28S rDNA sequences representing 19 species in the superfamily Opisthorchioidea and an outgroup taxon (Alaria alata, family Diplostomidae), six common human pathogenic heterophyids were identified and clearly resolved. The phylogenetic tree inferred from these sequences again confirmed anomalies in molecular placement of some members of the family Heterophyidae and demonstrates the need for reappraisal of the entire superfamily Opisthorchioidea. The new sequences provided here supplement those already available in public databases and add to the array of molecular tools that can be used for the diagnosis of heterophyid species in human and animal infections.

Syst. Parasitol.
Syst Parasitol 2017 Jan 6;94(1):35-49. Epub 2017 Jan 6.
Thad Cochran National Warmwater Aquaculture Center, Aquatic Research & Diagnostic Laboratory, Delta Research and Extension Center, College of Veterinary Medicine, Mississippi State University, Stoneville, MS, 38776, USA.
Saudi J Biol Sci
Saudi J Biol Sci 2017 Jan 9;24(1):30-35. Epub 2015 Sep 9.
Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand; The Applied Technology for Biodiversity Research Unit, Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200, Thailand.

The present study determined the prevalence and distribution of gastrointestinal helminths in domestic chickens (Gallus gallus domesticus) between November 2012 and August 2013. One hundred and twenty domestic chickens were purchased from villages in four districts of Phayao province; Mae Chai, Dok Khamtai, Chun and Chiang Kham. Morphological differences were used to identify the helminth species, and HAT-RAPD technique was used to differentiate among closely related species. Read More

The results revealed that the total prevalence of infection was 99.2%. Cestode and nematode infections showed the highest prevalence in rainy season, while trematode infections were low and only found in hot season. The species and their prevalence were: Ascaridia galli (50.8%), Heterakis gallinarum (86.7%), Prosthogonimus macrorchis (1.7%), Echinostoma revolutum (0.8%), Raillietina echinobothrida (48.3%), Raillietina tetragona (57.5%), Raillietina cesticillus (12.5%), Raillietina sp. (35.8%), Cotugnia chiangmaii (14.2%) and Cotugnia sp. (32.5%). The prevalence of helminth infections did not differ significantly between male and female chickens. HAT-RAPD analysis, the specific fragment of 400 and 250 bp indicated that Raillietina sp. and Cotugnia sp. found, respectively, differ from other closely related species. This study has confirmed that HAT-RAPD technique can be used to differentiate among related species combined with morphological observations.

J Anim Ecol
J Anim Ecol 2016 Dec 27. Epub 2016 Dec 27.
Oakland University, 2200 N. Squirrel Rd., Rochester, MI, USA.

Leaf litter subsidies are important resources for aquatic consumers like tadpoles and snails, causing bottom-up effects on wetland ecosystems. Recent studies have shown that variation in litter nutritional quality can be as important as litter quantity in driving these bottom-up effects. Resource subsidies likely also have indirect and trait-mediated effects on predation and parasitism, but these potential effects remain largely unexplored. Read More

We generated predictions for differential effects of litter nutrition and secondary polyphenolic compounds on tadpole (Lithobates sylvatica) exposure and susceptibility to Ribeiroia ondatrae, based on ecological stoichiometry and community-ecology theory. We predicted direct and indirect effects on key traits of the tadpole host (rates of growth, development and survival), the trematode parasite (production of the cercaria infective stages) and the parasite's snail intermediate host (growth and reproduction). To test these predictions, we conducted a large-scale mesocosm experiment using a natural gradient in the concentrations of nutrients (nitrogen) and toxic secondary compounds (polyphenolics) of nine leaf litter species. To differentiate between effects on exposure vs. susceptibility to infection, we included multiple infection experiments including one with constant per capita exposure. We found that increased litter nitrogen increased tadpole survival, and also increased cercaria production by the snail intermediate hosts, causing opposing effects on tadpole per capita exposure to trematode infection. Increased litter polyphenolics slowed tadpole development, leading to increased infection by increasing both their susceptibility to infection and the length of time they were exposed to parasites. Based on these results, recent shifts in forest composition towards more nitrogen-poor litter species should decrease trematode infection in tadpoles via density- and trait-mediated effects on the snail intermediate hosts. However, these shifts also involve increased abundance of litter species with high polyphenolic levels, which should increase trematode infection via trait-mediated effects on tadpoles. Future studies will be needed to determine the relative strength of these opposing effects in natural wetland communities. [Correction added after online publication on 5 January 2017: wording changed to 'which should increase trematode infection via trait-mediated effects on tadpoles'.].