scholarly journals GLOWORM-FL: A simulation model of the effects of climate and climate change on the free-living stages of gastro-intestinal nematode parasites of ruminants

2015 ◽  
Vol 297 ◽  
pp. 232-245 ◽  
Author(s):  
Hannah Rose ◽  
Tong Wang ◽  
Jan van Dijk ◽  
Eric R. Morgan
Keyword(s):  
Climate Change ◽  
Simulation Model ◽  
Free Living ◽  
Intestinal Nematode ◽  
Nematode Parasites

Nematophagous fungi in pasture: colonisation of sheep faeces and their potential for control of free-living stages of gastro-intestinal nematode parasites of sheep

2002 ◽  
Vol 42 (1) ◽  
pp. 7 ◽  
Author(s):  
F. S. Hay ◽  
J. H. Niezen ◽  
D. Leathwick ◽  
R. A. Skipp
Keyword(s):  
Laboratory Experiments ◽  
Nematophagous Fungi ◽  
Soil Nematodes ◽  
Arthrobotrys Oligospora ◽  
Free Living ◽  
Intestinal Nematode ◽  
Nematode Parasites ◽  
Fungal Propagules ◽  
Third Stage ◽  
Filter Type

Sheep faeces placed on a pasture in New Zealand in February and April were retrieved at intervals up to 28 days and examined for fungi that parasitise nematodes (nematophagous fungi). Monacrosporium haptotylum, Harposporium bysmatosporum, H. helicoides and a Nematoctonus sp. were present, respectively, in 37, 22, 13 and 8% of 283 samples retrieved in February and from 29, 14, 11 and 15% of 200 samples retrieved in April. Fungi entered faeces rapidly, being present in 35 and 54% of samples retrieved after 3 days in February and April, respectively. The ability of migrating soil nematodes to carry fungal propagules from soil into faeces was assessed in 2 laboratory experiments. Sheep faeces separated from soil by filters that allowed passage of both nematodes and fungi was colonised by H. helicoides more frequently than faeces on filters that excluded nematodes, indicating nematodes were vectors. However, Arthrobotrys oligospora, M. haptotylum and A. brochopaga occurred in faeces independently of filter type, indicating that these species grew into faeces. Two laboratory experiments examined the ability of nematophagous fungi, when inoculated into sheep faeces containing eggs of the gastro-intestinal nematode parasite Trichostrongylus colubriformis to reduce the number that developed to third-stage larvae. Monacrosporium gephyropagum, A. cladodes, A. conoides and A. oligospora reduced the number of third-stage larvae that emerged by 54–91% (P<0.05) in comparison to a control; however, M. haptotylum and H. bysmatosporum were ineffective. In a second experiment, several species of nematophagous fungi reduced the number of third-stage larvae that emerged by 41–96% (P<0.05) in comparison to a control, while others had no effect.

P-glycoprotein interfering agents potentiate ivermectin susceptibility in ivermectin sensitive and resistant isolates ofTeladorsagia circumcinctaandHaemonchus contortus

Parasitology ◽  
2009 ◽  
Vol 136 (9) ◽  
pp. 1081-1088 ◽  
Author(s):  
D. J. BARTLEY ◽  
H. McALLISTER ◽  
Y. BARTLEY ◽  
J. DUPUY ◽  
C. MÉNEZ ◽  
...  
Keyword(s):  
Epithelial Cell Line ◽  
Transport Activity ◽  
Free Living ◽  
Glycoprotein P ◽  
Intestinal Nematode ◽  
Nematode Parasites ◽  
Teladorsagia Circumcincta ◽  
P Glycoprotein ◽  
Transporter Family

SUMMARYP-glycoprotein (P-gp) homologues, belonging to the ATP Binding Cassette (ABC) transporter family, are thought to play an important role in the resistance of gastro-intestinal nematode parasites against macrocyclic lactones. The aim of this study was to investigate the influence of various P-gp interfering compounds on the efficacy of ivermectin (IVM) in sensitive and resistant nematode isolates. The feeding of IVM resistant and sensitiveTeladorsagia circumcinctaandHaemonchus contortusfirst-stage larvae (L1) was assessed using a range of IVM concentrations (0·08–40 nm) with or without P-gp inhibitors: valspodar, verapamil, quercetin, ketoconazole and pluronic P85. The P-gp inhibitors were selected on the basis of their ability to interfere with P-gp transport activity in an epithelial cell line over-expressing murine P-gp. In the presence of P-gp interfering agents, thein vitrosusceptibility to IVM of both sensitive and resistant isolates ofT. circumcinctaandH. contortuswas increased. These results show that compounds interfering with P-gp transport activity could enhance IVM efficacy in sensitive isolates, and also restore IVM sensitivity in resistant nematodes. These results support the view that ABC transporters can play an important role in resistance to IVM, at least in the free-living stages of these economically important gastro-intestinal nematodes.

scholarly journals Haematophagic Caenorhabditis elegans

Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 314-320 ◽  
Author(s):  
Veeren M Chauhan ◽  
David I Pritchard
Keyword(s):  
Caenorhabditis Elegans ◽  
Neutralizing Antibodies ◽  
Fluorescent Microscopy ◽  
Free Living ◽  
C Elegans ◽  
Vaccine Responses ◽  
Nematode Parasites ◽  
Significant Difference ◽  
Free Living Nematode ◽  
Bright Emission

AbstractCaenorhabditis elegans is a free-living nematode that resides in soil and typically feeds on bacteria. We postulate that haematophagic C. elegans could provide a model to evaluate vaccine responses to intestinal proteins from hematophagous nematode parasites, such as Necator americanus. Human erythrocytes, fluorescently labelled with tetramethylrhodamine succinimidyl ester, demonstrated a stable bright emission and facilitated visualization of feeding events with fluorescent microscopy. C. elegans were observed feeding on erythrocytes and were shown to rupture red blood cells upon capture to release and ingest their contents. In addition, C. elegans survived equally on a diet of erythrocytes. There was no statistically significant difference in survival when compared with a diet of Escherichia coli OP50. The enzymes responsible for the digestion and detoxification of haem and haemoglobin, which are key components of the hookworm vaccine, were found in the C. elegans intestine. These findings support our postulate that free-living nematodes could provide a model for the assessment of neutralizing antibodies to current and future hematophagous parasite vaccine candidates.

scholarly journals Effect of pasture species on internal parasites of lambs

1996 ◽  
pp. 59-62 ◽  
Author(s):  
T.L. Knight ◽  
R.A. Moss ◽  
T.J. Fraser ◽  
J.S. Rowarth ◽  
R.N. Burton
Keyword(s):  
White Clover ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Plantago Lanceolata ◽  
Gastrointestinal Nematode ◽  
Gastrointestinal Nematodes ◽  
Grass Species ◽  
Adult Nematode ◽  
Intestinal Nematode ◽  
Nematode Parasites

Increasing resistance of gastro-intestinal nematode parasites to anthelmintics and consumer resistance to the possibility of residues in animal products have prompted research on the effect of pasture species on nematodes and animal performance. Lambs (either infected with high rates of gastrointestinal nematodes or maintained nematode-free) were grazed on pure swards of chicory, high- or low-endophyte ryegrass, cocksfoot, tall fescue, lucerne, lotus, white clover or plantain. Infected lambs that grazed chicory had lower faecal egg counts and adult nematode populations, and higher carcass weights, than lambs grazed on plantain or the grass species; lambs that grazed legumes generally had intermediate counts, populations and weights. When kept parasite-free, carcass weights were up to 48% greater than in the nematodeinfected treatments. On farmlets run over 3 years, substituting 30% of the ryegrass area with lucerne or replacing the ryegrass with a multi-species mix consisting predominantly of bromes, tall fescue, phalaris, timothy and red and white clover, had no effect on gastrointestinal nematode larvae, lamb faecal worm egg or adult nematode numbers. It is concluded that a diet of pure chicory affects internal parasite populations but the small proportion included in the farmlet studies had no effect. Keywords: Cichorium intybus, Dactylis glomerota, Festuca arundinacea, gastro-intestinal nematodes, lambs, Lolium perenne, Lotus corniculatus, Medicago sativa, pasture species, Plantago lanceolata, Trifolium repens

Symbiotic bacteria of helminths: what role may they play in ecosystems under anthropogenic stress?

2016 ◽  
Vol 90 (6) ◽  
pp. 647-657 ◽  
Author(s):  
N.J. Morley
Keyword(s):  
Climate Change ◽  
Environmental Stress ◽  
Bacterial Communities ◽  
Bacterial Species ◽  
Symbiotic Bacteria ◽  
Anthropogenic Pressure ◽  
Anthropogenic Stress ◽  
Similar Function ◽  
Free Living ◽  
Terrestrial Habitats

AbstractSymbiotic bacteria are a common feature of many animals, particularly invertebrates, from both aquatic and terrestrial habitats. These bacteria have increasingly been recognized as performing an important role in maintaining invertebrate health. Both ecto- and endoparasitic helminths have also been found to harbour a range of bacterial species which provide a similar function. The part symbiotic bacteria play in sustaining homeostasis of free-living invertebrates exposed to anthropogenic pressure (climate change, pollution), and the consequences to invertebrate populations when their symbionts succumb to poor environmental conditions, are increasingly important areas of research. Helminths are also susceptible to environmental stress and their symbiotic bacteria may be a key aspect of their responses to deteriorating conditions. This article summarizes the ecophysiological relationship helminths have with symbiotic bacteria and the role they play in maintaining a healthy parasite and the relevance of specific changes that occur in free-living invertebrate–bacteria interactions under anthropogenic pressure to helminths and their bacterial communities. It also discusses the importance of understanding the mechanistic sensitivity of helminth–bacteria relationships to environmental stress for comprehending the responses of parasites to challenging conditions.

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