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PubMed2002

Targeted application of anthelmintics to control trichostrongylosis in dairy goats: result from a 2-year survey in farms.

The targeted application of anthelmintic treatments represents one of the current available solutions to slow down the development of anthelmintic resistance within worm populations. Within an experimental flock of dairy goats, control of gastrointestinal parasitism by such selective treatments, targeting the most receptive animals within a flock, was previously found to be effective and to have no detrimental consequences on milk production. The objectives of the current study were to verify the validity of this method in farm conditions. Eleven dairy goat farms from three main areas of production in France were surveyed for 2 years. In six farms, the survey was prolonged for a third year. During year 1, systematic treatments were applied during the grazing season whereas in year 2 and or year 3, treatments were given exclusively to the goats in first lactation and to the multiparous ones with the highest potential of milk production. The level of nematode infection was measured four times per year through individual coproscopical examinations and the mean annual production of milk was recorded. No significant changes in egg excretion nor in milk production were noticed in any farm during years 2 or 3 after switching from the systematic to the selective mode of treatments. These results confirmed that targeted application of anthelmintics might represent a way to combine the control of trichostrongyles and the prevention of anthelmintic resistance.

Animals↗
PubMed1997

Persistent efficacy of topical moxidectin against Dictyocaulus viviparus and Ostertagia ostertagi.

The persistent activity of moxidectin topically administered at the dose rate of 0.5 mg kg-1 bodyweight was evaluated against experimental nematode infection in 30 calves randomly allocated to six groups. Five groups were treated on days -42, -35, -28, -21 and -14. The 6th group remained untreated as a control. On Day 0, the calves were infected experimentally with 1000 Dictyocaulus viviparus and 50,000 Ostertagia ostertagi larvae and killed 3 weeks later. The formulation of moxidectin showed excellent activity against both parasites for up to 5 weeks (> 99%). Six weeks after treatment the reduction in the number of D. viviparus was still high (> 90%). No adverse reactions to moxidectin were observed in any of the animals.

Administration, Topical↗
PubMed1981

Acetylcholinesterase activity in Nippostrongylus brasiliensis during the course of a primary infection in normal and in protein-deficient rats.

Acetylcholinesterase (AChE) activity was measured in Nippostrongylus brasiliensis recovered during the course of a primary infection in normal and in protein-deficient rats. In well-nourished rats the amount of AChE present in N. brasiliensis increased as the infection progressed, concomitant with the development of the humoral response. In malnourished rats, there was a similar and parallel increase in the amount of AChE synthesized by worms between days 7 and 13 of the infection but as the infection progressed enzyme production decreased so that, by day 26 of the infection, the nematodes contained approximately the same amount of AChE as 8-day-old worms. The possible reasons for this change in enzyme production are discussed.

Acetylcholinesterase↗
PubMed2004

Sexual transmission of a nematode parasite of Wood Mice (Apodemus sylvaticus)?

Sexual transmission occurs commonly in microparasites such as viruses and bacteria, but this is an unusual transmission route for macroparasites. Here we present evidence which suggests that a nematode parasite of Wood Mice (Apodemus sylvaticus) may be sexually transmitted and we have classified the nematode using molecular data. Wood Mice were collected annually in the course of work on their reproductive physiology. Larval nematodes were found in the epididymides of 19.6% of males. It seems likely that they would be transmitted to females at ejaculation. To identify these larval nematodes, which we were unable to do using morphological features, we sequenced the 18S rDNA. Sequence comparisons with the molecular phylogeny of Blaxter et al. (1998) demonstrated that they were bursate nematodes (Order Strongylida). The relationships between strongylid taxa were poorly resolved by 18S rDNA. However, both distance and parsimony analyses grouped the nematode with the superfamily Metastrongylidea in a clade containing Filaroides and Angiostrongylus sp. Importantly, the sequences were distinct from those of Heligmosomoides polygyrus and Angiostrongylus dujardini, two common strongylid nematodes of Apodemus. We were therefore unable positively to identify these worms by matching their sequences with those from morphologically identifiable adult strongylid nematodes infecting Apodemus. These results demonstrate that an as yet unidentified strongylid is quite commonly found in large numbers in the male reproductive tract of Wood Mice. Further work is required to understand the biology and transmission dynamics of this interesting system.

Animals↗
PubMed2004

The effect of the host immune response on the parasitic nematode Strongyloides ratti.

The host immune response has profound effects on parasitic nematode infections. Here we have investigated how a range of infection parameters are affected by host immune responses and by their suppression and enhancement. The infection parameters considered were the number of parasitic females, their size, per capita fecundity and intestinal position. We found that in immunosuppressive treatments worms persist in the gut, sometimes with a greater per capita fecundity, maintain their size and have a more anterior gut position, compared with worms from control animals. In immunization treatments there are fewer worms in the gut, sometimes with a lower per capita fecundity and they are shorter and have a more posterior gut position, compared with worms from control animals. Worms from animals immunosuppressed by corticosteroid treatment reverse their changes in size and gut position. This description of these phenomena pave the way for a molecular biological analysis of how these changes in infection parameters are brought about by the host immune response.

Animals↗
PubMed2005

Definition of genetic markers in nuclear ribosomal DNA for a neglected parasite of primates, Ternidens deminutus (Nematoda: Strongylida)--diagnostic and epidemiological implications.

Ternidens deminutus (Strongylida) is a parasitic nematode infecting non-human and human primates in parts of Africa, Asia and the Pacific islands. The present study genetically characterized T. deminutus and defined genetic markers in nuclear ribosomal DNA (rDNA) as a basis for developing molecular-diagnostic tools. The sequences of the second internal transcribed spacer (ITS-2) of rDNA were determined for adult specimens of T. deminutus (Nematoda: Strongylida: Oesophagostominae) from the Olive baboon and the Mona monkey. The length and G+C content of the ITS-2 sequences was 216 bp and approximately 43%, respectively. While there was no sequence variation among individual T. deminutus specimens from the baboon, 6 (2.8%) nucleotide differences were detected in the ITS-2 between the parasite from baboon and that of the Mona monkey, which is similar to the difference (3.2%) between 2 other species of Oesophagostominae (Oesophagostomum bifurcum and O. stephanostomum) from non-human primates, suggesting significant population variation or the existence of cryptic (i.e. hidden) species within T. deminutus . Pairwise comparisons of the ITS-2 sequences of the 2 operational taxonomic units of T. deminutus with previously published ITS-2 sequences for selected members of the subfamilies Oesophagostominae and Chabertiinae indicated that species from primates (including those representing the subgenera Conoweberia and Ihleia) are closely related, in accordance with previous morphological studies. The sequence differences (27-48.3%) in the ITS-2 between the 2 taxonomic units of T. deminutus and hookworms (superfamily Ancylostomatoidea) enabled their identification and delineation by polymerase chain reaction (PCR)-based mutation scanning. The genetic markers in the ITS-2 provide a foundation for improved, PCR-based diagnosis of T. deminutus infections and for investigating the life-cycle, transmission patterns and ecology of this parasite.

Animals↗
PubMed1996

Essential role of Stat6 in IL-4 signalling.

Interleukin-4 (IL-4) is a pleiotropic lymphokine which plays an important role in the immune system. IL-4 activates two distinct signalling pathways through tyrosine phosphorylation of Stat6, a signal transducer and activator of transcription, and of a 170K protein called 4PS. To investigate the functional role of Stat6 in IL-4 signalling, we generated mice deficient in Stat6 by gene targeting. We report here that in the mutant mice, expression of CD23 and major histocompatibility complex (MHC) class II in resting B cells was not enhanced in response to IL-4. IL-4 induced B-cell proliferation costimulated by anti-IgM antibody was abolished. The T-cell proliferative response was also notably reduced. Furthermore, production of Th2 cytokines from T cells as well as IgE and IgG1 responses after nematode infection were profoundly reduced. These findings agreed with those obtained in IL-4 deficient mice or using antibodies to IL-4 and the IL-4 receptor. We conclude that Stat6 plays a central role in exerting IL-4 mediated biological responses.

Animals↗
PubMed1997

Sheep mast cell proteinase-1, a serine proteinase with both tryptase- and chymase-like properties, is inhibited by plasma proteinase inhibitors and is mitogenic for bovine pulmonary artery fibroblasts.

Sheep mast cell proteinase-1 (sMCP-1), a serine proteinase with dual chymase/tryptase activity, is expressed in gastrointestinal mast cells, and released systemically and on to the mucosal surface during gastrointestinal nematode infection. The potential for native plasma proteinase inhibitors to control sMCP-1 activity was investigated. Sheep alpha1-proteinase inhibitor (alpha1PI) inhibited sMCP-1 slowly, with second-order association rate constant (kass) 1. 1x10(3) M-1.s-1, whereas sheep contrapsin inhibited trypsin (kass 2.2x10(6) M-1.s-1) but not sMCP-1. Western-blot analysis and gel filtration showed that when added to serum or plasma, sMCP-1 was partitioned between alpha1PI and alpha2-macroglobulin. The possibility that significant cleavage of plasma proteins could occur before sMCP-1 was inhibited was investigated using gel filtration and SDS/PAGE after adding sMCP-1 to plasma. Cleavage of ovine fibrinogen occurred in the presence of excess alpha1PI and alpha2-macroglobulin, the alpha-chain being cleaved C-terminally and the beta-chain at the putative Lys-27. In addition, sMCP-1 was found to be mitogenic for bovine pulmonary artery fibroblasts, but was not mitogenic in the presence of soya-bean trypsin inhibitor. In terms of fibrinogen cleavage and fibroblast stimulation, sMCP-1 shows functional similarities to mast cell tryptase.

Amino Acid Sequence↗
PubMed2001

Cutaneous larva migrans: clinical features and management of 44 cases presenting in the returning traveller.

BACKGROUND: Cutaneous larva migrans (CLM) is the result of a nematode infection, and shows a characteristic creeping eruption. As travel to the tropics increases, many British citizens may be returning with this infection, which is often misdiagnosed or treated incorrectly. OBJECTIVES: To perform a retrospective survey of 44 cases of CLM presenting to the Hospital for Tropical Diseases in London over the last 2 years. METHODS: Cases were reviewed with regard to patient characteristics, source of infection, source of referral, clinical features and therapy. RESULTS: Most infections were acquired in Africa (32%), the Caribbean (30%) and South-east Asia (25%), but also in Central and South America. There was a history of exposure to a beach in 95% of patients and the median duration of symptoms was 8 weeks (range 1-104). Lesions mainly affected the feet (39%), buttocks (18%) and abdomen (16%), but the lower leg, arm and face were also affected. Multiple lesions were seen in seven of 44 cases (16%). Laboratory abnormalities were absent in all patients. Of 44 patients seen, four needed no treatment, 28 were cured by a single course of treatment, 11 required a second course of therapy and one patient was treated three times. Thirty-one patients received oral albendazole 400 mg daily for 3-5 days and 24 were cured (77%). Five patients received 10% thiabendazole cream topically for 10 days and four were cured (80%). Four patients received oral thiabendazole 1.5 g daily for 3 days and all required further therapy. CONCLUSIONS: In view of the range of treatment regimens recorded, a randomized controlled trial comparing topical and systemic therapies is warranted.

Administration, Cutaneous↗
PubMed1999

STAT6 deficiency in a mouse model of allergen-induced airways inflammation abolishes eosinophilia but induces infiltration of CD8+ T cells.

BACKGROUND: The TH2-type cytokines have been reported to contribute to the asthmatic response. STAT6 has an essential role in IL-4 signalling and in production of TH2 cytokines from T cells and is involved in IgE and IgG1 responses after nematode infections, indicating that STAT6 has an important role in allergic diseases. OBJECTIVE: In this study we investigated the effects of STAT6 deficiency on allergen-induced airways inflammation in mice. METHODS: Both ovalbumin (OVA)-sensitized STAT6 deficient (STAT6-/-) mice and wild-type C57BL/6 mice were challenged with aerosolized OVA. Changes in inflammatory cell infiltration and cytokine levels in lung tissue as well as serum immunoglobulin levels were analysed in OVA-challenged STAT6-/- and wild-type mice. RESULTS: The eosinophilia and lung damage normally resulting from aeroallergen challenge were not seen in STAT6-/- mice. Expression of TH2 cytokines (IL-4 and IL-5) in the lung tissue as well as IgE and IgG1 responses after OVA challenge were profoundly reduced in STAT6-/- mice, whereas expression of IFNgamma was the same in STAT6-/- mice and wild-type mice after OVA challenge. Immunocytochemical analysis of T cells showed the infiltration of CD4+ T cells but not CD8+ T cells increased into the lung of wild-type mice after OVA challenge. However, the OVA-exposed STAT6-/- mice demonstrated the infiltration of both CD4+ T cells and CD8+ T cells with a significant increase in percentage and total number of CD8+ T cells compared with OVA-exposed wild-type mice. CONCLUSION: These results indicate that factors which signal through STAT6 are important regulators of eosinophilia of allergic airway inflammation, regulating TH2-type cytokine production both in CD4+ T cells and CD8+ T cells.

Allergens↗
PubMed2003

Purification and characterization of mouse mast cell proteinase-2 and the differential expression and release of mouse mast cell proteinase-1 and -2 in vivo.

BACKGROUND: Gastrointestinal nematode infection is associated with mucosal mast cell (MMC) hyperplasia. In the mouse, this is accompanied by the release of substantial quantities of the chymase mouse mast cell proteinase-1 (mMCP-1) into the gut lumen and peripheral bloodstream. Expression of mMCP-1 is largely restricted to intraepithelial MMC and is thought to play a role in the regulation of epithelial permeability. MMCs also express mouse mast cell proteinase-2 (mMCP-2), but less is known about the expression or biological function of this proteinase. OBJECTIVES: (1) To purify and characterize mMCP-2. (2) To compare the expression and release of mMCP-2 and mMCP-1 in vivo using specific antibodies. METHODS: Bone marrow-derived mast cells (mBMMCs) were generated from mMCP-1(-/-) BALB/c mice. mMCP-2 was purified, characterized and used to generate rat and sheep polyclonal antibodies. The expression and systemic release of mMCP-1 and -2 were compared in vivo by immunohistochemistry and ELISA. RESULTS: mMCP-2 was successfully purified from mMCP-1(-/-) mBMMC and its identity confirmed by N-terminal amino acid sequencing. mMCP-2 bound [3H]-labelled DFP, indicating the presence of an active serine proteinase catalytic site, but showed little evidence of chymotryptic activity. MMC expressed comparable levels of mMCP-1 and -2 in the jejunum but not in the gastric mucosa, where mMCP-2 was more abundant. Expression of both proteinases increased substantially during primary Nippostrongylus brasiliensis infection and this was accompanied by a substantial increase in peripheral blood levels of mMCP-1 (70 microg/mL on day 12). By contrast, mMCP-2 was not detected in the serum of uninfected mice and only increased to approximately 25 ng/mL on day 12. CONCLUSION: As in the case of mMCP-1, mMCP-2 expression is restricted to MMC. However, mMCP-2 lacks chymase activity, is expressed at higher levels in gastric MMC and appears to be differentially released into the peripheral bloodstream.

Animals↗
PubMed2000

The spvB gene-product of the Salmonella enterica virulence plasmid is a mono(ADP-ribosyl)transferase.

A number of well-known bacterial toxins ADP-ribosylate and thereby inactivate target proteins in their animal hosts. Recently, several vertebrate ecto-enzymes (ART1-ART7) with activities similar to bacterial toxins have also been cloned. We show here that PSIBLAST, a position-specific-iterative database search program, faithfully connects all known vertebrate ecto-mono(ADP-ribosyl)transferases (mADPRTs) with most of the known bacterial mADPRTs. Intriguingly, no matches were found in the available public genome sequences of archaeabacteria, the yeast Saccharomyces cerevisiae or the nematode Caenorhabditis elegans. Significant new matches detected by PSIBLAST from the public sequence data bases included only one open reading frame (ORF) of previously unknown function: the spvB gene contained in the virulence plasmids of Salmonella enterica. Structure predictions of SpvB indicated that it is composed of a C-terminal ADP-ribosyltransferase domain fused via a poly proline stretch to a N-domain resembling the N-domain of the secretory toxin TcaC from nematode-infecting enterobacteria. We produced the predicted catalytic domain of SpvB as a recombinant fusion protein and demonstrate that it, indeed, acts as an ADP-ribosyltransferase. Our findings underscore the power of the PSIBLAST program for the discovery of new family members in genome databases. Moreover, they open a new avenue of investigation regarding salmonella pathogenesis.

ADP Ribose Transferases↗
PubMed2001

Involvement of complement and fibronectin in eosinophil-mediated damage to Nippostrongylus brasiliensis larvae.

By using IL-5 transgenic mice, it has been shown that eosinophils might play a key role in elimination of larval stages of nematode infections. The present study was carried out to clarify molecular mechanisms involved in the eosinophil-mediated killing of Nippostrongylus brasiliensis larvae. The larvicidal activity was observed in the presence of normal serum in vitro. Electron microscopic observations revealed firm attachment of eosinophils to the cuticular surface of larvae, which was damaged by electron-dense materials released from eosinophils. The larvicidal activity was abrogated by heat- or zymosan-treatment of the serum, whereas depletion of IgG or IgM from the serum did not interfere with eosinophil adhesion and killing. Moreover, pretreatment of eosinophils with monoclonal antibodies against CD11b or VLA-4 inhibited the eosinophil-mediated killing of larvae. Immunofluorescent staining demonstrated the deposition of C3c and plasma fibronectin on the cuticle of the larvae. These results indicate that interactions between CD11b and VLA-4 and their respective counter-ligands deposited on the cuticle are essential in eosinophil-mediated adhesion and damage to larvae of N. brasiliensis.

Animals↗
PubMed1996

Leukemia inhibitory factor mediates cytokine-induced suppression of myenteric neurotransmitter release from rat intestine.

BACKGROUND & AIMS: Exposure of rat longitudinal muscle myenteric plexus to the proinflammatory cytokine interleukin (IL) 1 beta mimics the effects of nematode infection on enteric nerve function through a hitherto unidentified protein intermediate. It is postulated that leukemia inhibitory factor (LIF), the downstream intermediate of several IL-1-induced neuroimmune interactions, mediates IL-1 beta-induced suppression of acetylcholine release from rat jejunum. METHODS: Preparations were preloaded with [3H]choline, and [3H]-acetylcholine release was induced by either electrical field stimulation or by 50 mmol/L KCl. Cytokines and anti-LIF antibodies were added to the preincubation media or to the superfusate before stimulation. RESULTS: Human recombinant LIF had no immediate effects, but preincubation with the cytokine induced a concentration-dependent (2-100 ng/mL) and reversible suppression of acetylcholine release from rat longitudinal muscle myenteric plexus. The effects of human recombinant LIF on acetylcholine release were reversed by anti-human recombinant LIF-neutralizing antibody. Human recombinant IL-1 beta (10 ng/mL) induced a similar suppression of acetylcholine release, and the addition of anti-rat LIF antibody abolished the effects of exogenous IL-1 on acetylcholine release. CONCLUSIONS: IL-1 beta suppresses neurotransmitter release from rat myenteric plexus via the induction of LIF as a downstream intermediate.

Acetylcholine↗
PubMed2004

How does a carabid predator find aggregations of slugs in the field? Electroantennograms and behavioural assays suggest chemical cues.

Field studies suggest that the generalist carabid predator and scavenger Pterostichus melanarius Illiger aggregates to patches with a higher density of slug prey. The mechanisms behind such aggregation are unknown. Experiments were conducted to test the hypothesis that they are responding to chemical cues. Electroantennograms (EAGs) showed no response by P. melanarius antennae to live, nematode-infected, injured or freshly killed slugs, but a strong response to dead slugs that had been allowed to decay for up to 48 h. Such a response would enable the beetles to find carrion in the field and may also, as dead prey are likely to be spatially correlated with live ones, provide a mechanism by which P. melanarius finds patches with a higher density of live slugs. Subsequent video analyses of P. melanarius responses to patches of slug mucus within arenas showed that beetles with intact antennae could detect these patches because they spent more time, and moved greater distances, within them and increased their rate of turning. Thus, at close range, P. melanarius used their antennae to detect slug mucus and hence, by implication, live slugs. The apparent contradiction between EAG data and behavioural experiments is discussed. Together these result confirm that P. melanariusdoes respond to chemical cues from its slug prey in ways that could lead to aggregation in areas of higher slug density in the field.

Animals↗