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Results for “NEMATODE INFECTIONS”

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PubMed2000

Use of a 14.2 kDa recombinant Cooperia oncophora protein in an ELISA for herd health monitoring of nematode infections in first grazing season calves.

An ELISA using a recombinant 14.2kDa excretory/secretory Cooperia oncophora protein (CoES14.2 ELISA) was evaluated for estimating level of cumulative exposure to infective Cooperia larvae in first grazing season calves. Data from one experiment were used to obtain a quantitative relationship between IgG levels and cumulative exposure. That relationship was validated against data from another experimental study and from natural field studies. The latter included different pasture management strategies with or without an anthelmintic treatment. Validation involved 'predicting' cumulative exposure for the groups of calves in the latter two datasets based on observed IgG levels measured with the CoES14.2 ELISA, and subsequently comparing those 'predictions' with observed cumulative exposures. Generally, 'predicted' cumulative exposures correlated well to observed exposures (r values of 0.7-0.9). However, 'predicted' cumulative exposures underestimated observed exposures in the natural field studies. Anthelmintic treatments in some of the groups of the natural field studies reduced the 'prediction' accuracy of the CoES14.2 ELISA. This suggests that cumulative exposure in relation to IgG levels is more accurately defined by the total amount of host-parasite contact than by the cumulative number of larvae ingested. It is concluded that IgG levels measured with the CoES14.2 ELISA allow evaluating how much exposure to infection calves have experienced in the first grazing season.

Animals↗
PubMed2000

Parenterally administered gastrointestinal nematode infective larvae viable after more than 15 years in liquid nitrogen.

After cryopreservation for 13.3-15.8 years, the viability of the infective larvae (L3) of Trichostrongylus axei, T. colubriformis, Oesophagostomum columbianum, Haemonchus contortus, Ostertagia circumcincta, T. falculatus, Nematodirus spathiger, Chabertia ovina and Dictyocaulus filaria was assessed in sheep, by being deposited at their predilection sites. D. filaria was, however, an exception, in that the L3 were injected into the jugular vein. The mean development of all the species was 22.8%, but if three species (O. columbianum, C. ovina and D. filaria), that developed poorly are disregarded, then the mean development was 33.4%, similar to previous tests after shorter periods of cryopreservation. The L3 of some of the species appeared sluggish when examined 10-15 min after being thawed, and in the case of H. contortus practically all the larvae of the original batch tested in the previous trials of the series appeared dead when thawed for use in the present trial, and were replaced by another batch of L3 of the same species. When re-examined after about 8 h, however, a high percentage of the L3 of the original batch appeared to have become revitalised, and their viability was tested in a trial reported elsewhere. The intestinal cells of the majority of the L3 of N. spathiger, O. circumcincta and C. ovina were vesiculated when they were thawed. Nevertheless, the degree of development of the former two species was of the highest in the trial, and it can be concluded that this phenomenon does not necessarily impede the viability of larvae.

Animals↗
PubMed1997

Persistent intestinal neuromuscular dysfunction after acute nematode infection in mice.

BACKGROUND & AIMS: Although most acute enteric infections in humans resolve, some herald the onset of chronic symptomatology and persistent gastrointestinal dysfunction--so-called postinfectious irritable bowel syndrome. This entity is poorly understood, and there are no animal models for testing hypotheses. The aim of this study was to investigate changes in intestinal neuromuscular function during and after recovery from acute intestinal inflammation due to primary Trichinella spiralis infections in NIH Swiss mice. METHODS: Morphometric scores and myeloperoxidase activity were used to monitor mucosal inflammation. Neuromuscular function was assessed in vitro by pharmacological or electrical stimulation of longitudinal muscle. RESULTS: Acute inflammation resulted in an approximately 50% reduction of villus height, an approximately 50% increase in crypt depth, and a threefold increase in myeloperoxidase activity. Carbachol- and KCl-induced contractions of longitudinal muscle were also increased threefold, whereas contraction induced by electrical field stimulation of intramural nerves was decreased by 60%. Mucosal morphology and myeloperoxidase activity rapidly returned to control values, but the increased muscle contractility and the decreased excitatory neurotransmission persisted as long as 42 and 28 days after infection, respectively. CONCLUSIONS: These findings show that transient mucosal inflammation alters enteric neuromuscular function; this alteration persists after recovery from the infection and mucosal restitution.

Animals↗
PubMedDate not supplied

Comparative aspects of plasma antioxidant status in sheep and goats, and the influence of experimental abomasal nematode infection.

This paper provides, for the first time, comparative data on the plasma antioxidant status of two ruminant species, namely sheep and goats. In addition, the influence of experimental infection with Teladorsagia circumcincta on antioxidant status in the same two species is compared and contrasted. In general terms, antioxidant status was significantly higher in uninfected kids than in lambs. Differences in protein sulphydryl groups and vitamin E concentrations were particularly noteworthy; trends were similar, however, for albumin, vitamin A and total antioxidant capacity (TAC). Parasitological results, based on worm burden, faecal egg counts and peripheral blood eosinophil numbers, confirmed that goat kids were more susceptible than lambs to experimental T. circumcincta infection. "Trickle infection" had a variable impact on both total and individual antioxidant status; particularly during the early weeks, the trend was for reduced values in lambs and increased values in kids, as compared with uninfected controls. Subsequent challenge infection was associated with a transient decrease in TAC and albumin in trickle-infected animals of both species, and in appropriate control animals. The observed differences in plasma antioxidant capacity between sheep and goats may have important implications in terms of the comparative resilience of sheep and goats to parasite infection.

Abomasum↗
PubMed1987

Systemic release of a mast cell proteinase following nematode infections in sheep.

An enzyme-linked immunosorbent assay (ELISA) for sheep mast cell proteinase (SMCP) has been developed. Concentrations of SMCP in homogenates of abomasal tissue from parasite-immune sheep (341 micrograms SMCP/g tissues) were raised when compared to those in normal (non-infected) abomasa (0.145 micrograms SMCP/g tissue). SMCP was not detected in sera from normal animals challenged with Haemonchus contortus but was present (less than 1.0 ng SMCP/ml) in sera from 8/11 immune sheep 2 h after intra-abomasal challenge with 1 x 10(6) exsheathed Haemonchus larvae. In two further experiments, the SMCP response in gastric lymph was monitored after homologous larval challenge in sheep immune to Ostertagia circumcincta and in normal controls. SMCP (less than 1.4 ng SMCP/ml) was detected in lymph from 2/3 and 4/5 immune animals between 1 and 4 days post-challenge with 50,000 larvae, but not from normal animals. SMCP was not detected in lymph from immune animals following challenge with 1000 Ostertagia larvae. The relatively low concentrations of SMCP in blood and lymph reflect the presence of proteinase inhibitor(s) which interfered with the ELISA.

Abomasum↗
PubMed1994

Local eosinophil- and mast cell-related responses in abomasal nematode infections of lambs.

Eosinophil numbers in peripheral blood and eosinophil potentiating activity (EPA) and sheep mast cell protease (SMCP) in efferent gastric lymph were monitored in lambs during infections with Ostertagia circumcincta. Worm burdens, eosinophil numbers in bone marrow, abomasal mucosa and gastric lymph node, as well as mast cell numbers and SMCP concentrations in mucosa and mucus, were determined in post mortem samples. In naive lambs, high and relatively uniform worm burdens were present 10 days after primary infection and these were associated with only mild blood and tissue eosinophilia. By day 21 worm burdens were markedly lower and more variable. There was more evidence of eosinophil and mast cell accumulation in mucosa, and numbers in bone marrow were also higher than on day 10. However, neither EPA nor SMCP were detectable in lymph. By contrast, EPA and SMCP were present in substantial amounts in draining lymph within 48 h of challenge (secondary) infection of previously exposed lambs. EPA was inversely related to worm burdens recovered on day 10, as were abomasal mucosal and mucus SMCP concentrations. Elevated eosinophil numbers were also consistently detected in blood, bone marrow, mucosa and gastric lymph node. The results suggest that host immune defence against secondary, but not primary, exposure to O. circumcincta involves a rapidly mobilised local inflammatory component.

Abomasum↗
PubMed2000

Inflammation-induced impairment of enteric nerve function in nematode-infected mice is macrophage dependent.

Trichinella spiralis infection in rodents is associated with suppression of ACh release from myenteric plexus that can be mimicked by macrophage-derived cytokines. We verified the presence of a macrophage infiltrate in the intestine during T. spiralis infection and determined the extent to which this cell type is responsible for the neural changes. C57BL/6 mice were infected with 375 T. spiralis larvae by gavage, and the presence of macrophages (F4/80 positive) in the jejunum was determined immunohistochemically. In another experiment, infected mice were treated intravenously with liposomes containing dichloromethylene diphosphonate (clodronate, Cl(2)MDP), which causes apoptosis of macrophages, and killed at postinfection day 6, and jejunal tissues were evaluated for the presence of F4/80-positive cells and for [(3)H]ACh release from the myenteric plexus. Infection caused an infiltration of F4/80-positive cells into the intestinal mucosa, muscle layers, and myenteric plexus region and a significant suppression of ACh release (50%). Depletion of F4/80-positive macrophages using Cl(2)MDP-containing liposomes prevented the suppression in [(3)H]ACh release, identifying macrophages as the cell type involved in the functional impairment of enteric cholinergic nerves.

Acetylcholine↗
PubMed1979

A clinical trial of oxantel and pyrantel against intestinal nematodes infections.

This study was conducted to determine the effect of oxantel/pyrantel tablets, oxantel suspension, pyrantel dry syrup and pyrantel tablets against T. trichiurus and A. lumbricoides infections. Twenty-four cases of mixed infections of T. trichiurus and A. lumbricoides were treated with oxantel/pyrantel tablets at a single dose of 20 mg/kg of body weight, and 49 cases of single infection of T. trichiurus were administered oxantel suspension at a single dose of 15 mg/kg of body weight. On the other hand, single infection of A. lumbricoides in 18 cases was administered pyrantel dry syrup at a single dose of 5 mg/kg of body weight. In the above 91 cases, the negative conversion rate and the egg reduction rate of egg out-put before and after the drug administration were examined by the cellophane thick smear method and Stoll's egg counting technique. A follow-up examination was carried out 3-4 weeks after the drug administration. Other 59 cases of single and mixed infection of T. trichiurus and A. lumbricoides were examined by the cellophane thick smear method only and administered pyrantel tablets at a single dose of 2.5 mg/kg of body weight. The results were summarized as follows: 1. The prevalence rates of T. trichiurus and A. lumbricoides infection in this study were 42.8% and 27.2% respectively by the cellophane thick smear method among 1,066 stool specimens. 2. The egg negative conversion rate and the egg reduction rate in the administration of oxantel/pyrantel tablets at a single dose of 20 mg/kg body weight were 75.0% and 97.8% respectively in T. trichiurus infection and 100% each in A. lumbricoides. 3. The egg negative conversion rate and the egg reduction rate in the administration of oxantel suspension at a single dose of 15 mg/kg body weight were 85.7% and 93.0% respectively in sinlge infection of T. trichiurus. 4. The egg negative conversion rate and the egg reduction rate in the administration of pyrantel dry syrup at a single dose of 5 mg/kg body weight were 100% each in single infection of A. lumbricoides. 5. The qualitative evaluation in cases of single and mixed infection of T. trichiurus and A. lumbricoides were by means of pyrantel tablets at a single dose of 2.5 mg/kg body weight, the cure being 100% against A. lumbricoides but 17.0% against T. trichiurus. 6. There were no undesirable side effects in this study and oxantel suspension and pyrantel dry syrup were well accepted and tolerated.

Journal Article↗