Halicephalobus deletrix infection in a horse in Scotland.
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Animals↗
Biomedical subjects
F Jackson
Publications and source records attributed to F Jackson.
Prevalence of anthelmintic-resistant nematodes in fibre-producing goats in Scotland.
Six cashmere goat herds in Scotland were surveyed to assess the prevalence of anthelmintic resistance and the species of nematode involved. Resistance was determined in vivo by a faecal egg count reduction test and in vitro using an egg hatch assay and specific faecal egg identification techniques. Benzimidazole resistance was present in five of the herds, insufficient eggs were obtained from the other herd to draw firm conclusions. Teladorsagia (Ostertagia) species predominated in four of the five herds in which resistance was detected and Haemonchus contorus was the dominant species in the other.
Animals↗
Multiple anthelmintic resistant nematodes in goats.
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Animals↗
Effects of dietary molybdenum on nematode and host during Trichostrongylus vitrinus infection in lambs.
The addition of molybdenum (0.05 mmol kg-1 dry matter) to the diet of lambs exposed for four weeks to a trickle (2500 third stage larvae per day) infection with Trichostrongylus vitrinus reduced the number and length of adult worms retrieved from the small intestine 11 days later: both effects were particularly marked in female worms from female lambs (P less than 0.01). Worms from lambs given molybdenum contained less proteinase enzyme activity and secreted less proteinases in culture irrespective of the sex of the host. Pathogenicity was not attenuated by molybdenum. Damage to the intestinal mucosa was severe in both dietary groups but infected females given molybdenum developed lower plasma albumin concentrations and lighter dressed carcases than those not given molybdenum. Neither the effects on the parasite nor those on the host could be attributed simply to molybdenum-induced copper depletion, using conventional measures of copper status. Molybdenum may be toxic to T vitrinus but may also facilitate or enhance the inflammatory process limiting larval establishment or increasing parasite rejection.
Administration, Oral↗
Effects of dietary molybdenum on nematode and host during Haemonchus contortus infection in lambs.
The addition of molybdenum (0.05 mmol kg-1 dry-matter) to the diet of lambs given a trickle infection of Haemonchus contortus larvae (500 third stage larvae d-1 over six weeks) reduced mean faecal egg counts (epg) from 3952 to 2312 +/- 402 by 32 days (P less than 0.02) and greatly reduced the mean number of worms recovered from the abomasum 14 days after infection ceased (907 compared with 4167: P less than 0.01). Infection reduced haemoglobin concentrations less in lambs given molybdenum although the difference was small relative to the reduction in worm burden. Lambs not given molybdenum had low intraepithelial mast cell counts in the abomasal mucosa and less abomasal hypertrophy than expected from abomasal parasitism. Molybdenum did not consistently reduce the copper status of the host or the parasite. Previous exposure to molybdenum greatly reduced protein but not proteinase activity in, or secreted by, adult worms cultured for eight hours. It is suggested that molybdenum either increased the inflammatory response which preceded worm rejection or that it indirectly enhanced that reaction by reducing the effectiveness of copper-dependent, anti-inflammatory enzymes in the gastrointestinal mucosa.
Abomasum↗
Interactions between Teladorsagia circumcincta and Trichostrongylus vitrinus infections in young lambs.
Groups containing six lambs that previously had been infected five times each week for four, eight or 12 weeks, either with 1000 Trichostrongylus vitrinus third stage larvae (L3) or 1000 T vitrinus L3 and 2500 L3 Teladorsagia (previously Ostertagia) circumcincta were challenged, along with six worm-free control lambs, with 3000 75Se-labelled T vitrinus L3. The lambs were killed 10 days after challenge. Those given a dual infection for four and eight weeks had significantly lower total T vitrinus numbers than monospecifically infected lambs. Significantly fewer radiolabelled larvae were recovered from the dual infected group killed after four weeks exposure to infection than from lambs infected monospecifically. The negative interaction between these two nematode species appears to be physiologically mediated and may be an important factor in accounting for differences in their seasonal prevalence.
Abomasum↗
Evidence of multiple anthelmintic resistance in a strain of Teladorsagia circumcincta (Ostertagia circumcincta) isolated from goats in Scotland.
The efficacy of ivermectin, fenbendazole and levamisole was determined in lambs individually infected with 5000 third stage larvae of Teladorsagia (Ostertagia) species isolated from a herd of goats with a history of benzimidazole resistance and where the efficacy of ivermectin had also suffered an apparent decline. Efficacies, calculated using geometric means, for groups where treatments were directed against adult worms were 90.3 per cent (ivermectin), 43.4 per cent (fenbendazole) and 100 per cent (levamisole). The efficacy of ivermectin against immature stages was 83.2 per cent. Ivermectin was highly effective (99.9 per cent) against a known susceptible ovine strain of Teladorsagia.
Animals↗
The influence of challenge dose, duration of immunity, or steroid treatment on mucosal mast cells and on the distribution of sheep mast cell proteinase in Haemonchus-infected sheep.
The distribution of granule-specific sheep mast cell proteinase (SMCP), was assayed by immunocytochemistry and quantified by immunoassay in sheep immune to Haemonchus contortus. Repeated infection with Haemonchus larvae over 10-12 weeks induced a pronounced mucosal mastocytosis, including intraepithelial globule leukocytes (GL), which, 7 days after ceasing this dosing regime, was associated with the inability of incoming larvae to establish within the abomasal mucosa. Loss of this resistance, due to the cessation of stimulation with Haemonchus larvae 84 days previously or to treatment of sheep with corticosteroid, was associated with a marked decline in mast cell density and concentrations of SMCP in abomasal mucosal tissues. Nevertheless, larvae also failed to establish in immune sheep rested from challenge 42 days previously and in which mast cell counts were not significantly different from those of control sheep. A small, but significant, release of SMCP was demonstrated in gastric mucus from immune sheep following larval challenge, whereas little or no SMCP was detected in mucus from naïve animals.
Abomasum↗
Bronchoalveolar lavage cell count and differential are not reliable indicators of amiodarone-induced pneumonitis.
Amiodarone-induced interstitial pneumonitis is a serious, frequently fatal untoward effect of a commonly used antiarrhythmic agent. Recent reports suggest that bronchoalveolar lavage (BAL) fluid cellular analysis might be used to diagnose amiodarone-induced pneumonitis. The purpose of this study was to determine if the diagnosis of amiodarone-induced pneumonitis could be made by patient history, pulmonary function evaluation, and examination of BAL fluid. We studied five groups of patients. Three of the five groups received amiodarone: patients receiving amiodarone without evident lung toxic reaction, patients with amiodarone-induced pneumonitis, and amiodarone-treated patients diagnosed as having other pathologic processes involving the lung. The two other groups examined were healthy volunteers and patients with interstitial lung disease from causes other than amiodarone. Pulmonary function tests included vital capacity (FVC), first second forced exhaled volume (FEV1), total lung capacity (TLC), and diffusing capacity for carbon monoxide (DCO). BAL fluid analysis included total and differential cell counts. We found that amiodarone-induced interstitial pneumonitis was not associated with an alteration in pulmonary function or BAL cellular composition which could permit its distinction from amiodarone-treated patients diagnosed as having an unrelated pulmonary process or patients with interstitial lung disease from other causes. The most frequent abnormality encountered in patients with amiodarone toxicity was a reduction in the percentage of macrophages in the differential cell count. The sensitivity, specificity, and predictive value of this finding was 82 percent, 69 percent, and 69 percent, respectively. The sensitivity, specificity, and predictive value of a > or = 15 percent reduction in DCO was 44 percent, 50 percent, and 36 percent, respectively. We conclude that amiodarone-induced interstitial pneumonitis remains a diagnosis of exclusion, and the role of BAL fluid analysis is to narrow the differential diagnosis through microbiologic culture and cytologic examination.
Aged↗
Anthelmintic resistance in Scotland.
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Animals↗
Anthelmintic resistant nematodes in goats.
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Animals↗
Benzimidazole resistance in sheep nematodes.
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Animals↗
Relative contribution of cattle to contamination of pasture with Nematodirus battus under an alternate grazing system of husbandry.
Calves, aged six months grazing on pasture on which lambs infected with Nematodirus battus had grazed the previous season, became infected and passed eggs of N battus. Transfer of these calves onto 'clean' pasture showed that their faecal contamination was sufficient to cause moderate infections of N battus in lambs grazing this area the following season. It was also shown that significant N battus contamination could survive on pasture for at least 18 to 24 months in the absence of further grazing by sheep. Under husbandry systems involving alternate grazing there is likely to be a combination of contamination by young susceptible calves, and a two year carry-over of infectivity.
Animal Husbandry↗
Effect of parasitism with Nematodirus battus on the pharmacokinetics of levamisole, ivermectin and netobimin.
The pharmacokinetics of levamisole, ivermectin and netobimin administered orally and by subcutaneous injection were compared in lambs exposed to a moderate challenge with Nematodirus battus and in parasite naive lambs. There were no significant differences (P greater than 0.05) in the bioavailability of any of the anthelmintics tested between parasitized and non-parasitized animals. Levamisole reduced nematode faecal egg output by more than 99% when administered by either route. Ivermectin was also highly effective (greater than 99%). Orally administered netobimin reduced egg output by more than 98% seven days after administration. However egg output was only reduced by 89% 21 days after administration, suggesting poor activity against the early parasitic stages of N. battus. Netobimin was not effective against N. battus when administered by the subcutaneous route and this was probably because very low plasma concentrations of its active albendazole metabolites were achieved.
Administration, Oral↗
Acute 'bilineal-biphenotypic' leukemia.
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Acute Disease↗