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PubMed1986

Seasonal comparisons of anthelmintic activity of levamisole pour-on in cattle in the USA.

Anthelmintic activity of a pour-on formulation of levamisole, applied during warm weather (16 degrees to 36 degrees C) at 10 mg/kg bodyweight, was evaluated in groups of naturally parasitised calves. This activity was compared to that obtained in similar groups of calves treated in the winter (-4 degrees to +7 degrees C). Controlled efficacy of the pour-on formulation was determined for each season by comparing mean worm burdens in treated calves sacrificed seven to nine days after treatment to non-treated controls. In these trials, burdens of Bunostomum phlebotomum, Cooperia species, Haemonchus placei, Nematodirus species, Oesophagostomum radiatum, Ostertagia ostertagi and Trichostrongylus axei in treated calves were reduced by 83.3 to 100 per cent in the summer and 89.2 to 100 per cent in the winter. Field investigations at nine locations across the USA compared changes in faecal egg counts for cattle treated and evaluated during warm summer months (27 degrees to 36 degrees C) to those treated during cold winter months (-18 degrees to +10 degrees C). Overall, faecal egg counts were reduced by 90.2 per cent in the summer trials and 94.0 per cent in the winter trials. The results of these trials indicate that there is no seasonal variation in the anthelmintic activity of this pour-on formulation of levamisole.

Animals↗
PubMed1992

Effects of diet on plasma concentrations of oral anthelmintics for cattle and sheep.

Groups of parasite-free lambs and calves which were either housed and fed hay and concentrates or were grazing on pasture were dosed separately with the oral anthelmintics fenbendazole and ivermectin (lambs only). The plasma concentrations of the drugs and their major metabolites were monitored during the period of their metabolism and excretion. The peak plasma concentrations and the availability of the drugs, as estimated by the areas under the plasma concentration-time curves, were significantly less in the grazing animals. When similar groups of lambs were dosed orally with the inert marker chromium EDTA, which has a particle size similar to the anthelmintics, it was observed that a higher percentage of chromium was excreted by the grazing lambs during the first 40 hours after dosing, suggesting that the extent of absorption in the grazing animals was less than in the housed animals.

Administration, Oral↗
PubMed1975

Effectiveness of anthelmintic drugs against Clonorchis sinensis infection of rabbits.

In order to find a highly efficient compound against Clonorchis infection, the anthelmintic activity of disophenol, Tremerad (SYD-230), dithiazanine iodide, dehydroemetine-late-release tablets(RO 1-9334/20), niridazole (Ambilhar), hexachlorophene (G-11), Hetol(1, 4-bis-trichloromethylbenzol) and Bilevon (niclofolan) was tested against Clonorchis sinensis experimentally infected rabbits. All drugs showed a progressive increase in efficacy as the dose rate. They were highly efficient against Clonorchis infection if sufficiently high, potentially toxic doses were given. The efficacy was evaluated by the number of detected worms with vital condition at autopsy after the treatment with above drugs. The high efficacy was observed at the following dose rates of each drugs, i.e. disophenol at a single dose of 30 mg/kg, Tremerad at the daily dose of 200 mg/kg for 10 consecutive days, dithiazanine iodide at the daily dose of 50 mg/kg for 6 consecutive days, dehydroemetine at the daily dose of 10 mg/kg for 10 consecutive days, hexachlorophene at the daily dose of 20 mg/kg for 10 to 15 consecutive days, Hetol at the daily doses from 50 to 100 mg/kg for 5 to 10 consecutive days, and Bilevon at a single dose of 8 mg/kg. Moderate effectiveness was shown in niridazole at the dose of 25 mg/kg for 10 days medication. The use of these anthelmintics for the clinical treatment of Clonorchis sinensis infection is discussed.

Journal Article↗
PubMed1977

Anthelmintic Efficacy Of Methyl-5-Benzoylbenzimidazole-2-Carbamate(Mebendazole) Against Multiple Helminthic Infections.

A clinical trial of Korean Patent mebendazole was undertaken upon some intestinal helminthic infections in 288 rural Koreans residing in Pochun and Jinyang Gun, from November to December, 1976. They were examined by the cellophane thick smear technique, Stoll's egg counting technique and/or Scotch-tape anal swab before and 3 weeks after the treatment. The administered dose of mebendazole was 600 mg, divided by 100 mg, twice daily for 3 consecutive days disregarding the body weight and the age of the cases. It was confirmed that mebendazole is very effective, broad-spectrum anthelmintic, especially against Ascaris, Ancylostoma, Trichostrongylus and Enterobius infections. Their negative conversion rate and egg reduction rate were respectively; 94.0 and 99.6 per cent in Ascaris, 71.4 and 97.3 per cent in Ancylostoma and 95.0 and 100 per cent in Trichostrongylus. The negative conversion rate in Enterobius was 92.3 per cent. The anthelmintic efficacy against T. trichiura infection was not satisfactory in spite of low worm burden (negative conversion rate, 27.3%, egg reduction rate, 65.5%).

Journal Article↗
PubMed1982

[Localization and isolation of anthelmintic activity on Clonorchis sinensis from stem cortex of Machilis thunbergii]

The present work was to localize and isolate the anthelmintic substance from stem cortex of Machilis thunbergii which grows in all parts of the Korea peninsula. The dried M. thunbergii bark was extracted with a solvent mixture (Methanol: Ethyl acetate/1:1) by a Soxhlet extractor at 70 degrees C for 24 hours, and then the extract was separated into solid matter (negative wormicidal) and benzene extract (positive wormicidal) by benzene solvent. The anthelmintic action was observed on the cercaria, the liberated metacercaria and the adult of Clonorchis sinensis. On the silica gel thin layer chromatography with a spot of benzene extract in benzene solvent, nine spots were observed in iodine chamber and the spot of Rf. 0.16 value of them appeared the most strong wormicidal effect on the cercaria and the liberated metacercaria of C. sinensis. Afterward, a 0.3 g colourless solid substance which was equivalent to the Rf. 0.16 value spot was isolated from the benzene extract of 3 kg M. thunbergii stem cortex by means of silica gel column chromatography using benzene carrier, and the adult of C. sinensis was killed within 6 minutes by 0.05 percent solution of the substance.

Journal Article↗
PubMed1982

[Isolation Of Anthelmintic Substance On Clonorchis Sinensis From Tuber Of Bletilla Striata]

The present work was done to isolate the anthelmintic substance from the tuber of Bletilla striata which grows Gangweon-do of the Korea peninsula. The dried B. striata tuber was extracted with ethyl ether by a Soxhlet extractor at 40 degrees C for 24 hours, and then the extract was separated into insoluble material (negative wormicidal) and soluble material (positive wormicidal) by petroleum ether solvent. The wormicidal substance was separated in the silica gel column chromatography from the petroleum ether extract, using benzene (90 %) and acetone (10 %) as a solvent. The anthelmintic activity was observed in vitro on the cercaria, the excysted metacercaria and the adult of Clonorchis sinensis. On the silica gel thin layer chromatography with the wormicidal substance in benzene : acetone/90 : 10, five spots were observed in iodine chamber and the spot of Rf. 0.18 value of them appeared the most strong wormicidal effect on the cercaria of C. sinensis. Afterward, a substance which was equivalent to the Rf. 0.18 value spot was isolated from the wormicidal substance by means of silica gel column chromatography using 1 part of ethyl acetate and 6 parts of chloroform carrier, and the excysted matacercaria and the adult of C. sinensis were killed within 14 minutes and 128 minutes in the substance.

Journal Article↗
PubMed2000

Effects of anthelmintic treatment and feed supplementation on grazing Tuli weaner steers naturally infected with gastrointestinal nematodes.

A study was carried out to determine the epidemiology of gastrointestinal nematodes in indigenous Tuli cattle and the effect of dietary protein supplementation and anthelmintic treatment on productivity in young growing cattle. Forty steers with an average age of 18 months were divided into 4 groups; 1) fenbendazole (slow release bolus) and cottonseed meal (FCSM group), 2) fenbendazole (FBZ group), 3) cottonseed meal (CSM group) and 4) control (no cottonseed meal and no fenbendazole) (control group). Performance parameters measured included worm eggs per gram of faeces (EPG), packed cell volume (PCV), albumin and live-weight gain. Results showed that faecal worm egg counts were lower and PCV was higher in the FCSM and FBZ groups than in the CSM and control groups (P < 0.01). Weight gains were higher in the CSM and FCSM groups than in the FBZ and control groups (P < 0.05). The cost benefits of anthelmintic treatment and dietary supplementation were apparent in this study. The improved growth performance of the FCSM, FBZ and CSM groups reflected a financial gain over the controls on termination of the study. The dominant genera of gastrointestinal nematodes on faecal culture, pasture larval counts and necropsy were Cooperia and Haemonchus. The incidences of Trichostrongylus, Oesophagostomum and Bunostomum were low.

Animals↗
PubMed2001

Effects of anthelmintics on the development of eggs of Angiostrongylus costaricensis in vitro.

Effects of the anthelmintics, pyrantel and levamisole, on egg development of Angiostrongylus costaricensis were studied in vitro. After 7 days, about 80% of eggs developed to first-stage larvae in Ham's F-12 medium with 10% foetal calf serum under 5% CO2. Significant inhibition of development was caused by pyrantel (10(-9) - 10(-8) g ml(-1)) and levamisole (10(-9) - 10(-8) g ml(-1)) (Mann-Whitney U-test; ), and none of the eggs developed to first-stage larvae in higher concentrations of these anthelmintics (10(-7) g ml(-1)). Furthermore, incubation with these drugs at 10(-8) g ml(-1) for at least 3 h or at 10(-4) g ml(-1) for 1 h caused irreversible effects on egg development.

Angiostrongylus↗
PubMed1992

[Resistance of small strongyles in an equine stud in South Africa to the benzimidazole anthelmintics].

This paper is apparently the first report of resistance of helminths of equids to anthelmintics in South Africa. While a strain of Cyathostominae from an Arab horse stud near Pretoria showed greatly reduced susceptibility to benzimidazoles in faecal egg reduction tests, ivermectin was apparently still unaffected. It is suggested that integrated methods of control such as alternation of horses and ruminants on pasture and mechanical removal of faeces should be used in addition to anthelmintics.

Animals↗
PubMed2004

Management and control of nematode parasites of small ruminants in the face of total anthelmintic failure.

Total failure of modern broad spectrum anthelmintics to control nematode parasites of sheep and goats is a reality, of rapidly increasing dimension, on many farms in the tropical / subtropical regions of the world. This is primarily associated with the highly pathogenic, blood sucking parasite, Haemonchus contortus, and where it now cannot be controlled by chemotherapy, annual mortalities exceeding 20% of the flock can be expected. Thus sheep and goat enterprises become totally unsustainable, unless major changes in management are effected. These must include a change away from reliance on suppressive anthelmintic treatment and to include several non-chemotherapeutic management options. In situations where livestock numbers need to be preserved and there is no opportunity to increase the grazing area available, then zero grazing with cut-and-carry herbage from uncontaminated pasturelands is the only option. In other circumstances stocking rates need to be substantially reduced, so that short-term rotational grazing can be effectively practiced. This strategy is improved if it is combined with the biological control of the free-living stages of the parasites, using the microfungus Duddingtonia flagrans. Monitoring the parasitological status of the animals by faecal sampling sentinel sub-flocks for nematode faecal egg counts, or the use of the FAMACHA procedure, are also valuable tools. Improving overall nutrition of the flock is an important adjunct to control. As a long-term priority, attempts to change the genotype of the flocks to those breeds that have been shown to possess natural resistance to H. contortus are worthwhile.

Journal Article↗
PubMed1991

Pathophysiologic effects of Ostertagia ostertagi in calves and their prevention by strategic anthelmintic treatments.

Pathophysiologic effects of Ostertagia ostertagi infection and their prevention by strategic anthelmintic treatments were studied in 3 groups each of 6 steer calves. Group-1 calves were noninfected controls. Group-2 calves were inoculated with 100,000 third-stage larvae on the 1st and 28th days of the experiment and grazed on pasture initially free of contamination. Group-3 calves were on a similar regimen as those in group 2, but were also treated with ivermectin 9 days after each larval inoculation. Group-2 calves had increased plasma pepsinogen and gastrin values and decreased weight gains, and total serum protein and albumin concentrations from the 2nd week of infection onward. They were anemic at 10 to 12 weeks and had lower carcass and meat quality at slaughter. Strategic anthelmintic treatments were effective in preventing these effects and calves in groups 1 and 3 had similar performances. On the basis of our findings, high pepsinogen values were related to worm burdens, whereas high gastrin concentrations were related to gastric lesions.

Abomasum↗
PubMed1986

Anthelmintic treatment of pastured dairy cattle in California.

The relationship of anthelmintic treatment for subclinical gastrointestinal nematode parasitism with resultant milk production was studied on 3 California dairies where animals were maintained on a pasture-based nutritional program. All of the animals that started lactating (freshened) during a 12-month period participated in trials in which coumaphos was given as a feed top dressing to animals averaging 30 days into lactation. All of the animals that freshened during the subsequent 12-month period from 2 of the same 3 dairies participated in trials in which thiabendazole was administered at or within 2 weeks before freshening. Anthelmintic administration during 2 consecutive lactation cycles under the conditions of the present study resulted in no consistent reproducible significant changes in milk production.

Animals↗
PubMed1984

Effect of anthelmintic treatment on the productivity of lambs infected with the intestinal nematode, Trichostrongylus colubriformis.

Liveweight gain, food intake, wool growth and concentration of serum constituents were measured in four groups of three-month-old lambs. Groups 1 and 2 were infected on five days each week with 2500 Trichostrongylus colubriformis larvae for 18 weeks. Group 2 lambs were treated with fenbendazole (5 mg kg-1) at week 10 and week 15. Group 3 lambs were similarly infected for 10 weeks, treated with fenbendazole, but given no further larvae. A fourth control group remained uninfected throughout the trial. All lambs were killed at week 20. Mean worm populations were 16,130, 430 and zero for groups 1, 2 and 3 respectively. Over the first 10 weeks of infection, liveweight gain was reduced by 52, 43 and 51 per cent and wool growth by 33, 28 and 27 per cent respectively, in groups 1, 2 and 3. Serum hypophosphataemia and hypoalbuminaemia occurred in all three infected groups. Between weeks 10 and 20 overall weight gain and wool growth in group 1 lambs were 44 and 46 per cent lower than the controls, whereas weight gains of group 2 and group 3 lambs were similar to or slightly higher than in the controls. However, wool growth in these two groups after treatment was only 73 to 74 per cent of control values. Serum phosphorus concentrations increased to control levels within one week of anthelmintic treatment and serum albumin concentrations by two to four weeks. The ability of group 2 lambs to improve their performance after anthelmintic treatment, in the face of continued challenge, was attributed to development of resistance to reinfection.

Animals↗
PubMed1982

[The effects of postparturient anthelmintic treatment on ewes and their lambs (author's transl)].

Anthelmintic treatment of ewes after lambing resulted in partial suppression of the spring rise in egg counts in Frisian milch-sheep, lambing early in March and a rather satisfactory suppression of the spring rise in Texel ewes lambing late in March. The Frisian and Texel sheep were treated with 44 mg/kg and 66 mg/kg thiabendazole respectively. Beneficial effects of treatment were not observed in the ewes or their lambs compared with the controls. Particularly, treatment failed to produce any improvement of the gain in weight in the lambs. In the Frisian ewes, the haemoglobin content was determined at regular intervals. Both in the treated and in the untreated group, the haemoglobin content decreased significantly. Moreover, this decrease was correlated with the increase in faecal Haemonchus egg counts These results and those of previous experiments in conjunction with findings reported in the literature, lead to the general conclusion that farm management is highly decisive in answering the question as to how serious trichostrongylid and strongylid infections will be and the extent to which anthelmintic treatment of the ewes could have a beneficial effect.

Animals↗
PubMed1981

Comparative anthelmintic efficacy of two schedules of mebendazole treatment in dogs.

Two schedules of anthelmintic oral treatment, using mebendazole powder, were compared in 73 dogs naturally infected with common helminth intestinal parasites. Mebendazole powder was administered to 26 dogs at doses of 22 mg/kg once daily for 3 days and was compared with the same dose given only daily for 5 days into 23 dogs. The 24 other dogs were kept as controls and received a placebo treatment for 5 days. Efficacy results for the 3-day treatment schedule of mebendazole were as follows: Toxocara canis, 100%; Uncinaria stenocephala, 100%; Ancylostoma caninum, 99.4%; Trichuris vulpis, 100%; and Taenia pisiformis, 93.9%. Mebendazole powder given on the 5-day treatment schedule was 100% efficacious against the foregoing parasites. Anthelmintic efficacy against Dipylidium caninum was not detected in either schedule of treatment.

Administration, Oral↗
PubMed1980

Repeated anthelmintic treatments and receptivity of mice to experimental infections with Heligmosomoides polygyrus (Nematospiroides dubius).

Two experiments were carried out to define the effect of repeated anthelmintic treatments with or without repeated infections by H. polygyrus on the receptivity of the mouse to subsequent infections by the same parasite. The aim of the first experiment was to show the effect of these interventions on the future development of host resistance. This experiment did not reveal a marked difference in behaviour between treated or non-treated animals. During the second experiment a modification of the acquisition of resistance during the period of infections and multiple treatments was looked for. It was shown that multiple treatments of the host during the period of immunity markedly improved the mechanisms of defense against a new infection. Any direct action of anthelmintics was ruled out in explaining this mechanism. Two drugs were compared: pyrantel tartrate and levamisole. No difference has been shown between these two drugs. It is possible, however, that the multiple treatments act by enabling a more intense renewal of the parasitic population and therefore by increasing the stimulus initiating protection.

Animals↗
PubMed1993

Immunologic changes in Ostertagia ostertagi-infected calves treated strategically with an anthelmintic.

Immunomodulation by Ostertagia ostertagi and the effects of strategic anthelmintic treatments were studied in 3 groups of 6 calves each: an infected group, inoculated with 100,000 third-stage larvae (L3)/calf at 1 and 28 days; an infected-treated group, similarly inoculated, but treated with ivermectin 9 days after each inoculation; and a noninfected control group. Calves were grazed on 2 previously clean pastures, with the infected and infected-treated calves sharing 1 pasture. All calves were inoculated at 12 weeks with Brucella abortus and infectious bovine rhinotracheitis vaccines, and at 13 weeks with a soluble O ostertagi L3 extract (SLE). Infected and infected-treated calves had lower blood lymphocyte responses to phytohemagglutinin than did control calves at 2, 4, and 14 weeks, whereas the infected calves had higher responses at 6 and 8 weeks (P < 0.05). Responses to pokeweed mitogen followed a similar pattern, whereas those to SLE were low in all calves. Infected and infected-treated calves had increased values of IgG1 to excretory-secretory antigens of L4 larvae, but no changes in the values of IgG1 to SLE. They also had lower values of IgG and IgM to B abortus and antibodies to infectious bovine rhinotracheitis at 13 weeks. The infected-treated calves, however, had higher blood lymphocyte and monocyte counts and lower eosinophil count than did infected calves. They also had reduced abomasal mucosa thickness, abomasal wall weight, and abomasal lymph node weight than infected calves. It was concluded that O ostertagi causes nonspecific suppression of cellular and humoral immunity, hypersensitivity reactions coexisted with immunosuppression, and strategic anthelmintic treatments attenuated hypersensitivity reactions and initiated better immune responses.

Abomasum↗
PubMed1976

The anthelmintic efficacy of fenbendazole against thiabendazole-resistant strains of Haemonchus contortus and Trichostrongylus colubriformis in sheep.

The anthelmintic efficacy of fenbendazole (methyl 5-(phenylthio)-2-benzimidazole carbamate) was tested in sheep against standardised strains of Hcaemonchus contortus and Trichostrongylus colubriformis, known to be resistant to thiabendazole (LD90 for thiabendazole against H ontortus was 200 mg/kg bodyweight and against T colubriformis was 150 mg/kg). Fenbendazole at dose rates of 5, 10 and 20 mg/kg per os reduced total worm counts in H contortus infected sheep by 66, 90 and 100 per cent respectively, with similar reductions recorded for worm egg outputs. For the thiabendazole resistant strain of T colubriformis, fenbendazole reduced total worm counts in infected sheep by 4, 44 (40-48), 79 (75-83), 96 and 100 per cent at dose rates of 5, 10, 20, 40 and 80 mg/kg per os. Significant suppression of worm-egg production by thiabendazole resistant T colubriformis was obtained with fenbendazole at dose levels of 5 mg/kg and above. The implications of these results are discussed in the light of the increasing occurrence of strains of trichostrongylid nematodes resistant to currently available benzimidazole anthelmintics.

Animals↗