Comparative efficacy of triclabendazole, nitroxynil and rafoxanide against immature and mature Fasciola hepatica in naturally infected cattle

In two trials the fasciolicidal activities of triclabendazole, nitroxynil and rafoxanide were assessed in cattle naturally infected with predominantly immature stages of Fasciola hepatica. Tablets containing 900 mg triclabendazole were administered orally at a dose rate of 12 mg/kg bodyweight. Rafoxanide and nitroxynil were used at a dose rate of 10 mg/kg, rafoxanide being given orally and nitroxynil by subcutaneous injection. Based on faecal egg counts nine weeks after treatment the efficacies were calculated to be 100 per cent for triclabendazole and 95.0 per cent for nitroxynil in the first trial and 98.4 per cent for triclabendazole and 52.9 per cent for rafoxanide 15 weeks after treatment in the second trial. In the first trial five animals from each of the three groups were slaughtered and their fluke burdens counted. Compared with the untreated control group the reductions in the fluke burdens were 96.9 per cent in triclabendazole treated cattle and 76.4 per cent in the nitroxynil treated group.     

Comparison of the activity of some fasciolicides against immature liver fluke in calves

The anthelmintic activities of nitroxynil, closantel and rafoxanide were tested in cattle against six- and eight-week-old infections of Fasciola hepatica. Administered by subcutaneous injection, nitroxynil and rafoxanide at dose rates of 10 and 3 mg/kg bodyweight respectively were 88.5 and 36.1 per cent effective in eliminating a six-week-old infection of F hepatica and 85.8 and 60.4 per cent effective against an eight-week-old infection. Closantel administered by intramuscular injection at a dose rate of 2.5 mg/kg bodyweight was 60.0 per cent effective against an eight-week-old F hepatica infection.     

Comparative efficacy of clorsulon and albendazole against Fasciola hepatica in cattle

In a dosage-confirmation trial, anthelmintic activities of clorsulon and albendazole against Fasciola hepatica were evaluated and compared. Twenty-eight cattle (8 to 12 months old) with natural F hepatica infections were randomly allotted to 4 groups of 7 cattle each: group 1, no treatment (controls); group 2, clorsulon suspension given orally at 3.5 mg/kg of body weight; group 3, clorsulon suspension given orally at 7 mg/kg; and group 4, albendazole paste given orally at 10 mg/kg. At necropsies, performed 7 and 8 days after treatment, control cattle harbored a geometric mean of 133.2 F hepatica, 16.0 of which were immature. Clorsulon administered at 3.5 mg/kg or 7 mg/kg resulted in greater than 99% removal of F hepatica, including immatures. Albendazole treatment resulted in a 76% overall reduction in F hepatica, including a 91% reduction of immatures. Fascioloides magna also were found in the cattle, but neither clorsulon nor albendazole caused significant reductions of the parasite. Adverse reactions to the 2 drugs were not observed.     

Field trial on comparative efficacy of four fasciolicides against natural liver fluke infection in cattle

A controlled trial was conducted to evaluate the current efficacy of albendazole (ABZ), rafoxanide (RFX), triclabendazole (TRC) or clorsulon (CLS) against Fasciola hepatica in naturally infected cattle. This trial was conducted in Turkey during the spring, the time of year when liver fluke infection is endemic. Fifty crossbred cattle were selected for inclusion in the trial based on finding eggs of F. hepatica in the feces. The cattle were weighed and randomly allotted into five groups of 10 cattle and treatments were as follows: Group 1 served as non-treated control (CONT), Group 2 was treated orally with ABZ at 12 mg/kg, Group 3 was treated orally with RFX at 10 mg/kg, Group 4 received TRC orally at 12 mg/kg and Group 5 received CLS administered subcutaneously (s.c.) at 2 mg/kg. On day 0 (inclusion day), individual fecal samples were collected on days 0 (inclusion day), 7, 14, 28 and 56, after treatment. The drug efficacy was assessed as a percentage of the egg or fluke reduction and body weight gain relative to the untreated control. The results in the study showed a mean reduction of egg counts by 66.7%, 68.2%, 78% and 84.2% in Groups 2-5, respectively. In conclusion, our results indicate that CLS is a highly effective compound for the treatment of F. hepatica in cattle under these field conditions.     

Treatment of Fasciola hepatica infection in horses with triclabendazole

Thirteen thoroughbred foals with an adult infection and a presumed immature infection with Fasciola hepatica were treated with 12 mg triclabendazole/kg bodyweight. The absence of eggs from samples of faeces examined at intervals up to 110 days after treatment showed that all the animals were cured. In a second trial the same dose of triclabendazole cured 11 of 12 foals whereas nitroxynil at 7 mg/kg cured only six of 12 foals. No side effects were observed after treatment.     

THE EFFICIENCY OF CLIOXANIDE AND RAFOXANIDE AGAINST FASCIOLA HEPATICA IN SHEEP BY DIFFERENT ROUTES OF ADMINISTRATION

Groups of sheep were infected with 100 viable metacercariae of Fasciola hepatica. The efficiencies of clioxanide and rafoxanide were evaluated against infections aged 6 and 12 weeks, by using 3 dose rates of each compound by each of 3 routes of administration. Clioxanide, at 40 mg/kg, administered orally and intra-ruminally against 6-week-old liver fluke was 85 and 90% efficient respectively. At 80 mg/kg intra-abomasally its efficiency was 43%. Clioxanide at 20 mg/kg was 96% efficient against 12-week-old liver fluke when given orally or intra-ruminally and 82% efficient when given intra-abomasally. Because of its lower efficiency intra-abomasally, clioxanide may be unsatisfactory in a proportion of sheep, for use against immature liver fluke at a dose rate of 40 mg/kg. It may be expected to give a moderate to high efficiency against mature infections at 20 mg/kg.     

The anthelmintic efficacy of albendazole against Fasciola hepatica and benzimidazole resistant strains of Haemonchus contortus and Trichostrongylus colubriformis in sheep.

The anthelmintic efficacy of albendazole (methyl [5-(propylthio) - 1H - benzimidazole -2 -yl] carbamate) against immature and adult Fasciola hepatica and against standardised strains of benzimidazole resistant Haemonchus contortus and Trichostrongylus colubriformis was evaluated in experimentally infected sheep. A single intrarumenal treatment of dose rates of 3.8 and 7.6 mg/kg was ineffective against immature (six weeks old) F hepatica. Dose rates of 5.7 and 7.6 mg/kg reduced the number of mature (12 weeks old) F hepatica by 70 and 91 per cent respectively. Dose rates of 5.7 and 7.6 mg/kg removed 92 and 99 per cent of four-week-old, benzimidazole resistant H contortus and 89 and 99 per cent of four-week-old, benzimidazole resistant T colubriformis.     

The activity of triclabendazole against immature and adult Fasciola hepatica infections in sheep

SUMMARY The efficiency of a new benzimidazole anthelmintic, triclabendazole, was tested against cumulative infections with Fasciola hepatica aged 1 to 12 weeks in sheep and compared with that of rafoxanide. At 10 mg/kg, triclabendazole was 99% effective in eliminating both immature and adult flukes. At a lower dose rate of 5 mg/kg, triclabendazole was highly effective against adults and significantly reduced the number of early immature flukes with an 87% overall reduction of fluke burden. Rafoxanide at 7.5 mg/kg showed high efficiency against adult fluke, but its effect on immatures was not significant, and overall efficiency was 64%.     

Comparative efficacy of closantel and triclabendazole against Fasciola hepatica in experimentally infected sheep

The effect of closantel (10 mg/kg orally) and triclabendazole (10 mg/kg orally) on the reappearance of a patent infection of Fasciola hepatica was studied in experimentally infected sheep. The treatments resulted in the interruption of faecal egg output for 11 weeks with triclabendazole and 13 weeks with closantel. Necropsy of untreated control animals revealed a mean burden of 360 flukes with a mean (+/- se) surface area of 171 +/- 64.3 mm2, whereas the fluke burdens in the closantel and triclabendazole-treated animals 14 weeks after treatment were 61 (83 per cent reduction) and 21 (94 per cent reduction), respectively. The surface areas of the flukes in the triclabendazole-group were comparable with the untreated controls (141 +/- 51.8 mm2), but the flukes in the closantel group were markedly smaller (43.1 +/- 26.9 mm2). It is concluded that closantel has, in epidemiological terms, a potency comparable with that of triclabendazole, despite its slightly lower efficacy against the very immature stages.     

Evaluation of clorsulon against immature Fascioloides magna in cattle and sheep

Efficacy of clorsulon was evaluated against infection with immature Fascioloides magna in 24 cattle and 12 sheep. Infections were induced by oral administration of 600 metacercariae/host. In cattle, clorsulon at dosages of 7 and 21 mg/kg of body weight was 65 and 100% effective against 8-week-old flukes, and 20 and 74% effective against 16-week-old flukes, respectively. In sheep, clorsulon at a dosage of 21 mg/kg was 92% effective against 8-week-old flukes. Significantly (P less than 0.05) more F magna were recovered from untreated sheep than from untreated cattle.     

Efficacy of a fenbendazole-triclabendazole combination against Fasciola hepatica and gastrointestinal nematodes in sheep

A fenbendazole and triclabendazole combination was tested against experimentally induced 6-and 14-week-old infections of Fasciola hepatica and naturally acquired infections of gastrointestinal nematodes in sheep. Forty-eight sheep were divided randomly into six treatment groups of eight animals each. At 7.5 and 10.0 mg kg-1 body weight (BW) (3.75 and 5.0 mg kg-1 BW of each drug), the drug combination was 98.3 and 99.7% effective against 6-week-old F. hepatica infections, and 100 and 99.9% effective against 14-week-old infections. At the same drug dosages, the drug combination was effective against naturally acquired adult Ostertagia spp. (97.3-100%) and adult Nematodirus spp. (90.3-99.9%). No adverse effects associated with treatment were noted.     

Efficacy of clorsulon for the treatment of experimentally induced infections of Fasciola hepatica in goats

A dose titration study was undertaken to determine the efficacy of clorsulon against the adult stage of Fasciola hepatica in goats. Thirty-nine goats were experimentally infected with metacercariae of F hepatica. At 14 weeks after infection, each goat was assigned randomly to 1 of 5 groups. Goats in groups 1 to 4 received a single oral administration of clorsulon at dosages of 3.5, 7, 11, and 15 mg/kg of body weight, respectively. The fifth group of goats (control group) was infected with F hepatica, but were not treated with clorsulon. Postmortem examination of goats at 3 weeks after treatment revealed mean reductions in numbers of flukes of 83, 98, 99, and 100% for groups 1 to 4, respectively. Mean percentage of reduction in eggs following treatment of groups was 82, 98, 100, and 100%, respectively. The clinical effects of clorsulon in 24 goats that were not infected with F hepatica were studied. Goats in groups 1 to 3 received a single oral administration of clorsulon at dosages of 7, 21, and 35 mg/kg, respectively, every other day for a total of 3 doses/goat. Group-4 goats (control group) received a vehicle placebo. Goats in group 3 were subject to postmortem examination at 14 days after dosing. Abnormal signs or lesions that could be attributed to clorsulon were not found in any goat.     

The pharmacodynamics of the flukicidal salicylanilides, rafoxanide, closantel and oxyclosanide

The pharmacokinetics of oxyclosanide, rafoxanide and closantel were investigated in sheep (n = 5). All three drugs were extensively (greater than 99%) bound to plasma proteins and the plasma concentration/time curve was best described by a tri-exponential equation. Closantel and rafoxanide had long terminal half-lives (mean 14.5 and 16.6 days, respectively) compared with oxyclosanide (mean 6.4 days). In a study of the efficacy of rafoxanide against Fasciola hepatica, a dose rate of 7.5 mg kg-1 against 6-week-old flukes appeared to be similarly effective to a dose rate of 2.5 mg kg-1 against 10-week-old flukes (86% and 88% efficacy, respectively), as assessed at autopsies carried out on all sheep when the flukes were 14 weeks old. Part of this putative efficacy against immature flukes may be due to rafoxanide persisting in the plasma and affecting the mature flukes when they reach the bile ducts.     

Efficacy of clorsulon and albendazole against Fascioloides magna in naturally infected white-tailed deer

The efficacy of clorsulon and of albendazole against Fascioloides magna were evaluated in 36 naturally infected white-tailed deer (Odocoileus virginianus) in southern Texas. A single oral dose of clorsulon suspension (12 to 30 mg/kg of body weight; mean = 24 mg/kg) was given to each deer and killed 153 (92%) of 167 mature flukes and 4 (80%) of 5 immature flukes recovered at necropsy. A single oral dose of albendazole paste (17 to 46 mg/kg; mean = 26 mg/kg) was given to each deer and killed 148 (89%) of 167 mature flukes and 4 (67%) of 6 immature flukes recovered at necropsy. In 82 nontreated control deer, 271 live flukes were recovered; dead flukes were not recovered.     

EFFICACY OF ALBENDAZOLE AGAINST FASCIOLA HEPATICA IN SHEEP

In series of 4 trials dose rates of 3.8, 4.75 and 7.5 mg/kg of albendazole were given to sheep either as a single or repeat dose such as may be given under field conditions. Efficacy against 6-to 7-week-old Fasciola hepatica ranged from 16.0% to 43.6%. Efficacy against mature 12- to 17-week-old fluke ranged from 74.4% to 94.5%.     

Efficacy of clorsulon against mature, naturally acquired Fasciola hepatica infections in cattle and sheep

Clorsulon (3.5 or 7 mg/kg of body weight) was given orally to mature cows (dairy or beef) and to mature mixed-breed sheep harboring patent infections of Fasciola hepatica. Eighteen animals of each species were assigned to a control group (drug vehicle) or to 1 of 2 treatment (3.5 or 7.0 mg/kg) groups of 6 animals each. On posttreatment days 8 (cows) or 14 (sheep), the animals were slaughtered for recovery of flukes. In cows, the efficacy (P values for treatment groups vs control) of clorsulon against infections of mature F hepatica was 99.21% (P less than or equal to 0.0065) at 3.5 mg/kg and was 100% (P less than or equal to 0.0039) at 7 mg/kg. In sheep, the efficacy was 93.33% (P less than or equal to 0.0104) at 3.5 mg/kg and was 100% (P less than or equal to 0.0039) at 7 mg/kg. These results indicate that clorsulon is a highly effective compound for the treatment of mature F hepatica in cows and sheep.     

国产三氯苯咪唑驱除山羊肝片形吸虫效果试验

以国产三氯苯咪唑对自然感染肝片形吸虫的山羊进行了驱虫试验，并以硝氯酚为药物对照。结果表明，三氯本咪唑5mg/kg体重的剂量对肝片形吸虫成虫和童虫的驱虫率分别为99.3%和92.9%，驱净率为75％；三氯苯咪唑10mg/kg体重的剂量对肝片形吸虫成虫和童虫的驱虫率均为100％，驱净率为100％；硝氯酚5mg/kg体重剂量对肝片形吸虫成虫驱虫率为100％，但对童虫的仅为74.3%，而驱净率仅为60％。在整个试验期间试验羊均无不良反应。     

Evaluation of oxfendazole against natural infections of gastro-intestinal nematodes and lung-worms in calves.

The anthelmintic activity of oxfendazole (Syntex) was tested in calves at dosages of 2-5 and 5-0 mg per kg. At both dose levels, oxfendazole showed 100 per cent efficacy against adult Ostertagia ostertagi, O lyrata, O cremensis, fifth stage Ostertagia spp and adult Haemonchus spp. Against adult Cooperia oncophora, efficacy was 99.8 per cent and 100 per cent at doses of 2.5 mg per kg and 5.0 mg per kg respectively while at both dose levels 100 per cent activity was recorded against C surnabada and fourth and fifth stage Cooperia spp. One hundred per cent efficacy was obtained with both dose levels against adult and fifth stage Dictyodaulus viviaprus; against Trichuris spp, percentage efficacy was 92 and 100 per cent at doses 2.5 and 5.0 mg per kg respectively. Oxfendazole showed higher efficacy than levamisole against Ostertagia spp but against the other species encountered, both anthelmintics possessed similar efficacy. Both anthelmintics significantly increased the calves' weight gains.     

An experimental study on triclabendazole resistance of Fasciola hepatica in sheep

The efficacy of triclabendazole in sheep experimentally infected with Fasciola hepatica was studied. Two groups of 12 lambs were infected with a susceptible (S) or a resistant (R) strain of F. hepatica. Eight weeks after infection, six lambs of each group (ST and RT) were treated with triclabendazole (10mg/kg). The other lambs were used as untreated controls (SC and RC). The parameters studied were: GLDH, gamma-GT, ELISA measuring antibodies against recombinant cathepsin-L(1) and eggs per gram faeces (epg). The lambs were slaughtered 16 weeks after infection and the number of flukes counted.The GLDH, gamma-GT levels and the OD value of the ELISA decreased as a result of the treatment in group ST. Patent infections were observed in all animals of groups SC, RT and RC. In group ST, occasionally a few eggs were found in five lambs. The percentage of flukes was 31.3 in SC and 37.6 in RC. In the treated groups ST and RT, the percentage of flukes was 0.06 and 33.6, respectively. These results corresponded to efficacies of 99.8% in the susceptible and 10.8% in the resistant strain. Since the resistant strain was isolated from a mixed cattle and sheep farm, it confirms the presence of triclabendazole resistance in the Netherlands.     

Chemotherapy of paramphistornosis in sheep

Controlled trials were used to assess the efficacy of various anthelmintics against immature and adult paramphistomes in 75 experimentally or naturally infected sheep. Albendazole (20 mg/kg), praziquantel (10 mg/kg), nitroxynil (10 mg/kg) triclabendazole (10 and 100 mg/kg), profenophos (25 mg/kg) and netobimin (15 mg/kg) had little or no activity against adult or immature fluke. Niclosamide at 100 mg/kg had high efficacy (99%) against intestinal fluke but none against adult fluke. A 2- tertiary-butyl benzthiazole compound (CGA 72630) at 25 mg/kg and resorantel at 65 mg/kg had very high efficacy against both adult and immature fluke in the rumen and small intestine respectively. The efficacy of other anthelmintics which have been used against paramphistomes in sheep is reviewed.