Treatment of immature and mature Fasciola hepatica infections in sheep with triclabendazole.

A new benzimidazole anthelmintic, triclabendazole (CGA-89317) was found to be highly efficient against mature and early immature Fasciola hepatica infections in sheep. At the dose rate of 2.5 mg/kg the efficiency was 90 and 98 per cent against flukes aged eight and 12 weeks respectively. At 5 mg/kg the drug was 92 and 98 per cent efficient against flukes aged four and eight weeks respectively and 100 per cent against 12-week-old flukes. An efficiency of 93 and 98 per cent was achieved against one-week-old flukes and 99 to 100 per cent against flukes aged two to four weeks at 10 mg/kg. At this dose rate the drug had 100 per cent efficiency against six-week-old flukes. If the dose was increased to 15 mg/kg, 98 per cent efficiency was achieved one day after infection. Triclabendazole was equally efficient when administered orally or by intraruminal or intra-abomasal injection. The maximum tolerated dose of 200 mg/kg was established.

CGA-72662--a new sheep blowfly insecticide.

The efficiency of 2-cyclopropylamino-4, 6-diamino-s-triazine CGA-72662 (proposed common name: cyromazine) for the control of blowfly strike was tested in fly cage and field trials on sheep. The safety to sheep and physico-chemical properties of the compound as they relate to blowfly control were also assessed. When the sheep were thoroughly jetted with a solution of CGA-72662 containing 1g of active ingredient per litre, the mean incidence of fly strike in 7 field trials was reduced from 16.5% to 1.5% over a period of 9 weeks. The incidence of strike in the treated sheep in 2 insectary tests, which imposed levels of fly activity far in excess of that usually encountered in the field, was reduced from 93% and 73% in untreated sheep to 2% and nil respectively over a period of 8 weeks. Jetting with CGA-72662 solutions 100 times greater than the recommended concentration did not produce any side effects in sheep. Three treatments at twice the recommended concentration during the first trimester did not affect pregnant ewes nor their progeny. The compound was safe to use in combination with common anthelmintics and with sheep dips used for control of lice. CGA-72662 was stable in solution. No stripping occurred in dips and it persisted on wool for a considerable period. A satisfactory alternative to the organophosphorus insecticides has been found in CGA-72662, since it provided a substantial increase in residual protection against blowfly strike with a high degree of safety.