Efficacy of an injectable ivermectin/clorsulon combination against Fasciola hepatica in sheep

Abstract

INFECTIONS of Fasciola hepatica are of considerable economic importance in sheep and cattle (Urquhart and others, 1989). Ivermectin, an avermectin belonging to the macrocycic lactone class of compounds, is highly effective against a broad spectrum of endoparasites and ectoparasites of sheep (Benz and others 1989), but members of this class of compound do not have useful or significant activity against F hepatica (Shoop and others 1995). Clorsulon is a sulphonamide compound that has been reported to have potent activity against F hepatica in cattle and sheep treated orally or intraruminally with doses of 3-75 to 15 mg/kg bodyweight others 1977, Zimmerman and others 1986). When administered by subcutaneous injection at 2 mg/kg bodyweight clorsulon alone or in combination with ivermectin reduced the number of F hepatica in cattle by 98-7 per cent (Robin and Gane 1990).To evaluate the broad spectrum antiparasitic activity of a combination of ivermectin and clorsulon against artificially induced F hepatica infections in sheep, an injectable product containing I1-0 per cent w/v of ivermectin and 0.0 per cent w/v of clorsulon (Ivomec-F; Merial) was administered subcutaneously at 0-5 ml/25 kg bodyweight (Eagleson and others 1997). This was found to be highly effective against nematode endoparasites and Psoroptes ovis, while efficacies against mature and eight-week-old immature flukes were recorded as 91.2 to 95-9 per cent and 79.5 per cent, respectively. The present study was undertaken to extend these data by evaluating the efficacy of this product in sheep naturally infected with F hepatica.Fourteen female Bergschaf sheep aged three to six years and weighing 45 to 76 kg were purchased in Austria after confirmation of F hepatica infection by faecal examination. They were fed hay and grass silage and housed indoors as a single group for 12 weeks to ensure that all flukes were mature at the start of the trial. The animals were ranked according to decreasing bodyweight on the day of treatment and seven replicates of two sheep each were formed. Within replicates, the animals were randomly assigned to either an untreated control group or were treated with the ivermectin/clorsulon combination at a dose of 0.5 ml/25 kgbodyweight (200 j.g ivermectin and 2 mg clorsulon/kg) adlministered once by subcutaneous injection.Faecal samples were examined for Fasciola egg counts (Happich and Boray 1969) seven days before treatment (day -7), at treatment (day 0) and at slaughter (day 14). For fluke recovery at necropsy, the, gall bladder and bile ducts were opened and the liver was cut into approximately 1 cm slices. Fluke counts were transformed to the natural logarithm of (count + 1) for calculation of geometric means and percentage reduction. Treatment comparison was made using Wilcoxon's rank-sum test in a randomisation procedure which leads to an exact probability of finding a statistic as extreme as or more extreme than the one observed.

Epidemiological and ultrasonographic investigation of bovine fascioliasis in smallholder production system in Eastern Nile Delta of Egypt

“…The most commonly used anthelmintic is ivermectin alone or in combination with clorsulon (e.g., ivomec plus), which are effective against wide range of external and internal parasites. Previous studies concluded that use of ivermectin in combination with clorsulon is an effective flukicide (Rehbein and Visser, 1999;Elitok et al, 2006;Hutchinson et al, 2009). Some farmers drenching their animals with other types anthelmintic such as albendazole or triclabendazole.…”

Fasciola hepatica : effects of the fasciolicide clorsulon in vitro and in vivo on the tegumental surface, and a comparison of the effects on young- and old-mature flukes

“…It is also effective against Fasciola hepatica infections in the rat, the host species used in the present study (Schulman et al 1979(Schulman et al , 1982a. Although clorsulon itself is not active against nematode and arthropod parasites, it is marketed in combination with ivermectin (Ivomec Super, Ivomec-F) as a broad-spectrum wormer (Rehbein and Visser 1999;Ibarra-Velarde et al 2001).…”

Activity of oxyclozzanide, nitroxynil, clorsulon and albendazole against adult triclabendazole resistant Fasciola hepatica

“…Lambs of adult fluke based on postmortem examinations (Rehbein and Visser 1999) or 98 per cent based on faecal egg counts (Corba and others 1996). The efficacy in the present study was lower (74 per cent).…”