Anthelmintic effectiveness of 2,6-diiodo-4-nitrofenol against Haemonchus contortus in sheep

Abstract

Preliminary field observations showed anthelmintic effectiveness of 2,6-diiodo-4-nitro-fenol (Disofen) when used against natural infections of Haemonchus contortus (Rudolphi,1803) in sheep during a period of approximately 60 days. No protection against Trichostrongylus sp., Ostertagia sp., Strongyloides sp., and Oesophagostomum sp., was observed. Three groups of sheep, free of Haemonchus contortus as determined by fecal examinations and maintained in worm-free quarters, were experimentally infected with 25,000 larvae of H. contortus 17, 36 and 56 days after medication with Disofen. Disofen significantly reduced the number of larvae that matured to adults, as determined by egg count, and lengthened the prepatent period in correlation with the approximation of infection to time of medication, i.e., to 64, 32 and 25 days, respectively, for the groups infected 17, 36 and 56 days after medication with Disofen.