Anthelmintic tests, chiefly with tetrachlorethylene, for the removal of the hookworm, Gaigeria pachyscelis, from infested sheep, with observations on the effects of this drug on other parasitic nematodes

Abstract

1. Doses of 3, 4, 5, 6, 10 and 15 c.c. of pure Tetrachlorethylene per sheep are not efficient for the removal of the hookworm – G. pachyscelis. 2. Doses of 3, 4, 5 and 6 c.c. pure Carbon tetrachloride are not efficient for the removal of the hookworm – G. pachyscelis. 3. A dose of 8 c.c. of a half-and-half mixture of Tetrachlorethylene and Carbon tetrachloride is not efficient for the removal of the hookworm – G. pachyscelis. 4. Doses of 1, 3 and 5 c.c. of Stafford Allen's Extract of Pyrethrum M.225 had no effect in the removal of hookworm – G. pachyscelis. 5. When dosed into the abomasum after administering 10 c.c. of a 2 per cent. Copper sulphate solution, 5 c.c. of Tetrachlorethylene in mineral oil was ineffective whilst 10 c.c. was very effective for removal of the hookworm – G. pachyscelis. After 2.5 c.c. of 10 per cent. Copper sulphate a dose of 5 c.c. was fairly effective. 6. n-Butyl chloride in 10 c.c. doses was only partially effective for the removal of the hookworm – G. pachyscelis – when dosed after Copper sulphate solution. 7. In a flock of sheep badly infested with this hookworm and also with wireworms, trichostrongyles and nodular worms 10 c.c. pure Tetrachlorethylene in an equal volume of liquid paraffin administered three times immediately after drenching with 10 c.c. of 2 per cent. CuSO₄ solution at intervals of 10 to 14 days was very effective for the removal, directly or indirectly, of all these worms, giving a percentage cure of 97 for hookworms and 83 for all the other worms. 8. The undesirable effects of Tetrachlorethylene during administration, i.e. coughing and choking, can be overcome by using a soap emulsion of the drug. 9. Experiments carried out with a view to overcoming the rapid absorption of the drug from the alimentary tract and its sequelae, i.e. giddiness and reduced efficacy, are described.