The studies reported here were conducted to investigate the effectiveness of
doramectin, given intramuscularly at the rate of 300 micrograms kg-1 of bodyweight, in the treatment of naturally acquired porcine nematodosis and
acariasis. Twenty pigs demonstrated to be naturally infected with pulmonary and gastrointestinal nematodes were used in one control study, and 22 pigs demonstrated to be naturally parasitized with Sarcoptes scabiei var. suis were used in a second study. In both studies, animals were evenly divided between
doramectin plus vehicle and vehicle-treated groups by restricted randomization. In the
anthelmintic study, all pigs were necropsied for parasite collection on post-treatment Days 14 and 15. The acaricidal evaluation study was 28 days in duration
after treatment, with mite population quantifications on the day of treatment and on post-treatment Days 7, 14, 21 and 28.
Doramectin proved 100% effective in the removal of Metastrongylus salmi, M. elongatus, M. pudendotectus, Strongyloides ransomi, Ascaris suum and Oesophagostomum dentatum. Levels of Hyostrongylus rubidus, Ascarops strongylina and Macracanthorhynchus hirudinaceus, as observed at necropsy in the
doramectin-treated pigs, were reduced by 99.2%, 99.5% and 62.1%, respectively, as compared with levels seen in the control pigs. In regard to Sarcoptes scabiei var. suis, no live mites were recovered from
doramectin-treated pigs during the 7-28 day post-treatment period. In conclusion,
doramectin proved highly effective in the treatment of naturally acquired porcine nematodosis and Sarcoptes scabiei var. suis infestation. In addition, all treatments were safe and well tolerated, with no adverse reactions noted in any trial animals.