see Coccidiosis: Coccidiosis of Pigs.
In pigs, GI helminths are almost always present; their main effects are loss of appetite, reduction in daily gain, poor feed utilization, and potentiation of other pathogens. Only rarely do they cause death.
Apart from good basic hygiene in pig houses, which should be emphasized, control of GI helminths is based on anthelmintic treatments and preventive measures, such as removing the pigs from contact with intermediate hosts. To reduce the risk of development of drug resistance, anthelmintic use should be preceded by helminth surveillance of a representative number of animals, and should be initiated only on demonstration of parasite eggs in the feces of the examined age groups. In-feed products include benzimidazoles, ivermectin, levamisole, and dichlorvos. A simple anthelmintic program is to treat sows and gilts ~10 days before breeding and again before farrowing, while weaners and feeders can be treated before entering clean pens, and boars at 4- to 6-mo intervals. Alternatively, an injection of ivermectin, also effective against lice and mange mites, may be given in a similar program. A different approach is to treat all adult pigs in the herd on the same day and to repeat every 3–6 mo or less, with the dosing interval being determined by fecal egg counts. In well-managed herds, it has not been possible to demonstrate a difference in these two strategies, and because the transmission to piglets within many modern farrowing units is negligible, there is no rationale for treating the sows before farrowing. Notwithstanding, a good management system incorporates practices aimed at preventing infections and does not use anthelmintic treatment as the sole method of controlling parasites.
Last full review/revision March 2012 by Allan Roepstorff, DSc, PhD, MSc