Parasite transmission in confined hogs

Abstract

Examinations of fecal specimens from swine of all ages maintained in a totally enclosed confinement facility in south Georgia were conducted in a 5-year survey (1977–1981) to determine the prevalence, intensity, and transmission patterns of intestinal nematode and protozoan parasites. Weaned pigs in the nursery had no detectable parasitic infections except sporadic Isospora suis in newly weaned pigs. Growing-finishing hogs had a low prevalence of Ascaris suum, Oesophagostomum spp. and Balantidium suis. Mean A. suum prevalence and mean eggs per gram feces (EPG) increased until about 200 days of age and then declined. Oesophagostomum spp. and B. suis prevalence and intensity tended to increase throughout life. Gilts (mean age 273 days) in the gestation unit had a higher ( P < 0.01) prevalance of A. suum and lower ( P < 0.01) prevalences of Oesophagostomum spp. and B. suis than sows (mean age 706 days). Similarly, A. suum EPG was higher ( P < 0.01) and Oesophagostomum spp. EPG and B. suis cysts per gram feces (CPG) were lower ( P < 0.01) in gilts than in sows. No evidence for a peri-parturient increase in parasite eggs or cysts was found. Instead, there was a higher prevalence of B. suis ( P < 0.01) in gestating than in lactating animals and more lactating sows than gestating sows were negative for parasites ( P < 0.01). Apparent differences due to location (gestation unit or farrowing unit) were largely attributable to age differences. Trichuris suis infections were rare and not shown to be established in the herd. Strongyloides ransomi in suckling piglets was controlled by anthelmintic therapy. I. suis occurred in piglets throughout the study but was never found in sows in the farrowing unit, either before or after birth of a subsequently infected litter of piglets. No parasites requiring intermediate hosts occurred.