Prevalence of antibodies to Toxoplasma gondii and Trichinella spiralis in 509 pigs from 31 farms in Oahu, Hawaii.

Serum samples from 509 pigs from 31 farms in Oahu, Hawaii were examined for antibodies to Toxoplasma gondii using the agglutination test in dilutions of 1:25, 1:50, and 1:500 and for Trichinella spiralis using the enzyme-linked immunosorbent assay. Toxoplasma gondii antibodies were found in 48.5% of pigs. Antibody titers were: 5.1% positive at 1:25 dilution, 28.6% positive at 1:50 dilution and 14.7% positive at 1:500 dilution. The prevalence of Toxoplasma gondii antibodies in garbage-fed pigs (67.3% of 199 pigs) was higher than in grain-fed pigs (33.8% of 180 pigs). Antibodies to Trichinella spiralis were found on seven of 31 farms. On five of these farms only a single serum was positive for Trichinella spiralis antibodies. The two remaining farms each had three positive sera (three of ten and three of 25 pigs tested); both of these farms fed garbage to pigs.