Distribution of Trichinella spiralis in the diaphragm of experimentally infected swine

The objectives of this study were to determine whether the distribution of Trichinella spiralis larvae within the diaphragm of infected swine was the same throughout five anatomically identifiable portions, and to assess the tenability of the Poisson model to describe the probability of detecting larvae in samples of digested tissue. To examine differences in levels of infection among the regions of the diaphragm, sixteen 2-month-old and fourteen 6-month-old swine were infected with approximately 300 T. spiralis larvae per animal. Since the infective dose was not adjusted for age (weight), higher infection rates resulted in the younger hogs. Because of this higher infection rate, the occurrence of positive samples judged to be free of larvae (false negatives), was lower for the younger hogs (0.9% vs 14.6%). Pooling over both age groups and across all five anatomical regions yielded the directional difference in false negative rates one would expect between 1 g and 5 g samples (viz., 12.3% for 1 g vs 2.6% ...