Trichinella spiralis (T1) and Trichinella T5: a comparison using animal infectivity and molecular biology techniques.

We compared Trichinella T5 of bobcat (Lynx rufus) origin with Trichinella spiralis (T1) by using animal infectivity and molecular biology techniques. Swine, SD rats, and CF1 mice were highly resistant to infection with Trichinella T5 but sensitive to T. spiralis, whereas deer mice (peromyscus maniculatus) had similar sensitivity to both parasites. The fecundity of Trichinella T5 in deer mice was 10-35-fold higher in comparison to the fecundity in laboratory rodents (SD rats and CF1 mice). Fecundity of T. spiralis was approximately the same in both groups. A western blot, using excretory-secretory proteins (ESP) from first-stage larvae of T. spiralis as antigen, showed similar banding patterns in the pigs infected with either T. spiralis or Trichinella T5, however, the homologous reaction was stronger than the heterologous reaction. Antibodies were detectable in swine sera commencing 3 or 5 wk postinfection with T. spiralis or Trichinella T5, respectively. Complementary DNAs encoding the 46-, 49/43-, or 53-kDa ESP showed 3.54, 1.94, and 5.91% differences, respectively, between the 2 parasites. Deduced amino acid sequences of the 3 cDNAs were different at 7.20, 5.08, and 8.55%, respectively. All recombinant proteins of the 3 cDNAs from both parasites could detect antibodies in positive sera. The sequences of cDNAs encoding the 46-, 49/43-, or 53-kDa ESP from T. spiralis are also compared to the previously reported sequences, and the differences are discussed.