PCR-BASED STUDY OF CONSERVED AND VARIABLE PNA SEQUENCES OF TRITRICHOMONAS-FETUS ISOLATES FROM SASKATCHEWAN, CANADA

The protozoan parasite Tritrichomonas foetus causes infertility and sp ontaneous abortion in cattle. In Saskatchewan, Canada, the culture pre valence of trichomonads was 65 of 1,048 (6%) among 1,048 bulls tested within a 1-year period ending in April 1994. Saskatchewan was previous ly thought to be free of the parasite. To confirm the culture results, possible T. foetus DNA presence was determined by the PCR. All of the 16 culture-positive isolates tested were PCR positive by a single-ban d test, but one PCR product was weak. DNA fingerprinting by both T17 P CR and randomly amplified polymorphic DNA PCR revealed genetic variati on or polymorphism among the T. foetus isolates. T17 PCR also revealed conserved loci that distinguished these T. foetus isolates from Trich omonas vaginalis, from a variety of other protozoa, and from prokaryot es. TCO-1 PCR, a PCR test designed to sample DNA sequences homologous to the 5' flank of a highly conserved cell division control gene, dete cted genetic polymorphic at low stringency and a conserved, single loc us at higher stringency. These findings suggested that T. foetus isola tes exhibit both conserved genetic loci and polymorphic loci detectabl e by independent PCR methods. Both conserved and polymorphic genetic l oci may prove useful for improved clinical diagnosis of T. foetus. The polymorphic loci detected by PCR suggested either a long history of i nfection or multiple lines of T. foetus infection in Saskatchewan. Pol ymorphic loci detected by PCR may provide data for epidemiologic studi es of T. foetus.