Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 12, 1998
Publication Date: N/A
Interpretive Summary: Morphological criteria alone are not sufficient to distinguish between the 5 species and 3 other genotypes of Trichinella. Consequently, confusing nomenclature has arisen and understanding of systematics and parasite ecology has been impeded. Herein, we identified a region with the large subunit ribosomal DNA that is post-transcriptionally excised from the RNA, exhibits variability in length among the various species and can be utilized as a diagnostic character for Trichinella species in a standard PCR reaction. This work will greatly facilitate the elucidation of parasites within this genus and easily enable epidemiological studies as well as permit species diagnosis from single larvae and therefore from host biopsies.
A method was developed to identify species and genotypes within the genus Trichinella using polymerase chain reaction (PCR) and specific oligomeric primers. Enzymatic amplification of two partially conserved and repetitive genomic DNA sequences that have been shown to be variable in length within the different Trichinella genotypes form the basis of this test. Within these regions of the genome, four sets of primers were evaluated from which two were chosen for their ability to differentiate among the genotypes under stringent primer annealing conditions while maintaining high yields of amplification product. Differences in the size of PCR products from multiple isolates of each genotype indicate sufficient variation to identify seven of the eight parasite groups within this genus. Identification of Trichinella genotypes will assist in distinguishing between sylvatic and synanthropic life cycles. Such information will be critical in tracing sources of trichinellosis by easily and umambiguously identifying likely host reservoirs and will provide valuable information for instituting methods of control.