Species-specific amplification by PCR of ribosomal DNA from some equine strongyles

The first and second internal transcribed spacer sequences of 28 morphologi cally-defined species of horse strongyle were characterized, and specific o ligonucleotide primers were designed for some species based on the nucleoti de differences. Utilizing these primers, a PCR approach was developed for t he specific amplification of ribosomal DNA of Strongylus vulgaris, Cyathost omum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus or Cyl icostephanus goldi. The method allowed the species-specific amplification o f parasite DNA derived from faecal samples and/or copro-cultures, demonstra ting the potential of thr approach for the diagnosis of equine strongyloido sis. The establishment of this PCR assay also has implications for studying the biology and epidemiology of equine strongyles and anthelmintic resista nce using faecal egg count reduction tests.