SPECIES-SPECIFIC PCR FOR THE PARASITIC NEMATODES HAEMONCHUS-CONTORTUSAND TRICHOSTRONGYLUS-COLUBRIFORMIS

Reliable species determination of gastrointestinal nematode parasites from sheep is usually carried out on third-stage larvae (L3) by visual differentiation. The culturing of L3 takes about 1 week so a reliable method that could use eggs for the determination would accelerate the procedure. We developed a polymerase chain reaction (PCR), using very small amounts of parasite DNA and an oligonucleotide set according to parts of the DNA sequence of a beta-tubulin gene from Haemonchus cont ortus, that can discriminate H. contortus DNA and Trichostrongylus col ubriformis DNA from each other and from several other sheep nematode p arasites. This method can be used for every stage of the parasite, inc luding eggs. For the first time a PCR method is reported to discrimina te between sheep nematode parasites.