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Title: MOLECULAR DELINEATION OF CYLICOCYCLUS NASSATUS AND C.ASHWORTHI (NEMATODA; STRONGYLIDAE)

Author
item HUNG, G - UNIV MELBOURNE, AUSTRALIA
item CHILTON, N - UNIV MELBOURNE, AUSTRALIA
item BEVERIDGE, I - UNIV MELBOURNE, AUSTRALIA
item MCDONNELL, A - UNIV GLASGOW, SCOTLAND
item Lichtenfels, James
item GASSER, ROBIN - UNIV MELBOURNE, AUSTRALIA

Submitted to: International Journal for Parasitology
Publication Type: Research Notes
Publication Acceptance Date: 6/25/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Strongyloid nematodes are a major cause of morbidity and mortality in equines in the United States. Resistance to antiparasitic drugs (currently the only means of controlling the nematode disease in horses) is common and alternative control methods for these parasites are needed to protect horses in the United States. Considerable research is underway worldwide to develop improved control strategies. This research requires the identification of the more than 40 nematode species that are parasitic in the large intestine and caecum of horses. This report provides molecular characters for two of the species of the genus Cylicocyclus that some workers had considered to be synonyms. The results will be used by researchers worldwide working to control these economically important nematodes.

Technical Abstract: The nucleotide sequences of the first internal transcribed spacer (ITS-1), 5.8S and second internal transcribed spacer (ITS-2) ribosomal DNA have been determined for Cylicocylus nassatus, C. Ashworthi and C. insignis. Pairwise sequence comparisons revealed differences between taxa ranging from 3.8-6.2% for the ITS-2 and 2.2-2.7% for the ITS-1. For the ITS-1, level of the sequence difference between C. ashworthi and C. Nassatus (2.2%) was equivalent to that between C. nassatus and C. insignis (2.2%), indicating that C. ashworthi and C. nassatus represent separate species. Theoretical restriction maps were constructed from the sequence data and a polymerase chain reaction-linked restriction fragment length polymorphism (PCR-linked RLFP) technique was established to unequivocally distinguish C. ashworthi from C. nassatus.