Molecular characterization of the first internal transcribed spacer of ribosomal DNA of the most common species of eyeworms (Thelazioidea: Thelazia).
Spirurid nematodes of the genus Thelazia cause ocular infection in several mammals and are transmitted by dipteran flies. Of the 10 described species, T. gulosa, T. rhodesi, T. skrjabini (affecting cattle), T. lacrymalis (affecting horses), and T. callipaeda (affecting carnivores and humans) are the most common. The aim of this study was to characterize the first internal transcribed spacer (ITS1) ribosomal DNA sequences of these 5 species. The length of the ITS1 sequences ranged from 357 bp (T. lacrymalis) to 905 bp (T. callipaeda). Interspecific differences ranged from 35 to 77%. Polymorphic sites were detected in each species. Intraspecific variation varied from 0.3 to 2.5%. The characteristics of the ITS1 of Thelazia spp. show similarities to those of other Spirurida. The findings of this present study show that the ITS1 represent a powerful genetic marker for the molecular identification of eyeworms and a useful tool for developing molecular epidemiological techniques to study Thelazia spp. transmission patterns and prevalence in definitive and intermediate hosts.
Otranto
Domenico
D
Department of Animal Health and Welfare, Faculty of Veterinary Medicine, University of Bari, P.O. Box 7, 70010 Valenzano, Bari, Italy. d.otranto@veterinaria.uniba.it
Traversa
Donato
D
D000818:Animals; D001483:Base Sequence; D002417:Cattle; D004275:DNA, Ribosomal / Q000737:chemistry*; D004285:Dogs; D005819:Genetic Markers; D014644:Genetic Variation; D006736:Horses; D008969:Molecular Sequence Data; D016415:Sequence Alignment / Q000662:veterinary; D013045:Species Specificity; D017205:Spirurida Infections / Q000469:parasitology / Q000662:veterinary*; D013802:Thelazioidea / Q000145:classification / Q000235:genetics*
D004275:DNA, Ribosomal; D005819:Genetic Markers