MOLECULAR CHARACTERIZATION OF A TOXOCARA VARIANT FROM CATS IN KUALA-LUMPUR, MALAYSIA

The ascaridoid nematode of cats from Kuala Lumpur, Malaysia. previousl y identified morphologically as Toxocara canis, was characterized usin g a molecular approach. The nuclear ribosomal DNA (rDNA) region spanni ng the first internal transcribed spacer (ITS-1), the 5.8S gene and th e second internal transcribed spacer (ITS-2) was amplified and sequenc ed. The sequences for the parasite from Malaysian cats were compared w ith those for T. canis and T. cati. The sequence data showed that this taxon was genetically more similar to T. cati than to T. canis in the ITS-1, 5.8S and ITS-2. Differences in the ITS-1 and ITS-2 sequences b etween the taxa (9.4-26.1%) were markedly higher than variation betwee n samples within T. canis and T. cati (0-2.9%). The sequence data demo nstrate that the parasite from Malaysian cats is neither T. canis nor T. cati and indicate that it is a distinct species. Based on these dat a, PCR-linked restriction fragment length polymorphism (RFLP) and sing le-strand conformation polymorphism (SSCP) methods were employed for t he unequivocal differentiation of the Toxocara variant from T. canis a nd T. cati. These methods should provide valuable tools for studying t he life-cycle, transmission pattern(s) and zoonotic potential of this parasite.