Identification of tissue-embedded ascarid larvae by ribosomal DNA sequencing.
Polymerase chain reaction (PCR) was applied to identify tissue-embedded ascarid nematode larvae. Two sequences of the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA), ITS1 and ITS2, of the ascarid parasites were amplified and compared with those of ascarid-nematodes registered in a DNA database (GenBank). The ITS sequences of the PCR products obtained from the ascarid parasite specimen in our laboratory were compatible with those of registered adult Ascaris and Toxocara parasites. PCR amplification of the ITS regions was sensitive enough to detect a single larva of Ascaris suum mixed with porcine liver tissue. Using this method, ascarid larvae embedded in the liver of a naturally infected turkey were identified as Toxocara canis. These results suggest that even a single larva embedded in tissues from patients with larva migrans could be identified by sequencing the ITS regions.
Ishiwata
Kenji
K
Department of Parasitology, Miyazaki Medical College, Kihara, Kiyotake, Miyazaki 889-1692, Japan. kishiwata@jikei.ac.jp
Shinohara
Akio
A
Yagi
Kinpei
K
Horii
Yoichiro
Y
Tsuchiya
Kimiyuki
K
Nawa
Yukifumi
Y
D000818:Animals; D017191:Ascaridida Infections / Q000469:parasitology* / Q000662:veterinary; D001199:Ascaridoidea / Q000145:classification* / Q000235:genetics / Q000254:growth & development*; D017164:Ascaris lumbricoides / Q000145:classification / Q000235:genetics; D017165:Ascaris suum / Q000145:classification / Q000235:genetics; D002371:Cat Diseases / Q000469:parasitology; D002415:Cats; D018509:DNA, Helminth / Q000032:analysis; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D004283:Dog Diseases / Q000469:parasitology; D004285:Dogs; D006801:Humans; D007814:Larva / Q000145:classification / Q000235:genetics; D008099:Liver / Q000469:parasitology*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013552:Swine; D013553:Swine Diseases / Q000469:parasitology; D014119:Toxocara / Q000145:classification / Q000235:genetics; D017166:Toxocara canis / Q000145:classification / Q000235:genetics; D014422:Turkeys / Q000469:parasitology
D018509:DNA, Helminth; D021903:DNA, Ribosomal Spacer