The Identification of Ticks in Taiwan and Kinmen Island

• Main Authors: Yi-Lun Tsai, 蔡宜倫
• Other Authors: James A. Lin
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/99947846375695876065

碩士 === 國立中興大學 === 獸醫學系 === 90 === Ticks are important vectors of human and animal diseases. Among the best-known human diseases transmitted by ticks are tick-borne relapsing fever, Rocky Mountain spotted fever, Q fever and Lyme disease. The aim of this study was to establish morphological and molecular identification methods for ticks from Taiwan and Kinmen island. After morphological identification, single strand conformation polymorphism (SSCP) was used to screen the samples for genetic variation within segments of the 12S rDNA, 16S rDNA, and cytochrome oxidase subunit I (COI) mitochondrial genes. Sequencing of individual polymerase chain reaction (PCR) product was completed to verify SSCP designations and phylogenetically classify tick species. By the results of morphological examination, ten species of tick were identified from Taiwan and Kinmen island including Rhipicephalus sanguineus Latreille, 1806, Rhipicephalus pumilio Schulze, 1935, Rhipicephalus haemaphysaloides Supino, 1897, Boophilus microplus Canestrini, 1887, Ixodes granulatus Supino, 1897, Amblyomma geoemydae Cantor, 1847, Haemaphysalis warburtoni Nuttall, 1912, Ixodes acutitarsus Karsch, 1899, Haemaphysalis phasiana Saito, Hoogstraal & Wassef, 1974 and Haemaphysalis campanulata Wargurton, 1908. SSCP failed to differentiate sequence variants (haplotypes) within single taxa. Additionally, SSCP failed to clearly differentiate R. sanguineus and R. pumilio for both the 16S and 12S rDNA fragments examined. SSCP of the 12S fragment could also not clearly differentiate R. sanguineus and R. haemaphysaloides. According to the sequence similarity and dendrogram constructed by 16S rDNA segments of 43 ticks, there are 95.1%~97.3% similarity between 17 ticks (including 8 R. sanguineus and 9 R. pumilio) and R. sanguineus reference strand (in Genbank of National Center for Biotechnology Information (NCBI)), 91.6%~93.8% similarity between 12 ticks (including 2 R. sanguineus and 10 R. haemaphysaloides) and R. sanguineus reference strand, 95.2%~100% similarity between 11 B. microplus and B. microplus reference strand, and 97.6%~98.3% similarity between 3 I. granulatus and I. granulatus reference strand. For the 12S rDNA analysis of 18 ticks, the similarity of 3 R. haemaphysaloides was 98.8%, the similarity of 8 ticks (including 3 R. sanguineus and 5 R. pumilio) was 98.7%, the similarity of 4 B. microplus was 95%, and the similarity of 3 I. granulatus was 99.1% In this study, the ticks of R. sanguineus from Taiwan and Kinmen island represent significantly different sequence. Although R. sanguineus and R. pumilio could be identified by morphology, they could not be completely differentiated by SSCP of the 16S rDNA, 12S rDNA and COI genes. After sequencing, the fragments on 16S and 12S rDNA amplified from R. sanguineus and R. pumilio were very similar and in some cases identical. Future work is required to identify reliable molecular markers to differentiate between these two species.