关键词: 犬硬蜱, 红狐, 形态学, 分子生物学, 新疆

Abstract:

Objective To identify suspected ixodid tick species from the body surface of wild red fox (Vulpes vulpes) carcasses in Xinjiang using morphological and molecular biological methods. Methods The ixodid ticks were collected from the body surface of wild red fox carcasses in Bortala Mongolian Autonomous Prefecture and Changji Hui Autonomous Prefecture of Xinjiang in 2018—2019 and observed morphologically with stereomicroscope. Five representative adult ticks (3♂, 2♀) were selected and the mitochondrial gene fragment 16S rDNA was amplified by PCR and sequenced, subsequently, sequences alignment was conducted by BLAST, and the phylogenetic tree was constructed by the maximum likelihood method and homology analysis was performed by MEGA 7.0 software. Results A total of 38 ticks were collected with 36 females and 2 males. The morphological observation and identification showed that the ticks basis capituli was obvious, oval in the pore area, palps and hypostome are long and thin, not closely arranged. The length of the hypostome was about equal to the width of the basis capituli; the peritreme was round and the center was sunken, the scutum are no festoon, no piebaldness and no markings and no eyes in the piebaldness. The foot surface was covered with brown-red enamel, which was relatively thin. The body surface is covered with hairs. The front half of the female tick scutum was covered by the shield, the genital apron is on the edge of genital aperture. The scutum of the male tick was completely covered by the shield, and the anal groove was of anterior groove type, the anal lateral plate and the anal plate were visible; which is consistent with the male I. canisuga morphological characteristics. PCR results showed that the target band of 460 bp was amplified from the DNA of all 5 ticks. Sequence analysis revealed that all the five representative ticks had the same 16S rRNA sequence. The sequence homology with I. canisuga (GenBank accession number: MG651937) from Tarim Basin, Xinjiang, China was 99.47%. The sequence homology with I. canisuga (GenBank accession number: KY962074) from the United Kingdom, France and Germany was 99.20%. Phylogenetic analysis indicated that the representative ticks were clustered to I. canisuga originated from Europe and Xinjiang Province in China, and close to I. lividus (GenBank accession number: KJ414534) and I. arboricola (GenBank accession number: KJ414461). Conclusion Using morphological and molecular biology approaches, I. canisuga was identified from the ticks found on the body surface of Xinjiang red fox, which is highly homologous with the species from Europe.

Key words: Ixodes canisuga, Red fox, Morphology, Molecular biology, Xinjiang