No distributional association between the tick Haemaphysalis longicornis (Acari: Ixodidae) and plant surface area

The questing height of the tick Haemaphysalis longicornis Neumann was studied on the plant species Solidago altissima L., Pteridium aquilinum Kuhn, Miscanthus sinensis Anderss, and Pleioblastus chino Makino in an abandoned rice field and in an ume (Japanese Apricot) orchard in a forest. On all plant species, the vertical distribution of tick adults and nymphs was not significantly correlated with the distribution of plant surface area. This result suggests that the questing height of this tick is related to the body height of its main animal host, the sika deer.     

Identification of two forms of cyclophilin from the hard tick Haemaphysalis longicornis

We have shown here the identification and characterization of two cyclophilin, cyclophilin A (CyPA) and B (CyPB), from the ixodid tick, Haemaphysalis longicornis. Both CyPA and CyPB contain the conserved peptidyl-prolyl isomerase (PPIase) domain, with CyPA consisting of 188 amino acids and CyPB of 216 amino acids. CyPA and CyPB share 50–67% amino acid sequence identity with the cyclophilins of other organisms, and are found in multiple organs throughout the developmental stages of ixodid ticks. In addition, recombinant CyPA and CyPB exhibited PPIase activity that could be inhibited by the cyclic peptides cyclosporin A (CsA). Silencing of CyPA through RNA interference has led to a significant reduction in the body weight of engorged ticks and their failure to lay eggs, in contrast to CyPB whose silencing did not result in any detectable phenotypic changes. Our results indicate that CyPA represents the major cyclophilin protein in H. longicornis involved in blood ingestion, viability, and oocyte development. This is the first report of cyclophilin proteins from ixodid and argasid ticks.     

孤雌生殖长角血蜱的哈氏器超微结构与发育

为阐明长角血蜱Haemaphysalis longicornis孤雌生殖种群的哈氏器结构及发育特征, 用扫描电镜对其各虫期哈氏器进行了观察, 分析了血餐对哈氏器发育的影响。结果表明： 该种群幼蜱、 若蜱和成蜱哈氏器形态结构基本相同, 均由前窝和后囊构成。幼蜱前窝感毛6根, 位于同一基盘; 若蜱和成蜱哈氏器相似, 前窝感毛7根, 其中1根孔毛位于外侧基盘, 另6根感毛位于内侧基盘。各虫期饱血后哈氏器大小均比饥饿状态下显著增大（P<0.05）。幼蜱前窝与后囊面积比值与若蜱相比无显著差异（P>0.05）, 若蜱前窝与后囊面积比值与成蜱相比差异显著（P<0.05）。各虫期哈氏器均在发育, 且血餐对哈氏器发育有重要影响。幼蜱至若蜱期哈氏器前窝与后囊的发育速度相似, 若蜱至成蜱期哈氏器前窝发育快于后囊。本研究结果在一定程度上揭示了孤雌生殖长角血蜱的哈氏器发育规律。     

Tick saliva microbiomes isolated from engorged and partially fed adults of Haemaphysalis flava tick females

The tick Haemaphysalis flava is one of the most significant blood‐feeding arthropod parasites and is a vector for numerous human and animal pathogens. However, a comprehensive investigation of the microbial communities found in the saliva of this tick species is lacking. This study used 16S rRNA Illumina sequencing to characterize the compositions of microbiomes present in saliva and whole tick samples isolated from engorged and partially fed adult H. flava females. This revealed that the bacterial diversity present in tick saliva increased after a prolonged blood meal, and that the species diversity found in saliva was significantly higher than that of whole ticks. Three bacteria phyla, in particular, made up more than 80% of the microbial community across all samples—Proteobacteria, Firmicutes and Actinobacteria. Furthermore, some of the genera identified in this study had not previously been reported in ticks before, such as Facklamia, Vagococcus, Ruminococcus, Lachnospira, Bradyrhizobium, Peptostreptococcus, Jeotgalicoccus, Roseburia, Brachybacterium, Sporosarcina, u114, Megamonas and Dechloromonas. Finally, we found that many of the isolated bacteria were opportunistic pathogens, indicating a potential risk to humans and livestock exposed to H. flava. These results will contribute to fully understanding the transmission of tick‐borne pathogens.     

长角血蜱若虫发育期20——羟基蜕皮酮含量变化与表皮发生的关系

用高效液相色谱和放射免疫分析对长角血蜱Haemaphysalislongicornis若虫发育期整体蜕皮激素(20-E)含量变化进行了测定,并用扫描电镜对其表皮结构及其发生进行了观察.20-E存在于若虫整个发育期,饥饿、吸血和饱血后前4天,激素水平低(0.71～1.30ng/头);饱血后6天明显增加,此时皮层溶离开始,蜕皮间隙形成;饱血后7天继续增加;饱血后8天,20-E含量达到高峰(8.70ng/头),此时若虫开始沉积新的上表皮;高峰后,20-E含量急剧下降,直到蜕皮前保持低水平,此期内沉积新的原表皮,旧表皮被部分吸收.上述结果显示出20-E含量急剧增加及其高峰分别与启动皮层溶离和新的上表皮沉积相吻合,20-E与新的原表皮沉积无关.     

Investigations into the natural infection rate of <Emphasis Type="Italic">Haemaphysalis qinghaiensis</Emphasis> with Piroplasma using a nested PCR

Here we describe the natural infection rate in China of Haemaphysalis qinghaiensis with four Piroplasma species, namely Theileria uilenbergi, T. luwenshuni, T. sinensis and Babesia motasi. Specifically, a nested PCR was designed based on 18S ribosomal RNA genes and its specificity and sensitivity were established. The result showed that 62 flat adult field H. qinghaiensis ticks (27 females and 35 males) out of 136 (55 females and 81 males) were infected by one or more parasites. All 62 (45.6%) were infected with T. uilenbergi; nine (five males and four females; 6.6%) were infected with T. luwenshuni; two (1.5%) females were infected with T. sinensis; and one (0.7%) male was infected with B. motasi. Twelve (19.4%) were infected with more than one pathogen. There was no significant difference in infection rate between males and females. The high figure 45.6% Theileria infection rate indicates the serious prevalence of theileriosis; while the presence of T. sinensis and B. motasi implies the potential existence of the corresponding diseases in the area studied.     

长角血蜱雌蜱感染嗜菌异小杆线虫后血淋巴的变化

用嗜菌异小杆线虫Heterorhabditis bacteriophora E-6-7(Hb E-6-7)感染长角血蜱Haemaphysalis longicornis雌蜱,测定感染后雌蜱血淋巴总蛋白含量、酯酶活性及酯酶同工酶的变化,以探讨昆虫病原线虫对蜱的致病机理。结果显示,雌蜱血淋巴总蛋白含量在Hb E-6-7感染后12 h显著增加,达到最大值92.21 μg/μL;在感染后24 h明显下降（49.06 μg/μL）;至感染后48 h降至34.25 μg/μL。雌蜱血淋巴酯酶活性在线虫感染后0～12 h内无显著变化;在感染24 h后迅速增加（OD_24h=0.1840,OD_36h=0.1940,OD_48h=0.2165）,与对照组差异显著。PAGE结果表明,线虫感染后导致雌蜱血淋巴酯酶同工酶电泳图谱发生变化,主要为电泳图谱两端a带和b带的消失以及一条c带的增加。上述结果表明,长角血蜱雌蜱被Hb E-6-7感染后其血淋巴总蛋白含量和酯酶发生变化,这种变化可能与蜱的防御和对昆虫病原线虫的适应有关。     

Ixodid tick species recovered from domestic dogs in Japan

The species of ixodid ticks (Acari: Ixodidae) recovered from domestic dogs in Japan between September to November 2000 and April to June 2001 were identified. A total of 4122 ticks, including 1624 larvae, 1200 nymphs, 1016 females and 282 males were removed from 1221 dogs during these periods. Haemaphysalis longicornis (Neumann) was the most frequently found (40.3% of dogs), followed by H. flava (Neumann) (16.1% of dogs), Rhipicephalus sanguineus (Latreille) (4.8% of dogs) and Ixodes ovatus (Neumann) (4.1% of dogs). Small numbers of H. hystricis (Supino), H. campanulata (Warburton), H. japonica (Warburton), H. ias (Nakamura and Yajima), I. persulcatus (Schulze), I. nipponensis (Kitaoka and Saito) and Amblyomma testudinarium (Koch) were also recovered. In the spring sample, a total of 1408 ticks (78 larvae, 411 nymphs, 792 adult females and 127 adult males) were recovered from 570 dogs. The autumn sample included a larger proportion of larval stage and fewer adult ticks (1546 larvae, 789 nymphs, 224 adult females and 155 adult males). Haemaphysalis longicornis, H. flava and I. ovatus showed a wide geographical distribution from northern to southern Japan, whereas R. sanguineus were mainly distributed in the subtropical Okinawa prefecture with a few exceptions. Dogs in rural areas more frequently carried H. longicornis, H. flava and I. ovatus than dogs in urban or suburban areas, whereas R. sanguineus was more associated with the dogs in urban/suburban areas. Exposure to a garden was significantly associated with R. sanguineus and exposure to woodland was significantly associated with H. flava and I. ovatus. This is the first systematic survey of canine ticks in Japan.     

Haemaphysalis longicornis: molecular characterization of a homologue of the macrophage migration inhibitory factor from the partially fed ticks

The macrophage migration inhibitory factor (MIF) has been identified from some vertebrates and invertebrates. MIF is related to inflammation, tumor growth, and angiogenesis in vertebrates. Here, we report the molecular characterization of a homologue of MIF from partially fed Haemaphysalis longicornis. The sequence analysis of the H. longicornis MIF (HlMIF) indicated that its deduced amino acid sequence has an identity of 77% with the MIF of the tick Amblyomma americanum. Western blot analysis using the anti-His-HlMIF antibody showed that HlMIF was up-regulated during blood feeding. Immunohistochemistry showed that the endogenous HlMIF in partially fed ticks was localized to the midgut and epidermal cells. Moreover, the functional assay revealed that the GST-HlMIF inhibited the migration of human monocytes. In conclusion, we consider that HlMIF may facilitate blood feeding by inhibiting host macrophage migration to the feeding lesion or may participate in the proliferation and differentiation of cells in the tick body.     

Deep sequencing and phylogenetic analysis of severe fever with thrombocytopenia syndrome virus from the tick,Haemaphysalis longicornis,in Korea

The Asian longhorned tick, Haemaphysalis longicornis, is widely distributed in China, Japan, and Korea and may transmit infectious diseases. Severe fever with thrombocytopenia syndrome (SFTS) is an important tick‐borne disease caused by the SFTS virus (SFTSV). Deep sequencing to confirm the presence of SFTSV in ticks has not been reported in Korea. To detect SFTSV, RNA was extracted from tick samples and analyzed using high‐throughput deep sequencing. Based on BLASTN results, numerous SFTSV reads were identified. Moreover, a nearly complete genome of SFTSV (JNU‐1 isolate) was obtained using Sanger sequencing. The genome of the JNU‐1 isolate includes three segments of 6,286, 3,299 and 1,642 nucleotides (nt) termed large (L), medium (M), and small (S), respectively. Also, phylogenetic and recombination analyses for each segment of SFTSV were performed using the JNU‐1 isolate. The three segments of JNU‐1 isolate were closely related to the genotype B known human‐derived Korean SFTSV isolate; the JNU‐1 isolate showed no recombination sites with other isolates. This study is the first report of detection of SFTSV from ticks using deep sequencing in Korea and provides information on the genetic diversity of SFTSV in East Asia.