Populations of the ticks Ixodes (Pholeoixodes) hexagonus and Ixodes (Pholeoixodes) canisuga infesting suburban foxes, Vulpes vulpes

Only two species of tick (Ixodes hexagonus and Ixodes canisuga) were found to infest suburban foxes. The populations of these two ticks were examined, their distributions within the host population described, and infestation levels of I hexagonus discussed in relation to the sex, age and behaviour of the host. The most important factor regulating the level of tick infestation is probably the degree of den usage by the host. The tick infestations were found to have minimal effect on the host, and even an abnormally high level of infestation found on one fox was not considered to be lethal.     

Exoskeletal Anomalies in Ixodes pavlovskyi pavlovskyi (Parasitiformes,Ixodidae)

Entomological Review - Types of exoskeleton anomalies and frequency of their occurrence were described in 437 females and 366 males of Ixodes pavlovskyi pavlovskyi Pomerantsev 1946, collected by...     

Ixodes trianguliceps (Parasitiformes, Ixodidae) in the southern Lake Baikal area

In the southern Lake Baikal area, in the region of the Khamar-Daban ridge, which borders the banks of Lake Baikal, there was found in abundant population the tick I. trianguliceps. Data on the ecology of the tick in this particular part of its distribution area and on its ecological links revealed by factor analysis of the tick's habitat of the first and second order by means of electronic computers are given.     

Characterization of spirochetes isolated from ticks (Ixodes tanuki, Ixodes turdus, and Ixodes columnae) and comparison of the sequences with those of Borrelia burgdorferi sensu lato strains.

Ixodes persulcatus serves as a tick vector for Borrelia garinii and Borrelia afzelii in Japan; however, unidentified spirochetes have been isolated from other species of ticks. In this study, 13 isolates from ticks (6 from Ixodes tanuki, 6 from Ixodes turdus, and 1 from Ixodes columnae) and 3 isolates from voles (Clethrionomys rufocanus) were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, rRNA gene restriction fragment length polymorphism, partial sequencing of the outer surface protein C (OspC) gene, whole DNA-DNA hybridization, and 16S rRNA gene sequence comparison. All of the results revealed that these Borrelia strains clearly represent at least two new species. A third is also likely, although additional strains have to be isolated and characterized before a separate species is designated. We designated all isolates of I. tanuki and C. rufocanus as group Hk501 and all isolates of I. turdus as group Ya501. Phylogenetic analysis based on 16S rRNA gene sequences distinguished these Borrelia strains from those belonging to hitherto known Borrelia species. Furthermore, the genomic groups, each with its own tick vectors with enzootic cycles, were quite different from each other and also from those of Lyme disease Borrelia species known to occur in Japan. The results of 16S rRNA gene sequence comparison suggest that the strain Am501 from I. columnae is related to group Hk501, although its level of DNA relatedness is less than 70%.     

Description of the larva, diagnosis of the nymph and female based on scanning electron microscopy, hosts, and distribution of Ixodes (Ixodes) venezuelensis

Abstract. The larva, nymph, and female of Ixodes (Ixodes) venezuelensis are diagnosed using scanning electron microscopy, and the larva is described for the first time. This ixodid tick is recorded from the northern neotropics as a parasite of five species of didelphid marsupials and eighteen species of rodents (one sciurid, two heteromyids, eleven murids, two dasyproctids, and two echimyids). Collection records of I. venezuelensis are presented for Costa Rica, Colombia, Panama and Venezuela, with the Costa Rican records being new and extending the known range of this tick by at least 300 km. Altitudinally, I. venezuelensis has been collected between elevations of 24 and 2410 m with most collections between 100 and 800m. The possibility that I. venezuelensis may be partheno-genetic is discussed.     

Sexual transmission of Borrelia garinii by male Ixodes persulcatus ticks (Acari, Ixodidae)

We investigated the transmission of Borrelia garinii and Borrelia afzelii between male and female Ixodes persulcatus ticks. For this purpose the infection rate of partners from tick couples was determined by polymerase chain reaction and reverse line blot. In couples, where the male tick was infected with B. garinii, four out of nine female partners carried B. garinii. In eight couples, male ticks had a dual infection of B. afzelii and B. garinii and three female partners were infected by Borrelia spirochetes. Two female ticks carried B. garinii, and one female tick had a dual infection. No evidence for transmission of B. afzelii from male to female ticks was found among seven couples. In 45 couples where the female tick was infected, not one male tick carried spirochetes. The difference in the B. garinii infection rate between male and female ticks among these couples is highly significant. Our data suggest that transmission of B. garinii from male ticks to female ticks does occur. Sexual transmission of this pathogen may play an important role in the maintenance of B. garinii in I. persulcatus. © Rapid Science Ltd. 1998     

Whole-Genome Sequencing of Borrelia garinii BgVir,Isolated from Taiga Ticks (Ixodes persulcatus)

Most Lyme borreliosis cases in Russia result from Borrelia garinii NT29 group infection. Borrelias of this group circulate exclusively in Ixodes persulcatus ticks, which are seldom found beyond Russia and the far east. Here we report the whole-genome sequence of Borrelia garinii BgVir isolated from an I. persulcatus female.     

Ixodes (Pholeoixodes) hexagonus, an efficient vector of Borrelia burgdorferi in the laboratory

Borrelia burgdorferi Johnson et al. was first isolated from the midgut of Ixodes dammini Spielman et al. in the U.S.A. and from the midgut of I.ricinus (L.) in Europe. I.ricinus was considered to be the only tick vector of this borrelia, in Europe, until I.hexagonus Leach, the hedgehog tick, was found to harbour spirochaetes. This paper reports an evaluation of the vector competence of I.hexagonus for the spirochaete B.burgdorferi. Transovarial and trans-stadial survival were demonstrated and the spirochaete was transmitted to laboratory mice via the bites of trans-stadially infected I.hexagonus females.     

Phenology of the tick, Ixodes ricinus, in its southern distribution range (central Spain)

The abundance, seasonal activity patterns and development rates of the tick Ixodes ricinus (L.) (Acari: Ixodidae), as well as microclimate features of the site of study, are described for a 9-year-long study (1994-2002) in north-central Spain. According to drag captures, larvae had a unimodal activity pattern, with a maximum observed around July-August, whereas nymphs displayed a bimodal pattern (May-June and August-September) with strong dominance of spring activity. An inversion of this pattern, with larger autumn peak, was observed in years with humid summers. Adults showed a small spring peak and a large autumn one. In the later years of the study, a small increase in the adult spring peak of activity was noticed, correlated with mild winters. Over the entire period of study, a clear increase in the total tick abundance was detected. Statistically significant differences between years were observed for some climate variables (saturation deficit, winter temperatures and number of days with temperatures above 6 degrees C), but a consistent and constant pattern of change was not observed in any climate variable. Temperature requirements for developing stages showed a sharp decrease in weeks 35-51 (eggs) and 38-50 (larvae and nymphs), a feature attributed to the presence of the morphogenetic diapause, beginning around September. Development rates obtained under quasi-natural conditions were almost twice those reported for other sites, suggesting an adaptation of this local, largely isolated I. ricinus population. According to drag captures and field-obtained development rates, interchange of nymphs between the two cohorts is common in this site, and seems to be influenced by the winter temperature and the date of larval engorgement.