The TickIxodes pavlovskyias a Host of Spirochetes Pathogenic for Humans and Its Possible Role in the Epizootiology and Epidemiology of Borrelioses

Abstract

The tick Ixodes pavlovskyi is taxonomically, morphologically, and ecologically close to the taiga tick Ixodes persulcatus, a major host and vector of Borrelia spirochetes. The recent range of I. pavlovskyi is disjoined into the Western Siberian and Far Eastern parts, with this tick being almost always sympatric with I. persulcatus. A total of 56 unfed adult I. pavlovskyi ticks from the biotope where this species was absolutely dominant (within the city limits of Tomsk, Western Siberia) and 50 I. persulcatus ticks from the vicinity of this city, where I. pavlovskyi was almost absent, were collected by flagging in May-June 2006, at the seasonal peak of their abundance. The guts and internal organs of individual ticks were inoculated into the Barbour-Stoenner-Kelly (BSK) medium. Thus, 35 Borrelia isolates were obtained and identified by means of polymerase chain reaction-restriction fragment length polymorphism analysis and sequencing of the rrfA-rrlB spacer and, selectively, an rrs gene fragment. The Borrelia infection rate in I. pavlovskyi (35.7 +/- 12.8%) was almost the same as in I. persulcatus (30.0 +/- 13.0%). Such a high infection rate in I. pavlovskyi shows that this vector can itself maintain natural foci of borreliosis, regardless of very low abundance or even absence of I. persulcatus. In both foci compared, Borrelia garinii prevailed in ixodid ticks (31 isolates). Three B. afzelii VS461 isolates were obtained from I. pavlovskyi. Therefore, independently of whether I. pavlovskyi or I. persulcatus is the main vector, B. garinii of two genomic groups, 20047 and NT29, can circulate in a natural focus, but B. garinii NT29 is more closely associated with I. persulcatus. Moreover, two isolates (one from I. pavlovskyi and one from I. persulcatus) proved to be completely identical to B. garinii ChY13p from I. persulcatus collected in China. The hypothesis is that these and other similar isolates described previously comprise an individual genomic group of B. garinii.

Multilocus Sequence Typing Implicates Rodents as the Main Reservoir Host of Human-Pathogenic Borrelia garinii in Japan

“…The reason remains unclear, but the inhabitant species of ticks may be associated with this geographical difference. Furthermore, Korenberg et al recently found that I. pavlovskyi and I. persulcatus ticks differ in their abilities to transmit borrelia (12). This finding may support the notion that the resident tick species contributes to the determination of the endemic species B. garinii.…”

Detection and genetic characterization of a wide range of infectious agents in Ixodes pavlovskyi ticks in Western Siberia, Russia

“…Indeed, several human pathogens have been detected in this tick species [36, 48, 51, 66, 67]; however, thorough investigations of the ability of I. pavlovskyi ticks to transmit a wide range of pathogens have not been conducted. In this study, the prevalence and genetic diversity of TBEV, KEMV, B. burgdorferi ( s.l .…”

“…The cause of the recent expansion of I. pavlovskyi ticks is unknown. Limited data have been reported on the detection of tick-borne pathogens in these ticks, including TBEV, KEMV, B. afzelii , B. garinii and B. miyamotoi [36, 43, 48, 51, 66, 67]. In addition, DNA of A. phagocytophilum and “ Ca.…”

Tick Surveillance for Relapsing Fever Spirochete Borrelia miyamotoi in Hokkaido, Japan

“…Moreover, I. pavlovsky i can serve as an additional vector for B. miyamotoi . I. persulcatus and I. pavlovskyi are closely related morphologically, ecologically and phylogenetically [17], [28]. The larvae and nymphs of both tick species have a wide range of feeding hosts, such as small mammals and birds.…”