Identification ofEhrlichiaspp. andBorrelia burgdorferiinIxodesTicks in the Baltic Regions of Russia

Abstract

The presence and distribution of Ehrlichia spp. and Borrelia burgdorferi sensu lato was demonstrated among ixodid ticks collected in the Baltic regions of Russia, where Lyme borreliosis is endemic. A total of 3,426 Ixodes ricinus and 1,267 Ixodes persulcatus specimens were collected, and dark-field microscopy showed that 265 (11.5%) I. ricinus and 333 (26.3%) I. persulcatus ticks were positive. From these samples, 472 dark-field-positive and 159 dark-field-negative ticks were subjected to PCR and subsequent reverse line blot hybridization. Fifty-four ticks (8.6%) carried Ehrlichia species, and 4 (0.6%) carried ehrlichiae belonging to the Ehrlichia phagocytophila complex, which includes the human granulocytic ehrlichiosis agent. The E. phagocytophila complex and an Ehrlichia-like species were detected only in I. ricinus whereas Ehrlichia muris was found exclusively in I. persulcatus, indicating a possible vector-specific infection. Borrelia garinii was found predominantly in I. persulcatus, but Borrelia afzelii was evenly distributed among the two tick species. Only two I. ricinus ticks carried B. burgdorferi sensu stricto, while Borrelia valaisiana and a newly identified B. afzelii-like species were found in 1.7 and 2.5% of all ticks, respectively. Of the dark-field-positive ticks, only 64.8% yielded a Borrelia PCR product, indicating that dark-field microscopy may detect organisms other than B. burgdorferi sensu lato. These observations show that the agent of human granulocytic ehrlichiosis may be present in ticks in the Baltic regions of Russia and that clinicians should be aware of this agent as a cause of febrile disease.

Ultrastructure and phylogenetic analysis of ‘Candidatus Neoehrlichia mikurensis' in the family Anaplasmataceae, isolated from wild rats and found in Ixodes ovatus ticks

“…The bacteria were found in R. norvegicus rats and Ixodes ovatus ticks in Japan and represent a novel genetic cluster, based on phylogenetic analysis of 16S rRNA gene sequences that included the bacteria found in R. norvegicus rats in China (Pan et al, 2003) and in Ixodes ricinus ticks in the Netherlands (Schouls et al, 1999). Of note, infection of I. ricinus ticks with similar bacteria in Baltic regions of Russia was reported by Alekseev et al (2001). A similar 16S…”

“…The bacteria were found in R. norvegicus rats and Ixodes ovatus ticks in Japan and represent a novel genetic cluster, based on phylogenetic analysis of 16S rRNA gene sequences that included the bacteria found in R. norvegicus rats in China (Pan et al, 2003) and in Ixodes ricinus ticks in the Netherlands (Schouls et al, 1999). Of note, infection of I. ricinus ticks with similar bacteria in Baltic regions of Russia was reported by Alekseev et al (2001). A similar 16S rRNA gene sequence and a gltA (621 bp) sequence of the bacterium 'Candidatus Ehrlichia walkerii' in I. ricinus ticks removed from asymptomatic humans in Italy Sanogo et al, 2003) were reported recently, although whether the humans from whom ticks were removed were infected with this agent was not mentioned.…”

“…The 16S rRNA gene sequence of the Schotti variant was detected in an I. ricinus tick in the Netherlands (Schouls et al, 1999); a similar agent was also detected by PCR and subsequent reverse line-blot hybridization (no DNA sequence is available) in I. ricinus ticks in the Baltic regions of Russia (Alekseev et al, 2001) and by PCR and sequencing in I. ricinus ticks collected from asymptomatic humans in northern Italy Sanogo et al, 2003). No mammalian host of these bacteria has been identified in Europe or Russia.…”

Molecular Identification of Ehrlichia Species and ‘Candidatus Neoehrlichia mikurensis’ from Ticks and Wild Rodents in Shizuoka and Nagano Prefectures, Japan

“…The remaining 6 sequences (Nagano21/22/28/30/32/33) were similar to that of 'Candidatus N. mikurensis' Schotti variant (similarity of 99.6%), which was identified from I. ricinus ticks in the Netherlands and Russia (1,19), and they were designated as the 'Candidatus N. mikurensis' 48 H. NAITOU ET AL Table 3. Closest relatives, sources, and locations of Ehrlichia species and 'Candidatus N. mikurensis' based on 16S rDNA sequences identified in this study Sequence ID in this study Closest relatives based on 16S rDNA Nagano21 sequence.…”

“…Only one species 'Candidatus Neoehrlichia mikurensis' belongs to this genus and it consists of three genetic variants; TK4456 R (or Rattus) from wild rats, Rattus norvegicus, in Mikura Island, Japan (or in China) (9,17); IS58 from I. ovatus ticks in Hokkaido, Japan (9); and Schotti from I. ricinus in the Netherlands and Russia (1,19).…”