Borrelia miyamotoi and Borrelia burgdorferi (sensu lato) identification and survey of tick-borne encephalitis virus in ticks from north-eastern Germany

Abstract

Background: Ixodes ricinus is the most common tick species in Europe and the main vector for Borrelia burgdorferi (sensu lato) and tick-borne encephalitis virus (TBEV). It is involved also in the transmission of Borrelia miyamotoi, a relapsing fever spirochete that causes health disorders in humans. Little is known regarding the circulation of Borrelia species and the natural foci of TBEV in northeastern Germany. The goal of this study was to investigate the infection rates of Borrelia spp. and of TBEV in I. ricinus ticks from northeastern Germany. Methods: Ticks were collected by flagging from 14 forest sites in Mecklenburg-Western Pomerania between April and October 2018. RNA and DNA extraction was performed from individual adult ticks and from pools of 2-10 nymphs. Real time reverse transcription PCR (RT-qPCR) targeted the 3′ non-coding region of TBEV, while DNA of Borrelia spp. was tested by nested PCR for the amplification of 16S-23S intergenic spacer. Multilocus sequence typing (MLST) was performed on B. miyamotoi isolates. Results: In total, 2407 ticks were collected (239 females, 232 males and 1936 nymphs). Female and male I. ricinus ticks had identical infection rates (both 12.1%) for Borrelia spp., while nymphal pools showed a minimum infection rate (MIR) of 3.3%. Sequencing revealed four Borrelia species: B. afzelii, B. garinii, B. valaisiana and B. miyamotoi. Borrelia afzelii had the highest prevalence in adult ticks (5.5%) and nymphs (MIR of 1.8%). Borrelia miyamotoi was identified in 3.0% of adults and registered the MIR of 0.8% in nymphs. Borrelia valaisiana was confirmed in 2.5% adult ticks and nymphs had the MIR of 0.7%, while B. garinii was present in 1.1% of adults and showed a MIR of 0.1% in nymphs. The MLST of B. miyamotoi isolates showed that they belong to sequence type 635. No tick sample was positive after RT-qPCR for TBEV RNA. Conclusions: The prevalence of B. miyamotoi in I. ricinus ticks registered similar levels to other reports from Europe suggesting that this agent might be well established in the local tick population. The detection of B. burgdorferi (s.l.) indicates a constant circulation in tick populations from this region.

Long-Term Study of Borrelia and Babesia Species Distribution in Ixodes Ricinus and Dermacentor Recticulatus Ticks Removed From Humans in Poland, 2016-2019

“…in ticks show signi cant temporal and spatial variations. Surprisingly, in our study, the annual prevalence of B. miyamotoi was relatively high (up to 15.8% in 2016) compared to other European studies in questing as well as feeding ticks where the prevalence usually did not exceeded 5% [19,22,23,35,[61][62][63][64][65]. In contrast, Springer et al [37] have con rmed B. miyamotoi infection in 7.4% of I.ricinus ticks removed from humans.…”

Distribution of Borrelia burgdorferi s.l. and Borrelia miyamotoi in Ixodes tick populations in Northern Germany, co‐infections with Rickettsiales and assessment of potential influencing factors

“…The average prevalence of Borrelia in I. ricinus is estimated at 12.3% in Europe (Strnad et al ., 2017). Regarding Germany, Borrelia prevalences in questing ticks between 7.2 and 34.1% have been determined in northern parts of the country (May et al ., 2015; Blazejak et al ., 2018; Raileanu et al ., 2020) and between 12.7 and 27.0% in the southern half (Hildebrandt et al ., 2010; Zubrikova et al ., 2020). Thus, despite differences in examination methods between the studies, regional differences in Borrelia prevalence in Germany are discernible.…”

Occurrence of tick-borne pathogens in questing Ixodes ricinus ticks from Wester Ross, Northwest Scotland

“…microti in questing nymphs from Wester Ross, this cannot necessarily be interpreted as a complete absence of enzootic circulation of these pathogens, because the prevalence of some of these pathogens can be low, for example, 0.1% for N. mikurensis in regions of Denmark [ 87 ], 0.6% for Ba. microti in Poland [ 88 ] and 1.5% in the UK (ticks pulled from dogs) [ 89 ], and 0.8% for B. miyamotoi in regions of Germany [ 90 ] and 0.5% in England (Table 1 ). In our sample of 2828 ticks, a prevalence of 0.1% would mean that there would be an expectation of around three ticks that test positive in our sample size.…”