Prevalence of various Borrelia burgdorferi sensu lato Borrelia burgdorferi sensu lato Borrelia burgdorferi species in Ixodes ticks in three Baltic countries

Abstract Borrelia burgdorferi sensu lato, a tick-borne spirochete, is the causative agent of Lyme disease, the most prevalent vector-borne disease in Europe and United States. However, the incidence of this disease is variable and the clinical picture depends on the pathogen species. The infectivity of Ixodes ticks with Borrelia, was 46 % and 35 % in 2000 and 2001 in Latvia, respectively, and 14 % in 2002 in Lithuania, assessed by nested polymerase chain reaction (PCR) amplifi cation of the plasmid OspA gene fragment of Borrelia. PCR-restriction fragment length polymorphism (RFLP) analysis of the 16S-23S (rrs-rrlA) rRNA intergenic spacer was used for typing of Borrelia directly in ticks. Species-specifi c primers and subsequent sequences analysis were used as another approach for Borrelia species typing. All three clinically relevant B. burgdorferi sensu lato genospecies (B. afzelii, B. garinii, B. burgdorferi sensu stricto) were detected in the ticks collected in Latvia. The same result was obtained earlier in Estonia. B. valaisiana, a possible infectious agent of Lyme borreliosis, was detected only in Latvia. Only B. afzelii and B. garinii species were detected in ticks from Lithuania. Different subspecies were also identifi ed. This study demonstrates the predominance of the genospecies B. afzelii in all three Baltic countries, and the circulation of different B. burgdorferi sensu lato subspecies in the environment. This knowledge might have a signifi cant importance for monitoring of Lyme disease in Europe

Detection and Characterization of Tick-Borne Encephalitis Virus in Baltic Countries and Eastern Poland

<div><p>Ticks were collected from the vegetation in the Baltic countries Estonia, Latvia, Lithuania and eastern Poland and analyzed for the presence of tick-borne encephalitis virus (TBEV) by amplification of the partial E and NS3 genes. In Estonia we found statistically significant differences in the TBEV prevalence between <i>I. persulcatus</i> and <i>I. ricinus</i> ticks (4.23% and 0.42%, respectively). In Latvia, the difference in TBEV prevalence between the two species was not statistically significant (1.02% for <i>I. persulcatus</i> and 1.51% for <i>I. ricinus</i>, respectively). In Lithuania and Poland TBEV was detected in 0.24% and 0.11% of <i>I. ricinus</i> ticks, respectively. Genetic characterization of the partial E and NS3 sequences demonstrated that the TBEV strains belonged to the European subtype in all countries, as well as to the Siberian subtype in Estonia. We also found that in areas where ranges of two tick species overlap, the TBEV subtypes may be detected not only in their natural vector, but also in sympatric tick species.</p></div

Sites of tick collections, a minimum infection rate (MIR) is shown in percentages.

<p>Sympatric area for <i>I. persulcatus</i> and <i>I. ricinus</i> tick species is dashed according to Karelis <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061374#pone.0061374-Karelis1" target="_blank">[15]</a> and Golovljova unpublished data.</p

Detection of TBEV in ticks in the Baltic countries.

*<p>MIR – minimum infection rate %.</p>‡<p>95% CI –95% binominal confidence interval including continuity correction by Wilson <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0061374#pone.0061374-Wilson1" target="_blank">[21]</a>.</p><p>- not detected.</p>a, b<p>Statistically significant differences (P<0.0001).</p

Primers and probe used for the detection of TBEV in Real Time PCR and nested PCR.

<p>Primers and probe used for the detection of TBEV in Real Time PCR and nested PCR.</p