Excerpt:

Several pathogenic Rickettsia species can be transmitted via Ixodes ricinus ticks to humans and animals. Surveys of I. ricinus for the presence of Rickettsiae using part of its 16S rRNA gene yield a plethora of new and different Rickettsia sequences. Interpreting these data is sometimes difficult and presenting these findings as new or potentially pathogenic Rickettsiae should be done with caution: a recent report suggested presence of a known human pathogen, R. australis, in questing I. ricinus ticks in Europe. A refined analysis of these results revealed that R. helvetica was most likely to be misinterpreted as R. australis. Evidence in the literature is accumulating that rickettsial DNA sequences found in tick lysates can also be derived from other sources than viable, pathogenic Rickettsiae. For example, from endosymbionts, environmental contamination or even horizontal gene transfer.

The occurrence of Toxoplasma gondii and Borrelia burgdorferi sensu lato in
Ixodes ricinus ticks from east Poland with the use of pcr.

Sroka J, Szymanska J, Wojcik-Fatla A.

Department of Occupational Biohazards, Institute of Agricultural Medicine,
Jaczewskiego 2, 20-090 Lublin, Poland. jack@galen.imw.lublin.pl

715 Ixodes ricinus ticks from 4 regions of Lublin macroregion (Piotrowice,
Polesie National Park, Dabrowa and Leczynsko-Wlodawskie Lakeland) were examined
for the presence of Borrelia burgdorferi sensu lato and Toxoplasma gondi, using
polymerase chain reaction (PCR) and nested-PCR methods. The clonal type of
samples tested positive for T. gondii was identified by amplification and
fragmenting with restrictions enzymes (RFLP-restriction fragment length
polymorphism). Positive results were confirmed by sequencing.

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PMID: 20047269