title: Exotic Rickettsiae in Ixodes ricinus: fact or artifact?
abstract: 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.
authors.affiliation: Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Antonie van Leeuwenhoeklaan 9, P,O, Box 1, Bilthoven, the Netherlands. Hein.Sprong@rivm.nl.
authors.forename: Ellen
authors.initials: E
authors.lastname: Tijsse-Klasen
authors.forename: Manoj
authors.initials: M
authors.lastname: Fonville
authors.forename: Leo
authors.initials: L
authors.lastname: van Overbeek
authors.forename: Johan Hj
authors.initials: JH
authors.lastname: Reimerink
authors.forename: Hein
authors.initials: H
authors.lastname: Sprong