Two mice models for transferability of zoonotic bacteria via tick vector.

Spotted fever and typhus-related diseases caused by rickettsiae, Lyme borreliosis induced by spirochetes from Borrelia burgdorferii sensu lato complex, and Q fever evoked by Coxiella burnetii, are important zoonoses occurring worldwide. In order to study the pathogenesis of these infections, the efficacy of vaccines from the perspective of protection against the pathogens, pathogen - pathogen interactions during co-infections or pathogen-vector-host interrelationship, a suitable animal model should be established. In this study, we evaluated two mouse models - the C3H/N and Balb/c strains for susceptibility to infection and ability to transmit the pathogens via tick vector and to reveal the potential interactions between various bacterial tick-borne agents. Our results indicated that the C3H/N and Balb/c mice are well-accepted models of B. afzelii infection. However, they are not suitable for interaction studies with R. helvetica since the animals did not acquire rickettsiemia and do not transmit Rickettsia sp. to feeding ticks.

A novel duplex real-time PCR permits simultaneous detection and differentiation of Borrelia miyamotoi and Borrelia burgdorferi sensu lato.

PURPOSE: For simultaneous detection of Borrelia miyamotoi (relapsing fever spirochete) and Borrelia burgdorferi sensu lato, we have developed a duplex real-time PCR targeting the flagellin gene (flaB; p41), a locus frequently used in routine diagnostic PCR for B. burgdorferi s.l. detection. METHODS: Primers and probes were designed using multiple alignments of flaB sequences of B. miyamotoi and B. burgdorferi s.l. species. The sensitivity and specificity of primers and probes were determined using serial dilutions (ranging from 10(4) to 10(-1)) of B. miyamotoi and B. burgdorferi s.l. DNA and of several species of relapsing fever spirochetes. Conventional PCR on recG and glpQ and sequencing of p41 PCR products were used to confirm the species assignment. RESULTS: The detection limit of both singleplex and duplex PCR was 10 genome equivalents except for B. spielmanii and two B. garinii genotypes which showed a detection limit of 10(2) genome equivalents. There was no cross reactivity of the B. miyamotoi primers/probes with B. burgdorferi s.l. DNA, while the B. burgdorferi s.l. primer/probe generated a signal with B. hermsii DNA. Out of 2341 Ixodes ricinus ticks from Germany and Slovakia that were screened simultaneously for the presence of B. miyamotoi and B. burgdorferi s.l., 52 were positive for B. miyamotoi and 276 for B. burgdorferi s.l., denoting an average prevalence of 2.2% for B. miyamotoi and 11.8% for B. burgdorferi s.l., and B. miyamotoi DNA was also detectable by PCR using artificial clinical samples. CONCLUSION: The duplex real-time PCR developed here represents a method that permits simultaneous detection and differentiation of B. burgdorferi s.l. and B. miyamotoi in environmental and potentially clinical samples.