Associations Between Coinfection Prevalence of Borrelia lusitaniae, Anaplasma sp., and Rickettsia sp. in Hard Ticks Feeding on Reptile Hosts

Abstract

An increasing number of studies reveal that ticks and their hosts are infected with multiple pathogens, suggesting that coinfection might be frequent for both vectors and wild reservoir hosts. Whereas the examination of associations between coinfecting pathogen agents in natural host-vector-pathogen systems is a prerequisite for a better understanding of disease maintenance and transmission, the associations between pathogens within vectors or hosts are seldom explicitly examined. We examined the prevalence of pathogen agents and the patterns of associations between them under natural conditions, using a previously unexamined host-vector-pathogen system--green lizards Lacerta viridis, hard ticks Ixodes ricinus, and Borrelia, Anaplasma, and Rickettsia pathogens. We found that immature ticks infesting a temperate lizard species in Central Europe were infected with multiple pathogens. Considering I. ricinus nymphs and larvae, the prevalence of Anaplasma, Borrelia, and Rickettsia was 13.1% and 8.7%, 12.8% and 1.3%, and 4.5% and 2.7%, respectively. The patterns of pathogen prevalence and observed coinfection rates suggest that the risk of tick infection with one pathogen is not independent of other pathogens. Our results indicate that Anaplasma can play a role in suppressing the transmission of Borrelia to tick vectors. Overall, however, positive effects of Borrelia on Anaplasma seem to prevail as judged by higher-than-expected Borrelia-Anaplasma coinfection rates.

Importance of Common Wall Lizards in the Transmission Dynamics of Tick-Borne Pathogens in the Northern Apennine Mountains, Italy

“…We identified R. helvetica, R. monacensis and R. hoogstraalii, which are added to R. slovaca and R. raoultii, the two other species that have a natural focus of transmission in our study area, associated to D. marginatus [30]. We detected R. helvetica in few attached I. ricinus larvae, as previously reported in studies on lizards in mountain areas of the Iberian Peninsula [21] and Slovakia [56], Madeira island [7] and the Netherlands [55]. The fact that R. helvetica was also identified in a tail tissue and that we observed ticks exclusively feeding in the axillary region indicates a disseminated infection.…”

“…Likewise, lizards on do not appear to be attractive hosts for D. marginatus immatures, although we abundantly collected this tick species by dragging and on small rodents [30,31,40]. This may be due to its nidicolous habits, that make immatures preferentially live in small rodents nests; nevertheless, D. marginatus was reported to infest lizards by other authors [56]. 95%CI for I. ricinus larvae were calculated using GEE with repeated measures; exact binomial 95%CI are given for I. ricinus and H. sulcata nymphs B. burgdorferi infection prevalence in attached nymphs, and the heterogeneity of genospecies, mirrors previous findings in questing ticks in the area [40].…”

“…Vaclav et al [56] studied the coinfection by Anaplasma spp., Rickettsia spp. and B. lusitaniae in I. ricinus attached on green lizards in Central Europe and concluded that the risk of tick infection with one pathogen may be dependent of the other pathogens.…”

“…Lizards are considered reservoir of Borrelia lusitaniae [42], and some authors also suggest that they may be reservoir of Spotted Fever Group (SFG) rickettsiae, R. helvetica and R. monacensis in particular [7,21,55]. Interestingly, multiple pathogens (B. burgdorferi s.l., SFG rickettsiae, Anaplasma phagocytophilum) have been shown to co-infect immature I. ricinus ticks feeding on lizards [14,56].…”

Update on Rickettsioses in Slovakia

“…In Slovakia, R. helvetica was identified by molecular biology in I. ricinus ticks [adults captured from vegetation , collected from free-living green lizards (Vaclav et al, 2011), or nymphs picked from P. modularis birds (Spitalska et al, 2011)], and in roe deer . Human cases were confirmed (Sekeyova et al, 2012c), and the first isolation of R. helvetica yield from ticks collected in Slovakia has recently been provided (Sekeyova et al, 2012b).…”