Role of sand lizards in the ecology of Lyme and other tick-borne diseases in the Netherlands

Abstract

BackgroundLizards are considered zooprophylactic for almost all Borrelia burgdorferi species, and act as dilution hosts in parts of North America. Whether European lizards significantly reduce the ability of B. burgdorferi to maintain itself in enzootic cycles, and consequently decrease the infection rate of Ixodes ricinus ticks for B. burgdorferi and other tick-borne pathogens in Western Europe is not clear.ResultsTicks were collected from sand lizards, their habitat (heath) and from the adjacent forest. DNA of tick-borne pathogens was detected by PCR followed by reverse line blotting. Tick densities were measured at all four locations by blanket dragging. Nymphs and adult ticks collected from lizards had a significantly lower (1.4%) prevalence of B. burgdorferi sensu lato, compared to questing ticks in heath (24%) or forest (19%). The prevalence of Rickettsia helvetica was significantly higher in ticks from lizards (19%) than those from woodland (10%) whereas neither was significantly different from the prevalence in ticks from heather (15%). The prevalence of Anaplasma and Ehrlichia spp in heather (12%) and forest (14%) were comparable, but significantly lower in ticks from sand lizards (5.4%). The prevalence of Babesia spp in ticks varied between 0 and 5.3%. Tick load of lizards ranged from 1 - 16. Tick densities were ~ 5-fold lower in the heather areas than in woodlands at all four sites.ConclusionsDespite their apparent low reservoir competence, the presence of sand lizards had insignificant impact on the B. burgdorferi s.l. infection rate of questing ticks. In contrast, sand lizards might act as reservoir hosts for R. helvetica. Remarkably, the public health risk from tick-borne diseases is approximately five times lower in heather than in woodland, due to the low tick densities in heather.

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.…”

“…in tissues and attached ticks was shown in several lizard species (Table 2). 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].…”

Spatiotemporal dynamics of emerging pathogens in questing Ixodes ricinus

“…All three rickettsial species have been previously found in The Netherlands (Sprong et al, 2009) with local prevalences varying from <1% ( R. conorii ) to as high as 66% ( R. helvetica ). Anaplasma phagocytophilum , the etiologic agent of human granulocytotropic anaplasmosis (Sprong et al, 2009), has been detected in Dutch ticks in several studies (Tijsse-Klasen et al, 2010, 2011b). Neoehrlichia mikurensis can be considered an emerging zoonosis, as more than eight human cases have been described in Europe since 2010, while previously it was considered non-pathogenic.…”

Occurrence of Amblyomma dissimile on wild crocodylians in southern Mexico

“…Furthermore, Álvarez del Toro (1974) suggested this case of parasitism was due to the presence of cattle in the area where the crocodile was captured. The role of crocodiles in the enzootic cycle of diseases transmitted by ticks is uncertain, but some species of lizards act as reservoir hosts of Rickettsia helvetica, a bacterium that causes fever and meningitis in humans (Fournier et al 2000, Nilsson et al 2010, Tijsse-Klasen et al 2010. Al though A. dissimile is a primary parasite of amphibians and reptiles (Burridge & Simmons 2003), it also parasitizes mammals and birds, and is known to transmit Ehrlichia ruminantium (Ricksettiales), a bacterium causing heartwater, a severe disease of cattle, goats, sheep, and other ungulates (Jongejan 1992, Guglielmone & Nava 2010, Scott & Durden 2015.…”