Ixodes ricinusDensity, and Distribution and Prevalence ofBorrelia burgdorferiSensu Lato Infection Along an Altitudinal Gradient

Abstract

In this study, we measured the phenology of Ixodes ricinus ticks and their infection with Borrelia burgdorferi sensu lato (sl) simultaneously along an altitudinal gradient to assess the impact of climate on the phenology of ticks and on their infection with B. burgdorferi sl. From 1999 to 2001, free-living I. ricinus ticks were collected monthly by flagging vegetation at three different altitudes (620, 740, and 900 m above sea level) on the slope of a mountain in Chaumont (Neuchâtel, Switzerland). I. ricinus ticks were examined for the presence of B. burgdorferi sl by using direct fluorescent antibody assay and isolation of spirochetes. Borrelia species were characterized by polymerase chain reaction followed by restriction fragment-length polymorphism. Tick density and tick phenology varied with altitude. Although the peak tick density decreased and the onset of ticks was delayed with altitude, the phenology was much more stable among years at the highest altitudes than at the lowest. The prevalence of B. burgdorferi infection in nymphs and adults decreased with altitude. The prevalence of infection differed significantly among years, and it was significantly higher in adults (30%) than in nymphs (21%). B. burgdorferi infection in adults was positively related with adult density, but this was not observed for nymphs. Five B. burgdorferi sl genospecies were successfully isolated: B. garinii, B. burgdorferi sensu stricto, B. afzelii, B. valaisiana, and B. lusitaniae. Mixed infections were obtained from five of 140 infected ticks. The greatest diversity in Borrelia species was observed at the lowest altitude where all five Borrelia species were present, whereas at the two highest altitudes, B. lusitaniae was not observed.

Survival of Ixodes ricinus (Acari: Ixodidae) Under Challenging Conditions of Temperature and Humidity Is Influenced by Borrelia burgdorferi sensu lato Infection

“…Overall prevalence of infection by Borrelia (34.8%) was similar to that of another study conducted in the same area (32.7%) (Casati et al 2004). Infection prevalence in adults was higher (39.6%) than in nymphs (25.5%), as often described in Europe (Rauter and Hartung 2005) and Switzerland (Casati et al 2004, Jouda et al 2004. Similarly, adult infections consisted more frequently of Ͼ160,000 spirochetes than those of nymphs.…”

“…Genospecies prevalence was in line with what had been observed in the same area: B. afzelii (33.8%), B. burgdorferi s.s. (10.3%), B. garinii (32.1%), B. myamotoi (3.1%), and B. valaisiana (20.2%) (Casati et al 2004, Jouda et al 2004, Morán Cadenas et al 2007b, Gern et al 2010. The Borrelia genospecies were similarly distributed among males and females.…”

Spatial Dynamics of Lyme Disease: A Review

“…Specifically, in the Czech Republic during the early 1980s, I. ricinus was not found at elevations >700 m asl, while more recent surveys have found population at elevations up to 1100 m asl (Daniel et al, 2003). Similarly, in Switzerland, tick densities were found to decrease with elevation, suggesting an altitudinal limit to tick survival corresponding with decreasing temperatures (Jouda et al, 2004). Similarly, in Sweden, the distribution of ticks has moved northward (Lindgren et al, 2000).…”

Do the level of energy reserves, hydration status andBorreliainfection influence walking byIxodes ricinus(Acari: Ixodidae) ticks?

“…3. The percentage of high-fat fully hydrated (H&F), low-fat fully hydrated (L&F), and low-fat moderately hydrated (L&M) Ixodes ricinus ticks that walked towards the wet (light grey bars) or the dry end (white bars) of the arena after 2 h. common one (Casati et al 2004;Jouda et al 2004;Morán Cadenas et al 2007;Gern et al 2010;Herrmann and Gern, 2010). B. bavariensis (6·8%), formerly B. garinii OspA serotype 4, a newly described genospecies (Margos et al 2009), is reported for the first time in the area, although it was already described in Switzerland (Staatswald) (Hu et al 2001;Huegli et al 2002;Pérez et al manuscript submitted ).…”