Vertical Distribution of the Tick Ixodes ricinus and Tick-borne Pathogens in the Northern Moravian Mountains Correlated with Climate Warming (Jeseníky Mts., Czech Republic)

Abstract

A study of the vertical distribution of the common tick Ixodes ricinus and tick-borne pathogens -tick-borne encephalitis virus (TBEV) and genospecies of Borrelia burgdorferi s.l. -was performed in the highest part of the Jeseníky mountain area (the Hrubý Jeseník Mts. with the highest summit Praděd, 1,491 m above see level). Altogether 1,253 specimens of all tick stages (607 larvae, 614 nymphs, 8 females and 24 males) were collected at the altitude 990-1,300 m above sea level on 12 collection sites by the flagging method. Altogether 1,207 ticks (8 females, 24 males, 568 nymphs and 607 larvae) were examined for the presence of tick-borne encephalitis virus and B. burgdorferi s.l. None of the samples contained TBEV, 35 samples (6% of adult ticks, 5% of nymphs, 0.7% of larvae) were positive for B. burgdorferi s.l. The most prevalent genospecies were B. afzelii (44%), B. garinii (28%), less frequent were B. burgdorferi sensu stricto (5%), B. valaisiana (3%). The rather large number of ticks (in absolute numbers as well as recounted to the index: average number of nymphs/worker/collection hour) and the presence of all developmental stages clearly demonstrate that there are viable local tick populations in all the sites, and that recorded ticks were not randomly individuals brought into higher altitudes by birds or game animals. The results are compared with the long-term (2002)(2003)(2004)(2005)(2006)(2007) monitoring of the tick altitudinal distribution in the Krkonoše Mts. and the conditions, which allow ticks to establish local populations up to the timberline in both mountain areas, are discussed. Simultaneously, changes in climatic conditions (especially the air temperature) monitored at 3 meteorological stations in the area of the Jeseníky Mts. were compared with the records from another 8 stations in other mountain areas in the Czech Republic. A very similar statistically significant trend of increasing mean air temperatures during the last three decades is found at all analyzed stations. The trend is most pronounced in the spring and summer months with the highest activity of I. ricinus ticks.

Mapping Climate Change Vulnerabilities to Infectious Diseases in Europe

“…The experts who participated in the survey stated that with climate change, Lyme borreliosis is expected to change its altitude and latitude distribution ( Figure 1A). This is in accordance with the literature regarding both observed relationships between climate variations and tick-borne disease incidence over the last four to five decades (Daniel et al 2009;Kaiser 1995;Lindgren and Gustafson 2001) and projected changes (Jaenson and Lindgren 2011), which estimate Lyme borreliosis becoming more prevalent in northern and central Europe and expanding to higher latitudes and altitudes. However, contributing factors other than climate, such as socio economic changes, may play important roles as well, particularly in central and eastern regions of Europe (Randolph 2008).…”

“…In particular, respondents from northern countries, compared with those from southern countries, considered the edge of the geographic distribution limits of vectorborne diseases, such as Lyme borreliosis and TBE, to be susceptible to the effects of climate change (Figure 1A,B). This appraisal is consistent with findings from the peer-reviewed literature; for example, the main European tick vector, Ixodes ricinus, lives for several years and has been observed to have markedly changed its latitude distribution (northern Sweden) and altitude distribution (the Czech mountains) over the last 30 years (Daniel et al 2009;Talleklint and Jaenson 1998). These distribution changes have been reported to be correlated with changes in the length of seasons (Jaenson and Lindgren 2011), climatic variations (Materna et al 2005), and the number of degree-days in different seasons with (Lindgren et al 2000).…”

Ecology ofBorrelia burgdorferi sensu latoin Europe: transmission dynamics in multi-host systems, influence of molecular processes and effects of climate change

“…Nevertheless, in some regions it has proved possible to relate disease incidence to climate, for example, a positive association with mild winters and warm, humid summers has been reported in southern Sweden (Bennet et al, 2006). in ticks can be regarded as a proxy for the presence of Lyme borreliosis in an area and Daniel et al (2009) reported that ticks that have recently colonized high-altitude habitats were infected with B. burgdorferi s.l., including the pathogenic genospecies, B. afzelii and B. garinii. Fine weather in summer is likely to result in an increase in outdoor activities generally, resulting in increased exposure to tick bites.…”

Immunogenetic Markers Definition in Latvian Patients with Lyme Borreliosis and Lyme Neuroborreliosis

“…Ixodes ricinus , which can transfer several pathogens simultaneously, is the most widespread tick in Europe [19,20,21,22,23,24]. In Poland, a neighboring country, an increased incidence of Lyme has been also observed over the last decade (Table 1) [20].…”

“…It is assumed that climate change, with milder winters and a longer growing season, has contributed to the increased incidence in endemic areas over the past three decades [21,22,23,24,25]. Ticks have a long life cycle, including three active life stages (larva, nymph, and adult).…”