The paradox of the binomialIxodes ricinusactivity and the observed unimodal Lyme borreliosis season in Hungary

Abstract

The change of ambient temperature plays a key role in determining the run of the annual Lyme season. Our aim was to explain the apparent contradiction between the annual unimodal Lyme borreliosis incidence and the bimodal Ixodes ricinus tick activity run -both observed in Hungary -by distinguishing the temperaturedependent seasonal human and tick activity, the temperature-independent factors, and the multiplicative effect of human outdoor activity in summer holiday, using data from Hungary in the period of 1998-2012. This separation was verified by modeling the Lyme incidence based on the separated factors, and comparing the run of the observed and modeled incidence. We demonstrated the bimodality of tick season by using the originally unimodal Lyme incidence data. To model the outdoor human activity, the amount of camping guest nights was used, which showed an irregular run from mid-June to September. The human outdoor activity showed a similar exponential correlation with ambient temperature to that what the relative incidence did. It was proved that summer holiday has great influence on Lyme incidence.

Lifestyle, habitat and farmers' risk of exposure to tick bites in an endemic area of tick‐borne diseases in Hungary

“…Nevertheless, it is important to be able to provide key alerting information on the timing and location of self‐prevention to improve the effectiveness of self‐prevention for these farmers. This, in particular, requires integrated knowledge of the spatio‐temporal dynamics of questing ticks and TBD risks in local environments (Egyed et al., ; Trájer, Bede‐Fazekas, Hufnagel, Bobvos, & Páldy, ; Trájer, Bobvos, Páldy, & Krisztalovics, ). The Hobbyists who tended not to engage in agricultural or recreational outdoor activities on a regular basis were also found to be highly exposed to tick bites.…”

A framework for predicting the effects of climate change on the annual distribution of Lyme borreliosis incidences

“…For a detailed review please refer to Pfäffle et al (2013) and the studies cited within. According to our previous findings (Trájer et al 2014), human-tick interaction can be estimated by human outdoor activity patterns related to camping guest night data. Although camping data may cover a limited part of outdoor activities, it can serve as a proxy for approximation.…”

“…The daily mean temperature data of the reference period (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008) were derived from the E-OBS 7.0 database of the European Climate Assessment & Dataset (Haylock et al 2008), while data of the future prediction period (2081-2100) were derived from the MRI CGCM 2.3.2a model driven by the SRES A1B emission scenario (Yukimoto et al 2006). Since the climatic and the geographical conditions are relatively homogenous in Hungary (Trájer et al 2013b, Trájer et al 2014 we could handle the country as a single unit in climatic terms. Pertinence of this simplification is proven by our previous findings on the homogeneity of LB seasonality within Hungary (Trájer et al 2013a).…”

“…In Hungary, the questing activity of I. ricinus nymphs and adults starts in March, reaches its maximum in April, shows its summer minimum in August and its second, less expressed peak in October (Széll et al 2006;Egyed et al 2012;Trájer and Földvári unpublished data). Despite of the bimodal distribution of tick activity and tick-borne encephalitis the distribution of Lyme borreliosis is unimodal (Zöldi et al 2013;Trájer et al 2014). Gray (2008) forewarns that the annual distribution of both I. ricinus activity and Lyme borreliosis may change significantly in the future due to climate change.…”

“…humidity and photoperiodicity) that are hard to access or incorporate in a model (Randolph 2009;Jore et al 2014;Cat et al 2017). The relationship between temperature and both the interstadial development rates and the daily questing rate is non-linear (Randolph 2004;Trájer et al 2014).…”