Tick-borne encephalitis (TBE) is a viral disease endemic in Eurasia. The virus is mainly transmitted to humans via ticks and occasionally via the consumption of unpasteurized milk products. The European Centre for Disease Prevention and Control reported an increase in TBE incidence over the past years in Europe as well as the emergence of the disease in new areas. To better understand this phenomenon, we investigated the drivers of TBE emergence and increase in incidence in humans through an expert knowledge elicitation. We listed 59 possible drivers grouped in eight domains and elicited forty European experts to: (i) allocate a score per driver, (ii) weight this score within each domain, and (iii) weight the different domains and attribute an uncertainty level per domain. An overall weighted score per driver was calculated, and drivers with comparable scores were grouped into three terminal nodes using a regression tree analysis. The drivers with the highest scores were: (i) changes in human behavior/activities; (ii) changes in eating habits or consumer demand; (iii) changes in the landscape; (iv) influence of humidity on the survival and transmission of the pathogen; (v) difficulty to control reservoir(s) and/or vector(s); (vi) influence of temperature on virus survival and transmission; (vii) number of wildlife compartments/groups acting as reservoirs or amplifying hosts; (viii) increase of autochthonous wild mammals; and (ix) number of tick species vectors and their distribution. Our results support researchers in prioritizing studies targeting the most relevant drivers of emergence and increasing TBE incidence.

In this paper we aim to add additional knowledge regarding the occurrence, origin and epidemiological features of the English sweating sickness. The English sweating sickness raged in five devastating epidemics with mortality rates between 30 and 50% between 1485 and 1551 throughout England, and on one occasion also affected mainland Europe, in 1529. The Picardy sweat, generally considered as the English sweating sickness’ lesser deadly successor, flared up in France in 1718 and caused 196 localized outbreaks with varying severity all over France and neighboring countries up to 1861. The English sweating sickness has been the subject of numerous attempts to define its origin, but so far all efforts have failed due to lack of material, DNA or RNA, that - using modern techniques and knowledge - could shed light on its cause. Although the time frame in which the English sweating sickness occurred and the geographical spread of the outbreaks is generally known, we will demonstrate here that there was more to it than meets the eye. We found reports of cases of sweating sickness in years before, after and between the 1485, 1508, 1517, 1529 and 1551 epidemics, as well as reports of sweating sickness in Italy and Spain. Conclusion. In spite of the fact that the English sweating sickness apparently has not caused casualties for a more than a century now, we suggest that -given the right circumstances- the possibility of re-emergence might still exist. The fact that up until today we have no indication concerning the causal pathogen of the English sweating sickness is certainly not re-assuring.