Microclimate and the zoonotic cycle of tick-borne encephalitis virus in SwitzerlandArchived
The focal distribution of tick-borne encephalitis virus (TBEV; Flaviviridae, Flavivirus) appears to depend mainly on cofeeding transmission between infected Ixodes ricinus L. nymphs and uninfected larvae.
Burri C, Bastic V, Maeder G, Patalas E, Gern L.Institute of Biology, Laboratory of Eco-Epidemiology of Parasites, University of Neuchâtel, Emile-Argand 11, 2000 Neuchâtel, Switzerland.Journal of medical entomology 2011 May;48(3):615-27.
The focal distribution of tick-borne encephalitis virus (TBEV; Flaviviridae, Flavivirus) appears to depend mainly on cofeeding transmission between infected Ixodes ricinus L. nymphs and uninfected larvae. To better understand the role of cofeeding ticks in the transmission of TBEV, we investigated tick infestation of rodents and the influence of microclimate on the seasonality of questing I. ricinus ticks. A 3-yr study was carried out at four sites, including two confirmed TBEV foci. Free-living ticks and rodents were collected monthly, and microclimatic data were recorded. A decrease in questing nymph density was observed in 2007, associated with low relative humidity and high temperatures in spring. One site, Thun, did not show this decrease, probably because of microclimatic conditions in spring that favored the questing nymph population. During the same year, the proportion of rodents carrying cofeeding ticks was lower at sites where the questing nymph density decreased, although the proportion of infested hosts was similar among years. TBEV was detected in 0.1% of questing ticks, and in 8.6 and 50.0% of larval ticks feeding on two rodents. TBEV was detected at all but one site, where the proportion of hosts with cofeeding ticks was the lowest. The proportion of hosts with cofeeding ticks seemed to be one of the factors that distinguished a TBEV focus from a non-TBEV focus. The enzootic cycle of TBEV might be disrupted when dry and hot springs occur during consecutive years.
VBORNET comment: 30/9/2011: This is further field evidence of the important role of co-feeding ticks in sustaining foci of Tick-borne encephalitis virus. Such field-based studies are crucial in ensuring that risk modeling approaches are evidence based, and in ensuring that the impact of changing weather or climatic trends can be properly assessed to understand and predict the changing transmission zones for TBE in Europe.
ECDC comment: European Commission updates communicable disease surveillance list - Lyme neuroborreliosis now under EU/EEA surveillance
2 Aug 2018 - ECDC will start monitoring disease distribution in the EU and collecting EU data through the epidemiological surveillance network comprising the European Commission, ECDC and national authorities for epidemiological surveillance.
European Commission decision to add tick-borne encephalitis to the list of communicable diseases to be covered by epidemiological surveillanceArchived
18 Sep 2012 - On 5 September 2012 the European Commission decision amending Decision 2000/96/EC as regards tick-borne encephalitis was published. As a result tick-borne encephalitis is added to the list of diseases to be covered by epidemiological surveillance within the Community.
High burden of tick-borne encephalitis in Slovenia-Challenge for vaccination policyArchived
11 Nov 2011 - Slovenia is one of the countries with the highest reported incidence rates of tick-borne encephalitis (TBE). Vaccination uptake is low, estimated to be 12.4%. TBE surveillance data for the last 20 years were analysed.