Sciensano collects information on the number of people diagnosed with tick-borne encephalitis in Belgium and on the place of infection (country where the person traveled). We also collect information on the circulation of the virus in animals and on areas at risk of tick bites in the country.
Surveillance of the disease in humans
Sciensano’s Epidemiology of infectious diseases division describes the epidemiology of vector-borne diseases in Belgium, monitors the epidemiology of the disease in Europe and assesses the risk that this disease could pose for Belgium. To this end, it works in collaboration with the National Reference Center which is in charge of the diagnosis (serology and seroneutralization) of the disease in humans (Institute of Tropical Medicine) and with the Viral diseases laboratory run by Sciensano, whose researchers are responsible for studying the presence of the virus in the animal world. The division also works hand in hand with the European Centre for Disease Prevention and Control (ECDC), which is responsible for surveillance in Europe and compiles data from Member States.
Surveillance de la circulation du virus TBE chez les animaux
Entre 2010 et 2016, le laboratoire « Maladies Virales » de Sciensano a réalisé plusieurs études de prévalence (tests sensibles de détection du virus) et de séroprévalence (tests spécifiques de séroneutralisation du virus) de l’infection par le virus de l’encéphalite virale à tique (TBEV) chez des animaux sentinels et dans la population animale réservoir. Serological studies can be used to determine whether the animal populations studied have been in contact with the virus at some point in their lives. These studies that make it possible to monitor the possible emergence of TBEV in Belgium are indeed useful to different health authorities to assess the potential risk to humans in different regions and local ecosystems of Belgium.
In 2010, the laboratory tested 650 cattle from the Belgian herd, selected from the bank of sera collected that year as part of the annual winter animal health surveillance of cattle. The seroprevalence of TBEV infection was thus estimated to be between 2.61 and 4.29%. Seroprevalence of TBEV infection was also assessed in the deer population. Based on the sera of 98 animals killed during hunts, collected between 2008 and 2013 in Flanders (the northern region of Belgium), the seroprevalence was estimated at 4.90%. In 2013, the seroprevalence of TBEV infection was assessed in the wild boar population. The analysis of sera from 238 animals collected in Flanders by hunters and veterinarians made it possible to estimate seroprevalence at 4.20%.
The “Viral Diseases” laboratory also carries out experimental studies to characterize the infection of Belgian wild rodents with TBEV. Wild rodents are considered the reservoir of the TBEV virus. Between 2015 and 2016, a prevalence study of TBEV infection was conducted in wild rodents caught in Wallonia (the southern region of Belgium) with the aim of isolating the TBEV virus in Belgium, but no positive result was detected among the rodents tested.
Mapping of risk areas for a tick bite
Sciensano 's TiquesNet project maps the areas where bites occur and the period of activity of ticks in Belgium. Citizensthemselves flag the bites they have suffered on the Tiquesnet website or on a mobile app (TiquesNet for IPhone or TiquesNet for Android). On the basis of the information presented on the website, people potentially exposed to tick bites can take appropriate preventive measures.