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Tick-borne encephalitis – a food safety risk for humans consuming unpasteurized milk/milk products from goat, sheep and cattle in Sweden and Finland

Published 2019-02-12

Tick-borneencephalitis – a food safety risk for humans consuming unpasteurized milk/milk productsfrom goat, sheep and cattle in Sweden and Finland


Tick-borne encephalitis (TBE) is the most severetick-borne viral disease in humans in Europe. Annually, around 200-300 humancases are reported in Sweden and 50-80 in Finland. TBEV (TBE-virus) may alsoinfect animals but usually no clinical signs develop. Human outbreaks of TBEhave also been associated with the consumption of unpasteurized milk or milkproducts in several European countries, especially in the eastern part. Ingeneral, small ruminants are in focus here and the virus has been detected inmilk. This food-borne transmission route seems not to be well-known amongconsumers. Pasteurization will eliminate the virus and for commercial milkpasteurization is generally compulsory, but it is not uncommon with consumptionof unpasteurized milk and milk products. In both Sweden and Finland there is agrowing interest and enterprise for small ruminant milk production and the milkis mainly for artisan cheese production in farm-based dairys.

The aim of this study is to estimate the prevalence ofTBEV-antibodies and which strains of the virus that are present in herds ofgoat, sheep and dairy cows in Sweden and Finland by analysing bulk tank milksamples. Also, we will achieve information on if ticks on farms with TBEVseropositive bulk-milk are TBEV positive and thereby recognize potential areaswith a food safety risk to acquire TBE. Lastly, we want to suggestrecommendations aimed to reduce such food safety risk.