Food-Borne Transmission of Tick-Borne Encephalitis Virus-Spread, Consequences, and Prophylaxis.

Alicja M Buczek,Joanna Wysokińska-Miszczuk,Alicja Buczek,Weronika Buczek

doi:10.3390/ijerph19031812

Abstract

Tick-borne encephalitis (TBE) is the most common viral neurological disease in Eurasia. It is usually transmitted via tick bites but can also occur through ingestion of TBEV-infected milk and dairy products. The present paper summarises the knowledge of the food-borne TBEV transmission and presents methods for the prevention of its spread. The incidence of milk-borne TBE outbreaks is recorded in central, eastern, and north-eastern Europe, where Ixodes ricinus, Ixodes persulcatus, and/or Dermacentor reticulatus ticks, i.e., the main vectors of TBEV, occur abundantly. The growing occurrence range and population size of these ticks increases the risk of infection of dairy animals, i.e., goats, sheep, and cows, with viruses transmitted by these ticks. Consumers of unpasteurised milk and dairy products purchased from local farms located in TBE endemic areas are the most vulnerable to alimentary TBEV infections. Familial infections with these viruses are frequently recorded, mainly in children. Food-transmitted TBE can be monophasic or biphasic, and some of its neurological and psychiatric symptoms may persist in patients for a long time. Alimentary TBEV infections can be effectively prevented by consumption of pasteurised milk and the use of TBEV vaccines. It is recommended that milk and dairy products should be checked for the presence of TBE viruses prior to distribution. Protection of dairy animals against tick attacks and education of humans regarding the epidemiology and prophylaxis of TBE are equally important.

Highlights

Tick-borne encephalitis virus (TBEV) is one of the most important human tick-borne viral pathogens in Eurasia
Due to the possibility of human TBEV infection through the consumption of unpasteurised milk and dairy products, the present study focuses on the determinants of the development of tick-borne encephalitis of nutritional origin in humans, the epidemiology and symptoms of this disease, and methods for the prevention of food-borne transmission of this virus
The expansion of the tick occurrence range and the increase in the tick population size have resulted in an increased risk of exposure of tick hosts, i.e., goats, sheep, and cows, to infection with TBE viruses, which are introduced with the saliva of ticks during blood ingestion

Summary

Introduction

Tick-borne encephalitis virus (TBEV) is one of the most important human tick-borne viral pathogens in Eurasia. Food-borne TBE can be diagnosed in humans, even in regions where the disease has not been previously reported This may be the case of travellers who become infected with the virus present in milk or dairy products in a TBE endemic area before returning to their country [40]. As many as 24 of the 30 countries with the highest consumption of milk and dairy products per capita are European countries [50] They are represented by the Baltic countries (Finland, Sweden, Denmark, Norway, Lithuania, Estonia) as well as central (Switzerland, Austria, Germany) and south-eastern (Slovenia, Croatia, Greece) European countries, where an increase in the TBE incidence is reported. Due to the possibility of human TBEV infection through the consumption of unpasteurised milk and dairy products, the present study focuses on the determinants of the development of tick-borne encephalitis of nutritional origin in humans, the epidemiology and symptoms of this disease, and methods for the prevention of food-borne transmission of this virus

Circulation of Tick-Borne Encephalitis Viruses in Nature

Methods for Prevention of Alimentary TBEV Infection and Determinants of Virus

Findings

Conclusions