Bulk Milk Tank Samples Are Suitable to Assess Circulation of Tick-Borne Encephalitis Virus in High Endemic Areas
Arnoldas Pautienius,
Gytis Dudas,
Evelina Simkute,
Juozas Grigas,
Indre Zakiene,
Algimantas Paulauskas,
Austeja Armonaite,
Dainius Zienius,
Evaldas Slyzius,
Arunas Stankevicius
Affiliations
Arnoldas Pautienius
Virology Laboratory, Institute of Microbiology and Virology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes str. 18, 47181 Kaunas, Lithuania
Gytis Dudas
Gothenburg Global Biodiversity Centre, Carl Skottsbergs gata 22B, 41319 Gothenburg, Sweden
Evelina Simkute
Laboratory of Immunology, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes str. 18, 47181 Kaunas, Lithuania
Juozas Grigas
Virology Laboratory, Institute of Microbiology and Virology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes str. 18, 47181 Kaunas, Lithuania
Indre Zakiene
Laboratory of Immunology, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes str. 18, 47181 Kaunas, Lithuania
Algimantas Paulauskas
Department of Biology, Faculty of Natural Sciences, Vytautas Magnus University, Universiteto str. 10, 53361 Kaunas, Lithuania
Austeja Armonaite
Laboratory of Immunology, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes str. 18, 47181 Kaunas, Lithuania
Dainius Zienius
Department of Veterinary Pathobiology, Faculty of Veterinary Medicine Lithuanian University of Health Sciences, Tilzes str. 18, 47181 Kaunas, Lithuania
Evaldas Slyzius
Department of Animal Breeding, Faculty of Animal Science, Lithuanian University of Health Sciences, Tilzes str. 18, 47181 Kaunas, Lithuania
Arunas Stankevicius
Laboratory of Immunology, Department of Anatomy and Physiology, Faculty of Veterinary Medicine, Lithuanian University of Health Sciences, Tilzes str. 18, 47181 Kaunas, Lithuania
A reliable surveillance strategy of tick-borne encephalitis virus (TBEV) is necessary to ensure adequate disease control measures. However, current approaches assessing geographical TBEV circulation are ineffective or have significant limitations. In this study we investigated a total of 1363 goat and 312 sheep bulk tank milk samples for the presence of TBEV. Samples were collected from systematically selected farms in Lithuania every 4–5 days from April to November in 2018 and 2019. To validate results, we additionally tested 2685 questing ticks collected in the vicinity of milk collection sites. We found 4.25% (95% CI 3.25–5.47) and 4.48% (95% CI 2.47–7.41) goat and sheep milk samples to be positive for TBEV, respectively. Furthermore, geographical distribution of TBEV in milk samples coincided with the known TBE endemic zone and was correlated with incidence of TBE in humans in 2019. When sampling time coincides, TBEV detection in milk samples is as good a method as via flagged ticks, however bulk milk samples can be easier to obtain more frequently and regularly than tick samples. The minimal infectious rate (MIR) in ticks was 0.34% (CI 95% 0.15–0.64). Therefore, our results confirm that testing milk serves as a valuable tool to investigate the spatial distribution of TBEV at higher resolution and lower cost.
