Bulk Milk Tank Samples Are Suitable to Assess Circulation of Tick-Borne Encephalitis Virus in High Endemic Areas

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.

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Distribution of Ixodes ricinus ticks and prevalence of tick-borne encephalitis virus among questing ticks in the Arctic Circle region of northern Norway

Ticks and Tick-borne Diseases ◽

10.1016/j.ttbdis.2017.10.002 ◽

2018 ◽

Vol 9 (1) ◽

pp. 97-103 ◽

Cited By ~ 28

Author(s):

A. Soleng ◽

K.S. Edgar ◽

K.M. Paulsen ◽

B.N. Pedersen ◽

Y.B. Okbaldet ◽

...

Keyword(s):

Ixodes Ricinus ◽

Encephalitis Virus ◽

The Arctic ◽

Arctic Circle ◽

Northern Norway ◽

Tick Borne Encephalitis ◽

Questing Ticks ◽

Ixodes Ricinus Ticks ◽

Tick Borne Encephalitis Virus

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Deep sequencing analysis of tick-borne encephalitis virus from questing ticks at natural foci reveals similarities between quasispecies pools of the virus

Journal of General Virology ◽

10.1099/jgv.0.000704 ◽

2017 ◽

Vol 98 (3) ◽

pp. 413-421 ◽

Cited By ~ 5

Author(s):

Naveed Asghar ◽

John H.-O Pettersson ◽

Patrik Dinnetz ◽

Åshild Andreassen ◽

Magnus Johansson

Keyword(s):

Deep Sequencing ◽

Encephalitis Virus ◽

Sequencing Analysis ◽

Tick Borne Encephalitis ◽

Natural Foci ◽

Questing Ticks ◽

Tick Borne Encephalitis Virus ◽

Deep Sequencing Analysis

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Revealing new tick-borne encephalitis virus foci by screening antibodies in sheep milk

Parasites & Vectors ◽

10.1186/s13071-020-04030-4 ◽

2020 ◽

Vol 13 (1) ◽

Cited By ~ 3

Author(s):

Amélie Wallenhammar ◽

Richard Lindqvist ◽

Naveed Asghar ◽

Sezin Gunaltay ◽

Hans Fredlund ◽

...

Keyword(s):

Milk Samples ◽

Sheep Milk ◽

Cell Extracts ◽

Tick Borne Encephalitis ◽

Questing Ticks ◽

Different Temperatures ◽

Risk Areas ◽

Focus Reduction ◽

Novel Strategy ◽

The Stability

Abstract Background Tick distribution in Sweden has increased in recent years, with the prevalence of ticks predicted to spread towards the northern parts of the country, thus increasing the risk of tick-borne zoonoses in new regions. Tick-borne encephalitis (TBE) is the most significant viral tick-borne zoonotic disease in Europe. The disease is caused by TBE virus (TBEV) infection which often leads to severe encephalitis and myelitis in humans. TBEV is usually transmitted to humans via tick bites; however, the virus can also be excreted in the milk of goats, sheep and cattle and infection may then occur via consumption of unpasteurised dairy products. Virus prevalence in questing ticks is an unreliable indicator of TBE infection risk as viral RNA is rarely detected even in large sample sizes collected at TBE-endemic areas. Hence, there is a need for robust surveillance techniques to identify emerging TBEV risk areas at early stages. Methods Milk and colostrum samples were collected from sheep and goats in Örebro County, Sweden. The milk samples were analysed for the presence of TBEV antibodies by ELISA and validated by western blot in which milk samples were used to detect over-expressed TBEV E-protein in crude cell extracts. Neutralising titers were determined by focus reduction neutralisation test (FRNT). The stability of TBEV in milk and colostrum was studied at different temperatures. Results In this study we have developed a novel strategy to identify new TBEV foci. By monitoring TBEV antibodies in milk, we have identified three previously unknown foci in Örebro County which also overlap with areas of TBE infection reported during 2009–2018. In addition, our data indicates that keeping unpasteurised milk at 4 °C will preserve the infectivity of TBEV for several days. Conclusions Altogether, we report a non-invasive surveillance technique for revealing risk areas for TBE in Sweden, by detecting TBEV antibodies in sheep milk. This approach is robust and reliable and can accordingly be used to map TBEV “hotspots”. TBEV infectivity in refrigerated milk was preserved, emphasising the importance of pasteurisation (i.e. 72 °C for 15 s) prior to consumption.

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TBE in South Korea

Tick-borne encephalitis - The Book ◽

10.33442/978-981-14-0914-1_12b-31 ◽

2019 ◽

Author(s):

Joon Young Song

Keyword(s):

South Korea ◽

Human Case ◽

Encephalitis Virus ◽

Surveillance Studies ◽

Tick Borne Encephalitis ◽

Tick Borne Encephalitis Virus

Although no human case of tick-borne encephalitis (TBE) has been documented in South Korea to date, surveillance studies have been conducted to evaluate the prevalence of tick-borne encephalitis virus (TBEV) in wild ticks.

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