On the possible association of the DS marker of tick-borne encephalitis virus strains with species of tick vectors

Over 50 million humans live in areas of potential exposure to tick-borne encephalitis virus (TBEV). The disease exhibits an estimated 16,000 cases recorded annually over 30 European and Asian countries. Conventionally, TBEV transmission to Ixodes spp. ticks occurs whilst feeding on viraemic animals. However, an alternative mechanism of non-viraemic transmission (NVT) between infected and uninfected ticks co-feeding on the same transmission-competent host, has also been demonstrated. Here, using laboratory-bred I. ricinus ticks, we demonstrate low and high efficiency NVT for TBEV strains Vasilchenko (Vs) and Hypr, respectively. These virus strains share high sequence similarity but are classified as two TBEV subtypes. The Vs strain is a Siberian subtype, naturally associated with I. persulcatus ticks whilst the Hypr strain is a European subtype, transmitted by I. ricinus ticks. In mammalian cell culture (porcine kidney cell line PS), Vs and Hypr induce low and high cytopathic effects (cpe), respectively. Using reverse genetics, we engineered a range of viable Vs/Hypr chimaeric strains, with substituted genes. No significant differences in replication rate were detected between wild-type and chimaeric viruses in cell culture. However, the chimaeric strain Vs[Hypr str] (Hypr structural and Vs non-structural genomic regions) demonstrated high efficiency NVT in I. ricinus whereas the counterpart Hypr[Vs str] was not transmitted by NVT, indicating that the virion structural proteins largely determine TBEV NVT transmission efficiency between ticks. In contrast, in cell culture, the extent of cpe was largely determined by the non-structural region of the TBEV genome. Chimaeras with Hypr non-structural genes were more cytotoxic for PS cells when compared with Vs genome-based chimaeras.

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“…ricinus . [ 19 – 23 ]. SIB-TBEV and FE-TBEV are the predominant subtypes in Siberia and Far Eastern Asia, where I .…”

Section: Introductionmentioning

confidence: 99%

Tick-Borne Encephalitis Virus Structural Proteins Are the Primary Viral Determinants of Non-Viraemic Transmission between Ticks whereas Non-Structural Proteins Affect Cytotoxicity

et al. 2016

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“…2 from Alekseev (1995)) contains both kinds of cement. The TBE virus strains transmitted by these ticks, which are being replicated in the glycoprotein producing cells, are dextran-sulphate susceptible (DS positive) (Dzhivanyan et al, 1974). The tender, transparent mass of the Ixodes ricinus cement consists of lipoproteins only and the 'ricinus' strains of the TBE virus replicated in the cell culture are DS-negative.…”

Section: Introductionmentioning

confidence: 99%

Preliminary studies on virus and spirochete accumulation in the cement plug of ixodid ticks

Alekseev

Burenkova

Vasilieva³

et al. 1996

Exp Appl Acarol

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We provide evidence that tick-borne encephalitis virus and Borrelia burgdorferi s.l. are accumulated in the cement plug in the host skin within the first few hours after tick attachment. Extirpation of the tick without the cement plug, even very soon after the attachment, did not prevent the transmission by Ixodes ricinus, Ixodes persulcatus or Dermacentor reticulatus to mice. This was within 1 hour in the case of the TBE virus and after 20-22 h of attachment, in the case of Borrelia and I. persulcatus. The epidemiological significance of these findings is discussed.

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“…Various abiotic (e.g., microclimatic conditions) and biotic factors (e.g., the presence of ticks-vectors, hosts of various tick developmental stages, and zoonotic reservoirs of the pathogen) have an impact on TBEV circulation in nature [10,16,63,64]. The main vectors of the virus are wide host-spectrum ticks such as Ixodes ricinus [65,66] and Dermacentor reticulatus [67,68] in various regions of eastern, central, western, northern, and southern Europe and Ixodes persulcatus in the north-eastern part of the continent [55,56,69,70]. TBEVs can probably also be transmitted by other species of ticks, e.g., Dermacentor marginatus [67,71] and Haemaphysalis concinna [72].…”

Section: Circulation Of Tick-borne Encephalitis Viruses In Naturementioning

confidence: 99%

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

Buczek

Wysokińska-Miszczuk

2022

IJERPH

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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.

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On the possible association of the DS marker of tick-borne encephalitis virus strains with species of tick vectors

Cited by 9 publications

References 0 publications

Tick-Borne Encephalitis Virus Structural Proteins Are the Primary Viral Determinants of Non-Viraemic Transmission between Ticks whereas Non-Structural Proteins Affect Cytotoxicity

Tick-Borne Encephalitis Virus Structural Proteins Are the Primary Viral Determinants of Non-Viraemic Transmission between Ticks whereas Non-Structural Proteins Affect Cytotoxicity

Preliminary studies on virus and spirochete accumulation in the cement plug of ixodid ticks

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

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