Detection of Tick-Borne Encephalitis Virus in Ear Tissue and Dried Blood Spots from Naturally Infected Wild Rodents
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Can ear tissue and dried blood spots support tick-borne encephalitis virus surveillance in wild rodents? A study by Pascoe and colleagues detected viral RNA in both sample types, offering evidence for sampling approaches that do not require sacrificing the animal. MP Biomedicals’ FastPrep-24 5G and Lysing Matrix Z were used to homogenize ear tissue before downstream RNA analysis.
Table of Contents
The research question: alternatives to destructive sampling
Monitoring tick-borne encephalitis virus (TBEV) in wildlife requires suitable biological samples. Collecting internal organs prevents repeat sampling of the same individual, creating a challenge for longitudinal studies.
In their 2023 study published in Parasites & Vectors, researchers investigated whether TBEV RNA could be detected in ear tissue and dried blood spots (DBS) obtained from naturally infected wild rodents. Here, non-destructive sampling refers to collecting samples without sacrificing the animal; it does not mean that tissue collection is non-invasive.
Study at a glance
Rodents were sampled at three woodland areas in the Netherlands where TBEV had previously been recorded. The researchers tested the collected samples for viral RNA using real-time reverse-transcription PCR (RT-PCR). Not every animal contributed both sample types.
Samples, materials and method
Samples: Ear tissue and dried blood spots (DBS).
Materials: FastPrep-24 5G and Lysing Matrix Z (MP Biomedicals).
Keywords: Tick-borne encephalitis virus, reservoir host, sampling, surveillance, FastPrep-24 5G, Lysing Matrix Z.
Method reported in the case study: Ear tissue was first removed from the ethanol and dried. The ear tissue was then placed in 400 µL MagNA Pure 96 External Lysis Buffer together with 200 µL Minimum Essential Medium (MEM) (Thermofisher Scientific) in 2-mL tubes with Lysing Matrix Z (MP Biomedicals). Samples were homogenized by bead beating for 40 s at 6.0 m/s (FastPrep-24 5G, MP Biomedicals).
The role of these products was to prepare the ear tissue for downstream analysis. The study did not compare homogenizers or demonstrate that this combination improved detection relative to another instrument or lysing matrix.
What the researchers found
TBEV RNA was detected in five of 117 rodents. All five positive individuals had a positive ear tissue sample. DBS was available for four of those five individuals, and two of those four DBS samples were positive.
| Species | Location | Sex | Breeding Status | Ear Tissue | Dried Blood Spot |
|---|---|---|---|---|---|
| Apodemus sylvaticus | B | Male | Adult | + (30.70) | + (25.38) |
| Apodemus sylvaticus | C | Male | Adult | + (30.71) | – |
| Apodemus sylvaticus | B | Female | Adult | + (29.12) | – |
| Myodes glareolus | C | Male | Adult | + (25.73) | + (32.94) |
| Myodes glareolus | A | Male | Adult | + (24.27) | NA |
Overview of biological samples collected from rodents that tested positive by real-time RT-PCR for tick-borne encephalitis virus. Ct scores are provided in brackets. +: RNA detected; -: RNA not detected; NA: no DBS available. Column headings and values follow the supplied case study; species capitalization is standardized.
No rodent had a positive DBS together with a negative ear tissue result. These findings show that the two sample types did not identify the same number of RNA-positive samples in this dataset. The percentages are observed positivity rates, not estimates of diagnostic sensitivity.
What this means for wildlife surveillance
The findings support further investigation of ear tissue and DBS as alternatives to destructively obtained samples for TBEV surveillance. Sampling that preserves the animal can enable study designs involving repeated observations over time.
Interpretation should remain specific to this study: only five animals tested positive, sample availability differed, and RNA detection alone does not establish the presence of infectious virus. The results do not show that ear tissue will outperform DBS in every setting.
Quick answers
Which MP Biomedicals products were used?
The researchers reported FastPrep-24 5G and Lysing Matrix Z for ear tissue homogenization.
Was FastPrep used to detect TBEV RNA directly?
No. It was used for sample homogenization. Viral RNA detection was performed downstream using real-time RT-PCR.
Were all five positive rodents also DBS-positive?
No. Two of the four positive rodents with an available DBS had a positive DBS result; the fifth had no DBS available.
Explore the research
Read the original publication for the complete study design, methods, results and limitations. For questions about MP Biomedicals sample preparation products, contact our technical support team.
Reference
Pascoe EL, de Vries A, Esser HJ, Koenraadt CJM, Sprong H. Detection of tick-borne encephalitis virus in ear tissue and dried blood spots from naturally infected wild rodents. Parasites & Vectors. 2023;16:103. doi:10.1186/s13071-023-05717-0.
This article summarizes published research and the accompanying MP Biomedicals case study. Product use reported in the publication does not imply endorsement by the authors.
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