Simkute et al.
The prevalence of tick-borne encephalitis virus in wild rodents captured in tick-borne encephalitis foci in highly endemic Lithuania
Viruses. 2024; 16(3):444. doi:10.3390/v16030444

Rodents are considered to represent an efficient reservoir for replication and maintenance of TBE virus. Therefore, rodents may be useful sentinels for detection of TBE foci. While mostly the findings of specific TBE antibodies in rodents are used as an indicator for TBE virus circulation in a given area, a scientific team in Lithuania focused on the detection of TBE virus RNA and tried to cultivate virus strains in murine neuroblastoma Neuro-2a cell culture.

In 2019/20, a total of 139 small rodents were trapped in different TBE foci, and TBE virus RNA could be detected in 104 (74.8%) homogenates of brain or internal organ mix suspensions. The viral genome could also be detected in 2/5 fetus suspension samples.

The detected viral RNA prevalence rate was significantly higher in rodents trapped when the average monthly air temperature was higher than 5°C. TBE virus RNA detection was relatively high in Apodemus flavicollus (77.6%), but lower in Apodemus sylvaticus and A. agrarius.

The study revealed that in confirmed TBE foci in Lithuania, viral RNA could be found in wild rodents. After sample cultivation in Neuro-2a cells, the detection rate of viral RNA and the overall prevalence rate increased significantly. Murine neuroblastoma cells are highly susceptible to TBE virus infection.

These results show that sample cultivation in cell culture is a highly efficient method for increasing TBE viral load to detectable quantities.

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