[Combined experimental infection of Microtus gregalis by tick-borne encephalitis and rabies viruses and probable interference].

Narrow-skulled voles (Microtus gregalis) were inoculated with tick-borne encephalitis (TBE) and rabies (RV) viruses isolated in the steppe zone of West Siberia. TBE infection was asymptomatic and nonlethal in all voles. The virus was eliminated from the voles between days 14 and 60 postinoculation. Only 1 of 26 tested animals produced anti-TBE antibodies in titer 1:20. RV infection was acute and lethal. All sick animals contained RV in the brain, 42.1% in salivary glands, 5.3% in the lungs and kidneys. The voles which survived RV inoculation had no RV. The voles inoculated with RV after TBE were less sensitive and had a longer incubation period in comparison with the animals challenged with RV alone. The differences augmented from day 0 to day 14 after TBE inoculation and became statistically significant on day 14. Later, 21 day after challenge with TBE virus, the differences almost disappeared. The role of possible interference in the evolution of virus-host interaction of Lyssaviruses is discussed.