LABORATORY ACQUIRED TICK-BORNE MENINGOENCEPHALITIS - CHARACTERIZATIONOF VIRUS-STRAINS

Background: The handling of tick-borne encephalitis (TBE) virus is pot entially hazardous, as indicated by a number of laboratory-acquired in fections in the prevaccination era. Objectives: (1) To reemphasize the hazard of handling TBE virus without being vaccinated by describing t he case of a laboratory-acquired full-blown TBE in a microbiologist wh o isolated the virus from a blood sample. (2) To molecularly character ize the causative virus strain isolated in Slovenia in comparison with the European prototype strain Neudoerfl. Study design: The virologica l diagnosis of the laboratory infection was established by serology an d virus isolation. The virus was characterized by restriction fragment analysis of PCR products of amplified genomic sequences and a panel o f monoclonal antibodies reacting with the major envelope protein. Resu lts: The laboratory infection, most probably acquired by aerosol, resu lted in a biphasic course of the disease with a severe meningoencephal itis in the second phase. Both by restriction fragment and monoclonal antibody analysis the Slovenian virus strains involved were indistingu ishable from the European prototype strain. Conclusions: This report c onfirms the potential hazard of handling TBE virus in the laboratory w ithout being vaccinated. The similarity of the virus isolates from Slo venia with the European prototype strain confirms the previously obser ved homogeneity of TBE virus strains from different European countries .