Objective:

The aim of our study was assess the seroprevalence of antibodies against the TBE virus in patients from northern and central Mongolia.

Methods:

During August 2003, 223 serum samples were drawn from volunteers of Selenga aimag, 110 serum samples were drawn from volunteers of Bulgan aimag and central aimag each. They were screened by a commercially available IgG ELISA (Dade Behring) and positive samples were subjected to a neutralisation assay. Samples, which yielded a neutralisation at 1:10 or higher were rated as positive.

Results:

Eleven patients from Selenga (4.7%) and one patient from Bulgan (0.9%) were found seropositive against TBE virus. No sample from central aimag was found positive. Neutralisation titres lay between 1:10 and 1:60.

About 20% of the patients reported a tick bite, which were usually acquired in the northern part of the country.

Conclusions:

Tick-borne encephalitis is likely to exist in the northern parts of Mongolia, where Ixodes scapularis occurs. In the central parts of the country, serological findings do not support the occurrence of this disease.