Precipitating antibodies to Crimean haemorrhagic fever virus in human sera collected in Hungary.

Agar-gel diffusion precipitation test was carried out with Crimean Haemorrhagic Fever (CHF) virus as antigen in serum samples collected in four areas of Hungary from 587 persons working in contact with animals, and in 169 animal sera collected in Hajdu-Bihar county, Hungary. Antibody was found in 17 human sera. All these but one, originating from a slaughterhouse worker in Budapest, had been collected from Hajdú-Bihar county. The highest titre was 1:16. All the animal sera proved to be negative. It is suggested that the CHF virus or a closely related virus is present, and may cause human infections in Hungary.