Serological investigations concerning the presence of antibodies to arboviruses in wild birds.

Serum samples from 8 species of migratory birds (Ardea cinerea, Plegadis falcinellus, Anas querquedula, Anser albifrons, Gavia arctica, Fulica atra, Phalacrocorax carbo, Larus minutus) were tested for the presence of hemagglutination-inhibiting (HAI) antibodies to alpha- and flaviviruses. HAI antibodies to alphaviruses (eastern equine encephalitis, western equine encephalitis, Sindbis, Middelburg, Semliki Forest) ranging in titer from 1/20 to 1/160 were detected in 46 serum samples; 22 serum samples gave positive reactions (titers: 1/20 - 1/80) to flaviviruses (West Nile, Ntaya). In certain cases antibodies to several antigens could be made evident in the same serum sample. The serological results are discussed in the light of the birds' migration pattern.