A serologic survey of hemagglutination-inhibition antibodies to human type A and B influenza viruses in wild pigs in Croatia

The method of hemagglutination inhibition on U microtitration plates was used to examine 101 wild pig sera for the presence of antibodies to three strains of human influenza virus A: A/Johannesburg/82/96, subtype H1N1; A/Nanchang/933/95, subtype H3N2; and A/Wuhan/359/95, subtype H3N2; and human influenza virus B/Beijing/184/93-like strain. All influenza virus strains used in the study have been circulating in most European countries for some twenty years. A positive titer of hemagglutination inhibition. antibodies (greater than or equal to1 : 20) for virus A/Johannesburg/82/96 (H1N1) strain was recorded in 19 (18.81%), for virus A/Nanchang/933/95 (H3N2) and A/Wuhan/359/95 (H3N2) strains together in 88 (87.12%), and for virus B/Beiljing/184/93-like strain in 68 (67.32%) wild pig sera. The sera were collected from wild pig hunt in February 1999 and February 2000. Results of the study provide preliminary data on the presence of antibodies to human influenza A (subtypes H1N1 and H3N2) and B viruses in wild pigs in Croatia.