[Epizootic swine influenza on animal farms in Brittany]

Since 1976, seroepidemiological surveys using radial haemolysis and isolation trials from samples collected from pigs at the abattoir showed that Brittany was an important reservoir of swine subclinical infections due to the human Influenza A viruses H3N2. Influenza A H1Sw N1Sw subclinical infections sporadically occurred from 1979 to 1981. In January 1982 an epizootic started in Finistère which spread from west to east. The H1Sw and N1Sw antigens of 28 stains isolated from 1979 to 1982 were studied with ferret and rabbit anti sera and appeared to be variants of the previous strains (1976-1967-1961-1930). A reinforced serological survey in pigs demonstrated that both Influenza A viruses H1Sw N1Sw and H3N2 simultaneously spread in herds. There is no actual prove of recent human infections by A H1Sw N1Sw virus.