Eradication of Brucella ovis from the Falkland Islands 1977-1993.

A campaign to eradicate Brucella ovis from sheep in the Falkland Islands, using a combination of serological tests and culling, was initiated in 1977 and continued until 1993 when, after a total of 65,266 tests had been carried out, the organism had been eradicated from the national flock. The paper discusses the relative values of the serological tests and suggests guidelines for maintaining the flock free of the infection.

In vitro comparison of foot-and-mouth disease virus subtype variants causing disease in vaccinated cattle.

Foot-and-mouth disease virus isolates of types O, A and SAT 2, from diseased animals in herds routinely vaccinated twice a year were compared antigenically with the vaccine strains in the complement-fixation, neutralization and radial immunodiffusion tests. It was found that strains which had readily infected vaccinated cattle had R values against the vaccine strain in the complementfixation and radial immunodiffusion tests of 30 or less, while strains causing primary outbreaks with little spread had R values of 30-40. Threefold differences in humoral neutralizing antibody concentration between the field variant and the vaccine strain in sera from vaccinated animals were likely to be significant in terms of protection.