Serological studies on leptospiral antibodies in dairy milkers in three regions of the South Island of New Zealand

The antibody levels to leptospiral antigens among dairy herds were determined and correlated with those of the milkers in three areas of the South Island of New Zealand. The milkers filled out an extensive questionnaire giving age and sex of the milker, as well as details of the herd milked and his/her association with it. The serological results are compared with these data and the value of such seroepidemiological studies examined from the point of view of the advantages of vaccinating cattle to protecting the milker from leptospirosis. Antibodies to L. interrogans serovar hardjo were the ones most frequently encountered among the milkers; however, antibodies to other serovars were also noted. Some animals in most herds had antibodies to serovar hardjo. These studies suggest that vaccinating cattle with serovar hardjo would not necessarily reduce the human incidence of leptospirosis in this population