Letters to the editor

Sir;- Outbreaks of ovine abortions caused by Campylobacter fetus fetus (previously C. fetus intestinalis) occur sporadically in mimy areas of New Zealand. The devastating effects on some flocks have stimulated recent studies of the disease,^(1)(3)(7) and have also led to the commercial production of a single strain vaccine (Campylovexin; Wellcome N.Z. Ltd, Auckland). However, it has been shown that single strain C. Fetus vaccines do not protect against serologically distinct strains.⁽²⁾ Since at least two different serotypes of C. fetus fetus are present in New ZealandY) it is not surprising that the commercially available vaccine is only partially effective in some outbreaks.⁽⁷⁾