Investigation of serology for diagnosis of outbreaks of botulism in cattle.

Serology has been used to diagnose retrospectively types C and D outbreaks of botulism in cattle in Australia and this study has investigated whether the approach would be applicable in England and Wales. Three hundred sera from routine surveillance submissions in England and Wales were used as a negative control population. Some stored sera were available from a small number of clinical cases of botulism and 125 samples were collected from cohort groups of clinical cases in four new outbreaks of botulism. Three of these outbreaks were identified as being caused by type D Clostridium botulinum toxin. Sera were tested by antibody ELISA in laboratories in Australia and Germany. There was no increase in the proportion of animals seropositive to type C or D antibody in the botulism-associated cattle. The proportion of samples which were seropositive to type D antibodies was <2% in both the negative control and outbreak populations. It was concluded that single time serology is unlikely to be helpful for retrospective diagnosis of outbreaks of type D botulism in England and Wales.