U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

October 2004


Journal of Wildlife Diseases, 40(4), 2004, pp. 749–753. © Wildlife Disease Association 2004. Permission to use.


We established a method of directly detecting Clostridium botulinum type C cells, while minimizing spore detection, in the intestinal contents of Mozambique tilapia (Oreochromis mossambicus). This technique involved extraction of predominantly cellular DNA from tilapia intestinal tracts and used a polymerase chain reaction assay to detect presence of type C1 toxin gene. We consistently detected C. botulinum type C cells in tilapia gastrointestinal contents at a level of 7.53104 cells per 0.25 g material or 1.93103 cells. This technique is useful for determining prevalence of the potentially active organisms within a given population of fish and may be adapted to other types of C. botulinum and vertebrate populations as well.