Detection of Clostridium botulinum toxin genes by PCR: New test now available at AHL to diagnosis botulism
Rebeccah McDowall1, Tanya Brock1, Kimani Rutherford1, Sarah Lippert1, Alexandra Reid2, Lenny Shirose3, Brian Stevens3, Claire Jardine3,4, and Ðurđa Slavić1
1Animal Health Laboratory, University of Guelph, Guelph, ON
2Ontario Ministry of Agriculture, Food and Rural Affairs, Guelph, ON
3Canadian Wildlife Health Cooperative, University of Guelph, Guelph, ON
4Department of Pathobiology, University of Guelph, Guelph, ON
AHL Newsletter 2023; 27(4):6.
Botulism is a frequently fatal paralytic disease of mammals and birds caused by the toxins produced by Clostridium botulinum, an anaerobic bacterium that persists in the environment in the form of dormant spores which can remain viable for years. C. botulinum produces seven distinct types of toxins, designated A through G. Two of these toxins, types C and E, most often cause disease outbreaks in animals. Type C affects filter-feeding birds, waterfowl, shorebirds, and domestic birds, as well as cattle, horses, and ranch mink. Type E, on the other hand, is relatively common in wild birds of the Great Lakes Region, and does not occur elsewhere in Canada.
Currently, no veterinary diagnostic lab in Ontario or Canada offers testing for C. botulinum. To replace the mouse inoculation test (MIT) used in the past, AHL verified a PCR-based detection of 6 C. botulinum toxin types A, B, C, D, E, and F. Whereas MIT is used for detection of C. botulinum toxins primarily in serum samples, PCR is used for detection of toxin genes and has been validated using liver and cloacal swabs from birds. There were no differences in detection observed between these two sample types, indicating that both are acceptable for PCR testing. As serum contains only C. botulinum toxin, not bacteria, it is not an acceptable sample for the C. botulinum PCR test. Furthermore, as this PCR is validated only for avian samples, samples submitted from mammals will be tested as non-routine (unvalidated) testing.
Funding for this project was provided by the Ontario Animal Health Network (OAHN) and supported by OAHN – Wildlife (https://www.oahn.ca/network/wildlife/).
To submit samples, collect liver or gastrointestinal content in sterile, leak-proof containers and refrigerate immediately. Ship to the lab in insulated container with freezer packs. The test code is ‘bot’ and the current fee is $120 per sample.