TSE reminder

MIKE HARDCASTLE

The Transmissible Spongiform Encephalopathies Surveillance programme administered by MPI is important to maintain our TSE-free status and access to international markets. At Gribbles Veterinary we strongly encourage vets to submit brains and cervical spinal cord from qualifying livestock.

This article is to highlight recent changes in TSE Surveillance.  Histopathology of representative brain areas used to be the initial screening test required for surveillance, however under new direction from the OIE (Office International des Epizooties), it is now mandatory that fresh cervical spinal cord is tested first (by ELISA and possibly Western Blot). Fixed brain should still be submitted in case histopathology or immunohisto-chemistry is required.

Unfortunately, from time to time in the past, we have received fixed brains without fresh tissue; if such incomplete submissions are received in the future, our current advice from MPI is that they would not compensate veterinarians for those cases.

It remains important that the entire fixed brain is submitted; and care is required in extracting these since the key sites for examination are easily damaged during removal. These are basically the mid-brain and hind-brain – see Figures 1 & 2* plus this MPI guide and the information sheet available on our website. Once again, a complete lack of required sites could jeopardise compensation.

Once the brain is removed, we recommend fixing it whole in the clinic (e.g. in a bucket of formalin) before submission; this allows shipping with minimal or no formalin, and the use of small containers or sealable plastic bags (please triple bag formalin fixed tissue) . If the brain must be transected to fit into containers for shipping, please avoid sectioning the mid-brain and hind-brain.

Figure 2. Standard sites for TSE exclusion from Appendix 2 of the Australia and New Zealand standard diagnostic procedure for TSE 2010.*
Figure 1. Bovine brain demonstrating the approximate location of the standard sites prior to dissection.