The reindeer was slaughtered on 9 September, and initial examination of samples submitted to the Norwegian Veterinary Institute led to the suspicion of infection. The Institute has now disproved the finding of CWD in the reindeer.
- We are releaved that this suspicion of illness can now be dismissed. This shows that the system works, and how some diagnoses require several steps to be made with the highest possible certainty, says department director for analysis and diagnostics at the Norwegian Veterinary Institute, Anna Karin Germundsson Hauge.
The initial investigations were carried out using ELISA testing on the submitted material. These detected prions in the lymph node and brain of the reindeer triggered suspicion. Subsequent testing disproved the initial result.
Department director Hauge explains how:
- Biological tests can sometimes react to something else in the sample than what it is supposed to detect, resulting in an incorrect result. Therefore, several alternative methods are often used to examine a sample. This multi-method approach ensures a correct analysis result.
- The ELISA test has a high sensitivity for both classical and atypical CWD. When a test becomes very sensitive, the accuracy may be somewhat reduced. In order to make the diagnosis of classical CWD, ELISA alone is therefore not sufficient, and the result must be confirmed or denied with another method. In this case, the other method, Western Blot, showed that the sample was negative for CWD, says Hauge.