**Denise Meyer \*,**†**, Anja Petrov** †**,**‡ **and Paul Becher \***

EU and OIE Reference Laboratory for Classical Swine Fever, Institute of Virology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Foundation, 30559 Hannover, Germany; anjapetrov@bundeswehr.org


Received: 21 October 2019; Accepted: 3 December 2019; Published: 5 December 2019

**Abstract:** Shipping of serum samples that were taken from pigs infected with classical swine fever (CSF) virus is frequently requested with the objective of serological analyses, not only for diagnostic purposes but also for exchange of reference materials that are used as control material of diagnostic assays. On the basis of the fact that an outbreak with CSF is associated with enormous economic losses, biological safety during the exchange of reference material is of great importance. The present study aimed to establish a pragmatic approach for reliable CSF virus (CSFV) inactivation in serum without impairing antibody detection. Considering the fact that complement inactivation through heating is routinely applied, the basic idea was to combine heat treatment with the dilution of serum in a detergent containing buffer in order to facilitate the inactivation process. The results show that treatment of serum samples with phosphate buffered saline-Tween20 (final concentration = 0.15%) along with incubation at 56 ◦C for 30 min inactivated CSFV and such treatment with ≤ 0.25% PBS-Tween20 does not impair subsequent antibody detection by ELISA or virus neutralization test. This minimizes the risk of virus contamination and represents a valuable contribution to a safer CSF diagnosis on a national and international level.

**Keywords:** classical swine fever; pestivirus; *Flaviviridae*; virus inactivation; complement inactivation; detergent; Tween20; antibody detection; safety; sample transport
