Production and calibration of the second batch of OIE anti-rabies positive reference serum.

The Biological Standards Commission of the World Organisation for Animal Health (OIE) oversees the preparation and validation of OIE-approved International Reference Standards for use in serological assays for detecting infectious diseases of animals or the adequacy of their immune response following vaccination against those diseases. The principal use of OIE-approved International Reference Standards is to harmonise serological testing and to promote the mutual recognition of test results for international trade. In the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, the organisation recommends the use of the OIE anti-rabies positive reference serum of dog origin to titrate serum samples in international units (IU)/ml for use in rabies serological tests. The first batch of OIE reference serum of dog origin was produced in1991 and was used internationally until the beginning of 2010. The preparation of the new batch began in 2012 and, in contrast to the previous batch, three commercial inactivated rabies vaccines based on the most frequently used vaccine strains (Pasteur Virus and Flury Low Egg Passage) were selected for the immunisation of dogs in accordance with OIE guidelines. In 2013, calibration was completed through an inter-laboratory test involving five OIE Reference Laboratories for Rabies with the Second World Health Organization (WHO) International Standard for Anti-Rabies Immunoglobulin being used as a reference standard in this calibration. After statistical analysis of the results, the consensus titre was established as 5.59 IU/ml. The technical and statistical data were submitted to the OIE for assessment. In February 2014, the OIE Biological Standards Commission adopted this serum as an OIE-approved standard reagent for rabies serology.