Cover by D.Meissner WHO/GRA These Guidelines were adopted by the WHO Expert Committee on Biological Standardization at its 59th meeting which took place in Geneva from 13 to 17 October 2008 and will be published in the WHO Technical Report Series. © World Health Organization 2010 All rights reserved. Publications of the World Health Organization can be obtained from WHO Press, World Health Organization, 20 Avenue Appia, 1211 Geneva 27, Switzerland (tel.: +41 22 791 3264; fax: +41 22 791 4857; e-mail: [email protected]). Requests for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – should be addressed to WHO Press, at the above address (fax: +41 22 791 4806; e-mail: [email protected]). 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However, the published material is being distributed without warranty of any kind, either expressed or implied. The responsibility for the interpretation and use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use. Contents 1. Introduction............................................................................................................................ 1 2. List of abbreviations and definitions used ........................................................................... 2 3. General considerations .......................................................................................................... 7 3.1 Historical background.................................................................................................... 7 3.2 The use of serum versus plasma as source material ...................................................... 7 3.3 Antivenom purification methods and product safety..................................................... 7 3.4 Pharmacokinetics and pharmacodynamics of antivenoms............................................. 8 3.5 Need for national and regional reference venom preparations ..................................... 8 4. Epidemiological background ................................................................................................ 8 4,1 Global burden of snakebites .......................................................................................... 8 4.2 Main recommendations.................................................................................................. 9 5. Worldwide distribution of venomous snakes....................................................................... 10 5.1 Taxonomy of venomous snakes..................................................................................... 10 5.2 Medically important venomous snakes.......................................................................... 13 5.3 Minor venomous snake species ..................................................................................... 15 5.4 Sea snake venoms .......................................................................................................... 16 5.5 Main recommendations.................................................................................................. 16 6. Antivenoms design: selection of snake venoms ................................................................... 17 6.1 Selection and preparation of representative venom mixtures ........................................ 17 6.2 Manufacture of monospecific or polyspecific antivenoms............................................ 17 6.3 Main recommendations.................................................................................................. 19 7. Preparation and storage of snake venom............................................................................. 19 7.1 Production of snake venoms for immunization ............................................................. 20 7.2 Staff responsible for handling snakes ............................................................................ 25 7.3 Main recommendations.................................................................................................. 26 8. Quality control of venoms ..................................................................................................... 27 8.1 Records and traceability................................................................................................. 27 8.2 National reference materials ......................................................................................... 28 8.3 Characterization of venom batches................................................................................ 28 8.4 Main recommendations.................................................................................................. 28 9. Overview of the production process of antivenoms ............................................................ 29 10. Selection and veterinary health care of animals used for production of antivenoms ...... 31 10.1 Quarantine period.......................................................................................................... 31 10.2 Veterinary surveillance and vaccinations ...................................................................... 31 10.3 Animal health surveillance after inclusion in the herd .................................................. 31 10.4 Main recommendations.................................................................................................. 32 iii 11. Immunization regimens and use of adjuvant....................................................................... 33 11.1 Animals used in antivenom production ......................................................................... 33 11.2 Venoms used for immunization ..................................................................................... 34 11.3 Preparation of venom doses ........................................................................................... 34 11.4 Detoxification of venom ................................................................................................ 35 11.5 Immunological adjuvants............................................................................................... 35 11.6 Preparation of immunogen in adjuvants ........................................................................ 35 11.7 Immunization of animals ............................................................................................... 36 11.8 Traceability of the immunization process...................................................................... 38 11.9 Main recommendations.................................................................................................. 39 12. Collection and control of animal plasma for fractionation ................................................ 39 12.1 Health control of the animal prior to and during bleeding sessions............................... 40 12.2 Premises for blood or plasma collection ........................................................................ 40 12.3 Blood or plasma collection session................................................................................ 40 12.4 Labelling and identification ........................................................................................... 40 12.5 Pooling........................................................................................................................... 42 12.6 Control of plasma prior to fractionation ....................................................................... 43 12.7 Main recommendations.................................................................................................. 43 13. Purification of immunoglobulins and immunoglobulin fragments in the production of antivenoms.......................................................................................................................... 44 13.1 Good manufacturing practices ....................................................................................... 44 13.2 Purification of the active substance ............................................................................... 44 13.3 Pharmacokinetic and pharmacodynamic properties of IgG, F(ab')2 and Fab................. 55 13.4 Main recommendations.................................................................................................. 56 14. Control of infectious risks...................................................................................................... 56 14.1 Background.................................................................................................................... 56 14.2 Risk of viral contamination of the starting plasma .......................................................