Collaborative study for the establishment of two European Pharmacopoeia Biological Reference Preparations for serological potency testing of tetanus vaccines for veterinary use.

The European Directorate for the Quality of Medicines (EDQM) has organised an international collaborative study, divided into two phases, aimed at producing and establishing two suitable reference sera for serological potency testing of tetanus vaccines for veterinary use for batch consistency demonstration. In phase I pools of sera were produced by immunising guinea pigs and rabbits with tetanus toxoid using the immunisation schedule prescribed by the European Pharmacopoeia (Ph. Eur.) for potency testing of tenanus vaccines for veterinary use. Following aliquoting and freeze-drying, characterization of the materials by immunochemical and biological assays enabled us to conclude that the sera should be suitable reference materials in respect of in-vitro assay methods for Clostridium (C.) tetani. The candidate (c) Ph. Eur. Biological Reference Preparations (BRP) were calibrated by Toxin Binding Inhibition test (ToBI) in phase II of the study by a large group of laboratories, including both manufacturers and official medicines control laboratories (OMCL). The activity of the proposed reference sera was determined by comparison with the existing equine monovalent World Health Organization (WHO) International Standard (IS). This study enabled us to provide a definitive value for the antitoxin activity of the reference preparations in respect of their anti-tetanus antibody content.

Investigations on the sporicidal and fungicidal activity of disinfectants.

The sporicidal and fungicidal activity of disinfectants was studied in a suspension test. Glutaraldehyde 4%, sodium-dichloroisocyanurate-dihydrate (2400 ppm active chlorine) and peracetic acid 0.25% demonstrated after 30 min of exposure at 20 degrees C in the presence of 4% horse serum a clear activity against spores of Bacillus cereus. Under the same conditions formaldehyde 4% and glutaraldehyde 2% were also found to be sporicidal, but only after a longer time of exposure. Spores of Bacillus anthracis and B. cereus appeared to be comparably resistant against the investigated disinfectants, whereas conidiospores of Aspergillus fumigatus and Aspergillus niger were less resistant. Of the micro-organisms tested Candida albicans proved to be slightest resistant, while spores of Bacillus subtilis were found the most resistant.

[A study of the efficacy of disinfectants against anthrax spores]. / Een onderzoek naar de werkzaamheid van ontsmettingsmiddelen ten opzichte van miltvuursporen.

The activity of disinfectants with regard to spores of Bacillus anthracis was determined in a suspension test. Creoline (10%) and also several other disinfectants for veterinary use showed no activity against spores of B. anthracis. Natriumdichloorisocyanuraat-dihydrate (2400 ppm active chlorine) and peracetic acid 0,25% demonstrated after 30 minutes of exposures at 20 degrees C in the presence of 4% horse serum a significant sporicidal effect. Under the same conditions formaldehyde 4% and glutaraldehyde 2% were also found to be sporicidal but only after 2 hours of exposure.

[Registering, licensing and investigating vaccines in animal disease control (author's transl)]. / Registratie, keuring en onderzoek van entstoffen in het kader van de dierziektebestrijding.

The registration, licensing and investigation of veterinary vaccines are discussed with reference to the producer, the user and the authorities. The significance of basic research by the producer, of testing by the authorities, of quality control and of evaluation (laboratory and field studies) in the control of animal diseases are examined more closely. The fact is stressed, that legislation concerning veterinary medicines in general and vaccines in particular should be well defined. All this is regarded as an integral part of recent developments in animal farming in the Netherlands.

[Meningo-encephalitis in mink caused by NCD virus (author's transl)]. / Meningo-encephalitis bij de nerts (mustela vison), veroorzaakt door het psuedovogelpest-virus

In 1970-1972 a great number of mink died of a meningo-encephalitis in the Netherlands. The results of the detailed microbiological and histopathological examination pointed to infection by NCD virus as the cause of the mortality. During the isolation of the NCD virus in embryonated hen eggs the haemagglutinating properties were extremely weak and incomplete; the normal haemagglutination of the NCD virus was not found until the mink isolates had been passed through chickens. Transmission experiments revealed that the pathogenicity of the NCD virus was relatively low in mink after i.c. and i.m. infection, very young mink being the most susceptible. The mink were doubtlessly infected with the NCD virus bij feeding with offal of infected poultry. There was in fact quite a high incidence of Newcastle disease on Dutch chicken farms in 1970-1972.