Infectious bovine rhinotracheitis: study on the experimentally induced disease and its prevention using an inactivated, adjuvanted vaccine.

Experimentally induced IBR was studied in calves. Intranasal challenge enabled reproducible results to be obtained, both from qualitative (clinical aspect) and quantitative points of view (virus excretion, temperature); local and general immunity were also evaluated. This challenge method is useful when studying IBR vaccines. The disease was also experimentally induced by putting healthy animals into contact with diffusor calves. A single injection of inactivated vaccine in oily adjuvant already conferred good protection; it was 100% successful against the experimentally induced disease when administered two times at a 7 or 14 day interval. Immunity obtained was long-lasting and even persisted up to one year. Therefore, this vaccine is advised for vaccination in both contaminated and high risk areas. Results obtained for both safety and potency suggest that this killed vaccine should be used rather than live vaccines.

Experimental rabies in cats: immune response and persistence of immunity.

Experimental rabies was studied in cats under defined conditions. A correlation between the virus dosage and the incubation period was established and results were compared with those published previously by others. the susceptibility of cats to rabies virus appears to be paradoxical. The persistence of the immunity induced by an inactivated rabies vaccine prepared form cell culture-propagated virus used in combination with feline panleukopenia vaccine, with or without adjuvant, was studied through severe virulent virus challenge. Complete protection was observed after more than 3 years following a single vaccination. A proposed vaccination schedule is discussed.

Immunisation against panleukopenia: early development of immunity.

The time necessary to obtain the immunity of cats against Panleukopenia has been studied by means of a modified live vaccine. This vaccine makes it possible to obtain a very early post-vaccinal immunity: the full immunity is reached 72 hr after the inoculation of the vaccine by the subcutaneous route. Furthermore, we have demonstrated that a sensitive kitten can be admitted in a contaminated environment immediately after vaccination without showing any clinical evidence of the disease.

[Prevention of animal rabies by an attenuated monovalent or mixed vaccine]. / Prophylaxie de la rage animale (ou veterinaire) par un vaccin inactivé monovalent ou associé.

In view of the advantages and disadvantages of the different rabies vaccines, classified according to the production method of the virus and according to their nature - activated or inactivated - the choice of an activated vaccine produced on cell cultures is particularly justified for developing countries. The production of this type of vaccine, as well as the methods and results of the activity and innocuity controls are shown in detail. The interest of combined vaccines for certain developing countries, particularly the combined vaccine rabies/foot-and-mouth disease for ruminants, is stressed. The use of this type of vaccine on a vary large scale (more than 20 million doses up to this date) has given complete satisfaction. It should be noted that the same principles have been successfully applied to the realisation of a vaccine for human use, which can be administered before as well as after contamination.

[Use of anti-foot-and-mouth disease vaccine in oil adjuvant in young cattle]. / Utilisation chez les jeunes bovins du vaccin antiaphteux en adjuvant huileux.

A comparative study of the activity of foot-and-mouth disease vaccines, both aqueous- and oil-adjuvanted, was carried out on young bovines from vaccinated mothers. The immunity of these animals against foot-and-mouth disease was controlled after the first vaccination and booster by serology (neutralizing antibody count and immunology virulence testing). After having followed the kinetics of decrease in seroneutralizing antibodies of maternal origin the animals were vaccinated at the age of 11 weeks either with aqueous-adjuvanted or oil-adjuvanted vaccine. A booster dose was given two months later. Blood samples were taken at regular intervals and two virulence tests were made, one 21 days after the first vaccination and the other six months after the booster dose.

[Production, control and use in swine of anti-foot-and-mouth disease vaccine in oil adjuvant]. / A propos de la production, du contrôle et de l'utilisation chez le porc du vaccin antiaphteux en adjuvant huileux.

A certain number of parameters involved in the manufacture, control and use of an efficacious vaccine against foot-and-mouth disease have been studied. This report considers the problems raised by the standardization of the raw material constituent to the vaccine as well as the different types of innocuity and activity testing carried out on sows, young pigs and bacon pigs. Special attention is given to virulence testing methods, to the criteria allowing evaluation of the quality of the vaccines and to the transmission of maternal immunity of the sows to their piglets and its incidence on the vaccination schedule.

[Testing the activity of anti-foot-and-mouth disease vaccine in cattle: quantitative methods of antigenic extinction]. / Contrôle d'activité du vaccin antiaphteux sur bovins: méthodes quantitatives d'extinction antigénique.

Two methods of evaluating the activity of the foot-and-mouth disease vaccine are compared, leading to the evaluation of the number of protective doses 50% or potency. These methods differ in sensitivity, precision and equivalence potency-percentage of protection. For the same vaccine the value of the PD50 is always larger than that of Pb. We chose the Pb method using a diluent containing no adjuvant. Standards based on the evaluation of average potency have not been taken into consideration; only those standards based on the evaluation of minimum potency ensure respect of OIE's recommendation. This recommendation: 70% minimum potency with 0.95 probability is not an easier alternative, since the average protection observed corresponds in fact to at least 90% taking into account the biological variability of bovines.

[Combined vaccines including 1 or several anti-foot-and-mouth valences]. / Vaccins associés comportant une ou plusieurs valences antiaphteuses.

Combined vaccines are used for many human and animal diseases. However, we have very few examples of combinations containing anti-foot-and-mouth valence which would allow easy immunization against differnet diseases without additional handling. Until now foot-and-mouth vaccination has been applied simultaneously with anti-brucellic vaccination (Baldoni, Renoux), andi-anthrax (Nobili) and vaccination against swine fever and Aujeszky's disease (Lysenko). During the last ten years we have particularly studied the association of anti-foot-and-mouth disease vaccines with anti-brucella and anti-rabies vaccines. We have shown the possiblity of combining these different antigens, either in classical aqueous vaccines in aluminum hydroxide, or in emulsified vaccines containing oily adjuvants. The anti-brucella valences may be agglutinogenic (H 38) or non-agglutinogenic (MacEwen 45/20). The combined vaccines "rabies + foot-and-mouth disease" and "brucellosis + foot-and-mouth disease" can be produced on an industrial scale. For many years millions of animals have been successfully vaccinated in France by means of a combined "rabies + foot-and-mouth disease" vaccine.

[Anti-foot-and-mouth vaccines combined with other bacterial or viral vaccines]. / Les vaccins antiaphteux associés à d'autres vaccins bacteriens ou viraux.

Medical and sanitary prevention of a growing number of major infectious diseases of bovines has led IFFA-Mérieux to investigate the association of vaccines and to define methods of utilization. Care has been taken to limit the number of interventions and at the same time to retain in the combined valences the efficacy they had when in a state of single constituent. The work which has been carried out for the last ten years, including the study of adjuvants as well as of incompatibility of associations, has permitted the improvement of formulas, reduced in volume (5 ml for a plurivalent dose), in aqueous excipient (aluminum hydroxide and saponin) or oily excipient (oil in water type). These formulas combine 3 foot-and-mouth disease valences with a rabies valence (fixed strain grown on cell culture) or with a brucellosis valence (strain B. abortus MacEwen 45/20 and B. melitensis H 38). The innocuity of these associations allows them to be used in sanitary compaigns; their efficacy is equal to that of monovalent vaccines. A logical vaccination calendar is proposed.

Live and killed virus vaccines: their use against the respiratory diseases of cattle.

The respiratory diseases of cattle are due to a combination of different factors among which figures a viral infection. The antiviral vaccination, perfectly possible owing to associated killed vaccines and live virus, is thus a very important element which must enter into every general plan of prophylaxis. Moreover, these plans will concern bacterial infections, conditions of rearing, etc. We have demonstrated that it is possible to produce good immunity in calves and sheep using a trivalent killed vaccine (parainfluenza 3, adenovirus 3 and reovirus 1). Possible interference with antibodies of maternal origin makes the multiplication of vaccine injections desirable.