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Biomedical subjects

G Chappuis

Publications and source records attributed to G Chappuis.

At least 19 recordsLinked to original sources

Efficacy of a baiting system for vaccinating foxes against rabies with vaccinia-rabies recombinant virus.

The efficacy of a vaccinia-rabies recombinant virus (10(8) TCID50) contained in a machine-made baiting system has been tested in 22 captive young foxes which were divided into three experimental groups of six and a control group of four foxes. Each fox in groups 1, 2 and 3 were fed one, two and three vaccine-baits, respectively, on successive days. The four unvaccinated foxes were housed separately. As shown by the incorporation of a tetracycline biomarker into their bones, all the baited foxes ingested at least one bait. Thirty days after baiting seroconversion to rabies was observed in 15 (83 per cent) of the foxes and seroconversion to vaccinia in 14 (78 per cent). Sixteen of the 18 (89 per cent) baited foxes resisted a rabies challenge 30 days after baiting. One cub was protected against rabies despite the absence of detectable anti-rabies antibody. The results demonstrate that the bait-sachet system permits a good release of the virus suspension into the mouth.

Animals

Use of a vaccinia-rabies recombinant virus for the oral vaccination of foxes against rabies.

The vaccination of wild animals against rabies has been developed most extensively in Europe. Experiments have demonstrated the efficacy of a vaccinia-rabies recombinant virus administered by the oral route in foxes. The innocuity of this vaccine was tested in the target species as well as in several non-target wild and domestic species. Because of its safety and heat-stability, this recombinant virus should offer an excellent alternative to the attenuated strains of rabies virus currently used in the field. A large scale field trial was conducted in Belgium in October 1988 to assess the efficacy of this new vaccine-bait systems.

Animals

ELISA detection of bovine viral diarrhoea virus specific antibodies using recombinant antigen and monoclonal antibodies.

A panel of monoclonal antibodies was prepared by immunization of BALB/c mice with Moredun (BD) virus strains. These antibodies were characterized by immunofluorescence and seroneutralization against BD, BVD and hog cholera (HC) virus strains, and radioimmunoprecipitation of BVD-infected cells extracts. The MAbs reacting with the majority of the Pestivirus strains recognize the 80 kDa antigen of the BVD cytophathic strains. The 80 kDa antigen of the BVD/Osloss virus strain has been cloned and expressed in E. coli as a fusion protein with beta-galactosidase. The fusion protein has been purified from inclusion bodies and used successfully as an antigen for ELISA detection of BVDV specific antibodies in bovine sera. A competitive ELISA using MAbs is more specific than a direct assay. These results compare well with the ones obtained with antigen extracted from BVDV-infected cells.

Animals

Use of vaccinia rabies recombinant for oral vaccination of wildlife.

A vaccinia rabies recombinant virus was constructed and shown to induce the synthesis of rabies virus glycoprotein in infected cells and to induce rabies virus neutralizing antibodies and protection in susceptible animals. Active when orally administered, this recombinant is a good candidate for the development of vaccines for wild animal rabies vectors. This recombinant was found stable, safe for target and non-target animal species, and protective for most of the rabies vectors. After extensive experimental studies conducted under controlled conditions, it as used in limited field trials and in an extensive open field trial. The preliminary results confirmed its basic properties and potential for rabies eradication.

Animals

Primary multiplication site of the vaccinia-rabies glycoprotein recombinant virus administered to foxes by the oral route.

The primary multiplication site of VVTGgRAB, a recombinant vaccinia virus (VV) expressing the rabies virus G glycoprotein, was studied in comparison with that of the parental VV Copenhagen strain, after oral administration to foxes. Foxes were fed with 10(8) TCID50 of either VVTGgRAB or VV and were sacrificed 12, 24, 48 or 96 h after inoculation. Both viruses were detected by viral isolation in the tonsils during the first 48 h after inoculation at titres between 10(2) and 10(4.3) TCID50/ml. Indirect immunofluorescence confirmed the presence of the virus in tonsils of some of the foxes. The polymerase chain reaction allowed the detection of VVTGgRAB in the tonsils of both of two foxes tested after 24 h, three of three foxes after 48 h, in the buccal mucosa of one of two foxes tested after 24 h and two of three foxes after 48 h and in the soft palate of one of two foxes tested after 24 h and one of three foxes after 48 h. VV was detected in the tonsils of one fox tested after 48 h, in the buccal mucosa of another fox tested after 24 h, and in the first fox after 48 h by the same reaction. Foxes were inoculated with virus isolated from fox tonsils 24 h after oral administration (with or without cell culture amplification) to perform back passages. No virus could be isolated in either case after this passage. The innocuity of VVTGgRAB was also demonstrated when foxes were inoculated with passaged virus.

Administration, Oral

Vaccination against pseudorabies with glycoprotein gI+ or glycoprotein gI- vaccine.

Subunit pseudorabies vaccines that contained only purified glycoproteins of either of 2 strains of pseudorabies virus (PRV) were prepared and subsequently tested for safety and efficacy. The strains of virus used for vaccine production differed in at least 2 properties. One strain (Kojnok) was virulent for pigs and was believed to code for the entire complement of viral glycoproteins. The other (Kaplan) was a deletion mutant that was unable to code for structural viral glycoproteins gI and gp63. Purified glycoproteins were dispersed in an oil-in-water emulsion and were administered IM to pigs. Both vaccines were found to be safe and effective immunogens. Neither caused any local or general reactions, as verified by examination of the injection site (local safety) and by vaccination of pregnant sows in PRV-infected and noninfected herds. Sows vaccinated with the gI+ or gI- vaccine protected their pigs at levels of 93 and 92%, respectively, against a severe challenge exposure that killed 98% of pigs born from nonvaccinated sows. Vaccinated pigs were tested for active immunity by intranasal challenge exposure with the NIA 3 strain. Protection was quantitated by measuring the relative daily weight difference, expressed in percent per day, between vaccinated and control pigs during the first week after challenge exposure (delta G7); the estimated differences were 2.25 and 2.13% for gI+ and gI- vaccines, respectively. The absence of gI and gp63 did not affect the efficacy of this type of subunit glycoprotein vaccines.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

The potency testing of pseudorabies vaccines in pigs. A proposal for a quantitative criterion and a minimum requirement.

A criterion for the potency testing of pseudorabies vaccine based on the difference between the mean weight gain during the seven days after pathogenic challenge of vaccinated or control piglets is proposed. This criterion, termed delta G7, has been studied as a function of initial weight variation of the animals, different challenge strains and the period between challenge and the end of the test. The statistical analysis of results optimizes the experimental parameters and gives rise to a quantitative test which discriminates between vaccinates and controls and substantiates a proposal for a minimum vaccine potency requirement. The implementation of the method proposed is compatible with current practice in control laboratories.

Animals

Comparative analysis of monoclonal antibodies against pestiviruses: report of an international workshop.

Thirty-three pestivirus strains were grown in cell culture and characterized by immunostaining with 19 monoclonal antibodies (MAbs) raised against hog cholera virus (HCV), with 42 MAbs against bovine viral diarrhoea virus (BVDV) and with 13 MAbs against border disease virus (BDV). Seven MAbs reacted with all pestivirus strains tested, eight MAbs detected only the seven HCV strains, three detected only the 16 BVDV strains. No MAb was found that was specific for BDV. BVDV and BDV strains were broadly cross-reactive with the MAbs, indicating a close relationship between these two species, whereas HCV strains were characterized as distinct from BVDV and BDV.

Animals

Use of recombinant vaccinia-rabies glycoprotein virus for oral vaccination of wildlife against rabies: innocuity to several non-target bait consuming species.

The pathogenicity of a vaccinia recombinant virus expressing the rabies glycoprotein (VVTGgRAB) was tested in several wild animal species which could compete with the natural rabies host, the red fox (Vulpes vulpes) in consuming vaccine baits in Europe. The following species were included in this study: wild boar (Sus scrofa), Eurasian badger (Meles meles), wood mouse (Apodemus sylvaticus), yellow-necked mouse (Apodemus flavicollis), bank vole (Clethrionomys glareolus), common vole (Microtus arvalis), field vole (Microtus agrestis), water vole (Arvicola terrestris), common buzzard (Buteo buteo), kestrel (Falco tinnunculus), carrion crow (Corvus corone), magpie (Pica pica) and jay (Garrulus glandarius). During the observation period, the 107 animals given the VVTGgRAB vaccine orally did not show any clinical signs. Daily monitoring for 28 days and postmortem examination did not result in the detection of pox lesions in the oral mucosa or the skin in mammals or the unfeathered portions of birds. VVTGgRAB seems to multiply in the mammalian species tested, since rabies seroconversion was observed in all of them. Birds failed to develop demonstrable rabies virus-neutralizing antibody. A seroconversion against vaccinia virus was observed in two of four wild boars. Serological results obtained in badgers and wild boars also demonstrates the absence of direct or indirect horizontal transmission of the recombinant virus. The potential of the recombinant virus for the immunization of badgers against rabies also was investigated. Only 50% of the badgers orally administered with 1 x 10(8.3) TCID50 of this vaccine were protected against rabies.

Administration, Oral

Evidence for a multiple innervation of cerebellar Purkinje cells by climbing fibers in adult ferrets infected at birth by a mink enteritis virus.

Newborn ferrets were inoculated with Mink Enteritis virus (parvovirus). They developed a cerebellar hypoplasia and presented severe ataxia. Electrophysiological study by intracellular recordings in the cerebellar cortex demonstrates that in these ferrets, like in other mammals, Purkinje cells deprived from granule cell input during development remain multiply innervated by climbing fibers in the adult.

Animals

[Diagnosis of enzootic bovine leukosis by the ELISA test of mixed and individual milk].

The ELISA test was applied to mixed milk from 325 cowsherds of the Landes region of France. From the 88 cowsheds giving a positive or inconclusive response, individual samples of milk were studied by the ELISA test, and individual samples of serum by the agar immunodiffusion test (1734 cows). The same procedure was carried out on 1250 animals in a sample of 49 cowsheds chosen at random from amongst the 237 cowsheds whose mixed milk gave a negative response to the ELISA test. The results confirmed the importance of the ELISA test applied to mixed milks, provided that the samples are studied several times per year, so as to minimize default errors. The study of individual milk allowed the identification of 92 to 94% of the infected animals, with a specificity of 98 to 99%. The systematic and repeated testing of mixed milks by the ELISA test should allow initial detection of infection and supervision of a satisfactory cost-efficiency report in the decontaminated cowsheds.

Animals

Study of the efficacy of an inactivated virus vaccine against porcine parvovirus.

The efficacy of an inactivated virus vaccine against porcine parvovirus has been studied by immunizing 4 sows during pregnancy. A parvovirus virulent strain has been inoculated to these sows and to two other unvaccinated sows used as controls. The infection was performed between the 52nd and the 57th day of gestation. In the litters born from the vaccinated sows, 82% of the piglets were alive and normal. Neither PPV antibodies nor antigen could be revealed in the stillborn fetuses born from the 4 vaccinated sows. Reversely, only 9.5% of the piglets born from the 2 unvaccinated sows were alive at birth, although they were probably infected during pregnancy. In total, 86% of fetuses in these 2 litters were mummified. A field study allowed to show that the double vaccination antibodies induced, persisted with constant titers for, at least, 13 months. Moreover, the reproductive performance of 413 gilts, vaccinated twice before mating, were not affected by this treatment.

Animals

[Diagnostic problems posed by respiratory infections of dogs].

The following viruses as well as bacteria and mycoplasma have been isolated from dogs with contagious respiratory disease: canine distemper virus; Canine adenoviruses (type 1 and 2); Parainfluenza type 2 (SV5); Reovirus type 1; Canine Herpesvirus; Bordetella bronchiseptica, Streptococcus, Pasteurella, Staphylococcus and Mycoplasma. The occurrence of these agents can be in direct relationship with: the evolution of a systemic disease; respiratory disorders being a regular or inconsistant symptom of this disease; the evolution of a disease restricted to the respiratory tract; the tropism of the bacterial or viral agent is exclusively respiratory; secondary bacterial complications to a primary viral infection; saprophyte state or latency without pathologic significance. These various infectious agents are implicated alone or in mixed infections and the wide variety of clinical symptoms don't allow to precise a clinical diagnosis. We will try to bring some bases allowing, by the help of laboratory an etiologic diagnosis. This diagnosis is essential for providing an efficient prevention. We will approach some parameters which we have been confronted with as regards Canine Distemper and Canine Adenovirosis. Our purpose is, through these examples of the canine pathology, to confirm and complete some other similar situations which can appear in other animal species.

Adenoviridae Infections

[Serological response of the dog after primary antirabies vaccination using adjuvant or non-adjuvant vaccines].

The serological responses following a primary vaccination carried out one year before in two groups of dogs which received an inactivated cell culture vaccine containing or not an adjuvant (alumine-hydroxide) are compared. Neutralizing antibody titers assayed in mice, obtained with only one injection of the adjuvanted vaccine are at the same or a greater level than those induced by two injections of the non-adjuvanted vaccine administered two to four weeks apart (statutory schedule of rabies primary vaccination applied in France).

Adjuvants, Immunologic

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.

Animals