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P Vannier

Publications and source records attributed to P Vannier.

At least 37 records · Page 2Linked to original sources
PubMed1992

Round table on control of Aujeszky's disease and vaccine development based on molecular biology.

A summary is given on the 4 topics which were discussed during the round table and which represent current knowledge on the molecular biology of Aujeszky's disease (pseudorabies) virus. They include a review on 1. the genome and gene products of the virus; 2. the viral genes associated with virulence; 3. the immunological role of the viral gene products and 4. studies intended to compare the efficacy of several commercially available vaccines and to establish a possible correlation between antibodies against individual structural viral proteins and degree of protection. It was concluded that gI deleted vaccines appear to be the best choice for use in intensive vaccination programmes towards eradication of Aujeszky's disease virus. However, there remains a need for development of more potent vaccines which induce strong humoral and cell mediated immune responses and afford complete protection, virological protection included. It is often observed that live vaccine strains which are completely avirulent lose much capacity to replicate and spread within the vaccinated animal. It is, however, not excluded that a certain degree of dissemination may be needed to be fully efficacious. Loss of virulence may thus be accompanied by too much loss of immunogenicity. An improved genetic stability of live vaccine strains when they are obtained by genetic manipulation, possibly justifies a more widespread dissemination of the vaccine strain in the body compared to that with conventionally developed strains or compared to what is presently allowed.

Animals↗
PubMed1992

Experimental infection of pigs with the porcine respiratory coronavirus (PRCV): measure of viral excretion.

Twelve pigs were experimentally infected with a porcine respiratory coronavirus (PRCV) by the oronasal route. Viral excretion was measured daily by two means-deep nasal swabs and air samples obtained in a cyclone sampler. Clinical signs were very slight on infected pigs. Airborne virus could be recovered from day 1 to day 6 post-infection in the cyclone sampler as well as in petri dishes placed in the same loose-box. Viral titres obtained from nasal swabs were significantly correlated with those obtained from air samples. Different collection media were compared. The most efficient media for the collection of infectious viral particles contained a protective agent such as foetal calf serum.

Air Microbiology↗
PubMed1992

Control of product batches (before and after registration). The French approach.

The issue of investigation into vaccine files and control in general has always been a delicate one. There are considerable economic and medical interests. The supervisor should not then thwart a step towards progress and should not appear as an economic brake. Yet he should guarantee to the users a certain quality in the marketed biological products. According to these principles, recommendations have been formulated to indicate tests that should be realized by manufacturers and related in files of request for Marketing Authorization. Consequently the level of requirements may seem quite high in France. But partners involved in the investigation of files and in vaccine controls as well as those who are concerned with the marketing of new biological products should guarantee their quality. In addition to investigating the file, controls are undertaken in France by State laboratories which specialize in a particular species. They are also applied research laboratories. These controls aim at checking the manufacturers' results. In France no systematic control is undertaken on successive vaccine batches before marketing. Controls are undertaken at random if information coming from users gives rise to suspicion about a vaccine or batch of vaccines which are causing problems. However systematic controls should be undertaken by a private or State laboratory for imported batches. In future, only control results will probably be required. However batch-to-batch controls are undertaken by a state laboratory for rabies vaccines and tuberculin. In conclusion, in France we favour controls before Marketing Authorization together with high specifications for manufacturers. State batch-to-batch control is not undertaken since present means do not encourage such a procedure, the interest of which are not obvious; furthermore, this procedure remains very restricting for manufacturers.

Animals↗
PubMed1992

Presentation of the directive 81/852/EEC (92/18) safety testing.

The aim of the directive is to define tests to be done by a manufacturer which are capable of providing as precise information as possible about the properties of the biological products concerning safety. These tests have to be done in the target species and the dose used should be that quantity of the product recommended for use and containing the maximum titre of potency. The samples for safety testing should be taken from a batch produced according to the manufacturing process. The vaccine is tested in normal conditions at the recommended dose and by each recommended route of administration to animals of each species and category it is intended to vaccinate. Objective criteria have to be recorded to measure possible adverse general and local effects. But tests in abnormal conditions of use may be necessary, such as administration of an overdose or repeated administration of one dose. Effects on reproductive function and progeny have to be studied as well as investigations which may be required in some cases to evaluate a possible adverse effect on the immunological function of the vaccinated animal. Special requirements seem to be appropriate for live vaccines: to evaluate the spread of the vaccinal strain from vaccinated to unvaccinated animals including, if necessary, wild species; to determine whether the vaccinal strain can disseminate in the vaccinated organism; to check for the absence of reversion to virulence of live stains especially for conventional vaccines. Field studies can therefore provide complementary information about safety.

Animal Diseases↗
PubMed1992

Report on the first outbreaks of the porcine reproductive and respiratory syndrome (PRRS) in France. Diagnosis and viral isolation.

We describe the first known occurrence in France of the porcine reproductive and respiratory syndrome (PRRS), a new porcine disease that first appeared in Germany in November 1990. Outbreaks of the disease appeared in November 1991 in Brittany (France), with comparable clinical features to those observed in other countries, were definitively confirmed by a serological analysis from the affected animals using an immunoperoxidase monolayer assay with PRRS-virus infected alveolar macrophages. Furthermore, we report the isolation from one serum of a filtrable agent that, in view of its cytopathic effect for porcine alveolar macrophages and of the serologic reactivity of the infected cells, appears similar to the Lelystad virus that has been implicated in the etiology of the disease.

Animals↗
PubMed1992

An enzyme linked immunosorbent assay (ELISA) for the detection of antibodies to the porcine reproductive and respiratory syndrome (PRRS) virus.

An indirect enzyme-linked immunosorbent assay (ELISA) has been developed for the rapid detection of antibodies to the porcine reproductive and respiratory syndrome (PRRS) virus in pig sera. Compared to the immunoperoxidase monolayer assay (IPMA) which was the only test available up till recently for serodiagnosis of the disease, the ELISA test proved to be more sensitive, particularly for early detection of antibodies. The test was also highly specific for the PRRS virus inasmuch as it scored negative all the hyperimmune sera directed to other swine viruses and the field sera sampled before the outbreak of the disease in Brittany (France). This easy test now provides further possibilities for epidemiological surveys and could also be a reliable tool for new sanitary prophylaxis of the disease.

Animals↗
PubMed1992

Protection of piglets born from ruminant pestivirus experimentally infected sows, and their contacts, to the challenge with hog cholera virus.

Two groups, A and B, of two specific pathogen-free pregnant sows were experimentally infected between the 25th and 29th days post-breeding with two strains of ruminant pestivirus: NADL cytopathic bovine viral diarrhoea virus for group A and Aveyron non-cytopathic border disease virus French strain for group B. Two other pregnant sows (group C) were kept uninoculated as control. When 7 weeks old, 8 piglets of group C were put in contact with 4 piglets of group A (group D), and 8 other piglets of group C with 4 piglets of group B (group E) in two separate pens with the purpose of testing the horizontal transmission of the viruses. All animals were kept under observation and serologically controlled at weekly intervals; two pigs of each group were finally submitted to a challenge with hog cholera virus. The two pigs of group E which were put in contact with the offspring of the border disease virus infected sow were protected; all other animals developed typical hog cholera symptoms and died. The relation between neutralizing titres of the sera to ruminant pestiviruses and protection to the challenge with hog cholera virus is discussed. The two protected pigs had high neutralizing antibody titres to border disease virus but no antibody to hog cholera virus at the time of the challenge. Though the two viruses look serologically distant, we surprisingly observed that infection with border disease virus protects against a superinfection with hog cholera virus.

Animals↗
PubMed1991

Induction of lactogenic immunity to transmissible gastroenteritis virus of swine using an attenuated coronavirus mutant able to survive in the physicochemical environment of the digestive tract.

A transmissible gastroenteritis (TGE) coronavirus mutant (188-SG), selected as attenuated and resistant to acidity and proteases of the digestive tract of adult pigs, was used as vaccine ("Nouzilly strain") in sows to protect suckling piglets against a challenge exposure carried out with a highly virulent TGEV strain. The pregnant sows were immunized once (42-49 days before farrowing) or twice (42-49 and 7-15 days before farrowing) by the oral, intramuscular or conjunctival route with the 188-SG strain. Sows exposed to virulent TGEV in the field and experimentally infected sows (two oral inoculations during pregnancy) were used as positive controls leading to high protection. The neutralizing antibody response to vaccination and/or infection was studied in serum and milk. No protection against mortality was observed in the litters of (1) the nine seronegative, susceptible sows, with piglet mortality of 65/70, (2) the seven once orally vaccinated sows, with mortality of 44/54, (3) the seven sows vaccinated twice by the conjunctival route, with mortality of 55/76. Moderate protection was observed in (1) the eight sows vaccinated intramuscularly twice with piglet mortality of 36/90, (2) the seven orally and intramuscularly vaccinated sows with piglet mortality of 31/51. In of 3 contrast, improved protection was observed in (1) the 10 sows vaccinated twice orally, with piglet mortality of 23/95, (2) the four naturally infected sows with piglet mortality of 6/41, (3) the six sows experimentally infected with virulent TGEV with piglet mortality of 1/59. No correlation was found between neutralizing antibodies titers in serum and milk and protection rate of the piglets. The results indicate that relative protective lactogenic immunity against TGEV is induced only by repeated ingestion of the attenuated 188-SG strain of TGEV.

Administration, Oral↗
PubMed1991

Vaccination of pigs against Aujeszky's disease by the intradermal route using live attenuated and inactivated virus vaccines.

Inactivated and live Aujeszky's disease virus vaccines were administered intradermally using a special device without a needle. The 88 pigs were vaccinated at the beginning of the fattening period, both under experimental conditions and in commercial herds. All the pigs were challenged at the end of the fattening period in isolation units. The same vaccines were also injected intramuscularly. Vaccination by the intradermal route induced good protection, similar to that conferred with live virus vaccine injected intramuscularly. The inactivated virus vaccine was not as effective when it was injected by the intradermal route. In animals vaccinated intradermally, there were no local lesions in the meat, but very small nodules were found in the dermis; these do not affect carcass quality. The effects of challenge exposure depended on the initial health of the animals, and a synthetic value (delta G) was used to interpret the data. In fattening pigs, intradermal vaccination required less animal constraint than intramuscular injection; administration could be verified by the presence of a papule at the site of inoculation, and pigs could be vaccinated while they were feeding. Injection without a needle also helps avoid bacterial contamination under farm conditions.

Animals↗
PubMed1991

Level of virulent virus excreted by infected pigs previously vaccinated with different glycoprotein deleted Aujeszky's disease vaccines.

Seven deleted Aujeszky's disease vaccines were compared for their ability to induce an immunity which suppresses virus excretion. For each vaccine, the levels of clinical protection and viral excretion were compared. Groups of eight pigs were vaccinated twice with attenuated deleted Aujeszky's disease vaccines (which do not express certain glycoproteins: gI, gX or gp63). Pigs were vaccinated at the beginning of the fattening period and challenge took place at the end of it when the pigs were 18-19 weeks old. Live virus vaccines were suspended in water or in an oil-in-water emulsion. The experiment was performed in three successive assays of two groups of eight pigs (except three groups for the first assay). At each assay, a control unvaccinated group of eight pigs was added to compare the effects of challenge between vaccinated and unvaccinated animals. In total, 80 pigs were involved in this experiment. All the vaccinated pigs excreted virus from 3 to 9 d after challenge. However the level of viral excretion and the duration of the period of excretion were reduced after vaccination and especially, when oil-in-water emulsion was used. There were obvious differences between vaccines. With some vaccines, when the level of viral excretion was low, the level of clinical protection was high. However, in other cases, the level of clinical protection could be good despite a higher level of viral excretion. The seroneutralizing titres were significantly and inversely related to a low level of viral excretion but not to the level of clinical protection.

Animals↗
PubMed1990

Restriction fragment pattern analysis of genomes from French isolates of suis herpes virus 1 (Aujeszky's disease virus).

Purified DNA from 45 isolates of suis herpes virus 1 (SHV1) collected between 1980 and 1987 from clinical outbreaks of Aujeszky's disease on French farms was compared by restriction fragment pattern (RFP) analysis. The BamHI generated RFPs were found to be distinguishable, confirming RFP analysis as a potential epidemiological tool. The RFP could be assigned to two established major electrophoretic types and different subtypes. The RFP analysis indicated that the majority of outbreaks were caused by ADV with a central European genome type. The heterogeneity of RFPs among PRV isolates recovered from the central nervous system, lung, and foetus was not restricted specifically to one clinical entity. Variations in the virulence of the 45 isolates studied in mice, chicks, or piglets were unrelated to the RFP subtypes. One unusual RFP has been described for one strain of low virulence.

Analysis of Variance↗
PubMed1990

Sequence analysis of the gene (6) encoding the major capsid protein (VP6) of group C rotavirus: higher than expected homology to the corresponding protein from group A virus.

Two overlapping c-DNA clones, which hybridized in Northern blots to RNA segment 6 of the prototype strain (Cowden) of group C rotavirus, were selected from a c-DNA library in pBR322 and sequenced. The gene 6 sequence obtained was 1349 nucleotides and contained a single long open reading frame encoding a protein of 394 amino acids (total MW, 44,479) which is in line with the size of the major capsid protein VP6. Comparison of the group C sequence with that of the corresponding group A rotavirus gene revealed homology levels of 55 and 42% for nucleotides and amino acids, respectively. These values were surprisingly high in view of previous immunological and nucleic acid hybridization data which failed to show any cross-reaction between group A and non-group A rotaviruses. The epidemiological implications of these observations are discussed.

Amino Acid Sequence↗
PubMed1990

Polymorphism of hyaluronidase in serum from man, various mouse strains and other vertebrate species revealed by electrophoresis.

Polymorphism of hyaluronidase (EC 3.2.1.35) was detected in the serum from 6 out of 20 vertebrate species by electrophoretic analysis. Electrophoresis was performed on a hyaluronan-containing polyacrylamide gel, that visualizes hyaluronidase activity upon incubation at acid pH. No hyaluronidase activity was detected in the sera of horse, swine, cattle, goat, sheep, rabbit, chicken, Triton alpestris, Triton palmatus, Triton vulgaris, pleurodeles, axolotl, eel and dog-fish. The 6 positive sera were from man, mouse, rat, Syrian hamster, dog and Triton cristatus. In each of these species, the electrophoretic banding pattern of hyaluronidase was different, as was the activity per unit volume of serum. Furthermore, in mice, the 12 strains analyzed could be divided into 3 groups, containing the following numbers of hyaluronidase bands; 8 (BALB/c/J, BALB/c/By, ICFW, SW, XVIInc/Z), 5 (DBA/2 Mrc Ico, DBA/2 Mrc Ico nu/nu, B10.D2/nSn), and 1 (C57B/Rho Ico, C57BL/6/By, C57BL/6/J Ico, C57BL/6/J Ico nu/nu). Human serum generally displayed only 1 band, although there was a 2nd faint band in a few cases and a 3rd in 1 case. Rat serum displayed 4 bands, Syrian hamster serum, 3, and dog and Triton cristatus serum, 1.

Ambystoma↗
PubMed1990

Silver staining of DNA restriction fragments for the ultrarapid identification of pseudorabies virus strains.

Restriction endonuclease analysis of pseudorabies virus DNA has been used to study various virus strains. To make use of a rapid technique for the identification of viral strains, studies have been undertaken to facilitate purification of the DNA from viral particles present in cytoplasmic fractions. The ultrasensitive photochemical silver staining of nucleic acid, described by Beidler et al. (Analytic Biochemistry 1982: 126) has been adapted and applied to the detection of pseudorabies virus restriction fragments. In a period of 5 h more than 1 microgram of DNA can be extracted from a 25 cm2 plastic flask containing infected cells and purified without ultra centrifugation. Low molecular weight DNA was separated from high molecular weight DNA by polyacrylamide gel electrophoresis. The restriction fragments were selectively visualized by silver staining which can detect 0.025 micrograms of total pseudorabies virus DNA. The electrophoretic DNA pattern of vaccine and wild strains has been studied using these techniques and the results agree with previously published data.

DNA Restriction Enzymes↗
PubMed1990

Diagnosis of swine influenza with an immunofluorescence technique using monoclonal antibodies.

Direct diagnosis of swine influenza infection by an indirect immunofluorescence technique using anti-nucleoproteine monoclonal antibody was compared with virus isolation. Five 8-week-old pigs were inoculated with 2 x 10(7) EID50 of strain A H1N1Sw/4115/85. Clinical signs developed in only three pigs. Antigen was detected in nasal epithelial cells obtained from all animals the first day after inoculation; the antigen was detected in one pig 6 days after the infection. Fluorescence was present in the nucleus, nucleolus and cytoplasm of infected cells. The indirect immunofluorescence test was specific and as sensitive as virus isolation in embryonated eggs, allowing a rapid diagnosis that could be achieved within hours.

Animals↗
PubMed1990

Disorders induced by the experimental infection of pigs with the porcine respiratory coronavirus (P.R.C.V.).

Five colostrum deprived hysterectomy-derived piglets were inoculated by the intratracheal route with a Porcine Respiratory Coronavirus (PRCV). The clinical effects and growth performances were compared with those in 5 similar piglets which were inoculated with Minimum Eagle Medium only. A transient hyperthermia, mild to severe dyspnoea, polypnoea and an obvious cessation of growth were recorded on infected pigs only whereas the control group did not show any adverse reaction after inoculation. The reasons for the variability of effects of experimental infection observed in previous trials, are discussed.

Animals↗
PubMed1990

A blocking ELISA to differentiate hog cholera virus antibodies in pig sera from those due to other pestiviruses.

The blocking ELISA technique was extended to comparative serology by using 3 different pestivirus strains: Hog cholera virus (HCV) Alfort strain propagated in PK15 cell line, Border disease virus (BDV) Aveyron strain in PK15 and BVD NADL** strain in fetal calf kidney (FCK) primary cells. Rabbit antisera to the Alfort HCV strain and Aveyron BDV strain were raised for use in the test. A bovine hyperimmune serum to BVD virus was also used for detecting antibodies specific to BVD virus. The ELISA was compared with the neutralisation test on various groups of field and experimetnal porcine sera. The results obtained with the ELISA were well correlated with the neutralisation test. Therefore the ELISA may be recommended as a differential serological test between HCV and other pestivirus antibodies in pig sera.

Animals↗