PubMed Health⌕ Search

Biomedical subjects

R Cariolet

Publications and source records attributed to R Cariolet.

34 records · Page 2Linked to original sources
PubMed1992

Air sampling procedure for evaluation of viral excretion level by vaccinated pigs infected with Aujeszky's disease (pseudorabies) virus.

Five groups of eight fattening pigs were vaccinated and then infected with Aujeszky's disease virus. Viral excretion was evaluated by two means: deep nasal swabbing and air sampling. It appeared that infectious airborne virus could be recovered from day 1 to day 6 after infection in the isolated units where control animals were raised. In vaccinated animals, airborne particles were also detected but the amount and duration varied in relation to their immune status at the day of virulent challenge: viral excretion was significantly lower in pigs presenting a high antibody level (1/16 to 1/64) just before infection. Results obtained with nasal swabs and with air samples were closely related. Despite its low sensitivity, the air sampling procedure could be considered as an efficient tool for reflecting infectious viral pressure in a confined atmosphere.

Air Microbiology↗
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

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↗
PubMed1992

Characterization and pathogenicity for pigs of a hog cholera virus strain isolated from wild boars.

One hog cholera virus strain isolated from an outbreak of the disease in a wild boar breeding herd in Brittany (France) in 1990 has been characterized with a panel of monoclonal antibodies to hog cholera virus and ruminant pestiviruses: the strain was found to be indistinguishable from that of other domestic pig isolates. The pathogenicity of the strain to domestic pigs was evaluated by infecting intranasally, intramuscularly and by contact 17 specific pathogen-free 6-week- and 12-week-old pigs. Sixteen of the 17 pigs showed symptoms of hog cholera. The virus was detected in the blood of the 16 pigs during all phases of hyperthermia which persisted up to death or the terminal phase, ie between 16 and 29 days post-infection. One animal recovered after presenting a mild form of the disease. This pig was the only one which raised antibodies to the virus. Typical hog cholera lesions were observed in 2 pigs only; the other animal showed very few pathological changes. No relationship between intensity or duration of the disease and pathological changes could be established.

Animals↗
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↗
PubMed1989

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

A study was undertaken of the protection induced by inactivated and live Aujeszky's disease virus vaccines. The vaccines were administered using a special device which, without the use of a needle, delivered the preparation intradermally. The trials were performed on 88 pigs which were vaccinated at the beginning of the fattening period both in experimental conditions and in pig herds. All the pigs were challenged at the end of the fattening period in isolation units. The results obtained were compared with those obtained using the same vaccines injected intramuscularly. It was shown that vaccination via the intradermal route induced good protection in the vaccinated animals and was similar to that conferred by live virus vaccine injected intramuscularly. The results, with the inactivated virus vaccine, were not so good when it was injected via the intradermal route. Studies with intradermal vaccination showed no local lesion or very small nodules strictly localized to the dermis. The results also confirmed that the effects of challenge exposure depended on the health status of animals prior to infection and show the necessity to use a synthetic value (delta G) to interpret the data and mainly to compare the results objectively. In fattening pigs this vaccination procedure is attractive because (i) less animal constraint is needed than would be for intramuscular injections, (ii) injection can be checked by the presence of a visible papula at the site of inoculation and, (iii) pigs can be vaccinated in the ham while they are feeding. Injection without a needle also contributes to avoiding bacterial contamination under practical farm conditions of vaccination.

Animals↗
PubMed1989

Rapid diagnosis of TGEV-like coronavirus in fattened pigs by indirect immunofluorescence labelling in nasal cells.

Diagnosis of TGEV-like coronavirus was made by an immunofluorescence technique using monoclonal antibodies directed against TGEV. Six, 15 weeks-old pigs were inoculated intratracheally with the strain P 6008 ST 4. No clinical sign was observed during the course of the infection. Viral antigens were detected in the cytoplasm of nasal cells obtained from swab in five animals as early as one day p.i. and during several days. The sensitivity and specificity of this method appeared to be comparable to virus isolation of this cell-adapted TGEV-like strain.

Animals↗
PubMed1986

Relevance of some behavioural criteria concerning the sow (motor activity and water intake) in intensive pig farming and veterinary practice.

In the pregnant tethered sow, water intake and motor activity were found to be related to urinary problems and productivity. Therefore, further studies were undertaken on these points. The 258 pregnant sows from eight breeding finishing herds were submitted to water intake control and the investigation of motor activity was performed on 125 pregnant sows from 6 herds. Despite the same process of water supply, the intake varied a lot from sow to sow (mean: 17 litres/day/pregnant sow, (sigma = 6.9 l). The major part of water was drunk during feeding time. The following factors were found associated with water intake: body condition, lameness, parity, stage of pregnancy. The relations between water intake and urine composition were assessed. A low water intake was close related to high urine gravity and to abnormalities (crystals, proteinuria, bacteriuria). The pregnant tethered sows spent an average time of 250 min in the standing position. A diurnal rhythm was clearly observed and it was synchronized by feeding time. The following factors were found to be related to the standing time: parity, body condition, lameness. The frequency of standing up per 24 hours was not related to the total standing time. Under farm husbandry, standing time is rather inconstant in individual sows on subsequent days. Since photo cell apparatus cannot be used as a routine in veterinary practice, we have looked for a more simple method: the position of the sows one hour after feeding time. This index gave an accurate view of the total standing time and represented a practical parameter for epidemiological purposes. The relevance of measuring water intake and motor activity in veterinary practice is discussed.

Animal Husbandry↗
PubMed1984

[Transmissible gastroenteritis: vaccination of sows in contaminated environment using inactivated virus in oil emulsion].

An oil emulsion vaccine against TGE was prepared using a virus suspension produced in tissue culture and inactivated by formaline. Intramuscular vaccination trials were performed on sows in the field from two herds (167 sows) which had been infected by TGE virus more than one year previously. Considering qualities of immunity after natural infection, the objective of the work was to try to give a new impetus to immunity in such herds using vaccination as a booster. After two vaccine injections the serological pattern of the herd was modified: negative serological reaction disappeared, the proportion of highly positive serological reactions increased and higher homogeneity was observed in the distribution of levels of neutralizing antibody reactions. In contrast, using protection tests in piglets against virulent challenge, there was no evidence of significant differences between litters from vaccinated sows (86% of piglets were protected) and those of unvaccinated sows (89% of piglets were protected). Our results suggest that passive protection given to piglets by lactogenic immunity following natural infection could last all the economic life of the sow. The interest of the vaccination as a booster of mammary immune response and its epidemiological consequences are discussed.

Animals↗
PubMed1984

Motor activity of pregnant tethered sows.

Continuous recording of body postures (standing or lying) using photocells connected to an event recorder was carried out on 125 pregnant sows tethered either by a thoracic girth or by a neck harness in six different farms, at different times of the year. Standing activity occupied an average of 250 min per day. This position occurred mainly during daytime, with amount of standing during the night (10 p.m. to 6 p.m.) averaging less than 2% of the total time. This mean value was found in 4 farms out of 6. However, on one farm, standing postures lasted 390 min and this hyperactivity was associated with stereotypes. In another farm, time spent standing did not exceed 180 min. In all cases, multiparous sows spent about 60% more time standing than first or second litter sows. Time spent standing was dependent on other animal characteristics such as physical condition and foot condition, and also on environmental factors. Activity rhythms were synchronized by food distribution. These results are discussed together with the potential of using motor activity to characterize adaptability of sows to tethering.

Animals↗
PubMedDate not supplied

Development of a complete ELISA using Salmonella lipopolysaccharides of various serogroups allowing to detect all infected pigs.

Although poultry is recognized as the major source of food-poisoning caused by Salmonella, pork also contributes to human infections. This study was therefore undertaken in order to develop a reliable serological method for the evaluation of the Salmonella status of piglets. A complete ELISA was performed using lipopolysaccharides of Salmonella Typhimurium, Anatum, Hadar and Infantis because these serovars were representative of the serogroups isolated from 30 contaminated fattening farms. S. Enteritidis was also added because of its importance in human infection and to include the O:9 antigen. This method potentially detects 100% of infected pigs. A significant correlation was found between this serological method and the bacteriological data from mesenteric lymph nodes (p = 0.01). In addition, both sensitivity and specificity were high (97% and 94% respectively). The ELISA test was therefore used in a cross-sectional study on 4 farms to evaluate when pigs became contaminated: seropositive pigs were only found for the 20 week old finishing pigs. The antibody response to Salmonella in piglets was also investigated: maternal antibodies persisted until 7 weeks of age and post-Salmonella contamination seroconversion was detected from 8 weeks of age onwards.

Animals↗
PubMedDate not supplied

Contamination of pigs by nose-to-nose contact or airborne transmission of Salmonella Typhimurium.

The aim of this study is to assess the risk of contamination by Salmonella Typhimurium of pigs by nose-to-nose contact or the airborne route. Thirty twelve-week-old SPF pigs were divided into 4 groups housed in 4 different rooms: the first room contained Salmonella-free control pigs (n = 4), the second room had 10(3) CFU S. Typhimurium inoculated pigs (n = 5) and non-inoculated "contact" pigs (n = 4), the third room had pigs (n = 8) receiving potentially contaminated air from the following room through a hole (4 pigs housed in the pen situated near the hole and 4 pigs in the pen at the opposite side of the room), and the fourth room had pigs (n = 5) inoculated with 10(6) CFU Salmonella Typhimurium and also non inoculated "contact" pigs (n = 4). The "contact" and the inoculated pigs were housed in adjacent pens allowing nose-to-nose contact. The 5 pigs orally inoculated with 10(6) CFU S. Typhimurium were bacteriologically and serologically positive 1 week later and their environment was contaminated as early as 1 day pi. The faecal samples of 4 nose-to-nose contact pigs were bacteriologically positive and one of them was seropositive 5 weeks pi before the pigs were commingled. The 8 pigs housed in the third room received S. Typhimurium by an active airflow coming from the contaminated room (1000 m3/hour). Their faecal samples remained negative until 8 weeks pi but the environmental swabs taken in the room close to the airinlet were contaminated 2 days pi and positive swabs were found elsewhere in the room 5 weeks pi. Two seropositive pigs were encountered 8 weeks pi in the pen situated near the hole. Only one among the 5 pigs inoculated with 10(3) CFU had bacteriologically positive faeces 1-week pi and the 4 pigs kept in nose-to-nose contact with them remained negative. A dose of 10(3) CFU was too small to induce persistent excretion and to stimulate a humoral immune response. However, the dose of 10(6) CFU induced contamination of nose-to-nose contact pigs and contamination of the environment by airflow.

Air Microbiology↗