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F Madec

Publications and source records attributed to F Madec.

At least 37 records · Page 2Linked to original sources
PubMed2000

A PCR assay used to study aerosol transmission of Actinobacillus pleuropneumoniae from samples of live pigs under experimental conditions.

The study describes a polymerase chain reaction (PCR) assay for the detection of Actinobacillus pleuropneumoniae. The test is based on the amplification of the omlA gene coding for an outer membrane protein of A. pleuropneumoniae. To test the specificity of the reaction, 19 other bacterial species related to A. pleuropneumoniae or isolated from pigs were assayed. They were all found negative in the PCR assay. The detection threshold of the test was 10(2) A. pleuropneumoniae CFU/assay. The test was then applied to the detection of A. pleuropneumoniae from tonsillar biopsies and tracheobronchial lavage fluids of pigs without a culture step. The detection of A. pleuropneumoniae in these samples was performed by PCR, by conventional culture and by bacteriology with immunomagnetic beads. The number of samples that were found positive by PCR was almost three times higher than the number of samples from which A. pleuropneumoniae was isolated by both bacteriological techniques. The detection of A. pleuropneumoniae in these samples allowed us to demonstrate its aerosol transmission to pigs under experimental conditions. The trial involved 18 specific pathogen free pigs. Six pigs, infected with A. pleuropneumoniae, were located in a unit A, together with four non-infected animals (contact pigs). Eight non-infected pigs (reporter pigs) were located in a unit B, adjacent to A. We detected A. pleuropneumoniae in samples from infected animals but also from 'contact' (unit A) and 'reporter' (unit B) pigs. The results of this study show that the simple preparation of the samples followed by the PCR assay may be a useful tool for epidemiological studies.

Actinobacillus Infections↗
PubMed2000

Experimental models of porcine post-weaning colibacillosis and their relationship to post-weaning diarrhoea and digestive disorders as encountered in the field.

The aim of this study was to develop a reliable model system of porcine post-weaning colibacillosis, and in doing so to assess the primary relationship of enterotoxigenic Escherichia coli to post-weaning diarrhoea and digestive disorders as encountered in the field. Six sequential experiments were carried out using 168 SPF piglets weaned into an optimal controlled environment at 28 days of age. The piglets were allocated to 23 treatment groups, 17 of which were inoculated either orally or intragastrically with enterotoxigenic strains of E. coli (LT+, STI+, STII+) possessing adhesive factors including K88 (F4). The piglets were challenged either once (Day 4 post-weaning) or on several days post-weaning, with the challenge load for each inoculation varying from 10(8) to 10(12) CFU. Overall 14.5% of inoculated pigs developed severe illness and died: these had lesions in their digestive tracts typical of colibacillosis. Diarrhoea occurred on at least 1 day in 50% of inoculated pigs, but was transient (1.7 days on average), appeared very soon after challenge (sometimes within half a day), and was accompanied by signs of depression and low weight gain. Generally a prompt recovery then occurred. In the second 2 weeks post-inoculation daily weight gain reached the same level in most inoculated groups of pigs as in the uninoculated controls. Only a small number of pigs developed a chronic enteritis lasting several days, as is typically observed in field cases. Diarrhoea was more common in the piglets that were tested adhesive positive to the K88 fimbriae receptor, but the disorders were no more severe in these animals. The response of all pigs depended primarily on the inoculum used, and especially on the challenge load. Although enterotoxigenic E. coli are clearly important in the aetiology of post-weaning diarrhoea, other factors are also required for the production of the chronic post-weaning digestive disorders and ill-thrift that are commonly encountered in commercial piggeries.

Animals↗
PubMed2000

Differential recognition of ORF2 protein from type 1 and type 2 porcine circoviruses and identification of immunorelevant epitopes.

Two types of porcine circovirus (PCV) have been isolated and are referred to as PCV1 and PCV2. PCV1 represents an apathogenic virus, whereas PCV2 is associated with post-weaning multisystemic wasting syndrome. The two PCVs are related, since they display about 70% identity based on nucleotide sequences. In order to discriminate between common and type-specific antigens, an immunocytological approach was used following transfections with cloned circovirus DNAs, as well as recombinant proteins expressed by either baculovirus or plasmid vectors. The ORF1-encoded proteins in the two viruses were shown to be antigenically related, whereas the ORF2 proteins were recognized differentially by polyclonal anti-PCV2 antibodies. Furthermore, PEPSCAN analysis performed on overlapping fragments of the genes encoding part of ORF1 and the entire ORF2 and ORF3 led to the identification of five dominant immunoreactive areas, one located on ORF1 and four on ORF2. However, only some ORF2 peptides proved to be immunorelevant epitopes for virus type discrimination. The potential use of ORF2-derived antigens as diagnostic tools is demonstrated.

Amino Acid Sequence↗
PubMed2000

Experimental aerosol transmission of Actinobacillus pleuropneumoniae to pigs.

In order to demonstrate the possible role of aerosol in the transmission of Actinobacillus pleuropneumoniae, an experiment including 18 specific pathogen-free (SPF), 10-week-old piglets, randomly distributed into 2 adjacent units, was carried out. In these facilities, air was forced through absolute filters to prevent any contact with infectious agents. During the first 6 d post inoculation, the 2 units were connected by a rectangular opening and the air circulation was forced by the ventilation system from unit A (inoculated pigs) to unit B (non-inoculated pigs). The A. pleuropneumoniae strain (biovar 1 serovar 9) was isolated in France from an outbreak of porcine pleuropneumonia. Two different infecting doses, 10(7) cfu/animal and 10(8) cfu/animal, were inoculated by intranasal route in 6 pigs of unit A. The infection spread quickly from the inoculated pigs to the non-inoculated pigs. Clinical signs were acute during the 4 d post inoculation: hyperthermia, respiratory distress and, sometimes, death (6 pigs of the unit A and 2 pigs of the unit B). All pigs seroconverted against A. pleuropneumoniae serovar 9 within 2 weeks. Lung lesions were severe: fibrinous pleurisy and lung hemorrhages in the acute stage, pleural adherences and focal pulmonary necrosis in the chronic stage. Actinobacillus pleuropneumoniae was isolated from the tonsils and/or lungs in 16 animals. It could be also isolated from the air of the experimental unit. This study showed that A. pleuropneumoniae was readily transmitted through aerosol over a distance of at least 2.5 m.

Actinobacillus Infections↗
PubMed1999

Measurement of the residual contamination of post-weaning facilities for pigs and related risk factors.

A survey was designed in France to assess residual contamination in post-weaning rooms within the 2 h prior to restocking when all the pigs of the previous batch had been removed (all in-all out) and after application of the 'in use' cleaning procedures. The protocol was based on the results of a pilot study and was considered 'a good compromise'. Special agar plates (Rodac plates) with a prominent agar medium surface were prepared and used to collect the bacteria. They were applied by impression onto the floors and the partitions between the pens. In all, 24 plates were applied per room. The culture medium was VRBG which mainly permits the growth of enterobacteria. The plates were incubated for 24 h (37 degrees C) and the Colony-Forming Units (CFU) counted. After sampling, measurements were made and information collected from the farmer to obtain potential explanations for the resulting microbiological data. The same scientist sampled 129 post-weaning rooms with slatted floors. Of the 3045 plates, 18.4% were negative and 12.8% were heavily colonized (> 300 CFU). A score combining six criteria based on the counts was produced, and indicated a wide spread of the rooms. The profile of circumstances associated with the different levels of the score was extracted. The following points should be respected to achieve low residual contamination: removal of the slurry from the pit below the slatted floor; damping to be started soon after pig removal; prolonged damping; thorough washing; disinfecting soon after washing; and attention to the recommended dosage of disinfectant. Smooth surfaces were found to be less contaminated than rough ones. It is concluded that cleaning and disinfecting operations must not be considered as minor tasks and should clearly be integrated into the process of pig production.

Animals↗
PubMed1998

Measurement of digestive disorders in the piglet at weaning and related risk factors.

A cohort study was carried out in France about postweaning digestive disorders in the piglet. One hundred and six farrow-to-finish farms were involved. In each of them, a batch of contemporary piglets was considered. A total of 12,034 piglets were ear-notched, evaluated during the suckling phase and weighed at weaning, at 14 and 28 days postweaning. Postweaning diarrhoea and mortality were recorded daily. Data were collected about diet composition and feed intake, housing and husbandry throughout the period. Weaning weight was 8.1 kg and weaning age was 27.2 days on average. Diarrhoea occurred in the pens after a 3-4-day latency period. Prevalence was maximum around 7 to 9 days after weaning and remained high until 21 days after weaning. Mortality was moderate (1.9%). Average daily gains were 283 and 489 g for the two subsequent 14-day periods postweaning. Descriptive multivariate methods indicated a strong pattern between diarrhoea, mortality and growth. The main risk factors associated with the digestive disorders were determined. The hygiene level at the reception of the piglets (cleanliness, level of temperature), management and husbandry level (air quality, group size and stocking procedure) were found to be important factors leading to risky or secure profiles. In addition, the feed intake of the piglet during the first week postweaning was strongly associated with the severity of the digestive disorders over the whole 28-day postweaning period of observation. It is concluded that prevention of postweaning digestive disorders could be based on the control of zootechnical conditions.

Animal Husbandry↗
PubMed1997

Epidemiological studies of pig diseases: 1. Use of French protocols for risk factor assessment to predict the health status of Australian herds.

OBJECTIVE: To determine in Australian pig herds the accuracy of French protocols for risk factor assessment. PROCEDURE: Data on health indicators and risk factors were collected for three syndromes, 'pre-weaning diarrhoea', 'post-weaning diarrhoea' and 'respiratory problems', using the French protocols. The protocols were used on 118 occasions in 32 Western Australian pig herds during 3 years (1988 to 1991). RESULTS: There was a wide variation in pre-weaning performance, for example growth rate was 107 to 273 g/day (< 200 g/day in 33% of herds). Respiratory lesions at weaning were associated with poor pre-weaning performance. Post-weaning (21 days after weaning) growth rate was 114 to 408 g/day (< 250 g/day in 54% of herds). In the grower herds, 91% of herds had pneumonia, and growth rate was 439 to 625 g/day (< 550 g/day in 54% of herds). Pleurisy as well as pneumonia was associated with reduced growth rate. The risk factor most closely associated with respiratory health status was air volume per pig. CONCLUSION: Risk factors were most accurate at predicting the health status in post-weaning problems. A weaning weight of at least 7.9 kg and weaning age of 30 days optimised weaner performance. Stocking densities and shed designs providing at least 3 m3 air volume and 0.6 m2 floor space per pig throughout the growing phase should be considered for an improved respiratory health status. Australian pig sheds often do not provide a satisfactory environment for optimum health. The technique of risk factor assessment as an aid to the maintenance of health in pig herds is applicable in Australia, but further research is necessary to determine the most important Australian risk factors.

Animals↗
PubMed1997

Epidemiological studies of pig diseases: 2. Post-weaning diarrhoea and performance in Western Australian pigs.

OBJECTIVE: To determine in Australian pig herds the accuracy of French protocols for risk factor assessment of post-weaning diarrhoea and illthrift. PROCEDURE: French protocols for the collection of data on health indicators and risk factors for post-weaning diarrhoea were conducted on 54 batches of weaner pigs from 28 Western Australian pig herds during three years. RESULTS: Large variations in post-weaning performance were found. About one-third of the batches were growing at < 200 g/day during the 3 weeks after weaning, and 54% had growth rates of < 250 g/day. Weaning age and weight of at least 30 days and 7.9 kg, respectively, optimised weaner performance. Other risk factors associated with little post-weaning diarrhoea and good weaner performance were high creep feed intakes, relatively little diarrhoea as suckers, and, contrary to expectations, large temperature fluctuations. CONCLUSION: Overall, the 'predictability' of post-weaning problems as assessed by measurement of risk status, was good. However, the model was less accurate at predicting the performance of a single batch of pigs.

Animals↗
PubMed1994

Immune response and persistence of the porcine reproductive and respiratory syndrome virus in infected pigs and farm units.

The kinetics of the serum antibody response to porcine reproductive and respiratory syndrome (PRRS) virus and the persistence of the virus after infection were determined in experimentally and naturally infected pigs. In an experimental study, four specific pathogen free (SPF) sows were infected with a French strain of PRRS virus at 90 days of gestation, and their piglets (the test piglets) were monitored for 29 weeks from birth. In one litter, antibodies against PRRS virus were absent before the piglets had ingested colostrum. Four days after birth, passive antibodies were present in the serum of these piglets, but they had disappeared by three weeks (just before weaning) when clinical signs were observed in a minority of the pigs. In a second litter, most of the piglets had no detectable antibodies until they were four weeks old, and clinical signs were observed during their second week of life. By eight weeks, antibodies were detected in all the pigs, and they persisted until observations ceased at 29 weeks. Two groups of three SPF pigs were placed in direct contact with the test piglets when they were four weeks old and a group of five SPF pigs was placed in indirect contact when they were 13 weeks old. The first two groups showed clinical signs and seroconverted but the third group did not. At 22 weeks old, two of the test piglets were subjected to movement stress and were given exogenous corticosteroids, after which the in-contact SPF pigs developed clinical signs and seroconverted.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Is the piglet a useful animal model of sudden infant death syndrome?

A prospective study of early death was conducted in a large population of piglets in order to investigate the causes of mortality and determine whether this species could be useful as an animal model of the sudden infant death syndrome (SIDS). 1,921 live-born piglets were closely monitored from birth to 2 months of age. The cause of death was analyzed in all the animals which died during this period. Complete histological, bacteriological and virological examinations of all sudden death animals were compared to identical examinations performed in age-matched control animals. 384 animals (20%) died during the study period and 8 sudden deaths were observed (0.4%). The principal causes of nonsudden death were overlaying (9.4%), hypotrophy (6%), infection (2%) and acute fetal suffering (1.4%). Bacterial infection was found in 6 of the sudden deaths. There was 1 case of suffocation and 1 unexplained sudden death. Compared to controls, there was a significantly greater prevalence of pathology (p < 0.01) and of positive tissue bacteriology (p < 0.05) in sudden death animals. The 6 sudden deaths due to bacterial infections were clearly different from the human syndrome. Suffocation is a known cause of sudden infant death. In the final analysis, only 1 animal (0.5/1000) had an outcome which could be assimilated with SIDS. It is concluded that although there probably exists a syndrome in the piglet equivalent to SIDS, its incidence is very low and major obstacles related to the high level of early mortality in this species hinder investigation.

Animals↗
PubMed1994

Prevention of metritis-mastitis-agalaxia syndrome in sows.

Data collection related to farrowing performances and health parameters was performed in 20 intensive pig farms in Portugal (100-800 sows each) over 7 yr (1985-1992). At-risk profiles were obtained regarding the metritis-mastitis-agalaxia (MMA) syndrome. Using prospective surveys and subsequent preventive veterinary medicine programs in pig farms, the profile of 347 sows was analyzed by multidimensional statistical methods, and we demonstrated the value of risk-factor analysis to fight this enzootic problem. We observed a decrease in the prevalence of MMA syndrome, an increase in piglet survival and in the number of weaned piglets per sow, and a decrease in sow mortality rate. Our studies have shown the value of risk-factor analysis to fight enzootic disorders.

Animal Husbandry↗
PubMed1994

Prevention of reproductive disorders in sows.

Data collection related to production performances and health parameters was developed in 31 intensive pig farms in Portugal (from 100-800 sows each) in 1,580 of 10,000 sows over 7 yr (1985-1992). Using prospective surveys and subsequent preventive veterinary medicine programs in pig farms, we demonstrated the value of risk-factor analysis in the improvement of production performances: an increase in litter size from 9.15 piglets born/litter (sd 2.93) to 13.4 (sd 2.13); an increase in number of weaned piglets per sow per year: 15.73 (sd 1.93) to 20.46 (sd 1.92); and a decrease in returns to oestrus (25.3 to 2.3%).

Animals↗
PubMed1994

Utility of obtaining descriptors prior to ecopathological studies.

Ecopathology is a method of analyzing states of health in the context of the conditions under which a disorder is present or absent. Complex, multifactorial diseases are of most concern in ecopathological investigations. Factors include, but are not confined to, the role of infectious agents. The method emphasizes the development of profiles of combinations of variables found to be characteristic of groups of individuals of farms in different relative health states. A wide, exhaustive data set may appear necessary, but the final protocols for large field surveys must be concise, suitable and manageable. Consequently, prior to large-scale ecopathological inquiries, preliminary work is required to set up adequate epidemiological indicators that describe pertinent objects or facts. These indicators, called descriptors, must meet certain requirements. They must provide objective and accurate data that can be standardized. Moreover, they must be relevant and available. These points are discussed.

Animal Diseases↗
PubMed1993

Blood pressure in the sow: an attempt of indirect measuring ante partum.

Farrowing disorders in the sow have detrimental consequences in pig farming and many points of the condition still remain obscure. It was suggested to investigate blood pressure since this might provide an early indication of farrowing disturbances. A first study involved 29 pregnant sows. Blood pressure was measured indirectly using a pediatric occlusive cuff unrolled around the base of the tail and connected to a manometer. The recordings were made on resting sows in recumbent position. The disposal was considered suitable. The values obtained showed a good repeatability. Then a prospective survey involving 122 sows was undertaken. Blood pressure was measured at the 111th day of pregnancy. Systolic values ranged from 89 to 142 mm Hg (mean: 112.4). Physical profile of the sows (weight, backfat thickness) slightly influenced systolic level. On the other hand the sows obtaining the lowest values for systolic pressure were more prone to develop a prolonged farrowing. According to the lack of a parallel direct blood pressure measurement, these results have to be taken with caution. The perspective of early detection of "at risk" individuals with respect to MMA through blood pressure measurement, needs further work.

Animals↗
PubMed1992

Farrowing disorders in the sow: a field study.

A prospective study was carried out in three intensive farms. 150 sows were individually followed from 20 days prior to farrowing to 5 days after farrowing. During the five post farrowing days, the prevalences of fever (rectal temperature greater than or equal to 39.8 degrees C), anorexia, vulval discharges and mammary gland disorders were 15.3%, 20%, 64.5% and 3.3% respectively. Parturition duration (piglet delivery) was 197 minutes on average. Farrowing lasted over 300 minutes for 10% of the sows. The 5 parameters were combined to build a score on farrowing disorders. The sows getting the highest rate of disorders tended to show specific physical features prior to farrowing. The oldest sows, the heaviest, those showing urinary infections or locomotor disorders were more predisposed to problems. Moreover affected sows gave birth to larger litters for a given parity.

Animals↗
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↗
PubMed1989

[Pathologic consequences of a severe influenza outbreak (swine virus A/H1N1) under natural conditions in the non-immune sow at the beginning of pregnancy].

Pathological consequences of a severe outbreak of swine influenza (H1N1 virus) in the non immune sow at the beginning of pregnancy, under natural conditions. A sudden acute outbreak of fever, depression, anorexia and coughing in a group of nulliparous sows from a herd that was currently under epidemiological investigation lead to build a particular disposal of observation. The clinical signs were daily recorded including rectal temperature. Blood was taken from the sows at the beginning of the troubles and 3 weeks later for the detection of Aujesky's disease, coronavirus TGE-like, Influenza viruses A/H1N1 and A/H3N2 and Mycoplasma hyopneumoniae. Viral detection was attempted from nasal swabs and aborted fetuses during the acute phase. The clinical study showed fever reaching near 41 degrees C on most of the pigs and lasting usually from 2 to 5 days. The diagnosis of Influenza (virus swine H1N1) was established both on serology (massive seroconversion) and on the detection of the virus from the nasal swabs and from an aborted fetus. The control of the lungs of sows "not in pig" and culled showed extended lesions of bronchopneumonia and Pasteurella multocida was found. The technical consequences of this severe outbreak of Influenza on reproduction were mainly important at the beginning of pregnancy. Over 13 sows inseminated less than 1 week before the outbreak, only 3 farrowed (respectively 5.5 and 12 piglets); 7 returned to oestrus and 3 "not a pig" at 21 days (echotomography) did not show signs of heat and were culled. Over 8 pregnant sows (1 month of pregnancy), 6 farrowed normal litters and total embryonic resorption occurred in 2 sows. Over 18 pregnant sows (more than 45 days gestation) one aborted.

Abortion, Veterinary↗