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S D'Allaire

Publications and source records attributed to S D'Allaire.

16 recordsLinked to original sources
PubMed2003

Epidemiology of Streptococcus suis serotype 5 infection in a pig herd with and without clinical disease.

The aim of this study was to describe the transmission and the kinetics of the infection caused by Streptococcus suis serotype 5 in a multisite farrow-to-finish pig herd. Most sows carried S. suis serotype 5 in their vaginal tract, but not in their nasal cavities, as demonstrated by immunomagnetic separation (IMS) technique. Their offspring became infected during farrowing, confirming vertical transmission. During the first 4 weeks of life, a low number of piglets were carriers of S. suis serotype 5 in their nasal cavities. However, when clinical signs appeared, the carrier rate significantly increased, suggesting that isolation from nasal cavities is a better indication of active transmission than of a carrier state. Clinical cases were present in animals between 4 and 8 weeks of age, when maternal antibodies were at their lowest level. Up to six different genotypes of the same serotype could be identified by random amplified polymorphic DNA; however, a single clone was responsible for all clinical cases studied. This clone could only be isolated from a single sow, indicating that its prevalence in breeding animals was low. Interestingly, 1 year later, clinical disease associated with S. suis serotype 5 spontaneously disappeared. At that time, the genotype responsible for the clinical signs was not detected in the herd and the levels of antibodies in sows and maternal antibodies in piglets were not higher than those of the previous year.

Animals↗
PubMed2002

Infectious agents identified in pigs with multifocal interstitial nephritis at slaughter.

One kidney was taken from each of 100 pigs at slaughter; 50 had gross lesions of multifocal interstitial nephritis and 50 had no gross lesions. Forty-nine of the affected kidneys had lesions that were characterised by the presence of either a few randomly distributed or numerous widely disseminated pale foci, 1 to 3 mm in diameter, on the cortical surface (white-dotted kidneys). Microscopically, these focal inflammatory lesions often had a distinct lymphofollicular pattern (follicular nephritis). Lesions of chronic vasculitis were observed in 21 of the affected kidneys. Histologically, the control kidneys had only small and sparse inflammatory foci. Standard bacterial cultures of kidneys of both groups were not significant, and cultures for the isolation of leptospires were all negative. Virological examination of the kidney homogenates by PCR did not reveal any porcine reproductive and respiratory syndrome virus and only a few cases were positive for the porcine circovirus type 1. However, porcine parvovirus (PPV) and porcine circovirus type 2 (PCV-2) were detected in many kidneys of both groups but in a significantly higher proportion of the kidneys with interstitial nephritis. There was a significant association between the lesions and the presence of PPV and PCV-2 with odds ratios of 7.5 (P<0.0001) and 3.4 (P=0.0074), respectively, and the odds ratio increased to 22.7 (P<0.0001) when both viruses were identified in the same kidney. However, a subsample of kidneys taken from both groups were negative by immunohistochemistry for the presence of PPV and PCV-2 antigens.

Animals↗
PubMed2002

Antibody response to an autogenous vaccine and serologic profile for Streptococcus suis capsular type 1/2.

An autogenous vaccine was developed, using sonicated bacteria, with a strain of Streptococcus suis capsular type 1/2. The objectives of this study were to evaluate the antibody response following vaccination and to assess the changes in antibody levels in pigs from a herd showing clinical signs of S. suis capsular type 1/2 infection in 6- to 8-week-old pigs. An enzyme-linked immunosorbent assay using the vaccine antigen was standardized. Results from a preliminary study involving 2 control and 4 vaccinated 4-week-old pigs indicated that all vaccinated pigs produced antibodies against 2 proteins of 34 and 43 kDa, respectively, and, in 3 out of 4 vaccinated pigs, against the 117-kDa muramidase-released protein. For the serologic profile, groups of 30 pigs from the infected herd were blood sampled at 2, 4, 6, 8, and 10 weeks of age. The lowest antibody level was observed between weeks 6 and 8, presumably corresponding to a decrease in maternal immunity. A marked increase was seen at 10 weeks of age, shortly after the onset of clinical signs in the herd. For the vaccination field trial, newly weaned, one-week-old piglets were divided into 2 groups of 200 piglets each (control and vaccinated); blood samples were collected from 36 piglets in each group at 2-week intervals for 12 weeks. A significant increase (P < 0.05) in antibody response was observed 4 weeks following vaccination and the level of antibodies stayed high until the end of the experiment. In the control group, the increase was only observed at 13 weeks of age, probably in response to a natural infection. The response to the vaccine varied considerably among pigs and was attributed, in part, to the levels of maternal antibodies at the time of vaccination. No outbreak of S. suis was observed in the control or vaccinated groups, so the protection conferred by the vaccine could not be evaluated.

Animals↗
PubMed1998

Development of an immunomagnetic method for selective isolation of Actinobacillus pleuropneumoniae serotype 1 from tonsils.

An immunomagnetic separation technique (IMS) for the selective isolation of Actinobacillus pleuropneumoniae serotype 1 was developed. Superparamagnetic polystyrene beads (immunomagnetic beads [IMBs]) were coated with purified rabbit immunoglobulin G specific for A. pleuropneumoniae serotype 1. The antibody concentration, the number of IMBs, the incubation time, and the temperature of incubation influenced the recovery of the target bacteria. The sensitivity of the IMS technique was 1,000-fold higher than that of direct culture. When tonsils from animals from infected herds were tested, significantly more positive tonsils were detected by the IMS technique (68%) than by the standard procedures (22%). The method represents an innovative and highly sensitive approach for the isolation of A. pleuropneumoniae from carrier animals.

Actinobacillus pleuropneumoniae↗
PubMed1998

Cutaneous and systemic necrotizing vasculitis in swine.

A systemic vasculitis involving particularly the skin and kidneys has been recently described in swine under the name dermatitis/nephropathy syndrome. Twelve pigs with gross cutaneous lesions typical of this condition were necropsied, and morphologic, immunohistochemical, microbiologic, and epidemiologic characteristics were studied. The pigs were divided into three groups comprising eight pigs with acute lesions, two with chronic lesions, and two with acute lesions kept for sequential skin biopsies. Acute skin lesions consisted of round to irregular, red to purple macules and papules that often coalesced to form large, irregular patches and plaques. With time, the lesions became covered by crusts and faded gradually, sometimes leaving scars. Characteristic distribution included the perineal area of the hindquarters, limbs, dependent parts of the abdomen and thorax, and margins of the ears. In the acute phase of the disease, necrotizing and leucocytoclastic vasculitis of small-caliber blood vessels were observed within the dermis and panniculus and in various extracutaneous locations such as the renal pelvis and synovial membranes. All pigs had macroscopic evidence of pneumonia and generalized lymphadenopathy. Microscopically, they had interstitial pneumonia and perivascular cuffing of mononuclear cells in various tissues including skin. The presence of immunoglobulins and complement was demonstrated by immunofluorescence in and around necrotic vessels of the skin in the early stages. Porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) antigens were detected by immunohistochemistry in macrophages located around vessels of the tissues examined (skin and kidneys) in acute and chronic cases. PRRSV RNA was demonstrated by reverse transcription-polymerase chain reaction in lung and spleen homogenates from all pigs. The PRRSV was isolated in cell culture from 11 of the pigs. These findings suggest that PRRSV infection may play a role in the pathogenesis of this systemic vascular disease of swine.

Animals↗
PubMed1996

Detection of antibodies against Streptococcus suis capsular type 2 using a purified capsular polysaccharide antigen-based indirect ELISA.

In the present study a purified capsular polysaccharide antigen-based indirect ELISA (CPS-ELISA) to detect antibodies against Streptococcus suis capsular type 2 was developed and compared with a whole cell antigen-based ELISA (WCA-ELISA). The WCA-ELISA presented a very low specificity when rabbit antisera to other capsular types were tested. Most of these cross-reactions were due to common proteins. The standardized CPS-ELISA gave satisfactory results using a concentration of 0.1 micrograms/well; most cross-reactions decreased significantly, with some exceptions, such as those shared by capsular types 1/2, 12 and 17. These cross-reactions were mainly due to common epitopes present in the capsule, as shown by immunoblotting. In a second experiment, the CPS-ELISA was used to detect antibodies in experimentally infected piglets. Despite the fact that capsular type 2 S. suis could be reisolated from all infected animals during and/or after the trial, antibody titers against a second infection. Sera from piglets experimentally infected were completely protected against a second infection. Sera from piglets experimentally infected with S. suis capsular types 1/2 or 12 presented cross-reactions at low dilutions, confirming data previously obtained with rabbit sera. Finally, sera of animals from herds with clinical signs associated with S. suis capsular type 2 did not present titers significantly different from those of disease free herds. From our results we concluded that the CPS-ELISA developed in this study can not be used as a diagnostic tool to identify infected animals.

Animals↗
PubMed1996

Survey of management and housing in farrowing quarters among independent and integrated swine farms in Québec.

Forty-eight randomly selected owner-operated swine breeding farms (independent farms) and 38 belonging to 5 integrated organizations specializing in swine production chosen from the largest in the province of Québec (integrated farms) were separately described regarding their general characteristics, sow feeding, management practises, and housing features in farrowing quarters. The parallel description of these 2 groups of farms aids in understanding what is done in the field. It also provides insight into potential differences between independent and integrated farms. Generally speaking, production tended to be more specialized and concentrated in integrated organizations. Specifically, more new practises seemed to have been adopted on the integrated farms, and their stockpersons seemed to have a more proactive style of management in farrowing quarters. Increased size of operations, proximity of information sources, profits yielded by new practises, and ease of implementation are discussed as explanations for this higher rate of adoption of new techniques among the organizations. These differences between the independent farms and the integrated organizations appeared to be all related to basic differences in their respective sizes. Although some differences were observed within, as well as between, each organization, many similarities were found across the majority of farms within each organization, thus supporting the existence of policies specific to each organization. Although these findings have to be confirmed before being generalized, they tend to suggest that independent swine farms and integrated organizations should be considered differently.

Animal Husbandry↗
PubMed1996

Psychodemographic profile of stockpeople working on independent and integrated swine breeding farms in Quebec.

As a part of a larger study, the psychodemographic profile of Quebec pig stockpeople was described based on a sample of 48 persons working on independent farms randomly selected in the Richelieu-Saint-Hyacinthe region, and on a convenience sample of 38 others employed by 5 organizations of integrated swine production chosen among the largest ones in Québec. The 2 groups of stockpeople were described separately because of the differences between the 2 types of production. Demographic data (age, sex, level of education, training and experience in swine production, seniority on the farm) were obtained through a face-to-face interview. The personality profile was assessed using a standard personality test (French translation of the Sixteen Personality Factor Questionnaire). Both the stockpersons on independent farms and those employed by the organizations were more reserved, emotionally stable, serious, conscientious, unsentimental, controlled, introverted, and less anxious than the average person in the general population. However, multivariate analyses revealed some differences between these two groups of stock-persons (P = 0.021) as well as between the employees of the different organizations (P = 0.0038). These differences in personality profiles may reflect differences in working conditions, particularly regarding the human relationships, and in corporate cultures of the organizations.

Animal Husbandry↗
PubMed1992

Optimizing longevity in sows and boars.

Longevity of sows and boars affects the productivity and economics of the herd. Implement a culling program that is tailored to the specific needs of the producer and the characteristics of the farm. Evaluate the removal policies regularly, estimate the longevity of breeding animals, calculate the nonproductive sow days associated with culling, and determine the major causes of culling and death. Once a longevity problem and its extent have been identified, the underlying problems and predisposing factors can be more easily corrected.

Animal Husbandry↗
PubMed1991

A prospective study of sow mortality in breeding herds.

This investigation was conducted to study the incidence and the causes of sow mortality in breeding herds. Data were obtained from 24 swine breeding herds with an average inventory of 3755 sows and served gilts for the total sample. Producers were involved for 12 consecutive months and agreed to submit to the diagnostic laboratory every dead or moribund sow and served gilt. The average herd death rate was 3.3% +/- 0.5 (SEM), but varied considerably among herds, ranging from 0% to 9.2%. A total of 137 sows and mated gilts died during the year, and these females had produced an average of 4.2 litters +/- 0.2 (SEM). The number of deaths was significantly higher during the months of July, August and October. The peripartum period appeared to be when sows were most at risk, with 42% of all deaths occurring during this short period of the reproductive cycle. The three major causes of death were heart failure (31.4%), torsions and accidents of abdominal organs (15.3%) and cystitis-pyelonephritis (8.0%). Other causes included endometritis (6.6%), uterine prolapses (6.6%), pneumonia (3.6%), gastric ulcers (3.6%), downer sow syndrome (2.2%), miscellaneous (8.0%) and unknown (14.6%).

Animals↗
PubMed1990

The evaluation of postmortem ocular fluid analysis as a diagnostic aid in sows.

This study was undertaken to evaluate the diagnostic usefulness of postmortem ocular fluid analysis in estimating the antemortem status of various serochemical constituents. Chemical values of serum and aqueous and vitreous humors were compared following different procedures. A blood sample and the 2 eyes were collected from each of 100 sows at a nearby abattoir. The results obtained from immediate centrifugation of ocular fluids after sampling were compared with those samples in which centrifugation was delayed by 2 hours. Two different postmortem intervals were used for sampling ocular fluids, 2 and 24 hours. Concentrations of urea, calcium, phosphorus, potassium, sodium, and chloride were determined from serum and humors. Delayed centrifugation did not affect chemical values of ocular fluids nor the relationships between serum and humors. Phosphorus and potassium values increased significantly with the postmortem interval in both aqueous and vitreous humors. The relationships between chemical values of ocular fluids and serum were determined using simple linear regression. There was a poor correlation between ocular fluid and serum values for all electrolytes; a significant correlation was found only for urea concentrations in both humors.

Abattoirs↗
PubMed1987

Culling patterns in selected Minnesota swine breeding herds.

This investigation was conducted to study culling patterns in swine breeding herds. Data were obtained from 89 Minnesota swine breeding herds and included 5918 sows and 1324 gilts for a total of 7242 culled femaled. Each producer was involved for 12 consecutive months. They were asked to record every female that was removed from the herd, the reason for its culling and its parity. The annual culling rate for the sample averaged 50%, but varied considerably between herds ranging from 15% to 85%. Culled females had produced an average of 3.77 litters. Half of the females culled did not produce more than three litters. Reproductive failure accounted for 32% of all removals. The average parity of the females culled in that category was only 2.37: almost 33% were gilts. Failure to conceive represented 75% of all females culled for reproductive failure. Proportionally, culling as a result of anestrus was higher in gilts. It accounted for 33% of all gilts culled for reproductive failure which was twice as much as for sows. Inadequate performance accounted for 17% of all removals. These sows had produced an average of 5.11 litters. These results indicated that few animals were culled on the basis of first litter performance. Old age comprised 14% of all removals and the average parity at culling for this category was 7.11. Death accounted for 12% and the average parity for these females was 3.40. Locomotor problems and peripartum problems were the cause of 28% and 23% of all deaths, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1986

Physiological responses to treadmill exercise and ambient temperature in normal and malignant hyperthermia susceptible pigs.

Ten susceptible and ten resistant pigs to malignant hyperthermia were used to observe the effects of exercise and ambient temperature on selected physiological parameters. Pigs were submitted to a ten minute exercise on a treadmill operating at a speed of 1.8 km/h and inclined to 11 degrees. Exercise in the first group was at an ambient temperature of 14 degrees C, and in the second at 29 degrees C. The right carotid artery was previously cannulated for blood pressure measurements and for repeated blood sampling during exercise. Arterial pressure, heart rate, rectal and cutaneous temperatures were recorded. Levels of cortisol, creatine kinase and its isoenzymes were measured. At 14 degrees C, exercise caused some physiological adjustments in susceptible animals; heart rate, skin temperature and cortisol levels increased (P less than 0.05). In resistant pigs, only the heart rate was elevated significantly following exertional stress at 14 degrees C. Exercise at 29 degrees C produced severe stress and marked physiological changes: heart rate, rectal and skin temperatures and cortisol levels increased significantly in both susceptible and resistant swine. At 29 degrees C, susceptible pigs also had higher levels of serum cortisol, total creatine kinase and MM isoenzyme (P less than 0.05) compared to resistant pigs. The results indicate that, following exertional or thermal stress, susceptible pigs undergo more extensive physiological changes than do resistant pigs. Similar levels of stress prior to slaughter may trigger physiological changes which in the susceptible pigs would likely result in pale, soft exudative myopathy.

Animals↗
PubMedDate not supplied

Serologic profile of a cohort of pigs and antibody response to an autogenous vaccine for Actinobacillus suis.

Actinobacillus suis is a commensal opportunistic pathogen in swine. However, in recent years, an increasing prevalence of clinical signs associated with A. suis has been observed in high health status herds in North America. The objectives of the study were to assess the kinetics of antibodies to A. suis in pigs from a herd showing clinical signs of A. suis infection and, to evaluate the antibody response in gilts following vaccination with an autogenous vaccine. An enzyme-linked immunosorbent assay (ELISA) using a saline extract of boiled-formalinized whole cells of a field strain as the coating antigen was standardized. This ELISA was used as a tool for monitoring, in a comparative way, the variations in A. suis antibody levels. The herd selected for the serologic profile was negative for Actinobacillus pleuropneumoniae infection and showed clinical signs of A. suis infection in 16 to 19-week-old pigs. A cohort of 20 pigs was blood sampled at 5, 8, 12, and 16 weeks of age. The lowest level of serum antibodies was observed between weeks 8 and 12, this probably corresponding to a decrease in maternal immunity. A marked increase in the antibody response was seen at 16-week of age, at the approximate time of onset of A. suis clinical signs in the herd. The evaluation of serum antibody responses to an autogenous vaccine revealed that the humoral immunity of gilts further increased following vaccination although the level of antibodies was already high prior to vaccination. The magnitude of the response to vaccination was higher when the level of antibodies was low prior to the first injection. The ELISA test seems to detect antibodies against the O-chain LPS.

Actinobacillus↗