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1.
This study evaluated the influence of chlamydial infections on lung function in conventionally raised pigs. Eight pigs aged 39-44 days were included in an aerogeneous challenge model (4 were exposed to Chlamydia suis; 4 served as controls). Nineteen pigs aged 5-27 weeks without clinical symptoms (but partly PCR-positive for chlamydial species) were examined over 6 months. For lung function testing, impulse oscillometry was used. In total, all 27 pigs underwent 465 lung function tests. Variables of ventilation (respiratory rate, tidal volume, minute volume), respiratory impedance (expressed as resistance and reactance within the frequency range 3-15 Hz), and model derived resistance of proximal and distal airways were measured. Experimental exposure to C. suis significantly affected lung function. Early distal airway obstruction (3-5 days after infection) was followed by an obstruction of proximal airways (7 days after infection). The breathing pattern was significantly changed (decreased tidal volume; increased respiratory rate). In symptom-free pigs having a naturally acquired presence of different chlamydial species in the respiratory system, no deterioration in lung function could be determined up to the age of 6 months. In conclusion, the consequences of respiratory chlamydial infections appear to vary from clinical inapparence to severe respiratory distress.  相似文献   

2.
This study was aimed at evaluating functional and inflammatory consequences of persistent chlamydial infections on the respiratory system in clinically inconspicuous calves aged 2-7 months. Thirteen calves persistently infected with Chlamydophila (C.) abortus and/or C. pecorum (Chl+) were compared to 12 calves without chlamydial infections (Chl-). In order to evaluate lung function, 36 non-invasive impulse oscillometry tests were performed per animal within 6 months. The group of chronically infected animals was distinguished by significantly higher peripheral airway resistance (indicating peripheral airway obstruction), significantly higher respiratory rates, and significantly higher minute volumes of ventilation. At the age of seven months, all calves were necropsied, broncho-alveolar lavage fluid (BALF) was obtained ex vivo, and lungs were examined histologically. Significantly higher concentrations of total protein and 8-iso-prostane (8-IP), as well as higher activities of matrix metalloprotease 2 were measured in BALF samples of Chl+ calves. Histologically, markedly activated bronchus-associated lymphoid tissue (BALT) causing partial obstruction of bronchiolar lumina was found in the apical pulmonary lobes of Chl+ calves. Chlamydial DNA was detected in the lung tissue of 7 out of 13 Chl+ calves by real-time PCR. In conclusion, respiratory chlamydial infection appeared to be associated with chronic inflammation of the lungs and airways. Despite the lack of clinical symptoms, pulmonary dysfunctions persisted in calves until the age of seven months. Data obtained in this study provide new insight illustrating the impact of nearly ubiquitous subclinical infections on the respiratory system.  相似文献   

3.
An experimental study of aerogeneous challenge in pigs was conducted in order to reveal characteristic features of porcine respiratory chlamydiosis. Eight conventionally raised pigs were exposed to a pathogenic strain of Chlamydia (C.) suis, four controls were mock infected. Besides pathological changes, the acute-phase and humoral immune responses, as well as the dissemination and transmission of the challenge strain was monitored in the course of infection. The data from clinical investigations, LPS-binding protein assay, antibody ELISAs, confocal laser scanning and light microscopy, immunohistochemical staining and PCR provided extensive evidence of the pathogenic potential of C. suis for the porcine respiratory system. This model appears suitable for further pathophysiological and immunological investigations of chlamydial respiratory infections and can also be recommended for studies of Chlamydia-associated infections of the human lung.  相似文献   

4.
Specific antibodies to plasmid-encoded protein pgp3 are known to be encountered in human Chlamydia (C.) trachomatis infections. In order to verify whether antibodies to this protein could be developed in animals infected with plasmid-carrying chlamydial strains, 454 animal sera were examined using a home-made pgp3 protein ELISA and Western blots (WB) of recombinant pgp3 protein from Chlamydophila (Cp.) psittaci. Likewise, 50 human sera were tested by ELISA and WB of recombinant pgp3 from C. trachomatis. The reactivity against pgp3 protein was compared to the reactivity against chlamydial elementary bodies (EBs) detected by microimmunofluorescence (MIF) test. The presence of pgp3-specific antibodies was demonstrated in most ducks and pigeons with Cp. psittaci infection detected by MIF, as well as in the majority of symptomatic cats and pigs infected with Cp. felis and C. suis, respectively, which reacted at high titres to Cp. felis and C. suis EBs by MIF. Moreover, most of the sera collected from patients with C. trachomatis culture-confirmed infection and seropositive to C. trachomatis by MIF, presented antibodies specific to C. trachomatis pgp3 recombinant protein. Therefore, pgp3 protein could be a useful marker of chlamydial infections in animals, as well as in humans.  相似文献   

5.
Accurate definition of respiratory health in pigs is an important problem for swine producers and veterinarians. In an approach to identify potential biomarkers, two-dimensional gel electrophoresis and mass spectrometry on bronchoalveolar lavage fluid (BALF)-derived proteins from pigs experimentally infected with Actinobacillus pleuropneumoniae were performed at different time points post infection. Mock-infected pigs were used as a control. It was shown that the antimicrobial peptides, prophenin-2 and PR-39, and the calcium-binding protein calgranulin C were reproducibly upregulated in BALF of pigs chronically infected with A. pleuropneumoniae. Concentrations of PR-39 were significantly (p<0.05) increased in BALF (median of 4.8 nM) but not in serum (median of 2.5 nM) on day 21 after infection. A Receiver Operating Characteristics (ROC) plot showed that PR-39 in BALF is an accurate and easily accessible marker to detect clinically healthy pigs convalescent from an experimental A. pleuropneumoniae infection. These results imply that PR-39 might have a potential as a general biomarker to determine porcine respiratory health.  相似文献   

6.
This study evaluated the influence of chlamydial infections on lung function in conventionally raised pigs. Eight pigs aged 39–44 days were included in an aerogeneous challenge model (4 were exposed to Chlamydia suis; 4 served as controls). Nineteen pigs aged 5–27 weeks without clinical symptoms (but partly PCR-positive for chlamydial species) were examined over 6 months. For lung function testing, impulse oscillometry was used. In total, all 27 pigs underwent 465 lung function tests. Variables of ventilation (respiratory rate, tidal volume, minute volume), respiratory impedance (expressed as resistance and reactance within the frequency range 3–15 Hz), and model derived resistance of proximal and distal airways were measured. Experimental exposure to C. suis significantly affected lung function. Early distal airway obstruction (3–5 days after infection) was followed by an obstruction of proximal airways (7 days after infection). The breathing pattern was significantly changed (decreased tidal volume; increased respiratory rate). In symptom-free pigs having a naturally acquired presence of different chlamydial species in the respiratory system, no deterioration in lung function could be determined up to the age of 6 months. In conclusion, the consequences of respiratory chlamydial infections appear to vary from clinical inapparence to severe respiratory distress.  相似文献   

7.
The pathogenicity of a single infection with Eperythrozoon suis and of a mixed infection of E. suis and Babesia trautmanni in experimentally-infected pigs, was described. In the pigs with a single infection, parasitaemia of E. suis was observed 4 days after blood inoculation. Although parasitaemia with this parasite was also observed on the 4th day in a mixed infection, the parasitaemia of B. trautmanni was not noted until 14 days after inoculation at a period when that of E. suis had started to fall. No parasitaemia was observed in any of the pigs in the splenectomized and unsplenectomized uninoculated control animals. The pigs carrying either single or mixed infections had pyrexia and their temperatures were consistently higher than those of the control animals. Infected pigs also showed anaemia with significant decline in Pcv, Hb and RBC values. The total WBC count rose in the infected pigs and the rise was more pronounced in pigs carrying E. suis alone. In addition, it was only in pigs infected by E. suis alone that a decline in the percentage of neutrophils and a rise in percentage lymphocytes was observed.  相似文献   

8.
Experimental airborne transmission of Streptococcus suis type 2 was studied in specific pathogen free piglets. Forty piglets were allotted to five groups of eight 7-week-old animals and housed in three separated units. Negative control pigs (group 1) were housed in unit A and infected batches were housed in units B (group 2) and C (groups 4). In units B and C, non-inoculated groups (groups 3 and 5, respectively), 40 cm distant from the respective inoculated group and without any physical contact between them, also took place. Six animals of groups 2 and 4 were inoculated intravenously with 2 x 10(8) colony forming units (cfu) of a mild and a high virulent S. suis strains, respectively. The remaining animals in these groups and pigs from groups 1, 3, 5 received broth medium in the same way. Differences among virulence of S. suis capsular type 2 were observed in inoculated pigs of groups 2 and 4. Pigs from group 2 became carriers, showing only mild symptoms. By contrast, animals from group 4 presented an acute form of the disease. All the indirect contact pigs in groups 3 and 5 had S. suis in palatine tonsils from day 6 after the infection and they presented clinical manifestations similar to those observed in experimentally infected pigs. Two direct contact animals were also contaminated in the upper respiratory tract but surprisingly they did not show any symptoms. Airborne transmission of S. suis in experimentally pigs was demonstrated in the present study. Indirect infections, as described in this study, are a more realistic way to infect pigs than other experimental procedures and may be used to further study the pathogenesis of the infection caused by this important pathogen.  相似文献   

9.
Pigs, asymptomatically infected with Actinobacillus pleuropneumoniae in their upper respiratory tract, can transmit the infection. Detection of such animals is indispensable to prevent the intake of the disease in a herd. This study was conducted to evaluate bacteriology, polymerase chain reaction (PCR) and serology for the detection of subclinically infected pigs. Pigs were inoculated onto the tonsils with an A. pleuropneumoniae serotype 9 strain (n=12, group 1) or phosphate buffered saline solution (PBSS) (n=5, group 2). To prevent infection of the lungs, pigs of group 1 were treated three times with sodium ceftiofur as an aerosol. A third group (n=5) was inoculated intranasally with the same strain. All animals were euthanized 30 days post-inoculation (dpi). In pigs of group 1, clinical signs were not observed. A small lung lesion was found in only one pig and A. pleuropneumoniae was isolated from this lesion. The bacterium was not isolated from the lungs of animals that did not develop lung lesions. A. pleuropneumoniae was demonstrated in tonsils of 9/12 animals using bacteriological isolation, whereas it was demonstrated in mixed bacterial cultures from tonsils of all 12 animals by PCR. In non-infected animals (group 2), clinical signs were not observed and A. pleuropneumoniae was not demonstrated in any sample. All intranasally infected animals (group 3) developed disease signs and lung lesions. High antibody titers against ApxI, ApxII and heat-stable antigens were detected in animals that developed lung lesions. Antibody titers against these antigens were low or absent in all other pigs. It was concluded that pigs carrying A. pleuropneumoniae in the upper respiratory tract generally do not show measurable antibodies in serum. Therefore, sensitive methods for the detection of the etiological agent such as PCR are required to identify carrier animals, while serological methods are not suitable.  相似文献   

10.
A recently developed porcine model for aerogenous infection with Streptococcus suis serotype 2 was applied in a study of the phases of bacterial colonization and initial invasion. Eighteen pigs were exposed to aerosolized S. suis serotype 2 after pre-exposure to mild acetic acid in aerosol. The animals were killed consecutively within the first six days after challenge. After death, all animals were necropsied and examined by bacteriology, histopathology, and immunohistochemistry. Systemic infection was established in four out of 18 animals exposed to S. suis serotype 2. All systemically infected animals developed clinical signs and lesions typical of the infection. In four additional animals, subclinical infection was demonstrated by re-isolation of S. suis from the palatine tonsil. However, in all 18 challenged animals, immunohistochemistry demonstrated S. suis serotype 2 antigen in the palatine and/or nasopharyngeal tonsils. In all four systemically infected animals, S. suis serotype 2 antigen was also found in the mandibular lymph node. These observations point towards the tonsils as possible portals of entry for S. suis serotype 2 with subsequent lymphogenous spread. Thus, the present findings parallel the proposed pathogenesis for S. suis serotype 1 infection in pigs.  相似文献   

11.
Three commercial enzyme-linked immunosorbent assays (ELISAs) were compared for the detection of antibodies to Sarcoptes scabiei var. suis using experimental sera of six 8-week-old pigs after contact infection with Sarcoptes scabiei var. suis. Six non-infected pigs were monitored as a control group. Blood sera were taken once a week from all animals. After successful infection the pigs were treated with an antiparasitic agent (12 weeks post infection (p.i.)) and the antibody titres were monitored until they were negative. The antibody levels of the experimental pigs reached the cut-off level 5 weeks after introduction of an infected animal to the group and were positive by both the Sarcoptes-ELISA 2001 PIG and the Acar-Test P-ELISA. Four weeks after treatment mean results showed optical densities (% OD) below the cut-off level in the Sarcoptes-ELISA 2001 and 8 weeks after treatment in the Acar-Test P-ELISA. In the Chekit Sarcoptest pigs had elevated antibody levels in comparison to control animals, but ODs remained below the given cut-off level at all times. In a second examination with Chekit Sarcoptest (different lot) and at a lower cut-off level, the sera of most of the piglets tested positive. Eight weeks after treatment, four from six pigs still had positive OD values. Therefore this investigation showed a higher sensitivity for the Sarcoptes-ELISA 2001 and the Acar-Test P-ELISA than for the Chekit Sarcoptest. Different test sensitivities must be considered when serologic methods are used for the diagnosis of swine sarcoptic mange, especially for monitoring and controlling eradication programs.  相似文献   

12.
Bronchoalveolar lavage (BAL) is a procedure that retrieves cells and other elements from the lungs for evaluation, which helps in the diagnosis of many pulmonary diseases. The aims of this work were to perform this procedure in dogs in the acute and chronic phases of an Angiostrongylus vasorum infection for cytological analysis and to evaluate the potential of this technique as a diagnostic method for this lung-heart worm. The BAL procedure was performed through the use of an endotracheal tube on seven A. vasorum infected dogs and on five non-infected dogs lined as a control group. Sixty days post-infection (dpi) active and live larvae were retrieved from the bronchoalveolar fluid (BALF) of all infected dogs. Furthermore, in one animal it was possible to retrieve larvae in its BALF before the pre-patent period. This work reports that the A. vasorum infection resulted in an increase of relative neutrophils and eosinophils counts. In contrast, there was a significant decrease in the alveolar macrophage relative count in infected animals from 60 to 330 dpi. This study shows that the BAL is an accurate technique for the diagnosis of canine angiostrongylosis. Moreover, the technique allows us to retrieve cells and other elements that line the lung surface for cytological evaluation, which provides information about inflammatory diseases, and the diagnosis and prognosis of pulmonary parasites such as A. vasorum.  相似文献   

13.
The H1N1, H3N2 and, more recently, H1N2 subtypes of influenza A virus are presently co‐circulating in swine herds in several countries. The objectives of this study were to investigate the pathogenesis of Sw/Italy/1521/98 (H1N2) influenza virus, isolated from respiratory tissues of pigs from herds in Northern Italy, and to evaluate its potential cross‐protection against the Sw/Fin/2899/82 (H1N1) strain. In the pathogenesis test, eight pigs were intranasally infected with H1N2 virus; at pre‐determined intervals, these animals were killed and necropsied, along with eight uninfected animals. In the cross‐protection test, sixteen pigs were infected by intranasal (i.n.) and intratracheal (i.t.) routes with either H1N2 or H1N1 virus. Twenty days later, all pigs were challenged (by the same route), with either the homologous H1N2 or heterologous H1N1 virus strains. Control group was inoculated with culture medium alone. On post‐challenge days (PCD) 1 and 3, two pigs from each infected group, along with one control pig, were killed. Clinical, virological, serological and histopathological investigations were performed in both the pathogenicity and cross‐protection tests. In the pathogenicity test, mild clinical signs were observed in two pigs during 3 and 4 days, respectively. Virus was isolated from two pigs over 6 days and from lung samples of pigs killed on post‐infection days 2 and 4. Seroconversion was detected in the two infected animals killed 15 days after infection. In the cross‐protection study, mild clinical respiratory signs were detected in all pigs infected with either the H1N2 or H1N1 virus. The virus was isolated from nasal swabs of almost all pigs till 6 days. After the challenge infection, the pigs remained clinically healthy and virus isolation from the nasal secretions or lung samples was sporadic. Antibody titres in H1N1 or H1N2 infected groups were similar, whereas the H1N2 sub‐type induced less protection against re‐infection by homologous and heterologous virus than H1N1 sub‐type. The controls had no signs of the disease. In the H1N2 infected pigs, a reduced number of goblet cells in nasal and tracheal mucosa and small foci of lymphomononuclear cell infiltrates in the submucosa were detected. Furthermore, the goblet cell reduction was related to the time of infection. Diffuse mild interstitial pneumonia was also recorded in pigs infected with the H1N2 virus and challenged with either H1N1or H1N2 pigs. These studies showed the moderate virulence of the H1N2 virus and a partial cross‐protection against heterologous infection.  相似文献   

14.
The phenomenon of persistence is well known from in vitro studies, where it is associated with the production of aberrant bodies, but its occurrence in vivo is less well documented. The objective of this study was to search for aberrant bodies in intestinal tissues from pigs, describe their ultrastructure, and investigate the suitability of immunohistochemical staining for chlamydial heat shock protein 60 (cHSP60) to detect such forms. Intestinal tissues derived from pigs naturally and experimentally infected with Chlamydia (C.) suis were examined by immunohistochemistry, transmission electron microscopy and immunogold electron microscopy. The chlamydial species involved in the natural infection were determined using an Array Tube Microarray to C. suis and Chlamydophila abortus. Ultrastructurally, aberrant bodies were detected in the gut of both naturally and experimentally infected pigs. Immunogold electron microscopy showed that the aberrant bodies were labeled less strongly than the normal forms by antibodies against LPS and cHSP60 respectively. It was concluded that aberrant bodies occur in vivo in pigs and that the gnotobiotic pig model might be suitable for the study of chlamydial persistence in vivo. The antibody against cHSP60 does not appear to be suitable to specifically detect such forms.  相似文献   

15.
Ten halothane-positive pigs (stress sensitive, group A) and ten halothane-negative pigs (stress insensitive, Group C) with a mean body weight of 36 kg were each inoculated orally with 50,000 sporocysts of Sarcocystis miescheriana. Twelve halthane-positive pigs (Group B) and ten halothane-negative pigs (Group D) served as non-infected controls. Thirteen weeks post infection (p.i.) the lean: fat ratios of the pigs of the infected groups A and C were lower (A, 1:0.41 +/- 0.09; C, 1:0.50 +/- 0.10) than those of the pigs of the non-infected groups B and D (B, 1:0.50 +/- 0.08; D, 1:0.55 +/- 0.08). The back-fat thickness, the fat thickness 'A' and the fat thickness 'B' were thinner in infected pigs than in non-infected pigs. The difference in Lendenst?rkespeckquotient (Loin Fat Thickness Quotient) (LSQ) between infected and non-infected pigs was not statistically significant. The values of the water-holding capacity were lower in infected pigs than in non-infected pigs, the difference being statistically significant only in the halothane-negative groups (C, 0.45 +/- 0.02; D, 0.48 +/- 0.04). The water-absorbing capacity was significantly higher in the infected groups (A, 5.92 +/- 3.99%; B, 2.26 +/- 1.08%; C, 8.96 +/- 2.90%; D, 4.97 +/- 2.51%). In conclusion, it can be said that there was a slight tendency towards a better carcass quality and a better water-binding capacity in infected pigs, although this was combined with reduced growth rates.  相似文献   

16.
Eight 15-week-old pigs, reared under specific pathogen-free conditions, were inoculated with Streptococcus suis serotype 2. The animals were monitored before and after challenge by measuring rectal temperature, recording specific clinical symptoms and collecting blood samples for haptoglobin determination. Twenty-four hours after infection, the average haptoglobin plasma concentration of the animal group increased significantly and reached a maximum 4 days post-inoculation, followed by a constant mean level until the end of the trial on day 10. In spite of individual differences between the animals, an increase in haptoglobin concentration of at least 2.5 times above normal was observed in all infected pigs 1 day after challenge. Twenty-four hours after challenge, lameness was observed in five animals and an elevated body temperature was observed in seven of the eight experimental infected animals. These are the classical clinical symptoms of streptococcal infection. Haptoglobin was shown to increase in acute S. suis infection in pigs.  相似文献   

17.
The role of the heat-labile haemolysin of Actinobacillus pleuropneumoniae in acute porcine pleuropneumonia was examined. A virulent strain was compared with an isogenic haemolysin-deficient mutant in experimental infections. The pigs which received the virulent strain showed clinical signs of acute respiratory disease whereas the animals infected with the mutant strain appeared to be less severely affected. At post mortem examination, both groups showed similar acute pulmonary lesions and pleurisy typical of A pleuropneumoniae infection. The bacterial antigen representing the haemolysin was detected in lung lesions infected with the parent strain but not in those infected with the mutant. These results demonstrate that the haemolysin of serotype 2 A pleuropneumoniae is not an essential factor for the production of the lesions of pleuropneumonia in pigs.  相似文献   

18.
The application of the enzyme-linked immunosorbent assay (ELISA) in the detection of Trichinella spiralis infections in pigs is presented. Two experiments using conventionally raised pigs infected with various numbers of T. spiralis larvae are described. Blood samples were collected for serological examination, prior to and at various days post infection (pi). At slaughter, on the 28th day pi, samples from the diaphragm were collected for isolation of muscle larvae by means of the digestion method. The results from these sera were compared with those from non-infected conventionally raised pigs. At day 28 pi, 21 out of 33 infected pigs showed positive ELISA results. In only two of those serologically positive animals were no larvae detected at slaughter. Of the 12 infected pigs with a negative ELISA result, only two harboured more than 3 larvae/g (the detection limit of trichinoscopy). Of the nine non-infected control animals, one had a false positive ELISA result. The significance of these findings in relation to slaughterhouse control is discussed. ELISA, therefore, presents an alternative to other detection methods for the control of T. spiralis infections in pigs.  相似文献   

19.
An efficient method of control of porcine eperythrozoonosis (PE) caused by Mycoplasma suis is eradication of infection by detection and removal of infected carrier animals. At present, only a few tests are available for the diagnosis of these latent M. suis infections in pigs. The objective of this study was to develop a PCR assay based on novel DNA sequences for the identification of M. suis-infected pigs. A 1.8 kb EcoRI DNA fragment of the M. suis genome was isolated from the blood of pigs experimentally infected with M. suis. Specificity of the DNA fragment was confirmed by DNA sequence analysis and PCR using primers directed against sequences contained in the 1.8 kb fragment. PCR products of 782 bp in size were amplified only from M. suis particles prepared from the blood of experimentally infected pigs but not from any controls, comprising blood from gnotobiotic piglets and a panel of bacteria including other porcine mycoplasmas. PCR results were confirmed by dot blot hybridisation. The applicability of the PCR assay to diagnose M. suis infections in pigs was evaluated by investigating blood samples from 10 symptomatic pigs with clinical signs typical of porcine eperythrozoonosis and blood samples from 10 healthy pigs. The M. suis-specific PCR product was amplified from all samples taken at episodes of acute disease as well as from samples taken during the latent stage of infection, thus demonstrating the suitability of the PCR assay for detecting latent infected carrier animals.  相似文献   

20.
Brucella suis biotype 1 was isolated from 13.1% of the pigs slaughtered in Kapuk Jakarta, West Java and from 15.09% of the pigs slaughtered in Surabaya, East Java. The prevalence of B. suis by means of the Rose Bengal Plate Test, was 22.3% for West Java and 14.9% for East Java. The Rose Bengal Plate Test detected more B. suis infected animals (73% of the infected animals) than did the Complement Fixation Test (41%) and the Serum Agglutination Test (54.5%). The high infection rate is a potential health danger for the abattoir workers.  相似文献   

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