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1.
Blood samples from 777 pigs, originating from 9 different herds, were collected at slaughter and examined for antibodies to Mycoplasma hyopneumoniae and Actinobacillus (Haemophilus) pleuropneumoniae by the indirect hemagglutination assay (IHA) and the complement fixation (CF) test, respectively. Results were compared to pathological and microbiological findings. Antibodies to M. hyopneumoniae in positive titers of 1/80 or higher were found in 62% of the samples. The relationship between positive IHA titers to M. hyopneumoniae and gross findings indicative of enzootic pneumonia of pigs (EPP), histological findings indicative of EPP, the isolation of M. hyopneumoniae and the demonstration of M. hyopneumoniae by indirect immunofluorescent testing ranged from 64% to 68%. No correlation was noted between positive IHA titers and the isolation of Mycoplasma flocculare. Positive antibody titers to A. pleuropneumoniae of 1/10 or higher were detected in 5% to 85% of the samples from individual herds. Positive titers to A. pleuropneumoniae serotype 2 were found in 71% to 79% of the sampled animals from herds with high frequencies of pneumonic lesions indicative of pleuropneumonia. In herds with low frequencies of pleuropneumonia, positive titers were recorded in from 0 to 4% of the tested pigs. However, no statistical association was found between pleuropneumonia and positive titers to A. pleuropneumoniae serotype 2 in individual animals. Twenty-one per cent of samples with positive CF titers to A. pleuropneumoniae showed antibodies to more than one serotype.  相似文献   

2.
Microorganisms associated with pneumonia in slaughter weight swine.   总被引：2，自引：1，他引：1       下载免费PDF全文
The lungs of 334 pigs were obtained from two slaughter plants in Minnesota and examined in detail. Macroscopic and microscopic evaluation, direct fluorescence for Mycoplasma hyopneumoniae and bacterial culture were done on all of them and a subsample of 50 were selected for virus culture. Mycoplasma hyopneumoniae, Pasteurella multocida and Haemophilus spp. were detected in 24.0%, 34.1% and 27.0% of the lungs, commonly in conjunction with each other. One isolate of Haemophilus pleuropneumoniae serotype 2 was detected and this represents the first report of its presence in the United States. No virus was detected in any of the lungs. Lungs with both M. hyopneumoniae and Pasteurella multocida had the greatest amount of macroscopic pneumonia (9.8% of the lung). Lungs with M. hyopneumoniae or P. multocida alone had 4.9% and 5.2% of the lung involved with pneumonia respectively. Lungs with Haemophilus sp. Taxon "minor group" had 3.8% of the lung involved which was not significantly different from lungs with none of these organisms being detected (1.6%). There was a positive correlation between the extent of M. hyopneumoniae infection, as scored by FAT and the amount of macroscopic pneumonia present (r = 0.46; P less than 0.001). Likewise, there was a positive correlation between the estimated concentration of P. multocida present, as scored by the relative number of colonies on blood agar and the amount of macroscopic pneumonia present (r = 0.60; P less than 0.001). Microscopically, the amount of lymphoreticular proliferation, polymorphonuclear cells and alveolar macrophages were evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
Attempts were made to recover and serologically identify mycoplasmas from the lungs of 50 pigs with mycoplasmal pneumonia and from 50 lungs without gross evidence of pneumonia. Mycoplasma hyopneumoniae and M. hyorhinis were respectively cultured from 30% and 50% of pneumonic lungs and the former species was also recovered from 12% of non-pneumonic lungs. Three other isolates (one from pneumonic and two from non-pneumonic lungs) differed in colonial morphology from M. hyopneumoniae and M. hyorhinis. The viability of these isolates could not be maintained on subculture and they were not identified serologically. The indirect immunofluorescence test was found to be highly specific for the identification and differentiation of M. hyopneumoniae and M. hyorhinis.  相似文献   

4.
Associations between pathogens in healthy pigs and pigs with pneumonia   总被引：2，自引：0，他引：2  
The aim of this study was to evaluate the associations between different pathogens in the development of pneumonia and bronchopneumonia in pigs. Samples of bronchoalveolar lavage fluid from 100 pigs showing no clinical signs and 239 pigs with clinical signs of respiratory disease were examined for Mycoplasma hyopneumoniae, Mycoplasma hyorhinis, US-type porcine respiratory and reproductive syndrome virus (PRRSV), EU-type PRRSV, porcine circovirus type 2 (pcv-2), influenza virus type A, alpha-haemolytic Streptococcus species, beta-haemolytic Streptococcus species, Pasteurella multocida, Bordetella bronchiseptica, Haemophilus parasuis and Actinobacillus pleuropneumoniae. These potential pathogens were detected more frequently in the pigs with respiratory problems than in the pigs with no clinical signs. pcv-2 and alpha-haemolytic streptococci were the pathogens most frequently detected; A pleuropneumoniae was isolated in only two cases. There were more often associations between the organisms in the pigs with clinical signs than in the healthy pigs. In particular, alpha-haemolytic streptococci and M hyopneumoniae were both associated with the presence of M hyorhinis, EU-type PRRSV, P multocida and B bronchiseptica, and alpha-haemolytic streptococci also occurred more often in pigs that were already infected with other pathogens. P multocida and B bronchiseptica were both significantly associated with M hyopneumoniae, alpha-haemolytic streptococci, EU-type PRRSV and US-type PRRSV.  相似文献   

5.
Pigs in three specialized fattening herds were studied with respect to the effect of infection with Mycoplasma hyopneumoniae on weight gain. Individual pigs were weighed four times at 4-week intervals during the fattening period and their daily weight gain over the rearing period was calculated. A blood sample was collected on each weighing occasion and analysed for the presence of antibodies to M. hyopneumoniae. The lungs of the principals were inspected at slaughter and the extent of pneumonic lesions was registered by a specially developed technique that has been proven to warrant a high degree of repeatability. No serum antibodies to M. hyopneumoniae were detected in one of the herds, and no pneumonic lesions were recorded at slaughter in that herd. In the other two herds, the prevalence of pigs with serum antibodies to M. hyopneumoniae increased from 6 to 54% and from 31 to 81%, respectively, during the fattening period. The prevalence of pneumonic lesions at slaughter in these herds was higher the later the pigs seroconverted. On the other hand, the extension of the lung lesions tended to be higher among pigs that seroconverted early during the rearing period. Infections with M. hyopneumoniae acquired early during the rearing, presumably strengthened by secondary infections and environmental errors, was found to decrease the daily weight gain of the pigs. However, even non-complicated M. hyopneumoniae infections acquired late in the fattening period were associated with reduced daily weight gain. That growth reduction was estimated to be at least 60 g (about 6%) after adjusting for herd, pen, initial weight and sex.  相似文献   

6.
Nine strains of mycoplasmas were isolated from the lungs of 5 pigs with clinical signs of naturally acquired enzootic pneumonia. Mycoplasma hyopneumoniae was isolated from the lungs of 1 pig and M. hyorhinis from the lungs of 4. An unidentified mycoplasma, which utilized arginine, grew rapidly in broth culture and produced centred colonies on solid medium, was isolated from the lungs of 4 pigs. The pathogenicity of the isolated strain of M. hyopneumoniae was determined by inoculation of pigs from an enzootic pneumonia-free herd. Enzootic pneumonia was produced in the lungs of all 5 pigs inoculated intranasally and intratracheally with broth cultures of the organism isolatied by limit dilution techniques. Enzootic pneumonia was produced in 3 of 6 pigs inoculated intranasally and intratracheally with M. hyopneumoniae purified by the passage of colonies on agar blocks. M. hyopneumoniae was isolated in pure culture from the lungs of all pigs with induced pneumonic lesions.  相似文献   

7.
The aim of this study was to investigate the incidence and influence of different causative organisms involved in the development of pneumonia and bronchopneumonia in pigs. Bronchoalveolar lavage fluid (BALF) from 339 pigs was examined molecular-biologically and culturally. The evaluation considered the following pathogens: Mycoplasma (M.) hyopneumoniae, Mycoplasma (M.) hyorhinis, PRRSV (US-Type), PRRSV (EU-Type), PCV-2, Influenzavirus Type A, alpha-haemolytic Streptococci, beta-haemolytic Streptococci, Pasteurella (P.) multocida, Bordetella (B.) bronchiseptica, Haemophilus (H.) parasuis and Actinobacillus (A.) pleuropneumoniae. This was followed by a pathological-anatomical examination in 168 pigs. Pathological-anatomical examination was evaluated for possible interstitial pneumonia, catarrhal-purulent bronchopneumonia and pleuritis. alpha-haemolytic Streptococci, PCV-2, H. parasuis, M. hyorhinis, M. hyopneumoniae, B. bronchiseptica, PRRSV (US-Type), P. multocida, PRRSV (EU-Type) and Influenzavirus Type A were evident in descending incidence in the BALF. A. pleuropneumoniae were only isolated culturally in two cases in the BALF. The frequency and semiquantitative detection rate in the bacteriological culture of alpha-haemolytic Steptococci, M. hyopneumoniae, P. multocida and B. bronchiseptica correlated significantly with the ascertained clinical evaluation score and the pathological-anatomical examination score. M. hyorhinis and Influenzavirus Type A only correlated with the severity degree of clinical appearance, while PCV-2 and PRRSV (US-Type) correlated with the frequency of pathological-anatomical changes. The higher the clinical score, the higher was the number of animals ascertained with five or more different pathogens. The more different causal agents were isolated in the BALF of one animal, the higher was the average pathological-anatomical examination score. For the diagnosis of pneumonia, especially when analysing facultative pathogens or secondary pathogens, a useful interpretation of analysis results is only possible in connection with a clinical and pathological evaluation.  相似文献   

8.
The interaction between Mycoplasma hyopneumoniae and Pasteurella multocida in experimental pneumonia was investigated in conventional pigs. The experimental animals were 49 days old when inoculated with M. hyopneumoniae; they were inoculated with P. multocida after 23 days, and killed 13 days later. In pigs inoculated only with P. multocida, clinical signs and lung lesions were not observed, and the agent was not recovered. Pigs inoculated with M. hyopneumoniae developed fever, moderate cough and dyspnea which tended to disappear, and small proliferative lung lesions from which M. hyopneumoniae was isolated. Pigs inoculated with both agents had higher fever, severe cough and dyspnea which tended to aggravate, and extensive exudative lung lesions from which organisms were isolated. All animals had similar growth rates, but the group infected with both agents consumed 60% more food. Therefore, M. hyopneumoniae causes mild pneumonia, whereas P. multocida is not pathogenic alone but aggravates the pneumonia initiated by M. hyopneumoniae.  相似文献   

9.
Comparison of Mycoplasma hyopneumoniae strains by serologic methods   总被引：3，自引：0，他引：3  
Six field strains of Mycoplasma hyopneumoniae isolated from pneumonic lungs of pigs, reference strains 11 and J of M hyopneumoniae, Ms 42 strain of Mycoplasma flocculare, and BTS 7 strain of Mycoplasma hyorhinis were compared serologically, using hyperimmune antisera produced in rabbits. All strains of M hyopneumoniae were closely related as determined with the disk growth-inhibition test; however, differences in zone sizes indicated that some antigenic heterogeneity existed. Cross-reactions were not detected between M hyopneumoniae, M flocculare, and M hyorhinis with the growth-inhibition test. The metabolic-inhibition test was more useful for detection of intraspecies antigenic difference than was the growth-inhibition test, since antigenic diversity was clearly detected among M hyopneumoniae strains. Slight cross-reactions were observed between M hyopneumoniae and M flocculare. Using 2-dimensional immunoelectrophoresis, antigenic differences were observed among M hyopneumoniae strains, although many common components also were detected in electropherograms. Mycoplasma flocculare possessed a close antigenic relationship to M hyopneumoniae, as determined by two-dimensional immunoelectrophoresis, whereas both organisms were less related to M hyorhinis. Evidence obtained in this study indicated that strains of mycoplasmas tentatively identified as M hyopneumoniae were similar antigenically, but evidence was obtained also of some diversity in antigenic structure among these strains.  相似文献   

10.
In a study of 4 sheep herds, 1 apparently healthy and 3 having respiratory problems, lesions typical of subacute or chronic pneumonia were found in 3–36 % of slaughtered lambs. Occurrence appeared to be related to certain environmental factors such as pasture, whereas moderate lungworm invasion was not found to contribute to subacute or chronic pneumonia. Relation between pneumonia and low carcass weight was established only in 1 herd.Lungs were subjected to microbiological examination. Mycoplasma ovipneumoniae was isolated from both normal and pneumonic lungs from all 4 herds. The prevalence was far higher in pneumonic (98 %) than in normal ones (28 %). Bacteria, mostly Pasteurella haemolytica, were also found in both pneumonic (49 %) and normal (18 %) lungs from all 4 herds. These results confirm the conclusions of a previous study that M. ovipneumoniae is of etiological significance in subacute or chronic pneumonia, whereas bacteria mainly occur as secondary invaders. M. ovipneumoniae appears, however, only to be a potential pathogen. Examinations for Mycoplasma arginini and virus were negative and these agents are considered to be of less significance in subacute or chronic pneumonia under Norwegian conditions.  相似文献   

11.
Sheep lungs obtained at slaughter from 4 herds from Central Norway were subjected to a macroscopical examination. Gross pulmonary findings included normal lungs, fibrous pleurisy, verminous nodules, atelectasis and consolidations of lobular and lobar extensions. A selection of lungs representing the various gross findings was subjected to microbiological and histological examinations. Pleurisy was associated wtih pneumonic consolidations and extension of lesions. Verminous nodules indicative of Muellerius spp. migrations occurred irrespective of gross pulmonary lesions or microbiological findings. A subacute or chronic pneumonia of a mixed proliferative exudative type was demonstrated in consolidated tissue. An association was found between the isolation of Mycoplasma ovipneumoniae and the presence of pneumonic lesions and between the number of organisms and extension of lesions. Histological findings highly indicative of this organism were proliferative changes in the bronchiolar and bronchial epithelium and intrapulmonary lymphoid tissue. The intensity of these changes was correlated to the number of mycoplasma organisms present. Mycoplasma ovipneumoniae is suggested to be of primary etiological significance regarding subacute or chronic pneumonia in lambs at slaughter.  相似文献   

12.
This study attempted to determine whether one multiplex polymerase chain reaction (PCR) is an effective adjunct method for diagnosing Mycoplasma hyopneumoniae and Mycoplasma hyorhinis infection, and whether M. hyorhinis should be considered as an enzootic pneumonia or porcine respiratory disease complex pathogen in Taiwan. To our knowledge, this study is the first to isolate and identify M. hyorhinis as a porcine pathogen in Taiwan. A novel isolation method and a multiplex PCR test were applied to detect and isolate M. hyorhinis. The correlation of M. hyorhinis with swine pneumonia was also examined using a challenge test. Based on weight, 18 pigs were assigned to three groups and housed throughout the study in a specific-pathogen-free (SPF) facility and provided with aseptic feed and water. Groups 1 (n=6) and 2 (n=6) were challenged with 5mL M. hyorhinis culture via tracheal intubation on day 1. The M. hyorhinis strains ATIT-1, -3, and-7 were used to infect group 1 and the strain ATCC 27717 was used for group 2. Culture medium was replaced by phosphate-buffered saline in group 3 (n=6). All pigs were slaughtered on day 28, and their lungs were removed for examination of lesions. Of the six pigs in group 1 challenged with wild-type strains, two had typical mycoplasma pneumonia lesions. No gross lung lesions were observed in groups 2 and 3. Although further examination is necessary to confirm that wild-type strains can cause pneumonia, it appears that M. hyopneumoniae is no longer the only mycoplasma pathogen implicated in the diagnosis of swine enzootic pneumonia (SEP).  相似文献   

13.
The 6-chloro analogue of norfloxacin (compound A) administered continuously in the feed at 400 ppm for 21 days markedly reduced the extent and activity of pneumonic lesions in pigs with pneumonia induced experimentally with an homogenate of pneumonic lung and broth cultures of Mycoplasma hyopneumoniae. Norfloxacin at 100 ppm or compound A at 200 ppm in the feed did not reduce the extent of lung lesions, although half the pigs treated with norfloxacin had lesions which appeared histologically to be healing. M hyopneumoniae was detected either by culture or immunofluorescence in the lungs of 60 per cent of the pigs treated with compound A at 400 ppm compared with all the pigs in the other groups. These results were related to the amount of drug in the lungs and body fluids during therapy. Only compound A at 400 ppm produced concentrations in the lungs and bronchial secretions exceeding the minimum inhibitory concentration against M hyopneumoniae. Mycoplasmacidal concentrations were not reached either in the lungs or bronchial secretions which might account partly for the frequent detection of M hyopneumoniae in the lungs after treatment. Drug resistance did not appear to be responsible for the persistence of M hyopneumoniae in vivo since the M hyopneumoniae isolates from the pigs after therapy were sensitive in vitro to both quinolones. As daily weight gain and feed-conversion efficiency improved in all groups of treated pigs compared with the controls, these effects were probably unrelated to the antimycoplasmal activities of the two quinolones.  相似文献   

14.
Relationships between macroscopic lesions and Polymerase Chain Reaction (PCR) detection of Mycoplasma hyopneumoniae (Mhp), Pasteurella multocida (Pm), Actinobacillus pleuropneumoniae (App), Haemophilus parasuis (Hps) and Streptococcus suis (Ssuis) of the lungs of 3731 slaughter pigs from 125 herds were assessed in France. Pneumonia and pleuritis were the most frequent lesions (69.3% and 15% of the lungs, respectively). Mhp, Pm, App, Ssuis and Hps were detected in 69.3%, 36.9%, 20.7%, 6.4% and 0.99% of the lungs, respectively. Mhp and Pm were associated with pneumonia at both the pig and herd levels. Pleuritis was not associated with any pathogen at the pig level, but was associated with a high percentage of pigs PCR-positive for App at the herd level. Measures focused on control of Mhp, Pm and App should significantly reduce the occurrence of both pneumonia and pleuritis.  相似文献   

15.
The objective of this experimental study was to determine the effects of aerial ammonia on disease development and bacterial colonization in weaned pigs inoculated with toxigenic Pasteurella multocida and Mycoplasma hyopneumoniae. Two groups of 10 pigs each were continuously exposed to 50 and 100 p.p.m. ammonia, respectively, and compared to a non-exposed control group of 20 pigs. Following aerosol inoculation with M. hyopneumoniae at day 9, all pigs were aerosol-inoculated with toxigenic P. multocida type A at days 28, 42 and 56. At day 63 they were euthanized. Clinical signs including coughing and respiratory distress were present in all groups following inoculation. No significant differences could be established in the extent or frequency of pneumonia between ammonia-exposed pigs and controls, or in the extent of conchal atrophy, the frequency of isolation of toxigenic P. multocida from conchae, tonsils, lungs and kidneys, or the average daily weight gain. The recovery of toxigenic P. multocida from nasal swabs following inoculation was significantly greater in pigs exposed to 50 p.p.m. ammonia or more as compared to the control group. In conclusion, high levels of ammonia combined with inoculations with M. hyopneumoniae and toxigenic P. multocida had no significant effect on disease development, but may have enhanced colonization by toxigenic P. multocida on the nasal turbinates.  相似文献   

16.
In order to study the occurrence of mycoplasmas among Norwegian sheep, lungs from a great number of different herds were collected at 3 abattoirs in Southern Norway. The presence of fermenting mycoplasmas and bacteria was examined in both normal and pneumonic lungs to determine whether recovery of these agents could be related to pneumonic changes. Pneumonic lungs demonstrated lesions typical of the condition described as subacute or chronic pneumonia.Mycoplasma ovipneumoniae was found in 87 % of the 126 pneumonic lungs and in 6 % of the 83 normal lungs. Bacteria, mostly Pasteurella haemolytica, were less frequently encountered in the pneumonic lungs, and usually in combination with M. ovipneumoniae. It is concluded that M. ovipneumoniae is widespread among sheep in Southern Norway and can be considered to have etiological significance in subacute or chronic pneumonia, whereas bacteria probably occur mainly as secondary invaders. Changes resulting from moderate invasion by lungworm were found in about half of the lungs, but just as frequently in normal as in pneumonic lungs, and accordingly did not appear to contribute to the pneumonia investigated.  相似文献   

17.
Mycoplasmas and other micro-organisms are recorded from a pig herd originally derived by hysterectomy. Complement fixation tests were positive for Mycoplasma hyopneumoniae 20 months after the first hysterectomy. Following a marked increase in pneumonic lesions found at slaughter, and after modifying the culture medium M hyopneumoniae was isolated. The principal micro-organism associated with this mycoplasma was Pasteurella multocida.  相似文献   

18.
Mycoplasma is the common name for the smallest free-living microorganisms, the Mollicutes. Mycoplasma hyopneumoniae is of great importance in veterinary medicine, causing enzootic pneumonia in pigs. M hyorhinis can cause polyserositis and may cause pneumonia in piglets. Oligonucleotides complementary to variable regions of 16S rRNA from these mycoplasmas were designed and used as probes for detection and identification of these mycoplasmas. The probe complementary to 16S rRNA of M hyorhinis gave a very weak cross-hybridisation with M hyosynoviae in filter hybridisation experiments, but not with any of the other porcine mycoplasmas tested. Three oligonucleotide probes complementary to M hyopneumoniae 16S rRNA were tested. One of the probes (Mhp6/30) was found to be specific to M hyopneumoniae, but the other two gave cross-hybridisation with M flocculare. Using the Mhp6/30 probe in direct filter hybridisation experiments, it proved possible to detect M hyopneumoniae in lung biopsies from experimentally infected pigs.  相似文献   

19.
Ten swine from each of five herds believed to be affected with mycoplasmal pneumonia of swine and ten swine from each of five herds believed to be mycoplasmal pneumonia-free were selected for postmortem study. Lungs from the 100 swine were examined; grossly and microscopically for lesions typical of mycoplasmal pneumonia of swine and culturally and by an indirect immunofluorescent procedure for the presence of Mycoplasma hyopneumoniae. Nineteen of the lungs had both gross and microscopic lesions typical of mycoplasmal pneumonia of swine and 13 (68%) of these were infected, i.e. were culturally and/or indirect immunofluorescent positive. Absence of gross lesions did not prove freedom from mycoplasmal pneumonia, 14 of 73 (19%) grossly normal lungs were found to be infected with M. hyopneumoniae. Comparison of the indirect immunofluorescent and cultural examination, as methods of diagnosing mycoplasma pneumonia, revealed that neither procedure alone was reliable in the case of negative results. Ten lungs were indirect immunofluorescent negative and culturally positive and seven were culturally negative and indirect immunofluorescent positive (11 lungs were positive by both procedures). It was concluded that a definitive diagnosis of mycoplasmal pneumonia of swine requires that M. hyopneumoniae be visualized in indirect immunofluorescent stained lung sections or that it be recovered culturally.  相似文献   

20.
To facilitate the control of enzootic pneumonia (EP) of swine caused by Mycoplasma hyopneumoniae, the complement fixation (CF) test has been used for the detection of M. hyopneumoniae antibodies. However, the CF test is a cumbersome and time-consuming technique and cross-reactivity are major drawbacks associated with this method. To circumvent these drawbacks, we have developed a double-sandwich enzyme-linked immunosorbent assay (ELISA), consisting of purified monoclonal antibody (Mab) against the 46 kDa surface antigen (P46) of M. hyopneumoniae and recombinant P46 protein expressed in Escherichia coli, for the detection of antibodies to M. hyopneumoniae in serum samples from pigs experimentally inoculated with M. hyopneumoniae and from naturally infected pigs, and compared the practical usefulness of ELISA using the CF test. In experimentally inoculated pigs, the CF and ELISA antibodies were detected at almost the same time, and a good correlation was demonstrated between the CF test and the ELISA. In a survey conducted on field samples, the seropositivity by ELISA in pigs of age 2-6 months was increased. At the time of slaughter, approximately 80% of the animals were seropositive for ELISA. However, a gradual decrease in the prevalence of ELISA positive samples was observed in sows with increasing parity. No correlation was seen between the results obtained with the two methods in the clinical samples. The CF test appears to have limited value for the diagnosis of EP in conventional herds because nonspecific reactions were frequently observed. Therefore, this ELISA is a useful alternative to the CF test currently used for the diagnosis of EP.  相似文献   

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