Marked increases in neuronal nitric oxide synthase (nNOS) mRNA and NADPH-diaphorase histostaining in adrenal cortex after immobilization stress in rats

The immunoprophylaxis of mycoplasmal pneumonia of swine (MPS) caused by Mycoplasma hypopneumoniae was investigated for the first time in fattening pigs in Croatia. The incidence of MPS was monitored in pigs weighing on average 27.5 kg (12 weeks old) after immunization with a M. hyopneumoniae vaccine. Of 350 pigs in each group, in the nonvaccinated group 55 animals (15.7%) were affected by pneumonia and 11 (3.1%) died of consequences of pneumonia, whereas in the vaccinated group 20 pigs (5.7%) were affected by pneumonia without any death due to the infection. In the nonvaccinated group 44% more pigs were individually treated with antibiotic, and these animals received in-feed therapy for more than 1/4 of the fattening period. Vaccinated pigs gained weight faster, at the rate of 0.745 kg/day (or 82 g/day more) than control animals. The mean score of lung lesions due to M. hyopneumoniae was 10.51 in the control pigs and only 0.54 in the vaccinated animals. The total tissue alterations on lungs due to M. hyopneumoniae, Pasteurella multocida and/or Actinobacillus pleuropneumoniae expressed as the mean-score were 13.21 in the control group and 2.98 in the vaccinated group. According to the results of evaluation of the M. hyopneumoniae vaccine in the field, the vaccine appeared to provide an adequate immunity in fattening pigs but was less effective when administered to younger pigs at 1-3 weeks of age.     

Tylosin tartrate and tiamutilin effects on experimental piglet pneumonia induced with pneumonic pig lung homogenate containing mycoplasmas, bacteria and viruses

The effects of tylosin tartrate and tiamutilin were examined in pneumonias induced experimentally in neonatal piglets with a homogenate of pneumonic pig lung, obtained from pigs with naturally acquired enzootic pneumonia. The homogenate contained mycoplasmas, including Mycoplasma hyopneumoniae (M suipneumoniae) and M hyorhinis, and certain bacteria and viruses. The experimental pneumonias generally resembled mycoplasmal pneumonia histologically but were complicated by aspiration pneumonia in some animals. both tylosin tartrate (50 mg/kg) and tiamutilin (10 mg/kg) administered orally twice daily for 10 days, beginning 14 days after intranasal infection, significantly reduced the incidence and severity of macroscopical pneumonic lung lesions. M hyopneumoniae could be isolated from the lungs of the unmedicated piglets, but not from drug-treated piglets. The numbers of M hyorhinis, Acholeplasma granularum, Haemophilus parasuis, Pasteurella multocida and P haemolytica in the lung tissue of the infected piglets were significantly reduced by drug therapy. The role of bacterial in the experimental infection appeared to be that of secondary invaders.     

Efficacy of doxycycline in feed for the control of pneumonia caused by Pasteurella multocida and Mycoplasma hyopneumoniae in fattening pigs

A multicentre, controlled, randomised and blinded study was carried out in three French pig herds to assess the efficacy of doxycycline administered in the feed for the control of pneumonia. About 20 per cent of 363 pigs from the three fattening units were diseased at the start of the study. Pneumonic lesions were found on pigs examined postmortem and Pasteurella multocida was isolated from the lungs of pigs in all the herds. Mycoplasma hyopneumoniae infection was confirmed either by detection in pneumonic lungs or by seroconversion in pigs sampled three weeks apart. P multocida, Bordetella bronchiseptica and Actinobacillus pleuropneumoniae were isolated from 64 per cent, 50 per cent and 2 per cent, respectively, of 148 nasal swabs. The following variables were significantly different between the treated and untreated groups (P < or = 0.001): the incidence of diseased pigs during the three weeks from the start of treatment (8.1 per cent in treated group v 35.4 per cent in control group), mean daily weight gain over the same period (934 g/day in the treated group v 834 g/day in the control group) and the cure rate of pigs which were diseased at the start of treatment (73.5 per cent in treated group v 35.3 per cent in control group). These data demonstrate that an average dose of 11 mg doxycycline/kg bodyweight per day in feed for eight days was effective in controlling pneumonia due to P multocida and M hyopneumoniae in these fattening pigs.     

A case report of extensive vitiligo

Minimum inhibitory concentrations of doxycycline and oxytetracycline were determined against 55 Pasteurella multocida strains, 59 Actinobacillus pleuropneumoniae strains and 26 Mycoplasma hyopneumoniae strains isolated from the respiratory tract of pigs. An additional set of 76 P multocida strains isolated from pneumonic pigs was tested for their minimum inhibitory concentrations of doxycycline. The P multocida and A pleuropneumoniae strains were isolated in France and the minimum inhibitory concentrations were determined by an agar dilution method. The M hyopneumoniae strains were isolated in the United Kingdom and minimum inhibitory concentrations were determined by a serial broth dilution method. All the strains tested were susceptible to doxycycline whereas 15 per cent of the P multocida strains and 22 per cent of the A pleuropneumoniae strains were resistant to oxytetracycline. Doxycycline concentrations inhibiting 90 per cent of strains were 1 microgram/ml for P multocida and 2 micrograms/ml for A pleuropneumoniae. The ratio of the minimum inhibitory concentrations of doxycycline and oxytetracycline ranged between 1/1 and 1/4 for the oxytetracycline-susceptible strains and between 1/16 and 1/64 for the oxytetracycline-resistant strains. All the M hyopneumoniae strains were susceptible to doxycycline and oxytetracycline, the concentrations inhibiting 90 per cent of strains being 1 microgram/ml and 2 micrograms/ml, respectively. These data confirm that doxycycline has a higher in vitro activity against pig respiratory pathogens than oxytetracycline.     

Are nasal swabs for swine appropriate for the diagnosis of bacterial pneumonia agents?

Nasal swabs and lungs of 150 pigs with pneumonia were tested by culture at post mortem examination. The isolated agents were Pasteurella multocida (P.m.), P. haemolytica, Bordetella bronchiseptica, Actinobacillus pleuropneumoniae, Staphylococcus aureus, Streptococcus spp. and Escherichia coli. P.m. was most frequently found, and this agent only showed a significant correlation between lungs and nasal swabs. In 80.6% of pigs with P.m. in the lung the agent was detected in the nose, too. Drug resistance patterns of P.m. isolates from lungs and noses of the single animals were identical or similar, also in case of different capsular types. The examination of porcine nasal swabs for bacteria capable of causing pneumonia should be limited to P. multocida. Demonstration of agents in lung material is generally more certain.     

Mycoplasma hyopneumoniae potentiation of porcine reproductive and respiratory syndrome virus-induced pneumonia

An experimental model that demonstrates a mycoplasma species acting to potentiate a viral pneumonia was developed. Mycoplasma hyopneumoniae, which produces a chronic, lymphohistiocytic bronchopneumonia in pigs, was found to potentiate the severity and the duration of a virus-induced pneumonia in pigs. Pigs were inoculated with M. hyopneumoniae 21 days prior to, simultaneously with, or 10 days after inoculation with porcine reproductive and respiratory syndrome virus (PRRSV), which induces an acute interstitial pneumonia in pigs. PRRSV-induced clinical respiratory disease and macroscopic and microscopic pneumonic lesions were more severe and persistent in M. hyopneumoniae-infected pigs. At 28 or 38 days after PRRSV inoculation, M. hyopneumoniae-infected pigs still exhibited lesions typical of PRRSV-induced pneumonia, whereas the lungs of pigs which had received only PRRSV were essentially normal. On the basis of macroscopic lung lesions, it appears that PRRSV infection did not influence the severity of M. hyopneumoniae infection, although microscopic lesions typical of M. hyopneumoniae were more severe in PRRSV-infected pigs. These results indicate that M. hyopneumoniae infection potentiates PRRSV-induced disease and lesions. Most importantly, M. hyopneumoniae-infected pigs with minimal to nondetectable mycoplasmal pneumonia lesions manifested significantly increased PRRSV-induced pneumonia lesions compared to pigs infected with PRRSV only. This discovery is important with respect to the control of respiratory disease in pigs and has implications in elucidating the potential contribution of mycoplasmas in the pathogenesis of viral infections of other species, including humans.     

Demonstration that Australian Pasteurella multocida isolates from sporadic outbreaks of porcine pneumonia are non-toxigenic (toxA-) and display heterogeneous DNA restriction endonuclease profiles compared with toxigenic isolates from herds with progressive atrophic rhinitis

Capsular types A and D of Pasteurella multocida cause economic losses in swine because of their association with progressive atrophic rhinitis (PAR) and enzootic pneumonia. There have been no studies comparing whole-cell DNA profiles of isolates associated with these two porcine respiratory diseases. Twenty-two isolates of P. multocida from diseased pigs in different geographic localities within Australia were characterised genotypically by restriction endonuclease analysis (REA) with the enzyme CfoI. Seven of 12 P. multocida isolates from nasal swabs from pigs in herds where PAR was either present or suspected displayed a capsular type D phenotype. These were shown to possess the toxA gene by polymerase chain reaction (PCR) and Southern hybridisation, and further substantiated by production of cytotoxin in vitro. The CfoI profile of one of these seven isolates, which was from the initial outbreak of PAR in Australia (in Western Australia, WA), was identical with profiles of all six other toxigenic isolates from sporadic episodes in New South Wales (NSW). The evidence suggests that the strain involved in the initial outbreak was responsible for the spread of PAR to the eastern states of Australia. Another 10 isolates, representing both capsular types A and D, were isolated exclusively from porcine lung lesions after sporadic outbreaks of enzootic pneumonia in NSW and WA. CfoI restriction endonuclease profiles of these isolates revealed considerable genomic heterogeneity. Furthermore, none of these possessed the toxA gene. This suggests that P. multocida strains with the toxA gene do not have a competitive survival advantage in the lower respiratory tract or that toxin production does not play a role in the pathology of pneumonic lesions, or both. REA with polyacrylamide gel electrophoresis and silver staining was found to be a practical and discriminatory tool for epidemiological tracing of P. multocida outbreaks associated with PAR or pneumonia in pigs.     

Oral immunization of mice with attenuated Salmonella typhimurium aroA expressing a recombinant Mycoplasma hyopneumoniae antigen (NrdF)

Mycoplasma hyopneumoniae is the etiological agent of porcine enzootic pneumonia, a commercially expensive respiratory disease of swine. Salmonella typhimurium SL3261 was used as a live carrier of plasmid pKF1, which encodes a 15-kDa recombinant M. hyopneumoniae protein. This expressed recombinant protein consists of the carboxy-terminal 11 kDa of a 42-kDa M. hyopneumoniae NrdF ribonucleotide reductase R2 subunit protein. Rabbit anti-15-kDa serum was able to inhibit the growth of viable M. hyopneumoniae J in vitro. When used as a live oral vaccine, S. typhimurium SL3261(pKF1) induced a significant secretory immunoglobulin A immune response in the lungs of mice orally immunized against the M. hyopneumoniae antigen. Utilization of live oral vaccines expressing potentially protective M. hyopneumoniae proteins, such as the NrdF antigen, which can stimulate a lung mucosal response against surface-accessible proteins may provide a cost-effective alternative to the present control strategies used for porcine enzootic pneumonia.     

Three cases of Pasteurella multocida infection in the respiratory tract

Pasteurella multocida (P. multocida) is well recognized as "normal flora" in the upper respiratory tract of cats, dogs and other animals. Recently, various infections due to P. multocida in human have been noted as pulmonary infections in the patients with chronic pulmonary diseases as well as skin abscesses or septicemia after an animal bite or scratch. We report here three cases of respiratory tract infections caused by P. multocida. The first two patients had acute exacerbation of bronchiectasis caused by P. multocida and the other patients with pulmonary emphysema developed pneumonia. These three patients improved by antibiotic therapy. In Japan, P. multocida respiratory tract infection is rare, but it may become more common in the future. Therefore, it seems to be important to take this pathogen into consideration in the management of chronic lung disease.     

Acute septicaemic pasteurellosis in Vietnamese pigs

Sixteen isolates of Pasteurella multocida were cultured from cases diagnosed as acute septicaemic pasteurellosis in Vietnamese pigs. The HSB-PCR assay provided rapid presumptive determination of 10 isolates of P. multocida identified as haemorrhagic septicaemia (HS) causing type B cultures (B:2, B:5, B:2,5). Serological designation using the Carter and Heddleston typing systems confirmed these findings, and identified the six HSB-PCR negative cultures as either A:1, A:3 or D:3,4. Biochemical fermentation and REP-PCR revealed phenotypic and genotypic identity between P. multocida type A:1 isolated from Vietnamese pigs and poultry. Marked homogeneity was also demonstrated among HSB-PCR positive swine isolates, which were shown to possess genotypic identity with P. multocida type B:2 from buffaloes diagnosed with HS.     

Immune response of sows vaccinated with attenuated transmissible gastroenteritis virus (TGEV) and recombinant TGEV spike protein vaccines and protection of their suckling pigs against virulent TGEV challenge exposure

OBJECTIVE: To compare recombinant transmissible gastroenteritis virus (TGEV) spike protein, (SP) R2-2, with attenuated live virus (ALV) vaccine in sows during late pregnancy. ANIMALS: 13 TGEV-seronegative sows and their pigs. PROCEDURE: At prepartum weeks (PPW) 6 and 4, sows of groups 1 and 2 received ALV via the oral/intranasal (O/IN) route. At PPW 2, group-1 sows received ALV IM and group-2 sows received SPR2-2 IM. Group-3 sows received SPR2-2 IM at PPW 4 and ALV O/IN at PPW 2. Sows of group 4 (negative controls) were inoculated O/IN with mock-infected ST cell fluids at PPW 6 and 4 and IM with Sf9 cell lysates at PPW2 (n = 2), or IM with Sf9 cell lysates at PPW4 and O/IN with mock-infected ST cell fluids at PPW2 (2). Serum, colostrum, and milk samples were tested for antibody to TGEV, and a lymphoproliferative (LP) assay was done on blood mononuclear cells. Suckling pigs were challenge exposed with virulent TGEV. RESULTS: Sows of groups 1 and 2 had higher IgG and significantly higher antibody titers in colostrum; their pigs had significantly higher serum antibody titer. At challenge exposure of their pigs, LP responses of group-2 sows were significantly higher than those of sows in the other 3 groups. Mean pig mortality ranged from 43 (group 2) to 92% (group 4). Significant negative correlations were observed among litter mortality and sow LP response, colostral titer, and pig serum titer at time of challenge exposure. CONCLUSIONS: In sows vaccinated twice with attenuated live TGEV, the recombinant SPR2-2 administered IM may be comparable to ALV administered IM as a booster. Vaccination failed to provide complete protection to suckling pigs after challenge exposure.     

Antibody responses of cattle to outer membrane proteins of Pasteurella multocida A:3

OBJECTIVE: To quantify the serum antibody responses to Pasteurella multocida A:3 outer membrane proteins (OMP) for cattle vaccinated with the homologous serogroup and to correlate those responses with the extent of experimentally induced pneumonia. ANIMALS: 29, 5- to 8-month-old beef-type calves. PROCEDURE: Calves were vaccinated SC or by aerosal exposure on days 0 and 7 with live or killed P multocida or phosphate-buffered saline solution (control) and subsequently challenge exposed with virulent P multocida. Antibody responses to P multocida A:3 outer membranes were quantified, using an ELISA. Antibody responses to individual OMP were detected by immunoblot analysis (western blot) and were quantified by densitometry. Antibody responses were compared among groups of calves and for various times after vaccination. Regression analyses were used to determine whether significant correlations existed between lesion scores and antibody responses to either whole outer membranes or to individual OMP. RESULTS: By ELISA, antibody responses to outer membranes for calves aerosol vaccinated with live P multocida were significantly (P < 0.05) greater than those for control calves or for killed P multocida vaccinates. There was a significant (P < 0.05) correlation between lesion score and antibody responses to outer membranes. By western blotting and densitometry, antibodies to 11 prominent OMP (100, 97, 90, 85, 74, 53, 46, 35, 32, 21, and 16 kd) were identified and quantified. In experiment 1, SC vaccination with live P multocida increased antibody binding to all protein bands except 85-, 74-, and 35-kd bands. Aerosol vaccination with live P multocida stimulated increases in antibody binding to all bands except 100 and 16 kd. Antibody responses to the 97-, 90-, 74-, and 35- kd bands were significantly (P < 0.05; greater for live aerosol vaccinates than for control calves. In experiment 2, antibody responses were not different between the killed P multocida vaccinates or control calves Antibody responses for live P multocida aerosol vaccinates were significantly (P < 0.05) greater than those for control calves for the 100-, 90-, 85-, 74-, 53-, 35-, and 16-kd bands. Regression analyses indicated significant correlations (P < 0.05) between lesion score and antibody responses to the 100-, 90-, 53-, 46-, 35-, and 32-kd OMP. CONCLUSIONS: Several OMP of P multocida type A:3 may be important for stimulating immunity to the organism in cattle.     

Dysphagia in patients with inclusion body myositis

OBJECTIVE: To determine whether ampicillin- and tetracycline-resistant strains of Pasteurella multocida and P haemolytica isolated from California cattle with pneumonia were spatially and temporally clustered and to compare overall estimates of percentages of these isolates resistant to these antimicrobials with estimates obtained on the basis of regional and temporal information. DESIGN: Epidemiologic study. SAMPLE POPULATION: Records of P multocida and P haemolytica isolates obtained from lung or tracheal wash samples collected from California cattle with pneumonia between July 1, 1991 and July 31, 1996. Only isolates obtained from samples submitted by dairies and calf ranches were used. PROCEDURE: Spatial clustering of ampicillin- and tetracycline-resistant isolates was assessed by use of nearest-neighbor and Cuzick and Edwards' analyses. Linear clustering along a north-south line was assessed by use of runs and maximum length of runs tests. Temporal clustering was assessed by use of scan tests. Spatial-temporal clustering was assessed by use of Barton's method. Regional estimates of percentages of P multocida and P haemolytica resistant to ampicillin or tetracycline were calculated. RESULTS: There was significant spatial clustering of resistant isolates and significant linear clustering along a north-south line. Significant differences in regional estimates of percentages of antimicrobial-resistant isolates were found. CLINICAL IMPLICATIONS: Results support the hypothesis that antimicrobial-resistant organisms can be clustered at the local level and reinforce the need to establish regional estimates of percentages of bacterial isolates that will be susceptible to commonly used antimicrobials.     

Human herpesvirus 6 infection as a risk factor for the development of severe drug-induced hypersensitivity syndrome

OBJECTIVES: To test suitability of radiographic evaluation of lung lesions as a substitute for lung lesion scores derived by examination at necropsy in challenge-exposure models of bovine pneumonia. ANIMALS: 10 calves selected by body weight from 20 multiple-source male Holstein calves approximately 1 to 2 months old enrolled in a Pasteurella multocida challenge-exposure study. PROCEDURE: Calves were paired on the basis of weight and randomly assigned within pairs to vaccine or control (saline solution) group. By use of deep tracheal cannulation, calves were challenge exposed with a culture of virulent P multocida, observed for 10 days, euthanatized, and necropsied, and the lungs were scored for pneumonic lesions. Radiographic views of the lung fields of the calves were taken before challenge exposure and before necropsy and were evaluated for alveolar disease by a veterinary radiologist. Lung lesion scores were compared with radiographic evaluations. RESULTS: There was a strong and significant correlation (R2 = 0.91, P < 0.001) between results of the evaluation of postchallenge-exposure radiographs and necropsy results. There also was also strong and significant correlation (R2 = 0.90, P < 0.001) between evaluation of the prechallenge-exposure radiographs and necropsy results. CONCLUSIONS: Radiographic evaluation of lung lesions correlates well with lung lesions found at necropsy. The findings emphasize the need for caution in interpreting the results of challenge-exposure studies of bovine respiratory tract disease in which small numbers of calves are studied.     

Effect of contrast agents on the activity of acid phosphatase in mouse neutrophils]

We report a case of Pasteurella multocida pneumonia and empyema in an otherwise healthy patient. The most frequently observed human complication with this microorganism is a local wound infection. Only a few cases of pneumonia have been described, and most of the patients were immunodeficient.     

Angiogenesis and expression of tenascin after transmural laser revascularization

OBJECTIVE: To evaluate the impact of maternal antibodies after challenge exposure of baby pigs with a homologous serovar of Haemophilus parasuis. ANIMALS: 7 gilts and their litters from a high health status farm. PROCEDURE: Gilts were vaccinated twice with a commercial bacterin that contained H parasuis serovar 4 and 5 or, as a control, adjuvant only. A group of pigs was also vaccinated similarly before challenge exposure. After early and late challenge exposure at 3 and 4 weeks, respectively, all pigs from vaccinated gilts were evaluated for clinical signs of infection, lesions, and antibody titer. RESULTS: All pigs coming from control gilts had severe signs of H parasuis infection. Macroscopic lesions included polyserositis and pneumonia, and bacteriologic examination confirmed H parasuis as the etiologic agent. Vaccinated pigs born to vaccinated gilts did not have clinical signs of disease. However, some vaccinated pigs born to control gilts had signs of nervous system dysfunction and lameness. There was no difference in lesion scores between early or late challenge exposure, but lesions scores for pigs from vaccinated and control gilts were different (P < 0.01). CONCLUSIONS: Under these experimental conditions, immune-naive and vaccinated pigs from vaccinated gilts were protected against systemic lesions when challenge exposed with a virulent strain of H parasuis. CLINICAL RELEVANCE: Vaccination of the gilt and pigs protects the latter from polyserositis, but results are not different from those for nonvaccinated pigs from vaccinated gilts. Maternal antibodies did not seem to interfere with vaccination of pigs at 1 and 3 weeks of age.     

The effect of vaccination against Mycoplasma hypopneumoniae in pig herds with a continuous production system

An inactivated Mycoplasma hyopneumoniae vaccine was evaluated in five pig herds clinically infected with enzootic pneumonia and practising a continuous production system in the growing/finishing unit. In each herd, a vaccinated and control group of approximately 47 pigs each were individually monitored from birth until slaughter. Vaccinated pigs received the first dose at about 1 week of age and the second approximately 3 weeks later. During all production stages, an equal number of vaccinated and control pigs was present in the same pen. Both groups were compared with respect to zootechnical parameters (major variables) and by means of serological, pathological, and bacteriological parameters (ancillary variables). Daily weight gain was improved by 14 gr/day during the period from 8 days of age until slaughter (P = 0.0486) and by 25 gr/day during the growing/finishing period (P = 0.0067). Mortality rate, and the costs for curative medication were not significantly improved by vaccination. The results of the ancillary variables are presented and discussed.     

Comparative evaluation of the sensitivity to Mycoplasma pneumoniae of organ cultures of the trachea and lungs of certain animals

A possibility was shown of cultivation of M. pneumoniae in the organ cultures of the trachea and the lungs of a pig embryo. 5-7-day guinea pigs, and 3-5-day chicks. The lung and tracheal explants of chicks possessed the greatest sensitivity to M. pneumoniae. M. pneumoniae strains were isolated from the nasopharyngeal smears and washings from the bronchi obtained in bronchoscopy of patients suffering from chronic pneumonia, with the use of organ culture of chick trachea. Explains of chick trachea could serve as a medium for the isolation of M. pneumoniae from the patients.     

Reflections on what makes a good teacher

Nine 3-week-old conventional pigs were inoculated intranasally with a Korean isolate of porcine respiratory coronavirus (PRCV). Three 3-week-old conventional pigs were kept as noninoculated controls. Three inoculated and one control pig were euthanatized at 5, 10, and 15 days postinoculation (DPI), respectively. All nine inoculated pigs developed respiratory disease. Interstitial pneumonia characterized by mononuclear inflammatory cell infiltration into alveolar septa were seen microscopically in all nine PRCV-infected pigs. Histopathologic changes were severe at DPI, modest at 10 DPI, and almost resolved at 15 DPI. PRCV antigen was not detected in bronchial and bronchiolar epithelium but was detected in interstitial macrophages in the lungs. This Korean isolate of PRCV appeared to replicate primarily within alveolar macrophages in the respiratory system of the pig.     

Lack of protection against avian cholera by vaccination with recombinant P6-like protein from Pasteurella multocida

The gene encoding the P6-like protein of Pasteurella multocida was cloned in the baculovirus expression system. Baculovirus-expressed recombinant protein was used to parenterally immunize 6-wk-old Nicholas broad-breasted white turkeys. Turkeys developed significant antibody titers to the recombinant protein as measured by enzyme-linked immunosorbent assay. Two weeks after the last immunizing injection, vaccinated turkeys were placed in contact with turkeys infected with P. multocida strain P1059, as were nonvaccinated control birds. No differences occurred in percent mortality between the two groups. We conclude that parenterally administered recombinant P6-like protein does not protect turkeys from avian cholera.