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1.
This study was aimed at evaluating the pathophysiology of pulmonary dysfunctions and inflammatory consequences of an acute respiratory chlamydial infection induced experimentally in conventionally raised pigs (aged 39-44 days). Eight animals were exposed to Chlamydia suis (C. suis) and four non-infected animals served as controls. The total observation period was from seven days before challenge to seven days post exposure. While non-infected control pigs did not exhibit any clinical symptoms, animals exposed to C. suis developed fever and were severely respiratory distressed within the first week after exposure. After C. suis infection, pulmonary dysfunctions were characterised by a significant decrease in the diffusion capacity of the lung (i.e. transfer factor of the lung for carbon monoxide; TL CO), a significant increase in the functional residual capacity (FRC), and significant changes in the pattern of ventilation (respiratory rate increased while the tidal volume decreased). In exhaled breath condensate (EBC), leukotriene B(4) (LTB(4)) and interleukin 6 (IL-6) showed a tendency to increase after infection. In the broncho-alveolar lavage fluid (BALF) of C. suis infected pigs, the activity of matrix metalloprotease 9 (MMP-9) was found to be increased compared to controls. BALF cytology was characterised by increased numbers of granulocytes and activated lymphocytes. Pulmonary inflammation in infected pigs was confirmed by post mortem histology. A prominent dissemination of chlamydial bodies in the lung was accompanied by an influx of macrophages, granulocytes and activated T-cells. Data obtained in this study provide new insight into the pathogenesis of acute respiratory chlamydial infections in pigs.  相似文献   

2.
This report describes the isolation in cell cultures of Chlamydia psittaci from cases of conjunctivitis in a colony of cats. The organism was identified in McCoy cell monolayers by staining the intracytoplasmic chlamydial inclusions with a fluorescent antibody technique, and serological evidence of chlamydial infection in cats was obtained by indirect immunofluorescence. The possible role of C psittaci as an ocular, upper respiratory and reproductive tract pathogen in cats is discussed.  相似文献   

3.
The prevalence of Chlamydia pecorum and Chlamydia pneumoniae infections in two free-range koala populations was assessed using genus-specific PCR combined with species-specific DNA probe hybridisation. Population A had a very high overall level of chlamydial infection (85%) with significantly more of these infections being due to C. pecorum (73%) compared to C. pneumoniae (24%). The second population had a much lower prevalence of infection (10%) with equal levels of both species. An important finding of this study was that. while five of 24 C. pecorum-infected koalas had clinical signs of the disease (both ocular and urogenital sites), none out of seven C. pneumoniae-infected koalas had signs of clinical disease. This suggests that C. pecorum may be the more pathogenic of the two chlamydial species infecting this host. The level of infection (assessed by intensity of the specific hybridisation signal) also differed between chlamydial species, with C. pecorum infections ranging from low to high grade whereas C. pneumoniae infections were always low grade. When the age of infected koalas was examined, 58% of young, sexually immature koalas were found to have C. pecorum infections, increasing to 100% of koalas in the older age groups. This suggests that, in this population at least, young koalas are readily infected with C. pecorum from their mothers. While the infection levels with C. pneumoniae were too low to be statistically significant, again, sexually immature koalas were found to be infected. The recent separation of chlamydial infections in koalas into two species is beginning to indicate different epizootiologies for koala C. pecorum compared to koala C. pneumoniae.  相似文献   

4.
Five mature rams and 4 bulls were inoculated parenterally with bovine or ovine chlamydial strains of type 1 and 2. One to 3 days later, all animals developed a chlamydemia lasting 4 to 8 days. Chlamydial agents were isolated from the semen near the end of the chlamydemic phase. All rams and 3 of 4 inoculated bulls excreted chlamydiae in the semen for 22 to 29 days. From 8 to 39 days after inoculation, selected rams or bulls were killed to test for chlamydial infection in the urogenital tract and other organs. Chlamydiae were isolated in developing chicken embryos from testis, epididymis, and accessory sex glands. Bulls examined 29 and 39 days after inoculation did not harbor chlamydiae. Chlamydiae were also not isolated from 3 control bulls which were from the same herd as the principal bulls. All inoculated bulls and rams had a group-specific chlamydial antibody response within 7 days. The titers reached maximal levels of 128 to 512 at 14 days after inoculation. Subsequently, the antibody titers decreased gradually. Seminal plasma collected at different times after animals were inoculated did not fix complement in the presence of chlamydial group antigen. The number of polymorphonuclear leukocytes in the semen increased during the experiment. The semen was grossly purulent in 2 rams inoculated with the type 2 chlamydial strain of polyarthritis.  相似文献   

5.
Seven vaccines prepared from pathogenic strains of different origin of Leptospira interrogans [serovars icterohaemorrhagiae (one strain) and copenhageni (6 strains)] were examined in protection tests on golden hamsters. Two of the copenhageni strains were used for challenge. The organs (kidneys, spleen, liver) in the vaccinated animals surviving challenge were protected to a varying degree. Low rates of survival were associated with a high incidence of Leptospira-positive findings, partly connected with focal lesions of the kidneys. On the other hand, in the groups in which all the animals survived, it was not possible to culture leptospires from their organs or to detect leptospiral antigen in these organs by immunohistochemical investigation. A protection of the organs that prevents vaccinated animals from shedding leptospires after infection clearly depends on the vaccine dose administered and the efficacy of the vaccine which can be measured in potency tests based on the survival rate as the relevant parameter.  相似文献   

6.
Cultures of bovine alveolar macrophages were inoculated with type-1 and type-8 adenoviruses, initially isolated from calves with respiratory tract disease, and functional properties of the cells were observed over a period of 10 to 11 days. Both viruses replicated in macrophages; viral titers were low (less than 3.75 log10 TCID50/0.1 ml), and intranuclear inclusions were detected by indirect immunofluorescence in 5 to 10% of the cells from 3 days after inoculation. Highest titers were induced by type-1 adenovirus, which also induced the greatest functional changes. Expression of Fc and complement receptors was reduced by both viruses, although the greatest effects were seen with type 1. Phagocytosis of Candida krusei cells was reduced following type 1 infection, whereas phagocytosis in type-8-infected cells was not different from that of noninfected macrophages. Ability to kill ingested Candida cells also was reduced following type-1 infection, whereas type-8-infected macrophages had lower killing ability only at 2 to 4 days after inoculation. Neither virus had substantial effects on the production of neutrophil chemotactic factors by the macrophages.  相似文献   

7.
Eight strains of Chlamydia psittaci isolated from swine with pneumonia, pleuritis, pericarditis, and enteritis were characterized through analysis of the major outer membrane protein gene ompA by a two-step polymerase chain reaction, by their interactions with cells in culture, and by the morphologic features and ultrastructure of intracellular inclusions. Amplified chlamydial ompA DNA fragments were differentiated by restriction endonuclease digestion. Chlamydial isolates were separated into 2 types on the basis of ompA restriction fragment length polymorphism. Strains of type L71 had finely granular inclusions, whereas those of type 1710S contained pleomorphic reticulate bodies (RB) in the inclusions, which are characteristic of aberrant chlamydial developmental forms. Chlamydial types L71 and 1710S required centrifuge-assisted inoculation for efficient infection of cell cultures. Cultivation in cell culture medium containing cycloheximide increased the numbers of chlamydial inclusions about 1.5-fold. These strains formed few elementary bodies in yolk sac cells of chicken embryos. Ultrastructurally, unique doublet RB were observed, particularly in strains of the ompA type L71. These doublets consisted of 2 RB, bounded by a cytoplasmic membrane, contained within a common cell wall and an extended periplasmic space. Ultrastructural examination of strains of the ompA type 1710S confirmed the aberrant chlamydial developmental forms, but evidence of viral infection of the RB as a cause of these aberrant forms was not found. The strain S45 isolated from intestinal sites of swine was a trachoma restriction fragment length polymorphism type. With the mouse biotype, it represented the second isolate from animals of Chlamydia trachomatis.  相似文献   

8.
The pathogenicity of a Chlamydia psittaci isolate of pigeon origin was assessed using a litter of gnotobiotic piglets. At 3 days of age, six piglets were inoculated intragastrically with egg-grown chlamydiae, the remaining six pigs were sham-inoculated. The animals were observed for clinical signs, and they were killed and necropsied sequentially between 4 and 15 days of age. Clinical manifestations consisted of slight softening of the faeces between 6 and 10 days post-inoculation (DPI). Immunohistochemistry revealed chlamydial replication predominantly in the small intestine, initially within villous enterocytes, after 4 DPI mostly in the lamina propria. Histopathology showed villous atrophy and increased numbers of inflammatory cells in the gut up to 6 DPI. Chlamydial stages of normal morphology were identified within enterocytes using transmission electron microscopy. An enzyme-linked immunosorbent assay (ELISA) run on faecal samples revealed shedding of chlamydial antigen from 3 until 11 DPI. Systemic dissemination of Chlamydia occurred to a limited extent according to polymerase chain reaction and immunohistochemistry results of several extraintestinal organs. Corresponding histopathological changes were minimal. Sera of all pigs were negative for anti-chlamydial antibodies using a complement fixation test. In conclusion, inoculation of this isolate in gnotobiotic piglets resulted in a productive enteric infection with mild lesions, weak systemic dissemination, and faecal shedding, indicating the pig as a potential host for avian chlamydiae.  相似文献   

9.
Pig lung alveolar macrophages provided a suitable cell culture system for primary isolation of ovine chlamydia and sustained their growth through several passages. In centrifuged preparations, titres of established strains compared favourably with those obtained in fertile eggs, and in parallel titrations on primary isolation, evidence of chlamydial infection was detectable in macrophages several days earlier than in eggs.  相似文献   

10.
Porcine Chlamydiaceae were cultivated under various culture conditions and we compared their growth characteristics with those of ruminant and avian strains. The combination of centrifugation assisted cell culture infection and cycloheximide treatment of Vero cell coverslip cultures provided the highest inclusion numbers with all chlamydial strains. Interestingly, the use of Iscove's modified Dulbecco's medium instead of Eagle's minimal essential medium significantly increased Chlamydia suis inclusion counts. C. suis and Chlamydophila pecorum inclusion numbers were markedly increased in CaCo cells, compared with Vero cells. This accelerated growth of porcine Chlamydiaceae under certain cultivation conditions may be helpful for the propagation of low chlamydial numbers or for their isolation from field samples. The intracellular distribution of porcine Chlamydiaceae in polarised CaCo cells clearly demonstrated differences between the chlamydial strains: C. pecorum 1710S inclusions were predominantly localised in the apical cytoplasm, C. suis S45 inclusions, however, were mostly situated in lower cytoplasmatic compartments. These findings might reflect biological differences in vivo.  相似文献   

11.
An inactivated vaccine against rabbit haemorrhagic disease (RHD), developed and tested in our laboratory, is produced commercially by Bioveta, Ivanovice, Czechoslovakia. Rabbits developed full protection against infection 3 weeks after the administration of a single dose. Antibodies were detectable from day 5 after vaccination. Naturally acquired antibodies were demonstrated in some rabbits kept on commercial farms. The virus survived at least 225 days in an organ suspension kept at 4 degrees C, at least 105 days in the dried state on cloth at room temperature (around 20 degrees C), and at least 2 days at 60 degrees C, both in organ suspension and in the dry state. Experimental infection of rabbits younger than 2 months was successful in some animals. Hares, guinea pigs, white mice, golden and Chinese hamsters, chinchillas and hysterectomy-derived, colostrum-deprived piglets were resistant to infection.  相似文献   

12.
Pig lung alveolar macrophages provided a suitable cell culture system for primary isolation of ovine chlamydia and sustained their growth through several passages. In centrifuged preparations, titres of established strains compared favourably with those obtained in fertile eggs, and in parallel titrations on primary isolation, evidence of chlamydial infection was detectable in macrophages several days earlier than in eggs.  相似文献   

13.
An isolate of Chlamydia psittaci from ovine pneumonia produced extensive pneumonia in red deer after endobronchial inoculation. Associated clinical signs lasting for several days included pyrexia, inappetance, increased pulse and respiration rate, and physical distress after handling, but no coughing or upper respiratory symptoms. Histologically, an acute exudative reaction was present after two days, and an early proliferative response after seven days. Both the clinical and pathological responses were more marked than those usually associated with chlamydial pneumonia in other large animals after endobronchial infection. A small survey for chlamydial antibody in wild red deer was negative.  相似文献   

14.
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   

15.
After simultaneous aerogenic and alimentary infection of quail by intra-nasal inoculation of a suspension of C. burnetii, the agent was reisolated 6 h after infection from lung and gut, from the 3rd day on from the spleen, at the 8th and 10th day from blood, and from the 8th day on from liver and kidney. C.burnetii was found in various organs up to 21 days after infection. In the majority of birds agglutinating antibodies could be demonstrated from the 18th day up to termination of the experiment 66 days after infection. On the basis of these results the course of a C. burnetii infection in birds is discussed.  相似文献   

16.
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   

17.
The pathogenesis of Venezuelan equine encephalitis (VEE) virus infection was compared in intraperitoneally inoculated mice (n = 24, 6 to 8 weeks old) and hamsters (n = 9, 90-110 g) using histopathology and immunohistochemical localization of VEE virus antigen. Infected mice developed paralysis, and the majority died by 9 days after inoculation. In contrast, hamsters did not survive beyond 3 days after inoculation, and they did not develop any neurologic signs. VEE virus antigen, demonstrated by immunoperoxidase staining, and pathologic changes were present in extraneural organs of both mice and hamsters. There was more severe involvement in hamsters, particularly in Peyer's patches of the distal small intestine. There was a severe encephalomyelitis in mice, but pathologic changes were not well established in the brains of hamsters before death. VEE virus antigen was widespread in the central nervous system of both mice and hamsters. VEE virus was found to be highly neurotropic in hamsters and had a similar distribution in the brain as in mice, but hamsters died from their extraneural disease before major central nervous system disease developed.  相似文献   

18.
《Veterinary microbiology》1998,62(4):251-263
The enteric pathogenicity of the ovine C. psittaci serotype 1 isolate S26/3 was assessed using a litter of gnotobiotic piglets. In one group, eight piglets were inoculated at 3 days of age; at 10 days, two of these were re-inoculated. In a second group, six animals were mock-inoculated at 3 days of age as negative controls; subsequently, at 10 days, three of these piglets were inoculated with C. psittaci. The animals were observed for clinical signs, killed and necropsied sequentially between 4 and 17 days of age. At necropsy, specimens were collected for histopathology, immunohistochemistry and serology. Clinical manifestations consisted of sporadic slight softening of faeces observed between 8 and 12 days post inoculation (d.p.i.) in pigs inoculated at 3 days of age and between 4 and 6 d.p.i. in those inoculated at day 10. Histopathological changes were minimal and inconsistent and occurred almost exclusively in the small intestine in pigs of 15 days of age and older; they consisted of a slight shortening of villi, of a small number of tongue-shaped villi and of villous fusions. Immunohistochemistry revealed small numbers of chlamydial inclusions in the small intestinal enterocytes of only five pigs, all killed within 5 d.p.i. An ELISA run on faecal samples collected daily after inoculation from six of the pigs showed that chlamydial antigen was excreted in the faeces. In pigs inoculated at 3 days, chlamydial antigen was detected inconsistently before, and consistently after 9 d.p.i. Pigs inoculated at 10 days excreted antigen consistently after inoculation until the end of their observation period (8 d.p.i.). Infective chlamydiae were detected from the faeces of inoculated piglets using Vero cell cultures. Sera of all pigs were negative for anti-chlamydial antibodies using a complement fixation test. In conclusion, enteric pathogenicity of C. psittaci serotype 1 in a litter of gnotobiotic piglets proved minimal. The results, therefore, indicate that serotype 1 C. psittaci is not likely to cause enteric disease in conventionally reared pigs. Nevertheless, a potential role of swine in the epidemiology of this agent should be considered with regard to spread of Chlamydia to other species.  相似文献   

19.
Gnotobiotic pigs were dosed orally with Campylobacter sputorum subspecies mucosalis, either alone, or combined with rotavirus or non-pathogenic Escherichia coli and Streptococcus bovis to study the behaviour of C s mucosalis in defined conditions, to assess intracellular parasitism of enterocytes by C s mucosalis, and if possible to establish an experimental model of porcine intestinal adenomatosis. C s mucosalis colonised the gut of gnotobiotic pigs, persisting for up to 47 days after infection, but did not induce adenomatosis. Despite evidence of limited penetration of the mucosa up to two days after infection, the majority of C s mucosalis remained in the gut lumen. Rotavirus did not enhance invasion of enterocytes by C s mucosalis. The presence of E coli and S bovis caused an increase in the total numbers of C s mucosalis in the gut, but did not affect their distribution. Thus C s mucosalis was largely non-pathogenic in gnotobiotic pigs.  相似文献   

20.
Three female beagle dogs inoculated with granulocytic Ehrlichia species were monitored for four to six months to determine whether there was evidence that the organisms persisted. The dogs were inoculated intravenously with blood containing an Ehrlichia species closely related to Ehrlichia equi and Ehrlichia phagocytophila, and identical to the human granulocytic ehrlichiosis agent with respect to its 16S rRNA gene sequence. The clinical signs were evaluated, and blood samples were collected for haematology, serum biochemistry and serology. Ehrlichial inclusions in the blood were monitored by microscopy, and ehrlichial DNA was detected by the polymerase chain reaction (PCR). Two of the dogs were injected with prednisolone on days 54 to 56 and days 152 to 154 after infection, and the other was injected with prednisolone on days 95 to 97 after infection. The dogs were euthanased and examined postmortem. Ehrlichial inclusions were demonstrated in the neutrophils and seroconversion occurred shortly after inoculation. Two of the dogs developed acute disease with rectal temperatures above 39.0 degrees C, after which no further clinical signs were observed. The administration of corticosteroids seemed to facilitate the detection of ehrlichial inclusions. Ehrlichial DNA was detected intermittently by PCR in blood samples from two of the dogs throughout the study. Persistent infection was demonstrated up to five-and-a-half months after inoculation.  相似文献   

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