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1.
Conventionally-delivered colostrum-deprived lambs were inoculated with either parainfluenza virus type 3 (PI3) alone or PI3 followed, 6 days later, by Pasteurella haemolytica (P.h.). Six out of 20 lambs died or were killed in extremis within 3 days of the inoculation of P.h.; the remainder were selected at random and killed from 1 to 28 days after the inoculation of P.h.Extensive pneumonic lesions developed in a large proportion of lambs inoculated with both agents but in none of those inoculated with the virus alone. Histologically, the pneumonic lesions fell into two categories: necrotic lesions, demarcated by a zone of either oat-cell or neutrophil infiltration, and a milder, purulent bronchopneumonia. Bacterial numbers tended to be higher in necrotic lesions than they were in purulent lesions. Virus titres in nasal secretions, on the day of inoculation of P.h. (day 6), also were higher in animals that developed necrotic lesions than they were in those that developed milder lesions. Nevertheless, titres were similar in both groups on day 4.Necrotic lesions persisted for at least 21 days as residual encapsulated abscesses which still contained viable P.h. whereas the milder, purulent bronchopneumonia was not detected later than 3 days after the inoculation of P.h..  相似文献   

2.
《Veterinary microbiology》2015,175(2-4):319-324
The bacteria present in the uterus during pyometra have previously been studied using bacteriological culturing. These studies identified Fusobacterium necrophorum and Trueperella pyogenes as the major contributors to the pathogenesis of pyometra. However, an increasing number of culture-independent studies have demonstrated that the bacterial diversity in most environments is underestimated in culture-based studies. Consequently, fastidious pyometra-associated pathogens may have been overlooked. Therefore, the primary purpose of this study was to investigate the diversity of bacteria in the uterus of cows with pyometra by using culture-independent 16S rRNA PCR combined with next generation sequencing.We investigated the microbial composition in the uterus of 21 cows with pyometra, which were obtained from a Danish slaughterhouse. Similar to the observations from the culture studies, Fusobacteriaceae, the family that F. necrophorum belongs to, was the operational taxonomic unit (OTU) observed in the largest quantities. By contrast, the Actinomycetaceae family, which includes T. pyogenes, constituted only 1% of the total number of reads. Thus we cannot confirm the previously reported role of species from this family in the pathogenesis of pyometra. Finally, we identified a large number of sequences representing three families of Gram-negative bacteria in the pyometra samples: Porphyromonadaceae, Mycoplasmataceae, and Pasteurellaceae. It is likely that these families comprise potential pathogenic species of a fastidious nature, which have been overlooked in previous studies. Our results increase the knowledge of the complexity of the pyometra microbiota and suggest that pathogens in addition to F. necrophorum may be involved in the pathogenesis of pyometra.  相似文献   

3.
Bacterial infections of the jaws are a common cause of death in macropods. Lesions and oral cavities from 50 affected animals yielded wide ranges of aerobic and anaerobic organisms. The most frequent isolate from lesions (81%) was Fusobacterium necrophorum, generally combined with other bacteria, but in 5 lesions, in pure culture. It was also isolated from 61% of mouths and this was the chief difference between the oral flora of affected and normal macropods. Other groups of organisms isolated from over 50% of lesions were: Gram-negative aerobic and anaerobic rods, streptococci, and anaerobic Gram-positive cocci. Actinomycetes were isolated from 29% of lesions and from one lesion in pure culture. Differences in the flora were detected between lesions in bone and soft tissue and between closed and open lesions. Antibiotics were given to 22 animals, but without significant differences in frequencies of isolation of organisms between treated and untreated groups, and with no permanent elimination of infection. It was concluded that, while different organisms might be present in the complex of “jaw disease”, the pathogenic agent in the majority of cases was F. necrophorum. Actinomycetes were capable of producing lesions in bone, but their role in “jaw disease” remains undefined.  相似文献   

4.
Groups of caesarian-derived, colostrum-deprived lambs aged 10 to 11 weeks were inoculated with the adenovirus WV419/75 followed 4, 6 or 8 days later by Pasteurella haemolyttica type Al (P.h.). Other groups of lambs were inoculated with the virus or P.h. alone.The majority of animals inoculated with P.h. 6 or 8 days after the virus developed an acute necrotizing bronchopneumonia and pleurisy, whereas, the bacteria were cleared rapidly from the lungs of the majority of animals inoculated with P.h. alone, and pneumonic lesions only rarely developed. Between groups, the development of bacterial superinfection and thus bronchopneumonia could not be related to virus titres in either the lung or nasal secretions. However, within individual animals that developed pneumonia, the distribution of virus paralleled the distribution of lesions.In animals inoculated with the virus alone (or the virus plus P.h. where bacterial superinfection did not develop) areas of epithelial cell proliferation and consolidation with basophilic intranuclear inclusion bodies in swollen epithelial cells were present. The consolidation and inclusion bodies had disappeared by 10 days after inoculation, together with the virus, but the proliferation of airway epithelium was still present 20 days after inoculation. On the other hand, when bacterial superinfection was present, areas of acute necrotizing bronchopneumonia were the predominant feature. These lesions were surrounded by a zone of consolidation with a massive neutrophil infiltration or, where bacterial numbers were high (usually ? 103.0/g), a band where oat-cells predominated although, in animals killed on day 14, oat-cells were still present but bacterial numbers were lower.  相似文献   

5.
Lameness in the dairy industry in New Zealand causes a problem in lost production, animal welfare and associated costs. To understand what bacteria may be present on the hooves of lame dairy cattle in this grass-fed system, samples were scraped from lame dairy cows and examined for the presence of Fusobacterium necrophorum (F. necrophorum) and Dichelobacter nodosus (D. nodosus) using the polymerase chain reaction (PCR). The PCR primers were designed to detect the presence of the lktA gene, which encodes a leukotoxin unique to F. necrophorum, and the fimA gene of D. nodosus. A total of 148 hoof scrapings were collected by farm staff over the period September 2005 to May 2006. F. necrophorum was detected in 79/148 of the samples, while D. nodosus was detected in 7/148 of the samples. The frequent finding of F. necrophorum within dairy herds in New Zealand is noteworthy and the occasional finding of D. nodosus on some dairy cattle suggests a possible role in both ovine and bovine hoof pathology.  相似文献   

6.
The aim of this study was to determine which of the two species, Fusobacterium necrophorum or Dichelobacter nodosus, are associated with hoof thrush in horses. Fourteen hoof samples, collected from eight horses with thrush and 14 samples collected from eight horses with healthy hooves, were examined for the presence of F. necrophorum, Fusobacterium equinum and D. nodosus. Only isolates with phenotypic characteristics representing Fusobacterium could be cultured. Total DNA extracted from the 28 hoof samples was amplified by using DNA primers designed from gene lktA, present in F. necrophorum subsp. necrophorum, F. necrophorum subsp. funduliforme and F. equinum, and gene fimA, present in D. nodosus. The lktA gene was amplified from five of the 14 infected hoof samples and from one hoof sample without thrush. The DNA sequence of the amplified ltkA gene was identical to the lktA gene of the type strain of F. necrophorum (GenBank accession number AF312861). The isolates were phenotypically differentiated from F. equinum. No DNA was amplified using the fimA primer set, suggesting that F. necrophorum, and not D. nodosus, is associated with equine hoof thrush. Hoof thrush in horses is thus caused by F. necrophorum in the absence D. nodosus. This is different from footrot in sheep, goats, cattle and pigs, which is caused by the synergistic action of F. necrophorum and D. nodosus.  相似文献   

7.
This study aimed to examine 1) whether selection for a superior allele at a single nucleotide polymorphism site (SNP; AB604331, g.420 C>A) of the chicken cholecystokinin type A receptor (CCKAR) gene in Miyazaki Jitokko chickens is detectable in commercial poultry farms, and 2) whether the reproductive traits of the Kyushu Rhode hens, as a maternal stock line of the Miyazaki Jitokko chickens, are affected by SNP selection. Conventional and A-allele fixed (improved) Miyazaki Jitokko chicks were hatched on the same day and raised in a battery cage until 7 days of age. The chicks were then deposited at two commercial poultry farms and reared until slaughter at 126 and 163 days for cockerels and pullets, respectively. Body weight on the day of hatching (day 0), at 5 days of age, and at slaughter were measured. The differences in the body weights of the farm and test groups at slaughter were analyzed using the generalized linear model. A-allele fixation increased the body weight at slaughter by approximately +123.5 g and +131.9 g in cockerels and pullets, respectively. No significant differences between the conventional and improved hens were detected in terms of egg-laying rate, fertilization rate, and hatchability in the Kyushu Rhode hens. The data suggest that fattening chicks can be supplied as usual, even if Kyushu Rhode hens are switched from the conventional to improved type. In conclusion, genetic improvements using the CCKAR SNP site as a marker were effectively established in terms of the growth of the Miyazaki Jitokko chickens in commercial farms and the reproductive traits of the Kyushu Rhode hens.  相似文献   

8.
Pasteurella multocida is a widespread respiratory pathogen in pigs associated with atrophic rhinitis and contributing to aggravation of the pulmonary lesions. The aims of the present study were to characterize isolates of P. multocida from porcine bronchopneumonia by pulsed-field gel electrophoresis (PFGE), PCR based capsular typing and multilocus sequence typing (MLST) and to compare clonal complexes outlined with the type of histological lung lesions to investigate if a correlation between clonal lineages and lesions might exist. Isolates of P. multocida were obtained from cases of cranioventrally located porcine bronchopneumonia. All lung lesions were described and classified according to histological lesions. A total of 139 isolates, from lung (n=111), pericardial sac (n=21) and kidney (n=7) of 111 pigs were described using PFGE with ApaI as the restriction enzyme. Furthermore, 20 and 29 isolates were characterized by capsular serotyping and multilocus sequence typing, respectively. PFGE demonstrated 15 different clusters showing 50% or more similarity. All selected isolates were of capsular serotype A and only three main sequence types (ST) were detected among the isolates. Associations were not found between histopathology and clonal complexes of P. multocida. In conclusion, PFGE demonstrated a high diversity of genotypes of P. multocida associated with porcine bronchopneumonia. However, isolates obtained mainly belonged to few STs, indicating that isolates of P. multocida associated with porcine bronchopneumonia originates from a limited number of clonal lineages and therefore might have adapted to porcine hosts. No correlation was demonstrated between genotypes and types of lesions, and extra-pulmonary spreading was only rarely demonstrated.  相似文献   

9.

Background

Anaplasma phagocytophilum infection in domestic ruminants is widespread in the coastal areas of southern Norway. The bacteria may persist in mammalian hosts. Several genetic variants of A. phagocytophilum exist. In the present study, we investigate whether superinfection occurs in the acute and persistent phase of the infection.

Methods

Five-month-old lambs of the Norwegian Dala breed were experimentally infected with two 16S rRNA gene variants of A. phagocytophilum, i.e. A. phagocytophilum variant 1 (GenBank accession number M73220) and variant 2 (GenBank acc. no. AF336220). Eighteen lambs were used, two lambs in each group. Eight groups were experimentally inoculated with either variant 1 or 2 on day 0. Six of these groups were then challenged with the other variant on either days 7, 42 or 84, respectively. One group was left uninfected. The occurrence of A. phagocytophilum in blood samples was determined using semi-nested PCR analysis and gene sequencing. Specific antibodies were measured by an indirect immunofluorescence antibody assay (IFA).

Results

A. phagocytophilum variant 1 and 2 differed significantly with regards to clinical reaction and cross-immunity in infected lambs. Both variants were found in the blood after challenge. However, variant 1 was detected most frequently.

Conclusion

The present experiment indicates that superinfection of different genotypes occurs during the acute as well as the persistent phase of an A. phagocytophilum infection, even in lambs protected against the challenged infection.  相似文献   

10.
Fusobacterium necrophorum, a Gram-negative, non-spore-forming anaerobe, is a normal inhabitant of the alimentary tract of animals and humans. Two types of F. necrophorum, subspecies necrophorum (biotype A) and funduliforme (biotype B), have been recognized, which differ morphologically, biochemically, and biologically. The organism is an opportunistic pathogen that causes numerous necrotic conditions (necrobacillosis) such as bovine hepatic abscesses, ruminant foot abscesses and human oral infections. The pathogenic mechanism of F. necrophorum is complex and not well defined. Several toxins, such as leukotoxin, endotoxin, haemolysin, haemagglutinin and adhesin, have been implicated as virulence factors. Among these, leukotoxin and endotoxin are believed to be more important than other toxins in overcoming the host's defence mechanisms to establish the infection. F. necrophorum is encountered frequently in mixed infections and, therefore, synergisms between F. necrophorum and other pathogens may play an important role in infection. Several investigators have attempted to induce protective immunity against F. necrophorum using bacterins, toxoids, and other cytoplasmic components. Generally, none of the immunogens has afforded statisfactory protection against Fusobacterium infections. Because of the unavailability of suitable immunoprophylaxis, the control of F. necrophorum infection has depended mainly on the use of antimicrobial compounds.Abbreviations CFU colony-forming units - DNA deoxyribonucleic acid - DNase deoxyribonuclease - Eh redox potential - ELISA enzyme-linked immunosorbance assay - LPS lipopolysaccharide - MPN most-probable number - PMN polymorphonuclear cells - rRNA ribosoma ribonucleic acid - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis - subsp. subspecies  相似文献   

11.
Post‐partum period has an important role in cows' breeding due to its effects on reproductive efficiency and subsequent pregnancy. Escherichia coli, Trueperella pyogenes (Arcanobacterium pyogenes), Fusobacterium necrophorum and Prevotella melaninogenicus are recognized as major pathogens associated with uterine endometrial lesions. The objective of this study was to identify these pathogens using the polymerase chain reaction (PCR) as a culture‐independent sensitive method. A total of 172 cows were examined 25–35 days post‐partum, and 128 cows were examined at 2 weeks later (39–49 days post‐partum). Uterine discharges were collected by covered plastic infusion pipettes. The prevalence of endometritis was greater in the first examination than the second (35.5% vs. 16%). E. coli was detected in eight of the samples, T. pyogenes was detected in 13 of the samples and F. necrophorum was detected in 11 of the samples. There was no positive sample of P. melaninogenicus. Uterine contamination by T. pyogenes and F. necrophorum in the first examination was higher than the second examination. T. pyogenes affected as a tendency the prevalence of clinical endometritis in first examination. Primiparous cows showed 4.02 times higher odds of clinical endometritis compared with second‐parity cows in first examination. A multiplex PCR protocol as a simple, less expensive, fast assay was introduced to identify E. coli, T. pyogenes and F. necrophorum.  相似文献   

12.
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13.
J A Linares  W L Wigle 《Avian diseases》2001,45(4):1068-1072
The present report describes a case of Staphylococcus (Staph.) aureus pneumonia in turkey poults. Initially, 3-day-old poults with a history of increased mortality were submitted for necropsy. The poults had severe bilateral consolidation of the lungs with miliary caseous nodules. The gross lesions in the lungs were highly suggestive of aspergillosis. The next day, postmortem examinations were performed on 60 dead poults at the farm, and all 60 had similar lung lesions. Histopathologic examination of affected lungs revealed severe subacute multifocal bronchopneumonia with intralesional bacteria. Tissue Gram stain of lung sections demonstrated gram-positive bacterial cocci. Gomori methenamine silver stain of the lungs failed to demonstrate fungal agents. The histologic distribution of the lesions suggested an aerogenous route of infection. Staphylococcus aureus was isolated in pure culture from affected lungs. Hatchery contamination was suspected because of the severity and early onset of the lesions. Bacterial monitoring at the hatchery demonstrated marked Staph. aureus contamination in two setters, a hatcher's air duct, and the poult room. Improved hatchery cleaning and disinfection prevented a reoccurrence of the problem.  相似文献   

14.
Immunoperoxidase assays were performed on 21 archived formalin-fixed, paraffin-embedded tissues from from American bison (Bison bison) with bronchopneumonia. Seven of the 21 bison had positive staining for Haemophilus somnus in alveolar exudate, visceral pleura, lung parenchyma, and chronic necrotic lesions, and H. somnus was isolated from tissues from 1 of these 7 animals. Results suggest that H. somnus is a respiratory pathogen in bison.  相似文献   

15.
Caseous lymphadenitis (CLA) is a chronic disease that affects sheep and goats worldwide, and its etiological agent is Corynebacterium pseudotuberculosis. Despite the economic losses caused by CLA, there is little information about the molecular mechanisms of bacterial pathogenesis, and current immune prophylaxis against infection has been unable to reduce the incidence of CLA in goats. Recently, 21 different mutant strains of C. pseudotuberculosis were identified by random mutagenesis. In this study, these previously generated mutants were used in mice vaccination trials to develop new immunogens against CLA. Based on this analysis, CZ171053, an iron-acquisition-deficient mutant strain, was selected. After challenge with a virulent strain, 80% of the animals that were immunized with the CZ171053 strain survived. Furthermore, this vaccination elicited both humoral and cellular responses. Intracellular survival of the bacterium was determined using murine J774 cells; in this assay, the CZ171053 had reduced intracellular viability. Because iron acquisition in intracellular bacteria is considered one of their most important virulence factors during infection, these results demonstrate the immunogenic potential of this mutant against CLA.  相似文献   

16.
BackgroundMalignant catarrhal fever (MCF) is a highly fatal lymphoproliferative disease of cattle, deer, bison, water buffalo, and pigs caused by the gamma-herpesviruses alcelaphine herpesvirus-1 (AlHV-1) and ovine herpesvirus-2 (OvHV-2).ObjectivesThis study aimed to determine the prevalence of OvHV-2 in sheep, goats, cattle, and buffalo in Rawalpindi and Islamabad, Pakistan, by applying molecular and phylogenetic methods.MethodsBlood samples were aspirated from sheep (n = 54), goat (n = 50), cattle (n = 46) and buffalo (n= 50) at a slaughterhouse and several farms. The samples were subjected to heminested polymerase chain reaction (PCR), followed by sequencing and phylogenetic analysis of the OvHV-2 POL gene and the OvHV-2 ORF75 tegument protein gene.ResultsThe highest percentage of MCF positive samples was in sheep (13%), whereas goat, cattle, and buffalo had lower positive percentages, 11%, 9%, and 6.5%, respectively. Four OvHV-2-positive PCR products obtained from sheep samples were sequenced. The sequences obtained were submitted to the NCBI GenBank database (MK852173 for the POL gene; MK840962, MK852171, and MK852172 for the ORF75 tegument protein gene). Phylogenetic analysis revealed a close similarity of study sequences with those of worldwide samples.ConclusionsThis study is the first cross-sectional study on the prevalence and molecular detection of OvHV-2 in apparently healthy cattle and buffalo that could be carrying OvHV-2 acquired from OvHV-2-positive sheep and goats. The results indicate that OvHV-2 is circulating in Pakistan. Further studies are needed to characterize OvHV-2 and elucidate further its prevalence.  相似文献   

17.
Neospora caninum is a worldwide distributed protozoan that may cause neuromuscular disease in dogs and reproductive failure in domestic and wild ruminants. One axis fawn (Axis axis) and four neonates from the same deer herd died at a zoo in Argentina within a four-month period. The fawn presented with dilatation of the anal sphincter at birth and incontinence, developed weakness and ataxia and died at 14 days of age. At necropsy, a mega formation of the distal large intestine was observed. Microscopically, non-suppurative encephalitis, suppurative bronchopneumonia, fibrin necrotic enteritis and degenerative changes in the liver were observed in hematoxilin and eosin-stained tissue sections, and thick-walled N. caninum-like cysts were observed in fresh brain samples. Serologic studies for N. caninum revealed an IFAT titer of 1:6400 in the fawn and 1:25, 1:400, 1:3200 and 1:6400 in the neonates. N. caninum DNA was detected in brain samples from the fawn and from one neonate by PCR, and the parasite was isolated in vitro from the fawn’ brain after passage through gerbils (Meriones unguiculatus) and gamma-interferon knock-out mice. N. caninum DNA obtained from the fawn, neonate and isolated parasites showed the same microsatellite pattern. This suggests a common infection source for both animals.The diagnosis of N. caninum infection was confirmed, suggesting its association with perinatal mortality in captive axis deer. To the best of our knowledge, this is the first report of clinical disease associated to N. caninum infection in axis deer and of isolation of the parasite from this wild ruminant species.  相似文献   

18.
Turkey breeder hens showed an increase in mortality beginning at 38 wk of age with no other clinical signs or changes in egg production. While no respiratory signs were observed in live turkeys, those that died consistently had gross lesions of pneumonia. Histopathology of lungs revealed serofibrinous bronchopneumonia, lymphofollicular reaction, and other features suggesting a bacterial etiology. However, except for incidental findings, bacteria were not visualized in the sections examined, and none were isolated in meaningful numbers on routine bacteriologic media. At 42 wk of age the flock showed serologic evidence of infection with Mycoplasma synoviae (MS), and MS was identified by both mycoplasma culture and polymerase chain reaction (PCR) procedures in samples from choanal clefts and tracheas. Results of lung histopathology and PCR tests were consistent with a diagnosis of pneumonia caused by MS.  相似文献   

19.
Tetrandrine (TET), a bis-benzylisoquinoline alkaloid from the root of Stephania tetrandra, is known to have anti-tumor activity in various malignant neoplasms. However, the precise mechanism by which TET inhibits tumor cell growth remains to be elucidated. The present studies were performed to characterize the potential effects of TET on phosphoinositide 3-kinase/Akt and extracellular signal-regulated kinase (ERK) pathways since these signaling pathways are known to be responsible for cell growth and survival. TET suppressed cell proliferation and induced apoptosis in A549 human lung carcinoma cells. TET treatment resulted in a down-regulation of Akt and ERK phosphorylation in both time-/concentration-dependent manners. The inhibition of ERK using PD98059 synergistically enhanced the TET-induced apoptosis of A549 cells whereas the inhibition of Akt using LY294002 had a less significant effect. Taken together, our results suggest that TET: i) selectively inhibits the proliferation of lung cancer cells by blocking Akt activation and ii) increases apoptosis by inhibiting ERK. The treatment of lung cancers with TET may enhance the efficacy of chemotherapy and radiotherapy and increase the apoptotic potential of lung cancer cells.  相似文献   

20.
A 3 yr old intact female Hellenic shepherd dog was referred due to depression, partial anorexia, fever, and a mild productive cough of 2 mo duration. Thoracic radiographs showed increased opacity of all of the left lung lobes. Upon bronchoscopy, a sanguineous, purulent discharge was detected in the tracheal lumen with hyperplastic tissue narrowing the left main stem bronchus. Cultures were positive for bacteria (Bacillus spp. and Clostridium spp.) but negative for fungi. Due to the severity of the lesions, a complete left lung pneumonectomy was performed. Histopathological examination of the excised lung tissues revealed a severe granulomatous bronchopneumonia with numerous alveolar macrophages laden with structures stained positively by periodic acid-Schiff and Grocott stain that had morphology consistent with fungi. PCR and sequencing of internal transcribed spacer regions 1 and 2 from genetic material extracted from paraffin-embedded pulmonary tissue confirmed the presence of Aspergillus fumigatus. Itraconazole was administrated for 5.5 mo and the dog was clinically normal 26 mo after surgery.  相似文献   

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