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1.
IFN-γ is considered as a key factor in protection against heartwater of ruminants, caused by the obligate intracellular bacterium Ehrlichia ruminantium. In this study, a better definition of the molecular masses of IFN-γ inducing proteins of the Gardel strain of E. ruminantium was obtained by the use of continuous flow electrophoresis (CFE) and sensitized polyclonal lymphocytes. Out of 15 E. ruminantium CFE fractions tested within the 14–39 kDa region, eight were commonly reacted to by all goats. Interestingly, half of these fractions fall within the 23–29 kDa region, shown previously to contain polymorphic B-cell epitopes. Thus, the results suggest that this region also contains T-cell epitopes potentially involved in protection. Also, several proteins were found to be more immunogenic than the serologically immunodominant MAP1 protein. Finally, high activity within the 15–19 kDa region was observed, which confirms previous work done with CD4+ T-cell lines obtained from cattle immunized with a South African strain of E. ruminantium. The proteins falling within the molecular weight ranges defined in this study may have potential as vaccine antigens.  相似文献   

2.
A study to estimate the prevalence of vancomycin-resistant Enterococcus faecium in faecal samples from pigs at slaughterhouses in Spain was carried out between November 1998 and January 1999 with 900 samples taken from four abattoirs representing 9.7% of all pig slaughtered in 1998. Using a selective enrichment broth with vancomycin (8 μg/ml), 64 samples (7.1%; 95% CI: 5.5, 9.0%) had E. faecium vancomycin-resistant strains that showed minimal inhibitory concentrations of 256 μg/ml (62 strains) and 512 μg/ml (two strains). Results by farm showed that 43 of the 240 pig farms represented in the sampling had at least one faecal sample with vancomycin-resistant E. faecium.  相似文献   

3.
The occurrence of the fox tapeworm Echinococcus multilocularis in Red foxes was studied in Belgium and a neighbouring region in The Netherlands. A total number of 1202 foxes were analysed (1018 in Belgium and 184 in The Netherlands) of which 179 were infected with E. multilocularis (164 in Belgium and 15 in The Netherlands). Further, the spatial distribution of infection among sampled foxes was analysed with an ellipsoidal gradient, demonstrating a decreasing prevalence in northwestern direction. Using this gradient, we showed that the spatial patterns of infection in Belgium and the neighbouring region in The Netherlands correspond, indicating a continuous distribution of E. multilocularis across the nation borders. Part of the Belgian data allowed investigating temporal changes in the spatial distribution of E. multilocularis. This revealed a northwestern spread of E. multilocularis.  相似文献   

4.
Antimicrobial resistance (AR) is an increasing phenomenon but its quantitative estimation remains controversial. The classical resistance percentage approach is not well suited to detect either emergence or low levels resistance. One option is to shift the focus from strains to hosts. This approach is applied to test for phenotypic diversity associated with diminished susceptibility to expanded-spectrum cephalosporins (DSESC) in faecal Escherichia coli from healthy food animals in Spain.

We performed E. coli enumeration in faecal samples of broilers (82 pooled samples) and pigs (80 pooled samples) at the slaughterhouse level, using Coli-ID plates alone and supplemented with cefotaxime at two levels (1 and 8 μg/ml). Antimicrobial susceptibility of isolates was tested by the agar diffusion method. Clustering was carried out using these numerical values and Ward and UPGMA methods.

When using plates supplemented with 1 μg/ml of cefotaxime for DSESC E. coli detection, 93% (76/82) of broiler pooled samples and 36% (29/80) pig pooled samples tested positive. When using 8 μg/ml of cefotaxime, 67% (55/82) of broilers and 13% (10/80) of pigs were positive. Nevertheless, the relative abundance of this phenotype was low in both animal species (range 0–4.3%). Irrespective of the clustering method (Ward or UPGMA), a noticeable phenotypic diversity was detected, especially from the plates containing 1 μg/ml of cefotaxime.

We concluded that: (a) E. coli with phenotype DSESC are common in broilers and pigs but are less frequent in pigs, and (b) the host approach is the most appropriate method for antimicrobial resistance assessment when null or very low levels of antimicrobial resistant bacteria are expected.  相似文献   


5.
多房棘球蚴(Em)是一种危害严重的人畜共患寄生虫。为探索非编码RNA在多房棘球蚴感染诱导小鼠肝枯否氏细胞(KCs)极化中的作用机制，本研究用多房棘球蚴原头蚴感染BALB/c小鼠，分离感染2月小鼠肝KCs，通过RNA测序分析，构建与多房棘球蚴感染引起的KCs M2型极化相关的竞争性内源RNA (competing endogenous RNAs,ceRNA)调控网络，并通过qPCR和miRNA过表达进行验证。结果表明，多房棘球蚴感染小鼠2月后，KCs M1型标志分子均显著下调，而M2型标志分子均显著上调。5个circRNA和9个miRNA参与M2型标志分子IL10、IL13、Arg1基因的表达调控，而且其表达趋势与测序结果及circRNA-miRNA-mRNA调节关系基本一致。另外，miR-466c-5p过表达导致了circ_0000372和IL13的表达下调，说明可能存在circ_0000372-miR-466c-5p-IL13轴的调节关系，并在多房棘球蚴感染诱导小鼠肝KCs极化中发挥重要作用。本研究为进一步揭示多房棘球蚴调控宿主巨噬细胞极化的相关机制提供了重要理论依据。  相似文献   

6.
We examined exogenous and endogenous development of Eimeria procera in experimentally infected grey partridges (Perdix perdix). Our examination included data on morphology, localization, duration of schizogony and gametogony and morphology of sporulated oocysts. The endogenous stages of E. procera developed in large numbers within the epithelial cells of caecal crypts. The asexual development comprised three generations of schizonts. The first fully developed macrogametes and microgamonts were observed on Day 5 post-infection (p.i.) in histologic section. The patent period began on Day 6 p.i. and ended on Day 11 p.i. with peak production of oocysts on Days 7 and 8. Long oval oocysts of E. procera measured 25.78–28.13 μm in length and 14.06–15.24 μm in width, sporulation time ranged from 18 to 24 h at 25°C and from 36 to 48 h at 20°C.  相似文献   

7.
This study investigated the effects of weaning age, diet, and classification of piglets as ‘eaters’ or ‘non eaters’ of creep feed in lactation, on production and diarrhoea after weaning. Four antimicrobial-free diets were offered in lactation and for 14 days after weaning: (i) wheat–soy based diet with animal and vegetable (‘mixed’) protein sources (COMM), (ii) heat-processed rice (HPR) with barley hulls and potato starch and mixed protein sources (RBHPS), (iii) HPR with sugar-beet pulp and mixed protein sources (RSBP), and (iv) HPR with mixed protein sources (R). Piglets were individually examined for diarrhoea daily for 14 days after weaning, and antibiotic treatments were individually recorded. Faecal swabs were taken on day 10 after weaning and scored for β-haemolytic Escherichia coli. There were significant main effects of weaning age and diet (both P < 0.001) on daily gain between weaning and 14 days after weaning. Pigs weaned later grew 50 g/day more than pigs weaned earlier, and pigs fed the COMM diet grew slower than pigs fed the rice-based diets. The number of antibiotic treatments was influenced by diet (P < 0.001), with most treatments (2.1) given to pigs fed the diet RBHPS. Faecal score was influenced by a weaning age and diet interaction (P < 0.01). There was no correlation (P > 0.05) between the number of antibiotics treatments and the E. coli score.  相似文献   

8.
A 2 × 2 factorial experiment was used to investigate the interaction between dietary crude protein (CP) concentration (200 vs 140 g/kg) and inulin supplementation (0 vs 12.5 g/kg) on nitrogen (N) excretion and intestinal microflora from 16 boars (n = 4, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy and lysine. Pigs offered the high CP diets had a higher excretion of urinary N (P < 0.01), faecal N (P < 0.01) and total N (P < 0.001) than the pigs offered the low CP diets. Inulin supplementation increased faecal N excretion (P < 0.05) and decreased urine: faeces N ratio (P < 0.05) compared to the inulin free diets. There was no significant effect (P > 0.05) of dietary treatment on N retention. There was an interaction (P < 0.05) between dietary CP concentration and inulin supplementation on caecal E.coli. Pigs offered the diet containing 200 g/kg CP plus inulin decreased the population of E.coli compared to the inulin supplemented 140 g/kg protein diet. However, CP concentration had no significant effect on the population of E.coli in the unsupplemented diets. Inulin supplementation increased caecal bifidobacteria (P < 0.01) compared to the inulin free diets. In conclusion, inulin supplementation favourably altered N excretion and lowered the population of E.coli at high CP concentrations.  相似文献   

9.
旨在探讨多房棘球蚴感染早期对小鼠肝脂质代谢的影响。选取60只清洁级BALB/c小鼠(6周龄，雄性)随机分为试验组和对照组，每组30只。试验组小鼠每只腹腔接种600个原头蚴，对照组小鼠腹腔注射等体积的PBS缓冲液。采用原位两步循环灌流及多步低速差速离心分离纯化肝实质细胞。利用高通量测序分析感染3月小鼠肝实质细胞差异表达的mRNA,并对其进行KEGG、GO分析和qRT-PCR验证。制备多房棘球蚴感染2、3和6月小鼠的肝组织切片，分别进行油红O染色，并通过qRT-PCR检测多房棘球蚴感染不同感染时期肝实质细胞脂质代谢相关基因的表达水平。结果表明，与未感染对照组相比，小鼠感染多房棘球蚴后3、6月肝脂肪沉积明显增多；感染2月的肝实质细胞脂质合成相关基因Scd1、Fasn和Srebf1,以及脂质氧化分解相关基因Acox1和Cpt1α均明显上调；感染3月的肝实质细胞Scd1、Fasn、Srebf1及Cd36的表达水平均明显升高，而Acox1、Cpt1α、Pparγ和Pparα的表达水平明显降低。上述结果表明，多房棘球蚴感染早期可能通过促进肝实质细胞的脂质合成，抑制脂质氧化分解，从而导致肝脂质沉积。  相似文献   

10.
Twenty four, 21-d-old female pigs were fed diets containing either skim milk powder (CON+), spray-dried bovine colostrum (7.5%, BC+) or spray-dried bovine plasma (7.5%, BP+) and were dosed orally with 1 × 109 CFU of E. coli O149:K88. Another group of 8 unchallenged pigs was fed the skim milk powder diet (CON−). On d 19 of the experiment all piglets were euthanased. Adverse effects of the E. coli challenge were observed variously throughout the small intestine in pigs consuming either the BC+ or BP+ diets. In this experiment, similar responses to the E. coli challenge were observed in both plasma and colostrum fed pigs, which suggests that spray-dried bovine colostrum may be a potential alternative to spray-dried bovine plasma.  相似文献   

11.
Molecular cloning and characterization of chicken NK-lysin   总被引：1，自引：0，他引：1  
  相似文献   

12.
Thirteen susceptible piglets, aged 40 days, were divided into two groups and were experimentally infected either with a Greek (myocardial) or a Belgian (reproductive) encephalomyocarditis virus (EMCV) strain (total dose 5 × 106 TCID50, intramuscularly and intranasally). Six piglets were placed in the same rooms, 24 h later, as contact controls. The following criteria were studied: ante mortem: clinical signs, serum cardiac isoenzyme activities (CK-MB and LD-1), viraemia, nasal and faecal virus excretion and serological response. Post mortem (after death or euthanasia): gross lesions, virus isolation from tissues, RT-PCR, as well as histopathological and immunohistochemical findings. The Greek strain was more pathogenic, producing mortality, with high cardiac isoenzyme activities and pronounced macroscopic myocardium lesions. The Belgian strain was able to induce mild heart lesions, as detected only by cardiac isoenzyme activity and histopathologically. All contact pigs were infected, within the first 1–2 days of their introduction, that coincided with the period of viral excretion by the experimentally infected pigs (up to the 3rd day post infection). Disease was mild, with no mortality.  相似文献   

13.
In order to determine the prevalence and risk factors for canine echinococcosis in different endemic localities in the Tripoli area of northwest Libya, stray dogs were examined post-mortem, and owned dogs screened for Echinococcus granulosus infection using a standardised genus specific coproantigen ELISA. The prevalence of E. granulosus infection at necropsy in stray-dogs was 25.8% (15/58, 95% CI 15.3–39.0%), and 21.6% (72/334, 95% CI 17.3–26.4%) of owned dogs tested were positive by coproantigen ELISA. Sheepdogs appeared to have a significantly higher copro-positive prevalence (19/19 positive, p = 0.003), compared to 23.6% of other dog classes (e.g. 52/220 guard dogs and household pets). Worm burdens in necropsied dogs ranged from 29 to 2900 (mean 1064) and were positively correlated to coproantigen ELISA OD values (rs = 0.87, p < 0.001), but negatively correlated with dog age (rs = −0.69, p = 0.001). Dog age was a significant factor in copro-prevalence as there was an increasing coproantigen-positive tendency in younger dogs (≤5 years, p = 0.04). A total of 45/132 (34%, 95% CI 25.9–42.1%) of farms/homestead had at least one dog that was coproantigen positive. Overall copro-prevalence in dogs by locality varied, with Alkhums (Leptis-Magna) district having the highest copro-prevalence at 38.7% (24/62, 95% CI 26.6–50.8%) (p = 0.001). Coproantigen testing of a cohort of owned dogs before and approximately 15 months after praziquantel treatment showed a significant decrease in the coproantigen positive rate from 21.6% (72/334) to 9% (21/233) post-treatment. The overall E. granulosus coproantigen positive rate (‘re-infection rate’) within the same cohort of dogs was 22 % (10/45) by 15 months post-treatment. Significant risk factors for a copro-positive owned dog were associated with non-restraint of dogs, and owners that did not de-worm their dogs. Home slaughtering of livestock and lack of knowledge about E. granulosus transmission were also significant risk factors for a canine coproantigen positive result.  相似文献   

14.
In order to evaluate the role of the AIDA-I of porcine diarrheagenic Escherichia coli strain PD20 serogroup O143 (AIDA-I+, STb+), a mutant strain PD20M (AIDA-I−, STb+) was generated from strain PD20 by an allelic exchange procedure. In addition, the full-length aidA gene was reintroduced into strain PD20M to generate the complemented strain PD20C (pTaidA, AIDA-I+, STb+). A non-pathogenic E. coli strain PD71 was used as negative control. Each strain was inoculated to newborn pigs via stomach tube. Severity of diarrhea was evaluated clinically and intestinal colonization was assessed by histology, immunohistochemistry (IHC), and transmission electron microscopy (TEM) including immunogold electron microscopy (IGEM). The adhesion pattern to HeLa cells, bacterial auto-aggregation and biofilm formation were evaluated in vitro. Pigs infected with strains PD20 or PD20C developed diarrhea 16 and 28 h after inoculation, respectively, in contrast to pigs infected with strains PD20M or PD71. Histology, IHC, TEM and IGEM examinations showed heavy bacterial colonization with biofilm formation in the large intestine, and marked in vivo expression of AIDA-I protein in pigs infected with strains PD20 or PD20C in contrast to pigs infected with strains PD20M or PD71. The in vitro assays showed marked diffuse adherence to HeLa cells, enhanced bacterial auto-aggregation and significant biofilm formation (p < 0.05) by the AIDA-I+ strains, when compared to AIDA-I− strains. These results demonstrate that expression of AIDA-I is essential for intestinal colonization and in vitro bacterial autoaggregation and biofilm formation. Thus, AIDA-I may be considered a significant virulence determinant in development of diarrhea caused by porcine diarrheagenic AIDA-I+ E. coli PD20 in piglets.  相似文献   

15.
Six chicks (3–6 weeks of age) were taken randomly from each of 200 broiler farms in northern Jordan, these chicks were submitted for post-mortem and parasitological examinations. Seven Eimeria spp. were identified: E. acervulina, E. brunetti, E. maxima, E. necatrix, E. mivati, E. mitis, and E. tenella. Half (50%) of the farms surveyed had all six chicks infected, 23% of the farms were free of the infection. E. tenella was the most prevalent species (39%) followed by E. necatrix (12%), E. brunitti (12%), and E. maxima (10%). Prevalences did not vary by flock size. Also, neither the use of coccidiostat nor previous coccidiosis clinical outbreaks was associated with the prevalence of coccidiosis.  相似文献   

16.
Prevalence of intestinal pathogens in Danish finishing pig herds   总被引：5，自引：0，他引：5  
Our aim was to determine the prevalence of the intestinal bacteria: Lawsonia intracellularis, Brachyspira hyodysenteriae, Serpulina intermedia, Brachyspira innocens, Brachyspira pilosicoli, pathogenic Escherichia coli (serogroups O138, O139, O141 and O149) and Salmonella enterica in Danish finishing pig herds. A total of 79 herds was randomly selected and visited during 1998. From each herd, 20 faecal samples were collected from individual pigs weighing 30–50 kg. Furthermore, 10 pooled pen samples were collected and examined for S. enterica. In total, 1580 faecal samples and 790 pen samples were collected and examined by polymerase chain reaction (PCR) or culture. L. intracellularis was found in 74 herds (93.7%), B. hyodysenteriae in two herds (2.5%), S. intermedia in 10 herds (12.7%), B. innocens in 27 herds (34.2%), B. pilosicoli in 15 herds (19.0%), pathogenic E. coli in 19 herds (24.1%) and S. enterica in eight herds (10.1%). The within-herd prevalences of L. intracellularis and B. hyodysenteriae were 25–30%; the within-herd prevalences of the other agents were 5–10%. Three herds (4%) were not infected with any of the bacteria and 25 herds (32%) were only infected with L. intracellularis.  相似文献   

17.
This study investigated the effect of dietary protein supply on growth performance, carcass composition and size of organs in pigs slaughtered at the age of 165 ± 2 d. In addition, we analysed muscle fibre properties and glycolytic potential of light muscles longissimus lumborum (LD), semimembranosus (SM), and gluteus superficialis (GS), and dark muscles infraspinatus (IS) and masseter (M) of 20 gilts and 20 barrows. Of these pigs, 16 were Finnish Landrace, 16 were Finnish Yorkshire, and 8 were crosses of these breeds. The pigs were fed low-or high-protein diets formulated to contain 6.0 and 9.5 g of apparent ileal digestible lysine/feed unit (1 fu = 9.3 MJ NE), respectively. The pigs were fed according to a restricted weight-based feeding scale (13–30 MJ NE/d). Lean meat, fat, bones, and skin of the carcasses as well as organs were dissected and weighed. The pH value was measured 45 min post mortem from LD, and 24 h post mortem from LD, SM and GS. Drip loss, lightness (L) and redness (a) were measured from LD, SM and GS. Pigs with a low-protein supply showed a lower growth rate (P < 0.01), carcass weight (P < 0.01), and carcass lean meat content (P < 0.01), but higher carcass fat content (P < 0.01) and smaller kidneys (P < 0.01) than did pigs with a high-protein supply. In LD, the differences in cross-sectional areas in all muscle fibre types (P < 0.05) between the feeding groups were significant; in GS we found significant differences in cross-sectional areas of type IIA and type IIB (P < 0.05), while in SM we found no differences in muscle fibre cross-sectional areas between the feeding groups (P > 0.05). We found no such differences in the dark muscles studied. We also took into account the effect of both the breed and sex on the studied properties. The low-protein diet increased glycolytic potential in porcine LD and SM, and decreased the pH value measured 45 min post mortem from LD. The dietary protein supply affected no other meat quality traits studied. A more rapid drop in pH in LD resulted in a lighter and less red meat with higher drip loss.  相似文献   

18.
The effects were evaluated of the inclusion of full fat linseed (125 g/kg) (LS) or linseed expeller meal (85 g/kg) (LSM) in diets for weaned piglets on growth performance and parameters of gut health and function. The diets were fed to groups of 12 post weaning single housed piglets. Three of the five treatments (Control (C)+, LS+, LSM+) were challenged with an enterotoxigenic strain of E. coli on day 6. Two treatments were not challenged (C− and LS−). The main response criteria were daily feed intake, body weight gain, faecal shedding of the E. coli, faecal consistency score, faecal nutrient digestibility and gut wall morphology and histology of the jejunal mucosa on day 18/19 of the study. Over the total experimental period (day 0–18) feed intake and body weight gain were highest in treatment C− and lowest in treatment LSM+ (P < 0.05). Feed conversion ratio did not differ between treatments over the total experimental period. Over day 10–12 of the study, the faecal digestibility of dry matter, ash and energy was higher for treatments C− and C+ compared to treatments LS−, LS+ and LSM+ (P < 0.05). There was no significant difference in the faecal shedding of E. coli between treatments C+, LS+ and LSM+. Intestinal mucosal histology and morphology were only slightly affected by the dietary treatments. It was concluded that the use of full fat linseed or linseed expeller meal did not show to be functional ingredients in diets for post-weaning piglet in terms of supporting gut health.  相似文献   

19.
Two studies were carried out: a preliminary study based upon 220 flocks visited twice to collect data on sheep-flock management and losses, and a second intensive 2 year (1984–1986) study carried out on 16 of the 220 flocks in one country.

Mean annual lamb mortalities were 17.6% (1984–1985) and 31.3% (1985–1986), and varied significantly according to nutrition. Pre-parturient deaths represented 27.3% (1984–1985) and 18.9% (1985–1986) of total deaths. The percentage of parturient deaths was very low (0.4%) for both years. Of the lambs necropsied, starvation/exposure complex contributed most to lamb mortality. Enteritis and septicemia represented the second most important cause. Of the enteritis cases, 18.5–63.2% of the samples analyzed were positive for Escherichia coli: 38.5% of the septicemia cases were positive for E. coli in 1985–1986 but none were positive in 1984–1985. E. coli K99 isolates were rare. Only one Salmonella isolate was made in 1985–1986. There were 16 cases (12.2%) of pneumonia in 1984–1985 and two cases only (1.5%) in 1985–1986. Of the cases examined, 18.8% were positive for Pasturella hemolytica and 25% were positive for Pasturella multocida in 1984–1985.

Its appears that lamb mortality can be reduced by improvement of nutrition and health care in many of these flocks. Further work should be done to provide information on the causes of lamb pneumonia as well as the potential for vaccination against lamb diarrhea (i.e. E. coli in these flocks.  相似文献   


20.
Seven healthy native goats in early lactation, weighing 30–40 kg, were used in this study. The right mammary gland of the seven does were infused with CpG-ODN at a dosage of 100 μg kg−1 body weight on the day 5 postpartum (PP). The left glands were used as controls and infused with sterile phosphate-buffered saline (PBS). On day 8 PP, the same dosage of CpG-ODN or PBS was again infused. On day 9 PP, the mammary glands (both right and left) of the seven does were infused with 6 × 106 colony-forming units (CFU) Escherichia coli and, at 0, 8, 16, 24, 48 and 72 h postinfection (PI), milk samples were collected from all glands. Goats were euthanized at 72 h PI and the mammary tissue harvested. Infusion with 6 × 106 CFU ml−1 E. coli induced acute mastitis. Histopathological evaluations showed that polymorphonuclear neutrophils (PMNs) were still present in alveoli at 72 h PI, but PMNs in the CpG-ODN-treated glands has disappeared. Bacteria counts in milk peaked at 16 h PI and CpG-ODN induced a significant decrease in viable bacteria from 16 h PI until the end of the experiment. This study showed that CpG-ODN promoted the expression of its specific receptor (TLR-9 mRNA) in mammary tissue, stimulated IL-6 production, reduced bacteria counts in milk, attenuated the impact of inflammation mediators on cells and significantly shortened the inflammation course. These results suggest that the CpG-ODN improved mammary gland defense and, thereby, had a beneficial effects against mastitis caused by E. coli infection in goats.  相似文献   

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