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1.
An acute disease with high mortality occurred in the ostrich farm and characterized by depression, severe diarrhea and sternal recumbency. Four dead ostriches of the farm were submitted to the National Veterinary Research & Quarantine Service, and diagnosed as necrotic enteritis. In the gross and histopathological examination, extensive diffuse fibrinonecrotic enteritis was found in the small intestine, especially jejunum. Clostridium perfringens was isolated from a pure culture from the duodenum and jejunum of these birds. Based on our current knowledge, this is the first report of an outbreak of necrotic enteritis in the ostrich in Korea.  相似文献   

2.
Ulcerative enteritis is found in a wide range of avian hosts but has not been described in psittacine birds. This case report describes ulcerative enteritis in four lories (two Trichoglossus sp. and two Eos sp.) that were found dead without any previous sign of disease. Macroscopically, all four birds showed good body condition. The only remarkable finding was a moderate dilatation of the small intestine with the presence of multiple yellow foci. Histologically, multiple ulcers extended into the submucosa and were filled with necrotic debris; bacteria and fibrin were observed in the intestinal mucosa. The liver and spleen exhibited a multifocal fibrinoid necrosis associated with a very moderate inflammatory reaction. Microbiological isolation revealed colonies of Clostridium colinum and Clostridium perfringens in the intestinal tract of the investigated birds.  相似文献   

3.
Role of Coccidia in the occurrence of necrotic enteritis of chickens   总被引：2，自引：0，他引：2  
Clostridium perfringens type A, Eimeria acervulina, and Eimeria necatrix were used to produce necrotic enteritis in chickens. The disease was produced in all groups of birds that received feed contaminated with C. perfringens. Mortality due to necrotic enteritis was highest (53%) in birds infected with E. acervulina before infection with clostridia. There was a significant difference in mortality rates between birds infected with E. acervulina and birds infected with E. necatrix before infection with C. perfringens. Mortality rates also differed significantly between the group infected with E. necatrix and the group that received only feed contaminated with C. perfringens. It was concluded that under field conditions, coccidia can play a significant role in the occurrence of necrotic enteritis when a sufficient number of toxigenic strain of C. perfringens type A is present. The pathological changes induced by clostridia and coccidia are described.  相似文献   

4.
Necrotic enteritis was reproduced experimentally in two week old broiler chickens by intravenous injection and also by oral administration of a pure culture of Clostridium perfringens. In the first experiment, gross and microscopic intestinal lesions, typical of necrotic enteritis, were observed in all diseased birds and mortality was obtained only in the group of birds that were injected with 0.4 ml or more of the pure culture of the microorganism. In the second experiment, the highest mortality was noted in the group of birds that received orally, in addition to the Clostridium culture, a solution of sodium bicarbonate, to obtain an alkaline intestinal content and opium to decrease the intestinal peristaltism. The gross and microscopie intestinal lesions of the diseased and killed birds were more severe than those observed in the other groups and were similar to those encountered in field outbreaks of necrotic enteritis.  相似文献   

5.
Increased mortalities in adult western bluebirds utilizing nestboxes were noted in western Oregon during 1998 and 1999. A necrohemorrhagic enteritis was found in 8 of 10 birds submitted for necropsy. Acanthocephalan parasites were present in four of eight birds with enteritis. Microscopic changes consistent with necrotic or ulcerative enteritis were commonly present. Anaerobic culture of the intestine yielded Clostridium perfringens in three of three birds. Genotype analysis of two of these isolates revealed them to be C. perfringens type A. Bacterial enteritis is believed to be the cause of the increased mortality rate, but further investigation is required to prove a definitive link to a clostridial agent.  相似文献   

6.
A total of 192 isolates of Clostridium perfringens were isolated from 99 broiler chickens and 93 capercaillies (Tetrao urogallus). Fifty of the isolates from broilers and 44 of the isolates from capercaillies were from birds with necrotizing enteritis, and the remainder were from birds without this disease. The isolates were tested for the production of three major toxins (alpha, beta, and epsilon) and four minor toxins (theta, gelatinase, mu, and nu). All isolates were found to be C. perfringens type A. Alpha toxin was produced in significantly larger amounts by isolates from birds with necrotizing enteritis than by isolates from birds without the disease, regardless of bird species. Isolates from broilers produced significantly more alpha toxin than did isolates from capercaillies.  相似文献   

7.
The intestines from 124 dead, sick and normal broiler chickens from 24 cases of necrotic enteritis were subjected to histological examination. Tissue sections from the duodenum, jejunum, ileum and ceca from each broiler were examined histologically for lesions of necrotic enteritis and the presence of coccidia. Lesions of necrotic enteritis were present in one or more areas of the intestine in all but six of 94 dead or sick birds and they were most common and severe in the jejunum. Coccidia were found in only small numbers in both diseased and normal birds.

Brown and Brenn stained sections showed Gram-positive bacilli intimately associated with early necrotic lesions on the tips of villi. Tissue sections from the intestines of sick birds permitted a proposed pathogenesis for this disease with the lesion starting at the tips of villi.

The similarity in pathogenesis and pathological lesions in this disease of broilers and Clostridium perfringens type C enteritis in baby pigs is discussed.

  相似文献   

8.
Currently, the factors/toxins responsible for Clostridium perfringens-associated avian enteritis are not well understood. To assess whether specific C. perfringens' toxinotypes are associated with avian enteritis, the isolates of C. perfringens from 31 cases of avian necrotic or ulcerative enteritis submitted between 1997 and 2005 were selected for retrospective analysis using multiplex PCR. C. perfringens was isolated from chickens, turkeys, quail, and psittacines. The toxinotypes of isolates from diseased birds were compared against the toxinotype of 19 C. perfringens isolates from avian cases with no evidence of clostridial enteritis. All C. perfringens isolates were classified as type A regardless of species or disease history. Although many isolates (from all avian groups) had the gene encoding the C. perfirngens beta2 toxin, only 54% produced the toxin in vitro when measured using Western blot analysis. Surprisingly, a large number of healthy birds (90%) carried CPB2-producing isolates, whereas over half of the cpb2-positive isolates from diseased birds failed to produce CPB2. These data from this investigation do not suggest a causal relationship between beta2 toxin and necrotic enteritis in birds.  相似文献   

9.
Necrotic enteritis is a disease of considerable economic importance to the global poultry industry. Clostridium perfringens has long been recognised as the etiological agent of the disease. However, disease initiation and progression is complex and appears to be precipitated by a range of predisposing factors. The present study investigated microbial interactions in the caecum of birds challenged with C. perfringens that developed necrotic enteritis. Bacterial populations of healthy and diseased birds, across two independent animal trials, were characterised by pyrosequencing of the V1-V3 region of 16S rRNA genes. Significant changes in the microbiota of infected birds were detected. Most of the affected bacterial species, including a number of butyrate producers, were reduced in abundance in infected birds compared to uninfected controls and a number of phylotypes, classified as Weissella species, were also more abundant in healthy birds. Conversely, some bacterial groups were more abundant in the C. perfringens-infected birds, for example, members of an unclassified order of Mollicutes showed a 3.7-fold increase in abundance in infected birds. Representative sequences from this novel order shared 99% identity with sequences previously detected in intestinal microbiota of chickens and humans, and have previously been shown to be represented in a number of samples originating from irritable bowel syndrome disease patients. We speculate that these newly identified perturbations in the composition of caecal microflora may play a role in the development and manifestation of necrotic enteritis.  相似文献   

10.
Summary A disease causing high mortality in young chickens following listlessness, inappetence and diarrhoea is described from Malawi. Haemorrhagic enteritis, splenic enlargement and congestion with petechial haemorrhages, and subcutaneous oedema were seen at post mortem.Clostridium fallax was isolated from affected birds. Coccidiosis was a possible predisposing factor.  相似文献   

11.
Necrotising enteritis had been the cause of death of 4.9 per cent in 5,177 nursed piglets, which was established by pathological examination. The number of piglets, in that context, which had come from industrialised sow breeding units was equivalent to 92 per cent. The nursed piglet held the third position, next to smaller ruminants (19.4 per cent) and fowl (6.0 per cent), with regard to the occurrence of Clostridium perfringens enterotoxemia or necrotising enteritis in 112,218 animals which were pathologically examined after death. Necrotising enteritis so far has been rare in the GDR. No regional accumulation has been observed. Several outbreaks on industrialised sow breeding units actually remained stationary. The occurrence of the disease may be favoured by a number of factors which are conducive to accumulation of Clostridium perfringens Type C in a given stock. Group keeping of pregnant sows, simultaneous farrowing of larger groups of sows, group treatment of nursed piglets, using neomycin, chloramphenicol, oxytetracycline, and other antibiotics to which Clostridium perfringens is primarily resistant or has acquired resistance in the course of time are some of those contributive factors. Transmission of Clostridium perfringens Type C through feedstuff is possible, though it would lead to a real outbreak only by high intensity of the contamination, and it played a minor role in proliferation of the disease. 3479 Clostridium perfringens strains were isolated from 9,481 animals, both clinically intact and after death, with 30 species being included. Type classification revealed 2454 strains of Type A (70 per cent), 204 of Type D (5.88 per cent), 164 of Type C (four per cent), and 48 of Type B (1.34 per cent). There were 688 atoxic strains (17 per cent). Swine is the major carrier of Clostridium perfringens Type C, with 87 per cent of all Clostridium perfringens Type C strains having been isolated from swine. Swine was followed by fowl (four per cent), sheep (four per cent), cattle, rabbit, and dog (1.27 per cent each). Clostridium perfringens Type C was obtained from the faeces of clinically intact sows in seven instances, including two cases with sows (0.46 per cent) from farms with no previous record of necrotising enteritis.  相似文献   

12.
Day-of-hatch broiler chicks housed in isolation units were each given, by oral gavage, 0.1 ml of Mucosal Starter Culture (MSC) or saline control. Each of the treated and control chicks was subsequently given a composite culture of three strains of bacitracin-resistant Clostridium perfringens (Cp) previously isolated from chickens with symptoms of necrotic enteritis. Some chicks were maintained on a corn-based diet provided ad libitum. Others were given the feed supplemented with 50% rye (a predisposing factor for necrotic enteritis). At 7, 14, and 21 days after receiving Cp, chicks were euthanatized, and cecal contents were diluted and plated on selective agar containing bacitracin. For chicks on corn feed, Cp numbers were similar in control birds and birds given MSC in three of four trials. In two of the trials that demonstrated no effect of MSC on Cp numbers, enterotoxin presence was determined. The number of birds with detectable Cp enterotoxin in their small intestine and the mean toxin levels were lower in the MSC-treated birds. In a fourth trial with birds on corn-based feed, mean Cp numbers and the number of Cp-positive birds were lower in the MSC-treated birds. For the two trials involving chickens on rye-supplemented feed, Cp numbers and the percentage of Cp-positive birds were significantly reduced in MSC-treated birds compared with control birds. Enterotoxin in birds receiving the 50% rye diet was at low levels or not detected in control and MSC-treated birds. Results suggest that MSC may reduce intestinal proliferation of Cp, a causative agent of necrotic enteritis in poultry and of foodborne disease in humans.  相似文献   

13.
The efficacy of penicillin G potassium (Pot-Pen) administered via drinking water to manage necrotic enteritis (NE) was investigated in a Clostridium perfringens (CP) challenge study using 1600 broiler chickens assigned to one of four treatment groups: nonchallenged, nonmedicated; challenged, nonmedicated; challenged, Pot-Pen 0.2 g/L; challenged, Pot-Pen 0.4 g/L. Overall mortality due to NE was significantly reduced among Pot-Pen-treated pens; mortality due to other causes did not differ among the treatment groups. Among all birds, growth performance parameters were significantly improved among Pot-Pen-treated pens. When considering birds randomly sacrificed 4 days post-Pot-Pen initiation, mean NE lesion scores were greatest among the challenged, nonmedicated pens; only one of 80 randomly sacrificed birds treated with Pot-Pen had NE lesions. Among the nonmedicated control pens, body weight (BW) was significantly greater among birds that did not have NE-associated lesions. When sacrificed birds were stratified by NE lesion score, there were no significant differences in BW among the treatment groups. Results of this study suggest that CP-associated subclinical disease can significantly reduce broiler performance. Furthermore, the positive effects of treatment with Pot-Pen appeared to be associated with the prevention and/or treatment of NE-specific lesions.  相似文献   

14.
NetB toxin from Clostridium perfringens is a major virulence factor in necrotic enteritis in poultry. In this study the efficacy of NetB as a vaccine antigen to protect chickens from necrotic enteritis was examined. Broiler chickens were immunized subcutaneously with purified recombinant NetB (rNetB), formalin treated bacterin and cell free toxoid with or without rNetB supplementation. Intestinal lesion scores and NetB antibody levels were measured to determine protection after mild oral gavage, moderate in-feed and heavy in-feed challenges with virulent C. perfringens isolates. Birds immunized with rNetB were significantly protected against necrotic enteritis when challenged with a mild oral dose of virulent bacteria, but were not protected when a more robust challenge was used. Bacterin and cell free toxoid without rNetB supplementation did not protect birds from moderate and severe in-feed challenge. Only birds immunized with bacterin and cell free toxoid supplemented with rNetB showed significant protection against moderate and severe in-feed challenge, with the later giving the greatest protection. Higher NetB antibody titres were observed in birds immunized with rNetB compared to those vaccinated with bacterin or toxoid, suggesting that the in vitro levels of NetB produced by virulent C. perfringens isolates are too low to induce the development of a strong immune response. These results suggest that vaccination with NetB alone may not be sufficient to protect birds from necrotic enteritis in the field, but that in combination with other cellular or cell-free antigens it can significantly protect chickens from disease.  相似文献   

15.
Necrotic enteritis is an enteric disease of avian species caused by the anaerobic bacterium Clostridium perfringens. The disease is regularly controlled in the broiler chicken industry with antimicrobials in feed but is reemerging in areas such as Europe where there is a ban on antimicrobials as growth promoters. To study prospective therapies, researchers must be able to reproduce this disease in a controlled environment, but this is not always possible because of differences in the pathogenicity of C. perfringens strains. Our objective was to test the potential of five isolates (SNECP43, 44, 47, 49, and 50), taken from field cases of necrotic enteritis, at recreating the disease in a controlled challenge experiment. SNECP43 and 50 were derived from a common clone, with SNECP50 passed in vivo and SNECP43 subcultured in vitro. Four hundred birds were divided into 16 pens, with three pens each receiving one of five treatments, with one control pen. Day-old birds were raised on a high wheat-based diet to promote necrotic enteritis development and were challenged with between 3.4 x 10(9) and 3.2 x 10(11) colony-forming units (cfu) of C. perfringens in feed for a period of 24 hr starting on day 13 of the challenge experiment. Lesion scores were assessed on two birds per pen sacrificed on day 17 and on any dead birds during the 25-day study. Growth performance was assessed up to 25 days, and mortality recorded throughout. Only SNECP50 produced necrotic enteritis mortalities significantly different (P < or = 0.05) from the control. The five isolates were also typed using pulsed-field gel electrophoresis to assess their genetic relatedness. All epidemiologically unrelated isolates were deemed genetically unrelated, whereas SNECP43 and 50 differed by only a single minor band. Toxin type was assessed using polymerase chain reaction (PCR), which was also used for the detection of the gene encoding the beta2-toxin.  相似文献   

16.
Avian necrotic enteritis is a major economic and welfare issue throughout the global poultry industry and is caused by isolates of Clostridium perfringens that produce NetB toxin. Previously we have shown that birds directly vaccinated with inactivated C. perfringens type A culture supernatant (toxoid) combined with recombinant NetB (rNetB) protein were significantly protected from homologous and heterologous challenge. In the present study the protective effect of maternal immunization was examined. Broiler breeder hens were injected subcutaneously with genetically toxoided rNetB(S254L) alone, C. perfringens type A toxoid and toxoid combined with rNetB(S254L). Vaccination resulted in a strong serum immunoglobulin Y response to NetB in hens immunized with rNetB(S254L) formulations. Anti-NetB antibodies were transferred to the eggs and on into the hatched progeny. Subclinical necrotic enteritis was induced experimentally in the progeny and the occurrence of specific necrotic enteritis lesions evaluated. Birds derived from hens immunized with rNetB(S254L) combined with toxoid and challenged with a homologous strain (EHE-NE18) at either 14 or 21 days post-hatch had significantly lower levels of disease compared to birds from adjuvant only vaccinated hens. In addition, birds from hens immunized with rNetB(S254L) alone were significantly protected when challenged at 14 days post-hatch. These results demonstrate that maternal immunization with a NetB-enhanced toxoid vaccine is a promising method for the control of necrotic enteritis in young broiler chickens.  相似文献   

17.
A cage study was conducted to demonstrate the effect of Entegard REV, a lysozyme-based antimicrobial blend, on the performance of broiler chickens and necrotic enteritis (NE) disease reduction of birds that were challenged with Eimeria maxima and Clostridium perfringens. In the experiment, challenge by the infectious agents without medication resulted in impaired feed consumption, weight gain, and feed conversions and caused high incidence of gross NE lesions and NE mortality rate. Entegard REV included in feed at 200 g/metric ton (MT) was very effective in reducing negative health effects in the birds after NE challenge, and its ability to control the disease was not statistically different from a commonly used antibiotic growth promotant, bacitracin methylene disalicilate, at 55 g/MT.  相似文献   

18.
C Riddell  X M Kong 《Avian diseases》1992,36(3):499-503
Necrotic enteritis was reproduced in broiler chickens by mixing cultures of Clostridium perfringens in the feed. Mortality due to necrotic enteritis was higher among chickens fed rations based on wheat, rye, barley, and oat groats than among chickens fed corn-based rations. Addition of pentosanase to a wheat-based diet did not affect the level of mortality due to necrotic enteritis. Addition of pectin and guar gum to different rations severely reduced growth rate and eliminated necrotic enteritis from test birds. Addition of glucose to a corn-based diet caused a small increase in mortality due to necrotic enteritis.  相似文献   

19.
Necrotic enteritis is an acute gastrointestinal infectious disease with high morbidity and mortality which caused by Clostridium perfringens. The disease not only harms the livestock health and animal welfare,but also has been an emerging threat for breeding industry and human health. Antibacterial drugs played a positive role on preventing this disease,however,drug-resistant strains were increasing with irrational use of antibiotics,the incidence of necrotic enteritis has drastically increased, prevention and treatment of it faced severe challenges. The author reviewed the characteristics of necrotic enteritis include the etiology,physicochemical properties, epidemiology and clinical signs,at the same time, the control measures and common drugs were summarized,and the new development trend and direction for prevention and treatment necrotic enteritis was objective analyzed, aiming to establish a comprehensive understanding of the disease,provide references for prevention and treatment of the disease.  相似文献   

20.
A novel toxin, NetB, has recently been identified in virulent avian Clostridium perfringens isolates and shown to be an essential virulence factor in a clinical necrotic enteritis isolate. To assess whether NetB is more generally associated with avian necrotic enteritis isolates we have screened a range of C. perfringens strains from geographically diverse locations for both the presence and expression of the netB gene. Forty-four isolates were derived from necrotic enteritis disease cases from Australia, Belgium, Denmark and Canada and 55 isolates from healthy chickens from Australia and Belgium. The majority of strains isolated from necrotic enteritis-affected birds were netB positive (70%) and there was an absolute correlation between the presence of netB and in vitro expression of the NetB protein. Only two of the C. perfringens isolates from healthy chickens carried netB. Sequencing of the netB gene from 23 positive isolates showed that NetB is highly conserved, with only one predicted amino acid (A168T) difference, in six isolates, compared to the published sequence. This change did not alter the in vitro activity of the NetB toxin. The gene encoding the recently discovered TpeL toxin was also screened using PCR and only found in a small proportion of NetB-positive isolates from diseased birds. A selection of NetB-negative isolates, originating from diseased birds, was unable to cause disease in a necrotic enteritis induction model. This study provides further evidence that NetB is important in pathogenesis and advances our current understanding of C. perfringens virulence factors in avian necrotic enteritis.  相似文献   

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