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1.
Two outbreaks of fowl cholera on a multiage free-range egg farm were investigated. The outbreaks occurred in 1994 and 2002. A total of 22 strains of Pasteurella multocida were available for study, 11 from the 1994 outbreak and 11 from the 2002 outbreak. Lesions typical of acute fowl cholera were seen in the 1994 outbreak, whereas both acute and chronic fowl cholera occurred in the 2002 outbreak. The isolates were examined in an extended phenotypic typing methodology, by a P. multocida-specific polymerase chain reaction (PCR), by the Heddleston somatic serotyping scheme, and by restriction endonuclease analysis (REA) typing using the enzyme HpaII. All 22 strains had the same phenotypic properties, all were confirmed as P. multocida by PCR, all were Heddleston serovar 4, and all had the same REA pattern. The results indicate that these 2 outbreaks were caused by the same clone of P. multocida--despite the 8-year time period between the outbreaks.  相似文献   

2.
SUMMARY: Biochemical profiles, restriction endonuclease analysis (REA) and ribotyping were used to investigate Pasteurella multocida isolates from outbreaks of fowl cholera on 7 turkey farms in New South Wales. While only a single isolate was available from 5 of the farms, multiple isolates, 4 and 12 respectively, were available from the other 2 farms. The available field evidence suggested that 8 outbreaks had occurred with one farm suffering 2 outbreaks. The isolates obtained were all confirmed as Pasteurella multocida . Biochemical profiles allocated the isolates to 4 groups, 3 being variants of P multocida subsp multocida and the fourth being P multocida subsp septica . REA performed with Hpall established 7 groups. Ribotyping using the Hpall digests probed with the 16S rRNA operon of Haemophilus paragallinarum recognised the same 7 groups as REA. Unlike the biochemical profiles, both REA and ribotyping provided a fine subdivision that identified outbreaks as either related or unrelated. The REA and ribotyping patterns as well as biochemical profiles were stable for all isolates from the outbreaks in which multiple isolates were obtained from either the same bird or from different birds. REA and ribotyping were found to be superior to biotyping methods for the investigation of fowl cholera outbreaks.  相似文献   

3.
Restriction endonuclease analysis (REA) and plasmid profile were used to study the epidemiology of Pasteurella multocida in a swine pyramid structure. The studied pyramid was comprised of a group of 12 swine farrow-to-finish farms related by unidirectional animal movement. P. multocida isolates were obtained from the lungs of 275 slaughtered pigs. Serotyping was performed by hyaluronidase sensitivity test and toxicity was investigated by the ELISA test. HpaII was used to cleave the P. multocida extracted DNA. REA patterns relationships were studied using the Sokal-Michener coefficients, and the dendrogram was built using the UPGMA system. The 218 P. multocida isolates obtained were distributed in 17 REA patterns. In 9 of the 12 farms studied only 2-3 REA patterns were detected, with one clearly predominant pattern. The 81 strains with plasmids were assigned to six plasmid profiles. REA and plasmid profiles proved to be good epidemiological tools for identifying different strains of P. multocida with the same phenotype.  相似文献   

4.
Restriction endonuclease analysis (REA) of whole-cell DNA was used to determine possible sources of Pasteurella multocida for each outbreak of fowl cholera occurring in turkey flocks in eight commercial poultry companies in California from October 1988 to September 1989. Over this period, 179 isolates of P. multocida were obtained from dead turkeys in 80 meat and breeder flocks on 43 premises. P. multocida was isolated from wildlife on five premises. Isolates were characterized by subspecies, serotype, presence of plasmid DNA, and REA type. In 52 (65%) flocks, all isolates of P. multocida had the same REA pattern as the M9 live vaccine strain following digestion of DNA with the restriction enzyme SmaI. Field strains of P. multocida were obtained from 27 (34%) flocks, and one flock (1%) yielded both M9 and a field strain of the organism. REA of field strains of P. multocida revealed 17 different SmaI REA types. Based on matching SmaI REA types, potential sources of P. multocida were identified for 15 of the 28 flocks infected with field strains of the organism, and transmission between turkey premises was a possibility in only seven flocks.  相似文献   

5.
Biochemical profiles, restriction endonuclease analysis (REA) and ribotyping were used to investigate a total of 38 Pasteurella multocida isolates from four separate outbreaks of pasteurellosis in Australian piggeries. Six isolates were obtained from Outbreak 1, 16 from Outbreak 2 and eight each from outbreaks 3 and 4. Outbreaks 1 and 2 were cases of pneumonic pasteurellosis while outbreaks 3 and 4 involved systemic pasteurellosis. Biochemical characterisation established that a number of different types of P. multocida were present in outbreaks 1 and 3 while outbreaks 2 and 4 were associated with a single type of P. multocida. Outbreaks 1 and 3 yielded isolates of P. multocida that belonged to the subspecies multocida and gallicida, with the subspecies multocida isolates being identified as biovar 3 (6 in total) or 12 (1 in total) and the subspecies gallicida isolates (7 in total) being identified as biovar 8. All 24 isolates from outbreaks 2 and 4 belonged to the subspecies multocida and were all biovar 3. REA and ribotyping showed that, in outbreaks 1 and 3, there were three different types of P. multocida in each outbreak with no common strains between the outbreaks. The molecular methods showed that only a single strain of P. multocida was associated with outbreaks 2 and 4, although the outbreaks were associated with strains that differed in REA profiles but shared a ribotype profile. This study has shown that both, systemic and pneumonic pasteurellosis can be associated with either a single strain or multiple strains of P. multocida. The results also indicate that the molecular typing methods of REA and ribotyping are superior to biochemical characterisation for epidemiological investigation of porcine pasteurellosis.  相似文献   

6.
Investigations for detection and differentiation of nine avian poxviruses (APVs) were carried out by the use of a polymerase chain reaction (PCR) combined with restriction enzyme analysis (REA) and further nucleotide sequence analysis. With one primer set, which framed a region within the fowl poxvirus 4b core protein gene, we were able to detect APV-specific DNA from 19 tested strains and isolates belonging to five defined Avipoxvirus species and four previously undefined isolated species. PCR results revealed no recognizable differences in size of amplified fragments among the different APVs. REA of PCR products with MseI and EcoRV allowed us to differentiate most of the tested avipox species. Nucleotide sequence analysis of the amplified fragments showed a nucleotide similarity of 72%-100% among the different species. Phylogenetic analysis documented five distinguishable sequence clusters in accordance with results obtained by REA. PCR in combination with REA and sequencing of the amplified fragments is a rapid and effective diagnostic system, and it is a new approach to refine epidemiologic studies of APV infections.  相似文献   

7.
The live, attenuated vaccine strains of Pasteurella multocida have been hypothesized to be responsible for homologous serotype outbreaks of fowl cholera on farms that use the commercial vaccines. We have further hypothesized that the naturally occurring Clemson University (CU) vaccine strain may be transformed to virulence by the acquisition of plasmid DNA. To test this hypothesis, we obtained seven homologous serotype (A:3,4) P. multocida isolates, all plasmid bearing, that were cultured from fowl cholera cases in vaccinated flocks and compared the isolates with the CU reference vaccine by molecular methods. Restriction fragment length polymorphisms (RFLPs) were detected by DNA/DNA hybridization with labeled probes specific for the cya, aroA, and rrn genes of P. multocida. The RFLPs obtained from BglII-digested genomic DNA probed with cya demonstrated no differences among the isolates. Although three isolates probed with aroA showed a RFLP identical to the vaccine strain, five isolates were distinctly different. Isolates probed with rrn grouped into three different restriction patterns that were dissimilar from that of the vaccine strain. Therefore, we have shown that these fowl cholera isolates are different from the CU vaccine strain and that these outbreaks were not vaccine related.  相似文献   

8.
Three California turkey premises that had repeated outbreaks of fowl cholera were studied for periods of 2 to 4 years. Using biochemical, serologic, plasmid DNA, and restriction endonuclease analyses of isolates of Pasteurella multocida from turkeys and wildlife on the premises, strains of the organism were found to be enzootic on two of the premises. On the third, a variety of strains of P. multocida were isolated from fowl cholera outbreak flocks.  相似文献   

9.
From Aug 1985 through July 1986, 720 meat turkey flocks on 160 California premises were monitored and outbreaks of fowl cholera (Pasteurella multocida) were investigated. Data from 43 outbreak (case) flocks were compared with data from 43 nonoutbreak (control) flocks. Outbreak flocks, compared with control flocks, were more likely to be located on premises with higher maximal bird capacity and history of fowl cholera outbreaks. The overall impression was that flocks in larger, newer, more intensively managed premises were at greater risk of fowl cholera outbreaks than were other flocks.  相似文献   

10.
The genomes of North American strains of leptospires belonging to serogroups Mini and Sejroe were analyzed and compared with those of reference strains by cleavage with restriction endonucleases. The isolates selected for this study, when typed by the serologic method, were identified as serovars szwajizak, hardjo, and balcanica. However, the results of restriction endonuclease analysis (REA) indicated that a different classification existed. The 2 isolates typed as serovar szwajizak seem to be georgia by REA. Isolates belonging to serovars balcanica and hardjo had REA patterns that differed from both reference strains. Differences were not observed in the REA patterns between balcanica and hardjo isolates. All hardjo and balcanica isolates examined are suggested to be classified into a previously described hardjo, REA subtype hardjobovis. Using the enzyme Hha1, these isolates were subdivided into 3 subgroups. When examining the REA pattern of the 17 reference strains in serogroup Sejroe, 3 identical pairs were observed: wolffi and roumanica; sejroe and polonica; and istrica and nyanza. The REA again indicated that it will be a valuable method for the classification of leptospires.  相似文献   

11.
A total of 91 isolates of Treponema hyodysenteriae which were obtained from 62 piggeries located around Australia were typed by serology and by DNA restriction endonuclease analysis (REA). The isolates fell into eight serogroups, of which groups B and D were the most common. Isolates with different REA patterns were recognised within serogroups, whilst a few isolates with the same REA pattern were placed into different serogroups. Some of the latter isolates were either from the same piggery or from farms with epidemiological links, thus indicating the bacteria may have altered their antigenic properties. A total of 31 different REA patterns were recognised amongst the Australian isolates. These comprised eight major patterns, with four of these being subdivided on the basis of minor differences in banding. Where a number of isolates were obtained from individual piggeries these all had the same REA pattern, and in one piggery isolates with the same pattern were recovered over a five year period. Plasmid bands were observed in 70 of the Australian isolates (77%), and in six of the seven overseas isolates included in the study for comparison. These plasmids did not affect the REA pattern. Of the States from which substantial numbers of isolates were examined, the greatest number of different strains (12 amongst 19 piggeries) were found from Victoria, and there were 10 REA patterns in strains from 24 piggeries in Queensland. Despite the large total number of different strains of T. hyodysenteriae in Australia, only three were found in more than one State.  相似文献   

12.
One hundred sixty meat-turkey premises in California were monitored for outbreaks of fowl cholera from August 1985 through July 1986. Nearly 27 million turkeys in 720 flocks were at risk during the year. Fifty-three flocks of approximately 3 million turkeys on 34 different premises experienced confirmed fowl cholera outbreaks. The epidemic curve for the year indicated that the majority of outbreaks occurred in the late summer and fall, particularly in October. The incidence of outbreaks during this time was not significantly associated with seasonal variation in the size of the turkey population. The mean flock age at outbreak was 10.8 weeks, with a range of 5-18 weeks.  相似文献   

13.
Natural disease outbreaks of erysipelas and fowl cholera occurred in several lines of turkeys maintained for genetic studies. There were line differences in mortality during both outbreaks, suggesting that there is genetic variation in resistance to these diseases. A line developed by selection for increased egg production had a higher mortality rate from fowl cholera than did the randombred control line from which it was developed. Both the egg line and its control line had a lower mortality rate in the erysipelas outbreak than did a line selected for increased growth rate. Both diseases induced high mortality in a line selected for increased growth.  相似文献   

14.
The relationship of an increase in fowl cholera outbreaks in turkeys with an increase in environmental temperatures during June, July, August, and September between 1959 and 1992 was analyzed. High environmental temperatures were found to be influential in the development of fowl cholera in turkeys. When the average monthly maximum environmental temperatures for 5 mo of July and 7 mo of August during the 13 yr between 1967 and 1979 were above 30.5 C, there was a significantly (P < 0.05) higher number of fowl cholera outbreaks in turkeys for each month than during the same months when the average maximum temperatures were below 30.5 C. To test the hypothesis that an increase in fowl cholera outbreaks was preceded by an increase in temperature, the pre- and postoutbreak temperatures for 46 selected outbreak clusters occurring between 1959 and 1992 were averaged. Both the average maximum and minimum temperatures for the latter 9 days of the preoutbreak period were highly significantly (P < 0.001) higher than those of the average cluster outbreak day and the following four postoutbreak days. Also, for the nine individual days of the latter pre-outbreak period, the daily average maximum temperature was significantly (P < 0.05) higher for 3 days and partially significantly (P < 0.10) higher for 3 days than that of the average cluster outbreak day, and the daily average minimum temperature was significantly (P < 0.05) higher for 2 days and partially significantly (P < 0.10) higher for 1 day than that for the average cluster outbreak day.  相似文献   

15.
Thirty-eight clinical isolates of Pasteurella multocida, recovered from a continuous flow, farrow-to-finish swine herd, were characterized by capsular serotyping and restriction endonuclease analysis (REA) in order to study the epidemiology of P. multocida pneumonia. Twenty-three of the 38 isolates obtained in the study belonged to serotype A. They displayed three REA patterns after digestion with HpaII, of which one designated A-3 represented 70% of the samples. The remaining 15 isolates were serotype D. Four different REA patterns were observed in the type D isolates. The REA type D-1 was most prevalent and accounted for 47% of the serotype D isolates. All serotype A isolates were nontoxigenic, whereas five (33%) of the serotype D isolates were toxigenic. Vertical transmission of P. multocida could not be demonstrated, and was probably not a major route of infection. The results of this study suggest that strains of P. multocida virulent for pigs exist and cause swine pneumonic pasteurellosis in continuous flow herds by horizontal transmission.  相似文献   

16.
Repetitive extragenic palindromic (REP)-PCR (polymerase chain reaction), enterobacterial repetitive intergenic consensus (ERIC)-PCR, and single primer PCR assays were employed to characterize 66 strains of Pasteurella multocida serogroup A:1 isolated from avian species belonging to different regions of India. REP-PCR resulted in amplification of REP sequences from the genome which were in the range of approximately 200 to approximately 3000 bp and accounted for a total of 54 distinguishing profiles (D=0.99). ERIC-PCR analysis also generated amplified products in the range of approximately 200 to approximately 3200 bp categorizing strains into a total of 50 different profiles (D=0.98). Amplification of repetitive regions using a microsatellite primer (GTG)(5), resulted in clear distinctive bands ranging from approximately 200 to approximately 2400 bp. Strains were assigned to 43 profiles (D=0.96). No correlation could be drawn between genotypic profiles and avian hosts with their geographical area of origin. Avian strains of P. multocida serogroup A:1 were found to be highly heterogeneous with diverse profiles. REP-PCR was found to be highly discriminatory and simple method for differentiation of phenotypically similar strains. The present study also indicated that PCR based amplification of repetitive regions of P. multocida is a rapid technique with good discrimination and could be employed directly for routine typing of field isolates from fowl cholera outbreaks.  相似文献   

17.
Five hundred twenty isolates of Pasteurella multocida, collected in California from September 1985 to November 1988, were characterized in the laboratory. Characteristics examined included serotype, capsular type, biotype (subspecies), and possession of plasmid DNA. Three hundred thirty-three isolates recovered from turkeys dying from fowl cholera, 88 isolates from liver turkeys in flocks with fowl cholera outbreaks in the recent past, and 99 isolates from wildlife captured on fowl cholera-outbreak and non-outbreak turkey premises were studied in this manner. Characteristics were fairly homogeneous among isolates, especially those obtained from turkeys. The majority of isolates were serotype 3,4, capsular type A, subspecies multocida, and lacked plasmid DNA. Common serotypes of isolates from turkeys and wildlife sampled on the same premises were noted in eight of 13 cases examined.  相似文献   

18.
Three fowl adenovirus (FAV) isolates (341, 344, and 215) obtained during 1996-97 from field outbreaks of inclusion body hepatitis/hydropericardium syndrome (IBH/HPS) affecting broilers and broiler breeders in Chile were characterized by virus neutralization tests (VNTs) and restriction enzyme analysis of a DNA fragment. Furthermore, the pathologic characteristics of one of these FAV isolates (FAV 341) was studied in experimentally infected chickens. The VNTs conducted with isolates 341 and 344 against reference strains and antisera belonging to each of 12 FAV serotypes demonstrated a close antigenic relationship with strain KR5 of the FAV serotype 4. Polymerase chain reaction using the primers H3/H4 and subsequent HpaII digestion was used for serotype identification of isolates 341 and 215. The length of the PCR products and the restriction profiles of isolates 341, 215, and the reference strain KR5 (FAV4) were identical. The present results confirmed the classification of all three isolates as FAV4. The pathogenicity test with 1000 mean tissue infectious dose of isolate 341 inoculated intramuscularly in 20-day-old specific-pathogen-free chickens resulted in the death of 9% (two birds) six days postinoculation (PI). Both birds showed characteristic IBH/HPS gross and microscopic lesions; the remaining birds, sacrificed at day 10 PI, showed less severe lesions. On the basis of epidemiologic and experimental data of the virulence of Chilean FAV isolates, and the pathogenicity results with isolate 341, we speculate that Chilean FAV strains may require an association with other agents (immunosuppressive agents) to induce IBH/HPS outbreaks in the field.  相似文献   

19.
鸡养殖中禽霍乱疾病的出现主要是由于多杀性巴氏杆菌感染的一种传染性疾病,主要会导致鸡只出现急性败血症和机体炎症反应等,慢性型感染会导致鸡只出现皮下及机体内脏器官、关节等的化脓性炎症反应。禽霍乱疾病在鸡养殖全年均会出现,尤其是在气温变化较大的时期疾病爆发的可能性更高。禽霍乱疾病在急性爆发的情况下病死率相对较高,同时短期内即会出现死亡的情况,难以进行有效的治疗,易导致鸡养殖户出现严重的经济损失。该文主要对鸡禽霍乱疾病的流行病学特点、临床症状及相关的防治措施进行论述。  相似文献   

20.
Recombinant outer membrane protein H (rOmpH) is a potential fowl cholera vaccine candidate. The present study was aimed at developing rOmpH formulations for intranasal administration. The rOmpH was purified and formulated with either Escherichia coli enterotoxin B (LTB) or CpG oligodeoxynucleotides (ODN) as an adjuvant. Antibody responses in chickens intranasally immunized with rOmpH in combination with 2 different adjuvants were significantly increased (P<0.05) post immunization. Chicken survival rates showed that rOmpH formulated with ODN and LTB elicited 90% and 70% protection, respectively. Our findings indicated that rOmpH formulated with ODN elicited protection better than that formulated with LTB. Therefore, the vaccines formulations in the present study can be considered new intranasal vaccine formulations for fowl cholera in chickens.  相似文献   

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