首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Between the summer of 1998 and the winter of 2000, Salmonella analysis was performed on 2128 single and 532 pooled manure drag swabs obtained from 133 California commercial egg laying farms. The isolation of Salmonella from all rows and from all flocks using single or pooled swabs was 80% and 92%, respectively. Hence, there was no statistical difference between single vs. pooled swabs in terms of identifying Salmonella on a row or flock basis. A total of 14 serogroups comprising 44 serotypes were isolated from 123 of 133 farms. When the top 10 serotypes were considered, there was no significant difference in the range of serotypes isolated by the two culturing methods. The overall S. enteritidis prevalence for California flocks was 10.5% (14/133). The overall row prevalence for S. enteritidis for all the farms was 1.1% (24/2128), and the overall pool prevalence was 2.4% (13/532). Sixty percent (12/20) of the S. enteritidis isolates from the positive farms were phage type 4, and 40% (8/20) represented five other phage types (1, 6B, 7, 8, and 28).  相似文献   

2.
The California Egg Quality Assurance Program uses the delayed secondary enrichment culture method for detecting Salmonella Enteritidis in environmental drag swabs obtained from commercial layer complexes. The turnaround time for this method is variable and is dependent on the prevalence of Salmonella, level of the Salmonella identification, and capabilities of the performing laboratory. On a sample basis, a range of 4 to 8 days is required to identify a Salmonella sp. to the serogroup level. Additional time is required to serotype group D Salmonella isolates. A Salmonella Enteritidis-specific polymerase chain reaction (PCR) assay was developed for use on drag swabs and chick box papers, and had a turnaround time of 3-4 days. The delayed secondary enrichment culture method and the Salmonella Enteritidis-specific PCR assay were compared on 942 drag swab and 85 chick box paper samples submitted from 217 and 22 premises, respectively, as part of the California Egg Quality Assurance Program. The PCR assay identified 43 positive Salmonella Enteritidis samples from 22 premises, whereas the culture method identified 24 group D Salmonella-positive samples from 16 premises. There was a significant difference (P = 0.001) in the proportion of positive samples as determined by the two assays. Complete serotyping of the group D Salmonella-positive cultures confirmed Salmonella Enteritidis in all but one sample that was identified as Salmonella Jamaica and was negative by the PCR assay.  相似文献   

3.
Prevalence was estimated for Salmonella enterica serotype eneritidis (SE) in layer house environments (n = 200 layer houses) and house mice (n = 129 layer houses) in 15 states throughout the United States. Environmental swabs were collected from manure, egg belts, elevators, and walkways. Live-catch rodent traps were placed for 4-7 days. Swabs and house mice were submitted to the laboratory for bacterial culture. Overall, 7.1% of layer houses and 3.7% of mice were culture positive for SE. The highest prevalence was in the Great Lakes region of the United States, and no SE was recovered from houses or mice in the southeast region. Presence of SE in layer houses was associated with age/molting, floor reared pullets, and number of rodents trapped. Cleaning and disinfecting houses between flocks was associated with a reduced risk. The prevalence of SE in mice from environmentally positive houses was nearly four times that of mice from environmentally negative houses.  相似文献   

4.
During the first weeks of 2003, after exotic Newcastle disease (END) was confirmed in commercial layer flocks in Southern California, it became apparent that the virus survival information in the literature varied widely and was difficult to extrapolate to current local conditions. The END Task Force used the information available in the literature and the recommendations of research scientists to establish protocols for safely handling manure from infected and depopulated premises. In an attempt to gain more applicable knowledge in the management of contaminated poultry manure in the course of the END outbreak, this virus survival study was designed and implemented. Environmental drag swabs were tested for END virus from two of the early-infected commercial ranches that consisted of several houses following immediate removal of the infected flocks. A total of 293 samples, composed of 168 manure drag swab pools, 72 dropping board swab pools, and 38 compost swab pools from 3 houses (ranch 1), and 180 manure belt scraper swab pools from ranch 2 were analyzed for ND virus isolation and characterization for 21 consecutive days postdepopulation. Thirteen manure drag swab pools (from houses 1 and 3) and two manure dropping board swab pools (from house 3) collected from ranch 1 were positive for END virus at 0, 1, 2, 3, 4, 7, 10, 12, and 16 days postdepopulation. No END virus was isolated after the 16th day following depopulation from any of the samples. All samples from ranch 2 were negative during the entire observation period.  相似文献   

5.
Between August 20, 2001, and September 17, 2002, 1429 samples including drag swabs, egg belt or egg rollout swabs, fan-blade swabs, rodent organ and intestinal pools, beetle (Alphitobius diaperinus) pools, housefly (Musca domestica) pools, chicken organ and intestinal pools, and egg pools were obtained for Salmonella culture from two flocks from two different commercial layer ranches. The two ranches were purposefully selected for the study based on their previous status of Salmonella Enteritidis isolation using environmental drag swabs in cooperation with practicing veterinarians. Salmonella sp. was isolated from 337 out of 979 (34.42%) non-egg samples. No Salmonella was isolated from 450 egg pools collected from either ranch. S. enteritidis was isolated from samples obtained from ranch 1 from manure drag swabs, 4/284 (1.4%); rodent organs, 1/24 (4.2%); and housefly pool cultures 1/21 (4.8%). Salmonella Enteritidis was isolated from ranch 2 from mouse organ and intestinal pool samples, 1/24 (4.2%). Salmonella group B was isolated from all sample types except the insects. There was a statistically significant difference in isolation rates among seven serogroups of Salmonella: groups B, C1, C2, D, E, K, and untypeable (Pearson chi-square 18.96, P = 0.002). Overall, statistically significant differences were observed with respect to Salmonella isolation among the types of samples taken (Pearson chi-square 118.54, P < 0.0001). Intensive monitoring for Salmonella Enteritidis can be used to optimize a Salmonella reduction program for an individual poultry biosecurity unit.  相似文献   

6.
An indexing system for hygiene variables associated with egg production was developed by use of data collected from chicken flocks in southern California. The data were analyzed by factor and regression analysis. On the basis of our findings, hygiene index in relation to egg production consists of ventilation system, cooling system, manure removal, and truck movement. Flocks kept under natural ventilation produced, on the average, 2% more hen-day eggs than flocks kept under artificial ventilation. Flocks placed in houses with roof sprinklers produced 3.3% more hen-day eggs, compared with flocks placed in houses with inside foggers and pad. Flocks kept under the system of frequent removal of manure produced 2% more hen-day eggs than flocks kept under the system for which the manure was removed less frequently. Flocks kept in farms that restricted trucks collecting dead birds from entering the premises produced 3.4% more hen-day eggs than those that allowed such trucks to enter the farm.  相似文献   

7.
Seven hundred fifty-one environmental samples were collected from 76 chicken layer houses in a voluntary Salmonella enteritidis (SE) survey study carried out in New York state between January 15 and April 8, 1991. SE was recovered from both houses on 1 farm. Sampling of manure pits and mice in hen houses was useful for SE screening. Phage types of SE from the environment, birds, and mice were identical. The rapid whole-blood test was unreliable, and culture of cloacal swabs was inadequate for detection of SE carriers. Culture of organs from chickens did not correlate well with results of environmental samples.  相似文献   

8.
应用双抗体夹心酶联免疫吸附试验 (DAS- EL ISA)在种鸡白血病的净化中 ,针对同一种鸡群 ,同时采用蛋清和肛拭作为试验材料 ,实验反映的结果不同 ;将产第一枚蛋为阳性的鸡隔离饲养 ,检测其以后蛋中 AL V的状况 ,结果发现 :在随后的 2 5天左右的每一枚蛋清中都能检测到 AL V:在不同种鸡场分别采用蛋清、蛋清和肛拭同时作试验样品进行净化 ,跟踪结果发现 :在不同种鸡场中 ,AL V阳性感染率都有不同幅度的下降。另一方面 ,检测雏鸡的胎粪 ,淘汰阳性者 ,到其产蛋期抽检蛋清 ,该群鸡 AL V阳性率有所下降  相似文献   

9.
  相似文献   

10.
This study examines drag swabbing distance, media for moistening the drag swabs, and site selection when sampling a laying facility by drag swabbing manure piles. Manure piles at a laying facility in California's San Joaquin Valley were sampled with drag swabs over various distances. Samples were cultured for Salmonella spp. with standard laboratory methods, and most probable number calculations. Salmonella spp. counts were expected to be highly variable because of reported clustering. Therefore, total bacteria and Escherichia coli, which were assumed to have a more uniform distribution on the surface of the manure, were additionally used as proxies for Salmonella. Media for moistening the swabs were compared by seeding postswabbing samples with Salmonella typhimurium, and culturing at different delay times. Total bacterial counts were compared between samples that were obtained from either wet or dry surfaces. Numbers of Salmonella spp. and total bacteria peaked within 120 feet of swabbing distance. Higher total bacteria counts were obtained by swabbing wet areas rather than dry areas, but the distance that could be swabbed effectively was shorter in wet areas. Moistening media selected for the swab resulted in statistically different culture counts, but did not show any important difference in maintaining Salmonella viability over a 48-hr period when the samples were kept at refrigerated temperatures. Once swabs became fully loaded with fecal material, bacterial numbers failed to increase with further use. Overuse of a swab may result in failure to detect Salmonella enteritidis on chicken manure if the distribution of this organism is clustered.  相似文献   

11.
As eggs represent now as ever the most important source for Salmonella infection in human beings and because of the currently occurring shift in housing conditions for laying hens from conventional cages to alternative systems it was studied whether the Salmonella prevalence in layers is influenced by the housing system. Following systems were considered: organic farming with free range management systems, floor management systems with free range, floor management systems without free range, conventional cages. 453 pooled faecal samples as single or double examination per herd from 329 flocks in different housing systems for table egg production from three Federal Lander were examined bacteriologically. The share of layer flocks which were Salmonella positive at least once independently of the housing system amounted to 32.2%. Analysis of the Salmonella findings in the single housing systems revealed that the share of Salmonella positive flocks was higher in conventional cage systems (46.3%) than in alternative housing systems (32.996% in organic farming with free range management systems, 21.9% in floor management systems with free range, 23.4% in floor management systems without free range).The results of the study clearly show that Salmonella Enteritidis (mostly phage type 4, other phage types rarely) presents with a share of 78% the dominant serovar in laying hens.The total number of all other serovars (apart from Salmonella Enteritidis and subspecies I rough) reached a share of ca. 14%, however, no other single serovar was dominant. As Salmonella Enteritidis is the predominant serovar in laying hens it is strongly recommended to use Salmonella Enteritidis vaccines for immunisation programmes of chickens during the rearing period. Because of the high prevalence of Salmonella organisms in the different housing systems, detailed information on the epidemiology of Salmonella in laying hens are needed to introduce effective control measures. Of particular interest is the question whether the Salmonella findings in laying flocks are the result of multiplication of already existing Salmonella organisms in the animals or whether the bacteria are introduced only during the laying period.  相似文献   

12.
Reasons for performing study: Increasing prevalence of anthelmintic resistance in equine nematodes calls for a reexamination of current parasite control programmes to identify factors influencing control efficacy and development of resistance. Objectives: To investigate if associations occur between prevalence of parasitic nematodes and management practices. Methods: German horse farms (n = 76) were investigated in 2003 and 2004. Information on farm and pasture management with respect to endoparasite control measures obtained using a questionnaire survey. Faecal examinations were performed in parallel. Results: Horses (n = 2000) were examined by faecal nematode egg counts, grouped into foals, yearlings and mature individuals for statistical analyses. Farms were categorised into 3 types, riding, stud farms and small holdings. Count regression models were used to analyse strongyle faecal egg count data. Following dichotomisation of faecal egg count (FEC) data, prevalence of strongyle and Parascaris equorum infections were assessed by logistic regression models as a function from various management factors. Yearlings on stud farms showed a 2‐fold higher risk of being positive for strongyle FEC, higher (i.e. ≥3 per year) anthelmintic drug treatment frequencies were associated with reduced strongyle infection rates only in mature individuals but not in foals or yearlings, foals on farms fertilising pastures with horse manure had a significantly higher risk of being P. equorum FEC positive and yearlings on stud farms were more often showing incomplete FECR following anthelmintic treatment compared to yearlings on other farm types. The mean yearly treatment frequencies per age group were: foals 4.52, yearlings 3.26 and mature horses 2.72 times, respectively. Conclusion and potential relevance: To delay the development of anthelmintic, resistance management should include additional nonchemotherapeutic parasite control strategies, FEC‐monitoring, controlled quarantine treatment of new arrivals and control of efficacy by the faecal egg count reduction test on a regular basis.  相似文献   

13.
为研究HR土鸡中存在的不同亚型禽白血病病毒(ALV)共感染的情况,本实验分别采集46只HR土公鸡的泄殖腔棉拭子和455枚鸡蛋卵白样品,采用ELISA试剂盒检测p27抗原;并采用相应的ELISA试剂盒分别检测卵黄中J亚型ALV(ALV-J)和AB亚型ALV(ALV-AB)抗体。结果表明:HR土公鸡泄殖腔棉拭子样品中p27检出阳性率为87%(40/46),卵白检出率为74.7%(340/455);而卵黄中ALV-J和ALV-AB抗体阳性率分别为0(0/30)和80%(24/30)。无菌采集初步筛选p27抗原检测为阳性的5只HR土公鸡的抗凝血接种CEF,采用抗ALV-J和ALV-A的单克隆抗体进行IFA检测,结果显示5份样品中ALV-A和ALV-J的阳性率均为100%(5/5)。同时选取HR土鸡分离株HR332进行PCR扩增鉴定,结果表明分离株HR332存在ALV-J(HR332J)和ALV-A(HR332A)。其中,HR332J与11株ALV-J国内外参考株的同源性为92.4%～97.9%;HR332A与ALV-A参考株RSA-A、MQNCSU的同源性分别为90.1%和89.7%,与国内分离株SDAU09E2的同源性为99.0%。本研究显示,地方品种HR土鸡存在不同亚型ALV共感染,同时ALV-A和ALV-J共感染同一个鸡的现象已经存在。  相似文献   

14.
本试验以80只300日龄的A品系蛋鸡为试验对象,分5个日龄段按翅号采集蛋清、泄殖腔棉拭子,无菌抗凝血和血清.用ALV p27抗原检测试剂盒检测蛋清和泄殖腔棉拭子.将无菌抗凝血分离血浆接种DF-1细胞,培养一周后用同样方法检测上清收集液,分析该群鸡只在不同日龄段泄殖腔棉拭子阳性、蛋清样本阳性和病毒分离阳性之间的相关性.用ALV-Ab抗体试剂盒检测各日龄段血清的抗体水平.此外,选取某一日龄段蛋清和泄殖腔拭子样本用4个不同厂家的ALV p27抗原检测试剂盒进行检测比较.结果表明,5个日龄段泄殖腔棉拭子平均阳性率为61％,蛋清样本平均阳性率为72.6％,病毒分离平均阳性率为48.8％.5个日龄段ALV的抗体阳性率一直为零;4个厂家的ELISA试剂盒对同一批样本的检测结果表明,IDEXX试剂盒的敏感度最高.本试验为外源性鸡白血病病毒检测及鸡白血病净化其方法的应用、试剂盒的选择、减少判定的误差、提高净化效果提供了一定的科学依据.  相似文献   

15.
This study was the first to examine the seroprevalence of Ornithobacterium rhinotracheale (ORT) within a commercial egg layer population. Serum samples collected from egg production companies were examined by serum plate agglutination test (SPAT) and outer membrane protein-based enzyme-linked immunosorbent assay (ELISA). Results show that 90% of layer flocks were positive by SPAT and 100% by ELISA. Of the pullet flocks examined, 43% and 52% were positive by SPAT and ELISA, respectively. Our study indicates that the prevalence of ORT antibody is high in the commercial layer population, suggesting that this respiratory pathogen can easily spread through multiple-age layer farms from older flocks to newly housed pullet flocks.  相似文献   

16.
Forty layer farms from 2 states participated in a study to examine the risk factors and incidence of Salmonella Enteritidis from multiple samples, including environmental drag swabs from the bird areas, feed, water, flies, rodents, live rodent traps, and environmental swabs from areas occupied by other livestock. Twenty-four of these farms had between 3,000 and 31,000 bird flocks (medium-sized flocks) and 16 had less than 3,000 birds (small-sized flocks). All were housed in cage-free production systems. Twenty-two farms included outside pasture areas for the birds. Most of the participants had just come under the FDA Egg Rule and had not yet tested their flocks (flocks under 3,000 birds are exempt) for Salmonella Enteritidis. Many, however, obtained their pullets from commercial Salmonella Enteritidis-clean breeder sources hatched in National Poultry Improvement Plan hatcheries. Vaccination against Salmonella Enteritidis was performed on 21 of the 40 farms (combination of live and killed vaccines). Salmonella Enteritidis was detected on 7 out of the 40 farms, primarily in rodents, their feces, or from swabs taken inside live traps. Of these 7 Salmonella Enteritidis-positive farms, 3 farms that had vaccinated their pullets with live Salmonella Typhimurium vaccine and killed-Salmonella Enteritidis vaccine; no Salmonella Enteritidis was isolated from the environmental drag swabs taken from the bird area or from the eggs on these farms. However, on the farms that had not vaccinated for Salmonella Enteritidis, the organism was isolated from 4 environmental drag swabs and 3 egg pools. The last 4 farms had flocks under 3,000 birds. No Salmonella Enteritidis was isolated from any of the samples of feed, flies, water, or swabs taken from other livestock areas. Based on the initial findings in this study, we suggest the 2 most important risk factors for Salmonella Enteritidis contamination inside the bird area and in the eggs in these small- and medium-sized flocks are the presence of infected rodents and the absence of an Salmonella Enteritidis vaccination program.  相似文献   

17.
One hundred twenty-nine multiplier breeder turkey flocks on 45 premises in California were monitored for outbreaks of fowl cholera (FC) (Pasteurella multocida) for 1 year (Aug. 1, 1985, through July 31, 1986). Fourteen (11%) flocks on 10 (22%) premises experienced outbreaks. Nine (64%) outbreaks occurred in the fall or winter. FC-outbreak flocks had significantly shorter lay cycles (24.6 weeks vs. 27.9 weeks) and correspondingly lower total egg production per hen (84 eggs vs. 103 eggs) than non-outbreak flocks. A case-control investigation was performed on 11 FC-outbreak (case) flocks, and nine non-outbreak (control) flocks. Case flocks were located statistically closer to other livestock species than were control flocks (0.28 miles vs. 0.68 miles) and were more likely to utilize on-farm disposal of dead birds.  相似文献   

18.
In order to study the effect of different test materials on the detected results of avian leukosis virus (ALV)-p27 antigen by ELISA, the cloacal swabs ALV-p27 antigen were detected by ELISA in 180-day local breeds hen, and the parts of the positive and negative chicken was selected to group test, the serum, egg whites and cell supernatant ALV-p27 antigen were detected by ELISA, the specific genes of ALV were detected by RT-PCR in blood.The results showed that serum, egg white and cell supernatant as ELISA test materials, the positive rate lower of than cloacal swabs, and serum ALV-p27 positive samples include all egg whites and cell supernatant positive samples in positive group.It was a significant correlation between ELISAs with serum and cell supernatant (linear equation:Y=1.8439X-0.1469, the correl was 0.937).In positive group, ALV-p27 gene positive rate lower than cloacal swabs ELISA, but higher than the serum, egg and cell culture medium, and ALV-p27 gene positive samples include serum positive samples by ELISA.ALV-J gp85 gene positive rate of 29.17%, and all positive samples were included in the serum ALV-p27 positive samples.The results suggested that the cloacal swabs as test material may occur false positive results, and egg whites and cell supernatant may occur undetected by ELISA ALV-p27 antigen assay in adult chicken, serum as test material in ELISA could more accurately reflect the state of adult chickens infected with ALV.  相似文献   

19.
In-house composting has the potential to improve the viability of the high-rise house for commercial egg production by producing a value-added product from the manure without requiring a separate composting facility. The feasibility of in-house composting depends in part on having the ability to handle the manure mass that accumulates over an extended period. This field study showed that in-house composting is possible for the length of an egg production cycle. Beginning with windrows of a carbon source, fresh pine sawdust or shredded yard waste, upon which manure fell from the cage rows above, compost volume grew rapidly in the first few weeks, but slowed after composting activity peaked, as indicated by compost temperatures. In cold weather, when ventilation rates were low, compost remixing temporarily produced high ammonia levels in the house, but ammonia levels at other times were comparable to or lower than those in an undisturbed house. The final compost was friable and nutrient-rich, although the handling quality of the yard waste compost was reduced by persistence of elongated woody pieces of the original carbon source. The ability to access the manure storage area of a high-rise house over a cycle of production gives potential to deliver manure amendments to improve nitrogen retention in the compost, which would have the effect of improving its fertilizer value and reducing ammonia emission from the house.  相似文献   

20.
为探讨不同检测材料对ELISA检测禽白血病病毒(ALV)-p27抗原结果的影响,试验首先对180日龄地方品种母鸡的泄殖腔棉拭子ALV-p27抗原进行ELISA检测,选取部分阳性鸡和阴性鸡进行分组试验,采用ELISA对试验鸡血清、蛋清和病毒分离的细胞培养液进行ALV-p27抗原检测,采用RT-PCR方法检测血液ALV特异性基因。结果显示,阳性组中以血清、蛋清和细胞培养液作为ELISA ALV-p27抗原检测材料,其检测阳性率均低于泄殖腔棉拭子,血清检测的阳性个体包含全部蛋清和细胞培养液ELISA检测的阳性个体。ELISA检测数据的相关性分析显示,只有血清和细胞培养液检测数据间存在显著性相关,线性关系方程为Y(细胞上清)=1.8439X(血清)-0.1469,R2=0.937;阳性组中ALV-p27基因检测阳性率低于泄殖腔棉拭子,但高于血清、蛋清和细胞培养液,其包含所有血清ELISA检测的阳性样品;外源性ALV-J gp85基因阳性率仅为29.17%,且阳性样品均属于血清ELISA阳性样品。综上所述,成年鸡以泄殖腔棉拭子作为ELISA ALV-p27抗原检测材料存在假阳性结果,蛋清和细胞培养液作为检测材料存在漏检的可能,血清作为ELISA检测材能够更准确地反映成年鸡群ALV感染状态。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号