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为了了解规模化养殖模式下鸡群新城疫和禽流感带毒情况和抗体滴度,从2007年9月~2008年8月,对规模化养殖场肉种鸡定期进行新城疫和禽流感带毒监测和抗体检测。每月采集鸡群气管和泄殖腔棉拭子各30份（抽检率0.3%）进行新城疫和禽流感病毒监测,每2周采集30份血样（抽检率0.3%）进行新城疫和禽流感抗体检测。研究结果显示,监测鸡群从进雏到淘汰未发现新城疫和禽流感病毒感染;从6.5周龄开始,鸡群新城疫和禽流感(H9亚型)抗体一直维持在免疫保护临界值以上,比较之下,禽流感（H5亚型）抗体上升较慢,且滴度比H9低（2～4）log2。 相似文献
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一、发病主要原因分析
1.毒力增强且污染严重.不少专家和学者实验证明,近年来新城疫病毒毒力已增强.鸡群高带毒率的原因,一方面是强毒日积月累形成的环境污染,由于消毒不力,病毒得不到消减反而增加;另一方面,鸡群中总有少数鸡处于临界免疫保护水平之下,这些鸡易受感染,感染后又成为新的带毒和排毒者,排出的病毒又传染给鸡群中抗体水平下降或不足的个体.从而导致病毒在一个鸡群中重复感染、循环出现,长期存在. 相似文献
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正1流感与新城疫疾病的诊断1.1血凝抗体用于发病鸡群的疾病诊断采用血凝抗体进行禽流感、新城疫等抗体进行测定,依据抗体滴度的高低和离散性有助于诊断。就抗体分布而言,鸡新城疫免疫鸡群抗体水平呈正态分布,血凝抗体高者仅占10%以下,低者在1%以下。反之为感染。因此,依据禽群的抗体水平高度和分布,结合临床症状和病、死鸡的剖检变 相似文献
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在某规模化鸡场的临床健康三黄肉鸡群中,于不同日龄采血,检测禽白血病(AL)AB亚群、J亚群,网状内皮组织增生症(RE)和传染性贫血(CIA)等4种免疫抑制性疫病的感染抗体,以及新城疫(ND)、禽流感(AI)H5亚型和传染性支气管炎(IB)的免疫抗体水平。结果发现鸡群受到ALV-AB、REV和CIAV感染。ALV-AB抗体阳性率为60%,ALV-J亚群抗体未检出,REV为75%,CIAV为100%。NDV免疫后平均抗体水平6 Log2;AIV H5抗体水平达到9.75 Log2;IBV阳性率100%,但在试验过程出现一次隐性感染。对上述7种疫病抗体阳性率或抗体水平进行相关性分析,未能找到明显的相关性规律。 相似文献
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胡满怀 《养殖与饲料．饲料世界》2010,(9):15-16
新城疫抗体监测工作是养鸡场经常测定鸡群抗体水平、掌握鸡群动态、决定免疫时机的重要手段.但往往因为操作者不能正确熟练地掌握这一技术或试验条件不具备,而影响检测结果,从而错失免疫良机,造成新城疫的流行,使鸡场遭受严重损失. 相似文献
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非典型鸡新城疫的病因研究初报（一） 总被引：7，自引：1，他引：6
应用血清学、生物学方法、从我省产蛋量下降、HI抗体在1：128以上的疑似非典型鸡新城疫（CND）病鸡群中分离到1株病毒，经鉴定和致病力测定，明确是1株ND强毒，毒力与F48E9相近，然后采用该株野毒感染不同抗体水平的3批蛋鸡及肉鸡，结果3批蛋鸡均是低抗体滴度组（1：10－1：40）发生了CND症状，感染后6－7天开始产蛋停止，经15－17天后才恢复产蛋，高抗体滴定组（1：80以上）无明显变化，无抗体对照组出现典型鸡新城疫变化，全部死亡；病毒感染后第6、10天监测HI抗体，结果低滴度组第6天达1：80－1：160，第10天达1：160－1：1280。试验结果表明，我们分离到的NDV，既可引起典型的ND，也可引起非典型的ND；高HI抗体蛋鸡产生非典型鸡新城疫的病因之一，是由于存在低抗体鸡群而发生了CND，其高HI抗体有竞争是由于强毒感染后产生的抗体。 相似文献
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A survey of Newcastle disease in Swiss laying-hen flocks using serological testing and simulation modelling 总被引：1，自引：0，他引：1
Newcastle disease (ND) is a highly contagious viral disease of birds particularly domestic poultry. Switzerland is currently declared free from ND; since vaccination is prohibited, the detection of antibodies against ND virus (NDV) results in the destruction of the respective flock (stamping-out policy). However, in 1995 and 1996, antibody-positive flocks were detected and sporadic ND outbreaks even occurred in Switzerland. Therefore, a serosurvey was done to look for evidence of NDV infections in Swiss laying-hen flocks. The survey was designed to provide 95% confidence of detecting at least one seropositive flock if the flock prevalence were 1%. Thirty blood samples from each of 260 commercial laying-hen flocks were collected during 1996 in a central poultry slaughterhouse. Sera were screened for NDV antibodies with a commercial blocking enzyme-linked immunosorbent assay (ELISA). Samples with a questionable or positive test result were retested with the same ELISA. A stochastic computer model was applied to define a cut-off number of test-positive samples to help to differentiate between true- and false-positive flocks and to estimate the true flock prevalence of infection. Four flocks were identified as NDV-seropositive and the NDV true seroprevalence among commercial laying-hen flocks in Switzerland was most likely between 1.35 and 1.55%. This indicates that Swiss laying-hen and parental flocks with more than 150 animals have been in contact with strains of NDV that cause subclinical infection in chicken, because no clinical symptoms have been observed. In this context, computer simulation was a useful technique to interpret survey results. 相似文献
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Newcastle disease (ND) is a highly contagious viral disease particularly of domestic poultry. Switzerland is currently declared free from ND. A serosurvey using an ELISA was performed to investigate infections with ND-Virus (NDV) in 260 Swiss laying hen flocks, 169 backyard poultry flocks and 1576 wild birds. For laying hen flocks, a stochastic model was applied to analyse the results from serological testing. Four laying hen flocks were identified as NDV-seropositive, and the true NDV seroprevalence in this population was most likely between 1.3 and 1.5%. NDV antibodies were also detected in five of the 169 backyard poultry-flocks. ND-antibody positive birds were found in 10% of all wild birds examined, with the highest proportions among cormorants, grebes, birds of prey, owls, and swifts. The study indicated that positive flocks must have been in contact with NDV strains causing sub-clinical infection, since no clinical signs had been observed. Moreover, trade of poultry or poultry eggs was considered to be an important factor associated with seropositivity in backyard poultry flocks. Contact to wild birds did not seem to be of major importance. 相似文献
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Otim Onapa M Christensen H Mukiibi GM Bisgaard M 《Tropical animal health and production》2006,38(4):285-289
The role of ducks in the transmission of Newcastle disease virus (NDV) to free-range village chicken was investigated experimentally.
Newcastle disease (ND) seronegative ducklings reared in a pen were infected oronasally with velogenic NDV of intracerebral
pathogenicity index (ICPI) 1.8 isolated from outbreaks in village chickens in Uganda. A first group of 3-week-old ND seronegative
chicks was mixed with the ducks and they were kept together for 7 days. Both ducks and chicks were observed for ND clinical
signs and any mortality, and they were bled and their sera were tested for ND antibodies by haemagglutination inhibition (HI)
test. The chicks were removed, euthanized and examined for any ND lesions, while the ducks were transferred to a fresh pen
and a second group of chicks was introduced and observed and treated as above. The ducks and the chicks tested positive for
ND antibodies 7 days post infection and contact, respectively, but showed no clinical signs, post-mortem lesions or mortality.
The mean ND antibody titre of the second group of chicks was lower than for the first group. This study has shown that although
ducks can be infected with velogenic NDV, they do not show clinical signs but are able to transmit NDV to in-contact chicks.
Further investigations are needed of the lack of clinical signs in the in-contact chicks and how long the ducks remain infective. 相似文献
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Munir K Muneer MA Tiwari A Chaudhry RM Muruganandan S 《Veterinary research communications》2007,31(7):909-929
Immunization against Angara disease virus (ADV), a serotype 4 avian adenovirus, and Newcastle disease virus (NDV), an avian
paramyxovirus serotype 1, is the mainstay of a broiler vaccination programme, while polyether ionophores usually form an essential
component of a broiler medication programme in most parts of India and Pakistan. The role of polyether ionophores in the protective
immune responses of broiler chickens vaccinated and challenged with ADV and NDV was investigated. A total of 1600 birds were
divided into eight groups of 200 birds each. First four groups were vaccinated against NDV and ADV, while the remaining four
served as unvaccinated controls. The first 3 groups of birds were administered salinomycin, monensin and cyclophosphamide
(CYP), respectively. The last group served as an untreated control. The same treatment schedule was also followed for the
next four unvaccinated groups. The post-vaccination and post-challenge serological responses to NDV and ADV, body and lymphoid
organ weight gains, post-challenge survival rate and detection of NDV and ADV in the tissues of infected birds were evaluated.
Birds administered salinomycin showed a significant stimulation of protective immune responses against both NDV and ADV as
compared to the untreated and CYP-treated birds. Monensin also enhanced the protective immune responses against both viruses
but the effect was not statistically significant. Thus, it is concluded that monensin and salinomycin augment the anti-NDV
and anti-ADV immune responses in broiler chickens, which supports their use in poultry flocks. 相似文献
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为了解江西省宜春地区鸡新城疫（ND）流行情况,在2016年3月—2017年3月对宜春地区樟树、丰城、高安、宜春、万载5个重点养鸡县（市）的31个鸡场的疑似患有ND的鸡群进行现场问询、跟踪调查。结果发现,鸡新城疫在宜春地区一年四季均有流行,其中冬季发生该病的频率相对高些,其次为春季,夏、秋季发生该病的频率相对低些;发病鸡只的日龄无差异性,各阶段的鸡只均可发生;整体发病率为20.1%-30.8%,死亡率为9.0%-25.4%,产蛋下降率为15.3%-38.8%。同时,利用SPF鸡胚对来自宜春地区5个县（市）的31个鸡场的214份病料进行新城疫病毒（NDV）分离,共分离到27株具有血凝性的病毒,经过血凝试验（HA）、血凝抑制试验（HI）及血清中和试验,最终确定23株为NDV。其中,除了2株毒力不能确定之外,其余21株均为NDV强毒株。将21株病毒用30日龄非免疫鸡进行攻毒试验,发病率为80%~100%,死亡率为60%~100%,发病鸡只均出现鸡新城疫感染的典型症状及病变。 相似文献
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应用电镜技术、血清学检查、生物学试验等方法,从未注射过疫苗的某自然发病鸡群分离出一株新城疫病毒。该分离株对１０日龄鸡胚的平均致死时间为１１６小时,静脉接种致病指数为０．０６,其毒力介于新城疫病毒的ＬａＳｏｔａ株与Ｖ４株之间。免疫原性试验结果表明,该分离株具有免疫后无不良反应、免疫后６天开始产生抗体、产生的抗体效价高、对新城疫强毒的攻击能１００％保护等特点,是一株良好的新城疫候选疫苗株 相似文献
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鸽新城疫病毒的分离及鸽群自然感染状况的调查 总被引：20，自引：3，他引：17
将在北京某信鸽群采集的两只具神经症状的病鸽脑组织悬液接种ＳＰＦ鸡胚后，分离出二株病毒分离物ＰＢ９６０１和ＰＢ９６０２，通过对鸡红血球的血球凝集试验，用已知鸡新城疫病毒（ＮＤＶ）高免血清任务在球凝集抑制试验（ＨＩ）及２～３月龄鸽的攻毒试验，证明这两个毒株为对鸽呈高致病性的ＮＤＶ。交叉ＨＩ试验表明，鸽ＮＤＶ分离株与鸡ＬａＳｏｔａ株间有很高的血清交叉反应，但也存在着一定抗原性差异。对扬州地区若鸽群中２－ 相似文献
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鸡新城疫病毒强毒株的分离鉴定及生物学特性研究 总被引：2，自引：0，他引：2
从黑龙江省某地发病鸡群中分离出一株病毒APMV1/chicken/China/HLJ-2/02,分离毒为速发型NDV强毒株,对经典NDV La Sota株免疫的雏鸡及高抗体母鸡仍有很强的致病力.本研究对分离株进行了生物学特性研究,并对部分基因进行了序列测定,序列已经发送Gene Bank,序列号为AY208695.采用NDV分离毒株制备成多价油乳剂灭活苗,免疫鸡群有良好的保护力. 相似文献
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Prevalence studies have shown that almost 100% of free-range chickens are infected with a wide range of parasites. The infections are mostly subclinical in nature, resulting in production losses and occasionally mortality. Newcastle disease (ND), on the other hand, results in high mortality rates during epidemics. ND is a limiting factor for increasing poultry production in many tropical countries, where frequent reports indicate vaccination failures. The aim of our study was to investigate the influence of helminths on the antibody response after vaccination against Newcastle disease of free-range chickens naturally infected with parasites. Sixty chickens were divided into six groups, of which three were vaccinated against ND with a live De Soto vaccine, while the other three remained non-vaccinated. One group within the vaccinated groups and the one within the non-vaccinated group was kept naturally infected with helminth parasites, while the other two groups in each set were dewormed with fenbendazole and niclosamide, and one of each of these groups was subsequently infected with Ascaridia galli. After vaccination, all the groups were followed for 5 weeks and their antibody titres were determined weekly using a HI test. All the birds were finally challenged 4 weeks after vaccination with a virulent velogenic ND virus obtained from a field outbreak. All the vaccinated chickens seroconverted and had high antibody levels after 3 weeks, but these dropped to low levels at 4 weeks after vaccination. After challenge, the antibody titres rose in the dewormed groups but not in the parasite-infected groups. After 5 weeks, all the parasite-infected animals had significantly lower antibody titres than the dewormed animals. All the vaccinated chickens survived the challenge infection, emphasizing the importance of the cellular immune response. Further studies are needed to examine the effects of the parasitic infection on protection against ND over a longer period. 相似文献