鸡禽流感的流行特点与防治

鸡禽流感又名禽流行性感冒或真性鸡瘟,是由禽流感病毒引起的一种人畜共患病,通常感染后,病禽的消化系统、神经系统、呼吸道系统会受到严重的影响。禽流感不仅给畜禽业带来了严重的经济损失,也会严重威胁人类的健康安全,需要引起养殖户和相关部门的高度重视。1禽流感的传播途径禽流感的感染途径有很多种,比如可以通过眼结膜、破损的皮肤、呼吸道和消化道等途径。比如飞沫传播,也可通过接触病禽或者其分泌物和排泄物,也可以是病禽接触过的饲料,垫草等。此病对任何日龄的禽类都易感,而且不分季节。一些昼夜温差变化幅度大,季节更换气温不稳定等恶劣天气可使此病的发生率升高。     

鸡禽流感鉴别诊断及防治措施

受到养殖管理气候条件以及环境污染等多方面因素的影响,禽流感等重大传染性疾病的发生流行率逐年上升,成为威胁家禽养殖产业常见病和高发病,一旦爆发流行,需要执行严格的扑杀无害化处理制度,防范病情的传播蔓延。由于禽流感具有较强的变异能力,具有多种血清型,不同血清型还包括多种亚型,各种血清型的相互叠加会表现出新的流行特征,使疾病的诊断和防控工作逐渐加大。该文在对青海省海东市乐都区鸡禽流感防控现状探讨的基础上,进一步明确禽流感的鉴别诊断方法,并提出防治方法。     

鸡低致病性禽流感防治研究

禽流感是家畜最常见的传染性病毒,主要是由于A型禽流感病毒引发的,它的重要侵害对象是禽类,禽流感按其性质可以分为高致病性禽流感、低致病性禽流感和无致病性禽流感,日常生活中最常见的禽流感是低致病性禽流感.为更好研究出防治低致病性禽流感措施,本文简单说明了和分析了低致病性禽流感的含义和它的流行特点.     

武汉地区鸡禽流感的特点和防治对策

鸡禽流感的病因为禽流感病毒(AvianInfluenza Virus,简称AIV)。该病毒属正粘病毒科流感病毒属。英国学者Wilson最早发现,并于1959年分离出禽流感病毒,报道鸡发生了流感。根据历史记载和依据国际兽疫局(OIE)规定的标准,在我国进行的有关检测和检验的结果表明,我国到目前为止,官     

鸡新城疫与鸡禽流感的鉴别诊断及防治

鸡新城疫、鸡禽流感都是由病毒引起的具有高度传染性的疾病,一年四季均可发病,且都以冬春两季多发,现就其鉴别诊断介绍如下。 一、易感动物 1.鸡新城疫:是由副粘病毒引起,易感动物是鸡,死亡率高于鸡禽流感。 2.鸡禽流感:由A型流感病毒引起,具有快速流行、持续时间长等特点,对禽类都有一定的互感性,鸡、鸭、鹅等禽类均易感染。     

高致病性鸡禽流感的卫生检疫防治策略

禽流感指的是禽类流行性感冒。禽流感的流行具有毁灭性,会造成严重的经济损失和人员伤害。为了进一步提高防控效果,本文介绍了高致病性鸡禽流感的症状表现,分析了病毒感染的流行特点,详细提出了卫生检疫防治策略。     

禽流感防治任重道远

其实,我们不能忘记,1918年来源于禽类的西班牙大流感,致使5000万—1亿人死亡; 其实,我们不该忘记,1957年禽流感与人流感病毒结合的亚洲型流感,致使100多万人死亡;     

鸡禽流感流行特点与防治措施

禽流感对养禽业有较大的危害,其感染范围广泛,能够感染大部分的水禽、野禽和家禽,而禽类在感染禽流感后发病率极高,且极易死亡,给养禽业带来了巨大的经济损失,因此需针对此深入研究和积极预防.本文对鸡禽流感的症状、流行特点、诊治进行分析,并提出防治对策.     

复方黄芪多糖防治禽流感临床试验

为检验复方黄芪多糖对禽流感的治疗效果 ,选用暴发禽流感 H9亚型的某鸡场 3栋鸡舍内 2 8周龄产蛋鸡 9179只为试验动物模型 ,各栋鸡完全分为试验组、对照组 ,各对照组用16 0 mg/ L的金刚烷胺饮水 ,试验组用复方黄芪多糖饮水 ,试验甲组剂量为 2 0 0 mg/ L,试验乙、丙组剂量为 16 0 mg/ L ,试验 14 d。结果表明 :各试验组与相应的对照组比较 ,在发病率上甲栋表现相同 ,乙栋表现显著性差异 (P<0 .0 5 ) ,丙栋表现极显著性差异 (P <0 .0 1) ;在死亡率上甲、乙两栋表现差异不显著 (P >0 .0 5 ) ,丙栋表现差异极显著 (P <0 .0 1) ;在产蛋率下降幅度上甲、乙、丙 3栋表现差异均极显著 (P <0 .0 1) ;在畸形 (软壳蛋等 )蛋率上甲、乙、丙 3栋表现差异均显著 (P <0 .0 5 )。复方黄芪多糖具有抗禽流感病毒作用 ,对产蛋率、蛋壳质量的恢复效果明显     

防治禽流感小常识

1病禽禽舍污染物及环境如何消毒流感病毒可随感染发病禽的粪便和鼻腔分泌物排出而污染禽舍、笼具、垫料等,但某些消毒剂可以将存活于禽舍的流感病毒杀死。对污染的禽舍进行消毒时,必须先用去污剂清洗以除去污物,再用次氯酸钠溶液消毒,最后用福尔马林和高锰酸钾熏蒸消毒。铁制笼具也可采用火焰消毒。由于粪便中含病毒量很高,因此在处理时要特别注意。粪便和垫料应通过掩埋方法来进行处理,对处理粪便和垫料所使用的工具要用火碱水或其它消毒剂浸泡消毒。2潜伏期最长21天高致病性禽流感的潜伏期从数小时到数天,最长时间可达21天。禽流感的传播…     

AIV感染雏鸡免疫器官淋巴细胞增殖功能变化

应用细胞培养技术及MTT法,对感染鹅源H5N1型AIV雏鸡胸腺和脾脏T细胞,法氏囊和脾脏B细胞增殖功能进行检测,结果发现,AIV感染雏鸡免疫器官T、B细胞增殖功能在感染初期比对照雏鸡明显降低,后期有所恢复,表明感染AIV后,雏鸡全身免疫功能受抑制。7日龄和21日龄AIV感染雏鸡均发病,但21日龄感染雏鸡免疫器官T、B细胞增殖功能下降时间比7日龄感染雏鸡短,而且相对滞后,死亡率也较低,表明21日龄雏鸡对AIV感染具有一定的抵抗力。     

Vaccination of cyclophosphamide-treated chickens against Newcastle disease virus infection

Newly-hatched chickens were treated with 3 mg of cyclophosphamide (CY) per day for 4 consecutive days. At 2 weeks of age, these chickens, together with a group of untreated controls, were vaccinated intranasally or subcutaneously with the La Sota strain of Newcastle disease virus (NDV). All chickens were challenged intranasally with the GB strain of NDV 2 weeks later. CY-treated, intranasally vaccinated chickens were highly resistant to NDV challenge, yet none of the chickens produced any detectable humoral antibodies to NDV; antibodies to NDV were detectable in the tracheal washings, however.     

鸡轮状病毒灭活油乳疫苗的制备与应用研究

利用从发生流行性腹泻的发病鸡中分离的轮状病毒,研制了鸡轮状病毒灭活油乳疫苗,并对该疫苗的安全性及免疫效果进行了测定.结果表明该疫苗安全可靠,注射后对增重、产蛋均无影响.免疫后14 d攻毒保护率可达98%以上,免疫期可维持6个月,4℃保存12个月,10℃～25℃保存3个月,免疫效果不变.对鸡轮状病毒油乳灭活疫苗在山东不同地区进行田间试验和扩大区域试验,结果表明该疫苗性能良好、安全,对蛋鸡、肉鸡、雏鸡的生产性能无明显影响,疫苗接种后保护率可达92%以上,可有效地控制该病的发生.     

Effects of a herbal complex against Eimeria tenella infection in chickens

A liquid and a powder made from a herbal complex consisting of Uncariae Ramulus cum Uncis, Agrimoniae Herba, Sanguisorbae Radix, Eclipta Prostrate Herba, Pulsatillae Radix, Sophorae Flavescentis Radix, Rehmanniae Radix and Glycyrrhizae Radix were studied for their anticoccidial activities in chickens. Chickens were administered with herbal liquid, powder, diclazuril or without medication during the study and challenged with oocysts of Eimeria tenella. Results indicated that the birds medicated showed less bloody faeces than those without medication. The intestinal lesion was mild in the chicks medicated with herbal liquid without significantly different lesion score when compared with uninfected chicks. The birds with medication had significantly higher body weight gains than birds without medication. Therefore, the herbal complex used in this study was effective against E. tenella infection in chickens.     

Anthelmintic activity of ivermectin against experimental Ascaridia galli infection in chickens

The efficacy of ivermectin against Ascaridia galli infection was evaluated in chickens under controlled laboratory conditions in two separate experiments. In each experiment 22 White Leghorn chicks were randomly assigned to three groups of 10 (infected-treated), 9 (infected-control) and 3 (uninfected-control) birds. Each bird in the former two groups was orally infected with 1,500 embryonated A. galli eggs. The chicks in the treated group were subcutaneously injected with ivermectin at a dose of 0.3 mg kg-1 body weight on Day 10 (Experiment 1) and Day 35 post-infection (Experiment 2) for immature and adult infections, respectively. The treated birds had 0.9% (Experiment 1) and 0.4% (Experiment 2) worm recovery compared with 8.7 and 8% in the infected-untreated controls of the respective experiments. The fall in post-treatment faecal egg counts was 81 and 92% in birds treated on Days 10 and 35, respectively. The drug was found to be 90 and 95% effective against immature and adult worms, respectively. The lower lesion score and post-treatment near-normal haematobiochemical picture in treated birds confirmed these observations. The treated birds also had a better growth rate than the untreated chickens. The mature worms in the intestinal lumen of the host were more sensitive to the treatment than the immature stages of the parasite in the tissue phase.     

Immune response to avian reovirus in chickens and protection against experimental infection

Objectives To assess the efficacy of the vaccination procedure and the effect of the transfer of maternal antibodies to progeny chickens on reovirus pathogenicity.
Design To vaccinate chickens and challenge progeny chickens with high doses of homologous and heterologous viruses.
Procedure High doses of reovirus strains RAM-1, 1091 and 724 were used to induce tenosynovitis lesions. High doses were produced by concentration of viruses grown in cell culture. Then similar doses of viruses were used to challenge immunised chickens progeny.
Result Vaccination of breeding hens with the RAM-1 strain of avian reovirus, which resulted in the passive transfer of neutralising antibody to progeny chickens, completely prevented the development of tenosynovitis in 80% of progeny chickens infected with the homologous virus. Even though multiple injection of hens resulted in broadening of the normal type-specificity of the neutralising antibody response against heterologous serotypes of avian reovirus, only marginal protection against strains of two heterologous serotypes of avian reovirus was obtained.
Conclusions A model for assessing the efficacy of vaccination against avian reovirus strains on clinical signs such as tenosynovitis was developed that overcome the normal low virulence of Australian strains of avian reovirus. Breeding hens can be immunised with Australian strain of avian reovirus with passive transfer of antibody via the yolk to the progeny chickens. Although the neutralising antibody response to three injections of inactivated virus decreased the specificity of the neutralising antibody response against antigenically heterologous strains of avian reovirus, the protective immunity appeared to retain type-specificity.     

The NS segment of H5N1 avian influenza viruses (AIV) enhances the virulence of an H7N1 AIV in chickens

Some outbreaks involving highly pathogenic avian influenza viruses (HPAIV) of subtypes H5 and H7 were caused by avian-to-human transmissions. In nature, different influenza A viruses can reassort leading to new viruses with new characteristics. We decided to investigate the impact that the NS-segment of H5 HPAIV would have on viral pathogenicity of a classical avian H7 HPAIV in poultry, a natural host. We focussed this study based on our previous work that demonstrated that single reassortment of the NS-segment from an H5 HPAIV into an H7 HPAIV changes the ability of the virus to replicate in mammalian hosts. Our present data show that two different H7-viruses containing an NS-segment from H5–types (FPV NS GD or FPV NS VN) show an overall highly pathogenic phenotype compared with the wild type H7–virus (FPV), as characterized by higher viral shedding and earlier manifestation of clinical signs. Correlating with the latter, higher amounts of IFN-β mRNA were detected in the blood of NS-reassortant infected birds, 48 h post-infection (pi). Although lymphopenia was detected in chickens from all AIV-infected groups, also 48 h pi those animals challenged with NS-reassortant viruses showed an increase of peripheral monocyte/macrophage-like cells expressing high levels of IL-1β, as determined by flow cytometry. Taken together, these findings highlight the importance of the NS-segment in viral pathogenicity which is directly involved in triggering antiviral and pro-inflammatory cytokines found during HPAIV pathogenesis in chickens.     

麻鸡混合感染的诊治

2001年5月,山西运城市某麻鸡种鸡场3万只200日龄、1万只170日龄麻鸡发生以呼吸症状为主,眶下窦肿胀,伴神经症状,拉黄色稀粪,病理解剖以气管喉头出血性炎症伴干酪样分泌物,纤维性心包炎,肝周炎,气囊炎,消化道出血及卵黄性腹膜炎等为主要特征的疾病.