肉鸡病毒性关节炎的诊断与防制

1病原 肉鸡病毒性关节炎是由呼肠孤病毒引起的传染病。病原为禽呼肠孤病毒,病毒可接种于鸡胚进行培养,病变的腱鞘经常规处理后经卵黄囊接种于5-7日龄的鸡胚,经5-6天后鸡胚死亡,胚体充血和出血,绒毛尿囊膜混浊,脾脏肿大,心肌有坏死灶。绒毛尿囊膜接种病毒时在其绒毛尿囊膜上形成大小不等隆起的疱斑。1日龄肉用雏鸡足垫内接种,第二天即可引起局部红肿等典型的病毒性关节炎。     

禽脑脊髓炎病毒HMM08株的分离鉴定及生物学特性研究

为明确禽脑脊髓炎(AE)病毒自分离流行毒株的生物学特性,以用于禽脑脊髓炎灭活疫苗的研制,以发病雏鸡脑组织为材料,进行SPF鸡回归试验、PCR检测、SPF鸡胚分离培养有限稀释纯化、特异性试验等,得到一株禽脑脊髓炎病毒,命名为HM08株,对该分离毒株的生物学特性进行研究的结果表明:该毒株纯净、无外源病毒污染,E1代病毒含量达到10~(5.56)EID_(50)/0.2 mL,E2代至E15代病毒含量稳定在10~(7.0)EID_(50)/0.2 mL以上;100倍稀释的E1代毒种,经卵黄囊途径接种6日胚龄SPF鸡胚,12 d内,引起AE特征性病变的病变率达100%;用E1代毒按照500 EID50/只对1日龄、7周龄的SPF鸡脑内接种,出现AE特征性病变的病变率达100%;以该毒制成的疫苗0.3 mL/羽份免疫鸡,能获得100%保护。表明HM08株是一株较好的AE疫苗候选毒株。     

鸡法氏囊病卵黄抗体对雏鸡首次免疫效果的影响

对鸡囊病卵黄抗体与雏鸡首次免疫效果的关系进行了研究。结果表明,种蛋中卵黄抗体水平无论高低,其孵化出的雏鸡首次接种弱毒疫苗后免疫效果均不佳,既测不到琼扩抗体,也低不住强毒攻击;若接种2次弱毒疫苗,则有半数以上的鸡出现可测性抗体,尽管抗体的琼扩效价较低,但有70％以上的鸡可抵抗强毒攻击;只接种弱毒疫苗的雏鸡,其卵黄抗体水平与免疫效果呈负相关。首次免疫若采用灭活油乳剂苗和弱毒苗同时接种:则免疫后既可测到琼扩抗体,又可抵抗强毒攻击,且琼扩抗体水平与保护效果呈正相关。     

鸡法氏囊病卵黄抗体对雏鸡首次免疫效果的影响

对鸡囊病卵黄抗体与雏鸡首次免疫效果的关系进行了研究。结果表明，种蛋中黄抗体水平无论高低，其孵化出的雏鸡首次接种弱毒疫苗后免疫效果均不佳，既测不到琼扩扩体，也抵不住强毒攻击，若接种２次弱毒疫苗，则有半数以上的鸡出现可测性抗体。尽管抗体的琼扩效价较低，但有７０％以上的鸡可抵抗强毒攻击；只接种弱毒疫苗的雏鸡，其卵黄抗体水平与免疫效果呈负相关。首次免疫若采用灭活油乳剂苗和弱毒苗同时接种；则免疫后既可测到琼     

新城疫、禽流感病毒同胚培养制备二联灭活疫苗工艺研究

基于新城疫病毒(NDV)LaSota株、禽流感病毒(AIV)SS株均可通过鸡胚接种增殖的特点,将2种病毒按一定比例稀释后混合接种鸡胚尿囊腔,一定条件下进行2种病毒的同胚培养。试验通过检测红细胞凝集试验(HA)、半数感染量(EID_(50))以及血清抗体效价检测等对培养产物进行评价。结果表明,2种病毒均可在鸡胚内增殖,最终选用10 000倍稀释的SS株与200倍稀释的LaSota株混合后,以0.1 mL/个接种于10日胚龄鸡胚,37℃培养96 h后收获。经半数致死量检测得LaSota株的EID_(50)为10~(7.5)/0.1 mL,SS株的EID_(50)为10~(7.63)/0.1 mL略低于单独接种的EID_(50)。结果表明,试验使用SS株与LaSota株按10 000:200稀释条件可以实现同胚培养,证明SS株对La Sota株的增殖具有干扰作用,但在一定条件下可以实现同胚培养。本研究为同胚接种制备二联疫苗提供科学依据。     

禽脑脊髓炎油乳剂灭活疫苗安全性检验及免疫保护性试验研究

该试验采用6日龄鸡胚、2日龄商品肉雏鸡和7日龄SPF雏鸡,分别进行了禽脑脊髓炎油乳剂灭活苗的鸡胚卵黄囊接种及雏鸡脑内和皮下接种试验,通过病理检验检测了疫苗的安全性,同时利用琼扩试验进行了疫苗的免疫效应性检测,利用攻毒试验进行了免疫保护性试验.结果表明,禽脑脊髓炎油乳剂灭活苗具有可靠的安全性和良好的免疫保护性,其琼扩效价可达1∶32.     

禽呼肠病毒琼扩抗原和血清的制备

以禽呼肠病毒S1133毒株尿囊腔接种10日龄无特定病原体(SPF)鸡胚,无菌收集24 h～120 h的死胚尿囊液,加1 mL/L的甲醛灭活,浓缩制得琼扩抗原;用该抗原制成灭活苗两次免疫SPF鸡,无菌采血分离制备阳性血清;选用SPF鸡无菌采血分离制备阴性血清.经过效价测定制备16单位琼扩抗原,8单位阳性血清;取免后的SPF鸡血样4个20～2-5稀释分别与1单位～8单位琼扩抗原做琼扩试验,确定了应该用4单位或8单位琼扩抗原做工作抗原;并以血清中和试验为参照证明琼扩试验在血清抗体监测中的可行性.本研究成功制备了禽呼肠病毒琼扩抗原与血清,为用琼扩试验定量检测禽呼肠病毒感染禽和疫苗免疫禽的抗体奠定了基础.     

与马立克氏病免疫失败有关的传染性法氏囊病病毒可增强鸡贫血因子的致病作用

SPF雏鸡腹腔接种0.1ml鸡贫血因子(CAA)82—2株或口服10~(3.5)EID_(50)传染性法氏囊病病毒(IBDV)GBF—1株,或在14、21或28日龄时间同时接种上述病毒。在第2个试验中,1日龄雏鸡皮下接种2200Pfu的火鸡疱疹病毒(HVT)H_2株;7日龄时,对接种的和未接种的雏鸡腹腔攻击2700Pfu的马立克氏病病     

禽脑脊髓炎油乳剂灭活疫苗安全性检验及免疫保护性试验研究

该试验采用6日龄鸡胚、2日龄商品肉雏鸡和7日龄SPF雏鸡，分别进行了禽脑脊髓炎油乳剂灭活苗的鸡胚卵黄囊接种及雏鸡脑内和皮下接种试验，通过病理检验检测了疫苗的安全性，同时利用琼扩试验进行了疫苗的免疫效应性检测，利用攻毒试验进行了免疫保护性试验。结果表明，禽脑脊髓炎油乳剂灭活苗具有可靠的安全性和良好的免疫保护性，其琼扩效价可达1：32。     

雏鸡禽传染性脑脊髓炎病毒的分离和鉴定

从两个具有典型症状的发病的肉雏鸡群采集病料，用５日龄鸡胚卵黄囊接种，分离到两株病毒（ＳＧＡＥ９４０１和ＳＧＡＥ９４０２），经中和试验，琼扩试验，雏鸡感染试验及鸡血清学保护试验，确诊所分离到的病毒为禽传当性脑脊髓炎病毒，从而首次从病原学角度证实了该病在四川省的存在。     

鸽新城疫野毒株的分离及生物学特性研究

对分离的Ｇ１、Ｇ２、Ｇ３３株鸽新城疫病毒进行了电镜检查、致病性指数测定、血凝试验（ＨＡ）,与鸡新城疫Ｌａｓｏｔａ毒株的交叉血凝抑制试验（ＨＩ）、致病性试验。测得鸡胚半数感染量（ＥＩＤ５０）分别为１０－８．４１,１０－７．５３,１０－７．８３;鸡胚最小致死量（ＬＤ）均为１０－４;鸡胚平均致死时间（ＭＤＴ）分别为８０ｈ,９０ｈ,９６ｈ;１日龄雏鸡脑内致病指数（ＩＣＰＩ）分别为１．６０,１．５０,１．５５;分离毒株与Ｌａｓｏｔａ毒株和其相应血清的交叉凝集抑制试验有明显差异。将分离毒株分别接种１月龄鸽各３只,４～１０ｄ全部出现典型神经症状,１５ｄ内死亡。结果表明所分离的３株病毒为鸽新城疫病毒,在抗原性上与鸡新城疫病毒存在一定差异,对鸡也有一定致病力。为制定防制措施,研制鸽新城疫疫苗,控制新城疫流行提供了科学依据。     

Re-evaluation of the pathogenicity of A/chicken/Alabama/75 (H4N8) influenza virus.

Avian influenza (AI) virus A/chicken/Alabama/7395/75 (H4N8), a putatively non-pathogenic virus associated with a self-limiting outbreak of severe disease in commercial layers, was selectively passed in chickens or in cell cultures and then in chickens to determine whether virus with increased pathogenicity would emerge. When 20 derivatives of the parental virus were each inoculated intranasally and intratracheally in leghorn hens, mortality rates ranged from zero (0/24) to 25% (6/24); mortality was 4% (1/24) for hens inoculated with the parental virus. Many virus reisolates (51/144) from hens that died exhibited high pathogenicity, killing at least six of eight intravenously inoculated 4-week-old chickens. Most derivatives examined produced plaques in trypsin-free cell cultures more efficiently than the parental virus, but the highest plaquing efficiencies observed (10%) were lower than would be expected (100%) for highly pathogenic subtype H5 or H7 AI viruses. These results confirm that the Alabama H4N8 virus can acquire increased pathogenicity upon passage in chickens and suggest that it may have acted alone in producing the severe disease observed in laying chickens in Alabama.     

Vaccination for fowl plague

Influenza A/turkey/Oregon/71 virus has antigenic characteristics of fowl plague virus but is avirulent for chickens. The virus was inoculated intratracheally in chickens at several dosage levels and resulted in the formation of antibody and immunity against fowl plague. The avirulent virus replicated in chickens and was recoverable by tracheal swab specimens up to 4 days after inoculation. Although the virus was transmitted to contact controls at the time when their cagemates were inoculated, it was not transmitted to contact controls placed with chickens inoculated 24 hours earlier. After 10 passages in chickens, the virus remained avirulent for chickens and turkeys.     

Response of white leghorn chickens of various genetic lines to infection with avian leukosis virus subgroup J

In Experiment 1, chickens from various white leghorn experimental lines were inoculated with strain ADOL-Hcl of subgroup J avian leukosis virus (ALV-J) either as embryos or at 1 day of age. At various ages, chickens were tested for ALV-J induced viremia, antibody, and packed cell volume (PCV). Also, at 4 and 10 wk of age, bursal tissues were examined for avian leukosis virus (ALV)-induced preneoplastic lesions with the methyl green-pyronine (MGP) stain. In Experiment 2, chickens harboring or lacking endogenous virus 21 (EV21) were inoculated with strain ADOL-Hcl of ALV-J at hatch. All embryo-inoculated chickens in Experiment 1 tested positive for ALV-J and lacked antibody throughout the experimental period of 30 wk and were considered viremic tolerant, regardless of line of chickens. By 10 wk of age, the incidence of ALV-J viremia in chickens inoculated with virus at hatch varied from 0 (line 0 chickens) to 97% (line 1515); no influence of ALV-J infection was noted on PCV. Results from microscopic examination of MGP-stained bursal tissues indicate that ALV-J can induce typical ALV-induced transformation in bursal follicles of white leghorn chickens. Lymphoid leukosis and hemangiomas were the most common ALV-J-induced tumors noted in chickens in Experiment 1. At termination of Experiment 2 (31 wk of age), 54% of chickens harboring EV21 were viremic tolerant compared with 5% of chickens lacking EV21 after inoculation with ALV-J at hatch. The data indicate that genetic differences among lines of white leghorn chickens, including the presence or absence of EV21, can influence response of chickens to infection with ALV-J.     

Increased virulence of modified-live infectious laryngotracheitis vaccine virus following bird-to-bird passage.

Modified-live (ML) infectious laryngotracheitis (ILT) vaccine viruses, both tissue-culture-origin (TCO) and chicken-embryo-origin (CEO), were passaged 20 times in specific-pathogen-free chickens. After serial bird-to-bird passage, increased virulence was observed for CEO virus but not TCO virus. Increased mortality and increased severity and duration of respiratory disease were observed in chickens inoculated with chicken-passaged CEO viruses; only mild respiratory disease (no mortality) occurred in chickens inoculated with chicken-passaged TCO viruses. These findings suggest that ML ILT vaccine viruses may increase in virulence after bird-to-bird passage.     

鸭源新城疫病毒的生物学特性

用鸡胚尿囊腔传代法从23个鸭泄殖腔拭子中分离到1株病毒，经血凝(HA)和血凝抑制(HI)试验鉴定为新城疫病毒。该毒株ELD50为5．85log10，鸡胚平均致死时间(MDT)为92．5h，1日龄鸡脑内致病指数(ICPI)为0．5，6周龄鸡静脉接种致病指数(IVPI)为0．3，属于中等偏弱毒力的毒株。该毒株不引起6周龄雏鸡发病。结果表明家鸭也能感染NDV。     

Persistent infection with chicken anaemia virus and some effects of highly virulent infectious bursal disease virus infection on its persistency

Chicken anaemia virus (CAV) infectivity and the effect of highly virulent infectious bursal disease virus (hv IBDV) infection on CAV's infectivity were examined in chickens inoculated with CAV or inoculated dually with CAV and hv IBDV. Five chickens inoculated dually with hv IBDV at 35 days old and then with CAV at 40 days old exhibited no clinical signs of disease, but showed atrophic bursae of Fabricius when necropsied 4 weeks later. Upon examining the chickens at 7 days postinoculation (dpi) with CAV, it was found that hv IBDV infection had inhibited production of virus neutralising (VN) antibody to CAV, and that it was possible to recover CAV from plasma of these chickens. Although VN antibody to CAV appeared after 14 dpi, CAV was recovered from blood cells (BC s) at high titres ranging from 10(2.5)to 10(5.5)TCID(50)/0.1 ml, 7 to 28 dpi in IBDV -induced immunosuppressed chickens. In addition, CAV was sporadically recovered, using rectal swabs, from the dually inoculated chickens at low titers, ranging from 10(1.0)to 10(2. 0)TCID(50)/0.1 ml). In contrast, although CAV was recovered from BC s in most of the chickens inoculated with CAV alone, the titers were lower (10(1.0)to 10(2.5)TCID(50)/0.1 ml). No CAV was detected from the rectal swabs of these chickens. The results of virus recovery were confirmed by polymerase chain reaction. This study first examined the persistency of CAV in BC s and the effective enhancement of primary CAV infection as a result of immunosuppression caused by hv IBDV infection.     

Immunosuppressive effect of a highly virulent infectious bursal disease virus isolated in Japan.

The immunosuppressive effect of infectious bursal disease virus (IBDV) on vaccination against Newcastle disease (ND) was compared among 2-, 3-, and 4-week-old chickens inoculated with the highly virulent IBDV field isolate 90-11 and the reference serotype 1 strain GBF-1. In all age groups, isolate 90-11 severely suppressed antibody response to ND vaccination and protective vaccinal immunity against ND. In contrast, chickens inoculated with strain GBF-1 and vaccinated with ND vaccine were well protected from the ND virus challenge. The mitogenic response to phytohemagglutinin of splenic lymphocytes from chickens inoculated with isolate 90-11 or strain GBF-1 was significantly lower than that of uninoculated controls. There was no difference between the two inoculated groups in responsiveness, although lymphocyte depletion in the thymus was more severe in chickens inoculated with isolate 90-11 than in chickens inoculated with strain GBF-1.     

实验性鸡大肠杆菌病病理学动态变化

用致病性大肠杆菌O18分离株和／或低致病性禽流感病毒（Mildly pathogenic avian influenza virus ,MPAIV)接种10－12日龄SPF鸡。在接种后1－96h进行临床症状与大体病理变化、组织学观察发现：大肠杆菌接种组、MPAIV接种组和健康接种组除扑杀鸡外未见鸡死亡，MPAIV与大肠杆菌混合接种组除扑杀鸡外死亡率为24％。混合接种组的病变比大肠杆菌接种组出现的时间早，恢复也慢，各脏器的病理变化更严重。MPAIV主要引起各实质器官的坏死，结果表明，大肠杆菌经气管内接种后试验鸡主要表现为呼吸道的炎症反应；MPAVI可使鸡大肠杆菌病严重化。     

THE ISOLATION AND CHARACTERISATION OF A NEWCASTLE DISEASE VIRUS FROM AN EXOTIC PARROT

SUMMARY A Newcastle disease virus was isolated from a salmon-crested cockatoo (Cacatua moluccensis) illegally introduced into Australia. Viral-characterisation and chickentransmission studies indicated that the isolate, G5320/1, was a lentogenic pathotype. It caused a severe respiratory disease in chickens exposed oronasally at 1-day old and in chickens housed at 1 day of age with chickens infected with Newcastle disease virus. No harmful effects were detected in 5-week old chickens inoculated intravenously or oranasally with the virus.