鸡减蛋综合症油佐剂灭活苗对开产蛋鸡的免疫效果和接种对产蛋率的影响

鸡减蛋综合症油佐剂灭活苗对开产蛋鸡的免疫效果和接种对产蛋率的影响王茂法，符正根，陈春生（黄岩市畜禽防检站）试验采用鸡减蛋综合症（ＥＤＳ—７６）油佐剂灭活苗，对饲养在离病鸡群３００ｍ左右处的同品种、同日龄、同一类饲养管理方式的２４０日龄罗蔓鸡进行预防接...     

新城疫-传染性支气管炎-减蛋综合征三联油乳剂苗免疫对比试验

用血凝抑制试验（ＨＩ）监测自制ＮＤＲＩＢＥＤＳ、ＮＤＫＩＢＥＤＳ三联油乳剂灭活苗免疫鸡的抗体水平,并进行相应强毒攻击,同时以ＮＤＥＤＳ二联、ＲＩＢ、ＫＩＢ等自制油苗和进口ＮＤＲＩＢＥＤＳ三联油苗作对照。在此基础上,用自制三联苗免疫产前鸡４批共３８５２只,进行了田间免疫试验。结果表明：１用各种疫苗免疫后,第２０天鸡体ＨＩ抗体达峰值,维持３个月左右,至免疫后３６０天,ＮＤ抗体仍维持在８０ｌｏｇ２以上,ＲＩＢ、ＫＩＢ和ＥＤＳ的ＨＩ抗体均在７０ｌｏｇ２以上。经检验不同疫苗免疫的鸡相应抗体在同时期内均无显著差异（Ｐ＞００５）。２攻毒试验也表明,自制苗和进口苗具有同等的免疫效果,均获良好的免疫保护。３田间免疫试验表明,自制三联苗免疫效果良好。     

鸡产蛋减少综合症(EDS-76)油乳剂灭活苗免疫效力试验

用四批鸭胚尿囊液?羊水混合制备的鸡产蛋减少综合症油乳剂灭活疫苗,分别免疫35日龄非免疫鸡,每羽鸡肌肉注射0.5 mL,不定期采血,连续检测HI抗体的动态变化.这四批疫苗免疫后,10d均可产生坚强的免疫力(HI效价为7.5log2),到第30天血清中HI效价达到高峰(10.7log2),直到第180天,其HI效价仍为8.3log2?免疫后30 d用强毒攻击,观察15d,免疫组未见异常表现?而对照鸡于攻毒后第10天,产蛋下降,出现软壳蛋,说明四批疫苗对eds-76均有良好的保护性.     

鸡新城疫油乳剂灭活苗与弱毒苗免疫效果比较

控制非典型鸡新城疫，用油乳剂灭活苗免疫是切实可行的手段。油乳剂灭活苗免疫后，抗原在体内长时间缓慢释放，可产生坚强而持久的免疫力，即在血清学上可产生高水平且比较均匀的抗体，在临床上，免疫鸡新城疫强毒感染后不患病，产蛋也不下降。较之弱毒疫苗免疫可大大减少免疫次数，减少因非典型鸡新城疫造成的死亡，提高生产性能。为了验证鸡新城疫油乳剂灭活苗的兔疫效果．我们自1993年8月份至1994年12月份，分别在十二个大型养鸡场进行了鸡新城疫弱毒苗免疫和油乳剂死活苗免疫效果对比试验。鸡新城四弱毒苗免疫程序是：1蛋鸡7－14日龄鸡…     

Isolation and identification of adenovirus 127, the causative agent of egg drop syndrome (EDS), from commercial laying hens in South Africa.

A drop in egg production associated with loss of pigment and soft-shelled eggs was experienced on a farm in the Western Cape. Investigations revealed high levels of antibodies against adenovirus 127, the causative agent of egg drop syndrome (EDS) in chickens which were not vaccinated against EDS. A cytopathic agent was subsequently isolated in chicken embryo liver cell cultures and identified as EDS virus by haemagglutination inhibition and neutralization tests.     

Egg transmission of egg drop syndrome 1976 virus in fowl

Summary

Egg transmission of egg drop syndrome 1976 virus (BC14 virus) in fowl was demonstrated in the second and third week after experimental infection. Eggs of BC14 virus infected hens were incubated weekly after disinfection with formaline gas. After 18 days of incubation, eggs with live embryos were homogenized. This egg material was fed to adult hens, housed in isolators.

Seroconversion in these birds demonstrated egg transmission.

It is suggested that egg transmission occurs as a result of viremia.     

Egg transmission of egg drop syndrome 1976 virus in fowl

Summary Egg transmission of egg drop syndrome 1976 virus (BC14 virus) in fowl was demonstrated in the second and third week after experimental infection. Eggs of BC14 virus infected hens were incubated weekly after disinfection with formaline gas. After 18 days of incubation, eggs with live embryos were homogenized. This egg material was fed to adult hens, housed in isolators. Seroconversion in these birds demonstrated egg transmission. It is suggested that egg transmission occurs as a result of viremia.     

Detection of antibodies to egg drop syndrome virus in chicken serum using a field-based immunofiltration (flow-through) test

A simple, user-friendly, and rapid method to detect the presence of antibodies to egg drop syndrome 76 (EDS) virus in chicken sera based on an immunofiltration (flow-through) test was developed. Purified EDS virus antigen was coated onto nitrocellulose membranes housed in a plastic module with layers of absorbent filter pads underneath. Following addition of serum to be tested and washing, monoclonal antibodies or polyclonal serum to chicken immunoglobulin G (IgG) was used as a bridge antibody to mediate binding between EDS virus-specific IgG and protein A gold conjugate. The appearance of a pink dot indicated the presence of antibodies to EDS virus in the sample tested. The results could be obtained within 5-10 min. The developed immunofiltration test could detect antibodies in the sera of experimentally vaccinated chickens from 2 wk postvaccination. With field sera samples, this test was positive in samples having hemagglutination inhibition titers of 8 and above. This test has the potential to be used as a field-based kit to assess seroconversion in EDS-vaccinated flocks.     

Serological examination and egg production of progeny of fowl experimentally infected with egg drop syndrome 1976 virus

Following EDS'76 virus (BC14 virus) infection of breeder chickens by the conjunctival route, vertical transmission occurred in the first week after infection. In the progeny which had been infected with EDS'76 virus by the vertical route, increasing haemagglutination inhibiting (HI) titres to BC14 virus and increasing numbers of birds with HI titres were observed from 3 weeks to 15 weeks of age. Sixty-one per cent of the hens and 77 per cent of the cocks had 2 log HI BC14 virus titres exceeding 4 at an age of 15 weeks. Some birds which han been serologically negative throughout the rearing period, seroconverted between 25 and 28 weeks of age. This phenomenon occurred in hens as well as in cocks. Simulation of stress twice during the laying period by injection of corticosteroid hormone did not increase the number of birds serologically positive to EDS'76 virus. EDS'76 was observed in the group of hens that was vertically infected, since egg production was significantly depressed between 28 and 34 weeks of age. Probably this was mainly the results of a production drop in the hens showing serconversion at 27 or 28 weeks of age. In this group of fowl vertically infected with EDs'76 virus, serologically positive birds appeared to be protected for the greater part to BC14 virus challenge at 50 weeks of age, while negative birds seemed to be fully susceptible. Chicks hatched from eggs collected in the third and fourth week after infection of the dams had maternal antibodies. Fertility and hatchability of apparently normally shelled eggs seemed not to be affected after BC14 virus infection of the dams. Intensive contact with contaminated faeces is probably an indispensable condition for lateral transmission of the virus.