Beck J R, Swayne D E, Davison S, Casavant S, Gutierrez C
Southeast Poultry Research Laboratory, USDA-ARS, 934 College Station Road, Athens, GA 30605, USA.
Avian Dis. 2003;47(3 Suppl):1196-9. doi: 10.1637/0005-2086-47.s3.1196.
Determination of the avian influenza (AI) status of a flock has traditionally been done by detection of serum antibodies. However, for many diseases, detection of antibodies in egg yolk has been effective in monitoring the disease status of laying flocks. This study compared the utility of egg yolk vs. serum for determining AI status in laying hen flocks. Specific-pathogen-free white leghorn hens were inoculated via the respiratory tract with a low-pathogenic H7N2 AI virus or sterile allantoic fluid or subcutaneously with an inactivated oil emulsion vaccine produced from the same AI virus or normal allantoic fluid. Antibody levels were determined by the agar gel immunodiffusion (AGID) test, the hemagglutination-inhibition (HI) test, and the enzyme-linked immunosorbent assay (ELISA). Anti-influenza antibodies were detected in sera of all live virus-inoculated hens by day 7 postinoculation (PI) (AGID and ELISA tests), but detection of antibodies in egg yolk was delayed by a few days, with all being positive by day 14 PI. Sera from all vaccinated hens were positive by day 14 PI (AGID and ELISA tests), and egg yolk was positive by day 18 PI. The HI test was less sensitive than the ELISA and AGID tests in detecting anti-influenza antibodies in both sera and yolk. Serum and yolk from all control birds remained negative throughout the study. These studies show that currently used serologic tests can detect antibodies in serum and yolk samples from hens exposed to live AI virus or from those that have been vaccinated. Antibody is detected earlier in the serum than in the yolk and antibody is detected earlier from birds exposed to a live infection compared to birds vaccinated with an inactivated oil emulsion vaccine.
传统上，通过检测血清抗体来确定禽群的禽流感（AI）状况。然而，对于许多疾病，检测蛋黄中的抗体在监测产蛋鸡群的疾病状况方面很有效。本研究比较了蛋黄和血清在确定蛋鸡群AI状况方面的效用。将无特定病原体的白来航鸡通过呼吸道接种低致病性H7N2禽流感病毒或无菌尿囊液，或皮下接种由同一禽流感病毒或正常尿囊液制成的灭活油乳剂疫苗。通过琼脂凝胶免疫扩散（AGID）试验、血凝抑制（HI）试验和酶联免疫吸附测定（ELISA）来测定抗体水平。在接种活病毒的所有母鸡血清中，接种后第7天（PI）通过AGID和ELISA试验检测到抗流感抗体，但蛋黄中抗体的检测延迟了几天，到接种后第14天全部呈阳性。所有接种疫苗的母鸡血清在接种后第14天通过AGID和ELISA试验呈阳性，蛋黄在接种后第18天呈阳性。在检测血清和蛋黄中的抗流感抗体方面，HI试验比ELISA和AGID试验灵敏度低。在整个研究过程中，所有对照鸡的血清和蛋黄均保持阴性。这些研究表明，目前使用的血清学检测可以检测出接触过活禽流感病毒或接种过疫苗的母鸡血清和蛋黄样本中的抗体。血清中抗体的检测比蛋黄中早，与接种灭活油乳剂疫苗的鸡相比，接触活感染的鸡体内抗体检测更早。
