Ogata Tsuyoshi, Yamazaki Yoshinao, Okabe Nobuhiko, Nakamura Yosikazu, Tashiro Masato, Nagata Noriko, Itamura Shigeyuki, Yasui Yoshinori, Nakashima Kazutoshi, Doi Mikio, Izumi Youko, Fujieda Takashi, Yamato Shin'ichi, Kawada Yuichi
Chikusei Health Center, Ibaraki Prefectural Government, Ibaraki, Japan.
J Epidemiol. 2008;18(4):160-6. doi: 10.2188/jea.je2007446. Epub 2008 Jul 7.
H5N2 avian influenza virus infection of humans has not been reported thus far. The first H5N2 avian influenza infection of poultry in Japan occurred in Ibaraki.
The subjects were workers at 35 chicken farms in Ibaraki Prefecture, where the H5N2 virus or antibody was isolated from chickens. None of the subjects exhibited influenza symptoms. The H5N2-neutralizing antibody titers of the first and second paired sera samples were compared. To investigate the possible factors for this increase, the H5N2-neutralizing antibody titer (1:40 or more) was calculated for the second samples. A logistic regression analysis was performed to examine the association of these factors with H5N2-neutralizing antibody positivity.
We performed Wilcoxon matched-pairs signed-ranked test on data collected from 257 subjects, and determined that the H5N2 antibody titers of the second paired sera samples were significantly higher than those of the first samples (P < 0.001). The H5N2 antibody titers of paired sera of 13 subjects without a history of seasonal influenza vaccination within the previous 12 months increased 4-fold or more. The percentage of antibody positivity was 32% for subjects with a history of seasonal influenza vaccination (28% of all subjects) and 13% for those without a history of the same. The adjusted odds ratio of H5N2-neutralizing antibody positivity was 4.6 (95% confidence interval: 1.6-13.7) for those aged over 40 and 3.1 (95% confidence interval: 1.6-6.1) for those with a history of seasonal influenza vaccination within the previous 12 months.
The results suggest that this may have been the first avian influenza H5N2 infection of poultry to affect humans. A history of seasonal influenza vaccination might be associated with H5N2-neutralizing antibody positivity.
迄今为止，尚未有人类感染H5N2禽流感病毒的报告。日本首次发生的家禽H5N2禽流感感染疫情出现在茨城县。
研究对象为茨城县35家养鸡场的工作人员，这些养鸡场的鸡中分离出了H5N2病毒或抗体。所有研究对象均未出现流感症状。比较了第一份和第二份配对血清样本的H5N2中和抗体滴度。为了探究这种升高的可能因素，计算了第二份样本的H5N2中和抗体滴度（1:40及以上）。进行逻辑回归分析以检验这些因素与H5N2中和抗体阳性之间的关联。
我们对257名研究对象收集的数据进行了Wilcoxon配对符号秩检验，确定第二份配对血清样本的H5N2抗体滴度显著高于第一份样本（P < 0.001）。在过去12个月内无季节性流感疫苗接种史的13名研究对象的配对血清中，H5N2抗体滴度升高了4倍或更多。有季节性流感疫苗接种史的研究对象（占所有研究对象的28%）的抗体阳性率为32%，无接种史的研究对象的抗体阳性率为13%。40岁以上人群的H5N2中和抗体阳性的校正比值比为4.6（95%置信区间：1.6 - 13.7），过去12个月内有季节性流感疫苗接种史的人群的校正比值比为3.1（95%置信区间：1.6 - 6.1）。
结果表明，这可能是首例影响人类的家禽H5N2禽流感感染。季节性流感疫苗接种史可能与H5N2中和抗体阳性有关。
