Tiensin Thanawat, Nielen Mirjam, Vernooij Hans, Songserm Thaweesak, Kalpravidh Wantanee, Chotiprasatintara Sirikan, Chaisingh Arunee, Wongkasemjit Surapong, Chanachai Karoon, Thanapongtham Weerapong, Srisuvan Thinnarat, Stegeman Arjan
Department of Livestock Development, Ministry of Agriculture and Cooperatives, Bangkok, Thailand.
J Infect Dis. 2007 Dec 1;196(11):1679-84. doi: 10.1086/522007. Epub 2007 Oct 25.
This present study is the first to quantify the transmission of avian influenza virus H5N1 within flocks during the 2004 epidemic in Thailand. It uses the flock-level mortality data to estimate the transmission-rate parameter ( beta ) and the basic reproduction number (R(0)). The point estimates of beta varied from 2.26/day (95% confidence interval [CI], 2.01-2.55) for a 1-day infectious period to 0.66/day (95% CI, 0.50-0.87) for a 4-day infectious period, whereas the accompanying R(0) varied from 2.26 (95% CI, 2.01-2.55) to 2.64 (95% CI, 2.02-3.47). Although the point estimates of beta of backyard chickens and fighting cocks raised together were lower than those of laying hens and broiler chickens, this difference was not statistically significant. These results will enable us to assess the control measures in simulation studies. They also indicate that, for the elimination of the virus, a critical proportion of the susceptible poultry population in a flock (i.e., 80% of the population) needs to be vaccinated.
本研究首次对2004年泰国禽流感疫情期间H5N1禽流感病毒在鸡群中的传播进行了量化。研究利用鸡群层面的死亡率数据来估计传播率参数（β）和基本再生数（R(0)）。β的点估计值在感染期为1天时为2.26/天（95%置信区间[CI]，2.01 - 2.55），在感染期为4天时为0.66/天（95%CI，0.50 - 0.87），而相应的R(0)则从2.26（95%CI，2.01 - 2.55）到2.64（95%CI，2.02 - 3.47）不等。虽然一起饲养的后院鸡和斗鸡的β点估计值低于蛋鸡和肉鸡，但这种差异无统计学意义。这些结果将使我们能够在模拟研究中评估控制措施。结果还表明，为了消除病毒，鸡群中易感家禽群体的关键比例（即群体的80%）需要接种疫苗。
