Takizawa T, Ito T, Tanaka T, Mizumura Y
Natl Inst Anim Health Q (Tokyo). 1980 Summer;20(2):60-7.
Following the simulation mode., G-3, of Gumboro disease outbreak, Model G-4 was constructed. The algorithm for computer simulation is shown in a flow chart. The postulates added to those for Models G-1 and G-2 are as follows: (1) The source of contamination is the virus remaining in the house and declining gradually in value with the lapse of time. (2) Any diseased bird excretes the virus during a certain period, so that the virus may be added to the source of contamination. (3) The morbid status of the diseased bird becomes worse in process of time, but the infection remains subclinical until a threshold value is reached. Beyond this value the bird becomes clinically diseased. In this model, more than 20 parameters are involved, and random numbers used for expressing the individual differences in the four variables, viz., the level of innate resistance, parentally conferred immunity, virus-intake, and threshold of clinical manifestation.
在模拟传染性腔上囊病爆发的G - 3模式之后，构建了G - 4模型。计算机模拟算法如图所示。添加到G - 1和G - 2模型假设中的假设如下：（1）污染源是留在鸡舍内且随时间推移价值逐渐下降的病毒。（2）任何患病禽类在一定时期内都会排出病毒，因此病毒可能会添加到污染源中。（3）患病禽类的病态随时间推移会恶化，但在达到阈值之前感染仍处于亚临床状态。超过这个值，禽类就会出现临床疾病。在这个模型中，涉及20多个参数，以及用于表达四个变量个体差异的随机数，这四个变量即先天抵抗力水平、母体给予的免疫力、病毒摄入量和临床表现阈值。
